Dimensional analysis
Buckinghams II method
Let x1 , x2, x3, x4 ,xn be thenvariables
Let x1 be the dependent variable
And x2, x3, x4,xn are the independent variables
Let the no of variables involved in a problem is m’
Let the variable having ‘n’ no of fundamental dimensions
According to buckinghamII method
Variables are rearranged as (m-n) dimensionless terms
Let the dimensionless terms are II1, II2,II3, …II(m-n)
II(m-n)= f(repeating and non repeating variables)
Examples:
Calculating the frictional pressure drop in a long circular pipe
Variables
Pressuredrop P
Length L
Diameter D
Height of roughness e
Density of fluid ſ
Viscosity u
Velocity v
P f(L,D,e,d’, u’,u)
Total no of variables 7
No of fundamental variables = 3
Dimensionless terms = 7-3 =4
Repeating variables are
Length , velocity density
II 1 = [L]a1[v]b1 [ſ] c1 P ---à1
II 2 = [L]a2[v]b2 [ſ] c2 e ---à2
II 3 = [L]a3[v]b3 [ſ] c3 D ---à3
II 4 = [L]a4[v]b4 [ſ] c4 u ---à4
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s.no
quantity
units
dimensions
1
pressuredrop
Kg/Nsec2
M L -1T-2
2
length
M
L
3
velocity
m/sec
LT-1
4
diameter
M
L
5
density
Kg/m3
M L-3
6
viscosity
Kg/msec
M L -1T-1
7
roughness
m
L
From eq 1
M0 L 0T0 = [L] a1[LT-1]b1 [ML-3]c1 [M L -1T -2]
Equating the powers of M terms on both sides
0 = c1+1 ----à5
C1 = -1
Equating the powers of L terms on both sides
0= a1+b1-3c1-1-à6
Eqauting powers of T terms on both sides
0 = -b1 -2 --à7
;; b1= -2
Substitute c1 and b1 values in eq 6
: a1 -2 -3(-1)-1=0
; a1= 0
Substituting values of a1 b1 and c1 in eq 1
II 1 = [L ] 0 [u ]-2 [ſ ] -1 P
II 1 = P/u2ſ
Solve in the same way for II2 , II3, II4, and analyse your capability
On solving you ‘ll get
II2 = e/L
II3 = D/L
II4 = u/LVſ
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Rayleigh’s method
Let Q1 , Q2 , Q3 – Qn are n no of variables ,
Let Q1 is the dependent variable and remaining are independent variables
According to rayleighs method
Q1 = f(Q2, Q3 , Q4,--Qn)
Q1 = k [Q2]a [Q3]b [Q4]c -----[Qn]z
with the same example
P = f( L, D, v,u , ſ)
P = [D] a[v]b[ ſ]c [u] d[L]e
s.no
quantity
units
dimensions
1
pressuredrop
Kg/Nsec2
M L -1T-2
2
length
M
L
3
velocity
m/sec
LT-1
4
diameter
M
L
5
density
Kg/m3
M L-3
6
viscosity
Kg/msec
M L -1T-1
7
roughness
m
L
M L -1T-2 = [L]a [LT-1]b [ML-3]c [M L-1 T-1]d [L]e
Equating powers of M
1= c+d--à1
Equating powers of L
-1 = a+b-3c-d+e-à2
Equating powers of T
-2 = -b-d-à3
From eq 1
;;C= 1-d -à4
;; b= 2-d-à5
Substitute eq 4 & 5 in eq 2
-1 = a+(2+d)-3(1-d)+e-d
;; a+2-d-3+3d-d+e
;;a +d+e =0
‘’ a= -(d+e)
P = k [D]-(d+e) [v]2-d [ſ]1-d [L]e [u]d
P/ ſv2 = K[ Dvſ/ u]-d [ L/D]e
Wednesday, January 4, 2012
biotecholdpapers
OLD QUESTION PAPERS
SET-3
1) Write about : a) bacterial locomotion b) bacterial shapes
2) Write about the medicinal importance of plants. Discuss the industrial products got from plants
3) Briefly explain the life cycle of Ascaris worm
4) Describe the double helix structure of DNA.
5) Explain in brief the organs and organ systems present in the human body and describe their major functions.
6) Discuss various neurotransmitters and explain the mechanism of synaptic transmission
7) Write short notes on: a) biofuel b) biofertilizer c) biosensor d) biopesticide
8) Write short notes on: a) gene cloning b) r DNA technology c) Hybridization d) Genemanipulation
SET-4
1) justify � �viruses have both, living as well as non-living characteristics�
2) discuss about the pests of cotton plant.
3) How does fasciolopsis buski as parasite affect man?
4) Write about the main events occurring during DNA replication.
5) Explain the human body fluid compartments and describe the intracellular and extra cellular body fluids and their functions.
6) Describe the olfactory area in the nose with the help of a diagram and explain the mechanism of olfaction
.7) Define biotechnology nad explain the areas of interest in biotechnology.
8.What is hybridoma technique and how monoclonal antibodies are being extensively used for human health care. Explain with examples.
NEXT
SET-3
1) Write about : a) bacterial locomotion b) bacterial shapes
2) Write about the medicinal importance of plants. Discuss the industrial products got from plants
3) Briefly explain the life cycle of Ascaris worm
4) Describe the double helix structure of DNA.
5) Explain in brief the organs and organ systems present in the human body and describe their major functions.
6) Discuss various neurotransmitters and explain the mechanism of synaptic transmission
7) Write short notes on: a) biofuel b) biofertilizer c) biosensor d) biopesticide
8) Write short notes on: a) gene cloning b) r DNA technology c) Hybridization d) Genemanipulation
SET-4
1) justify � �viruses have both, living as well as non-living characteristics�
2) discuss about the pests of cotton plant.
3) How does fasciolopsis buski as parasite affect man?
4) Write about the main events occurring during DNA replication.
5) Explain the human body fluid compartments and describe the intracellular and extra cellular body fluids and their functions.
6) Describe the olfactory area in the nose with the help of a diagram and explain the mechanism of olfaction
.7) Define biotechnology nad explain the areas of interest in biotechnology.
8.What is hybridoma technique and how monoclonal antibodies are being extensively used for human health care. Explain with examples.
NEXT
biotecholdpapers
OLD QUESTION PAPERS
SET-1 1.write short notes on: a) bacterial shapes diversity b) bacterial reproduction
2.write short notes on: a) Auxins b) Gibberlins
3.what is meant by energy flow in ecosystem?
4.write about: .a) .nitrogenous bases in DNA b.differences between DNA and RNA
5.Explain in brief the organs and organ systems present in the human body and describe their major functions.
6.Discuss various neurotransmitters and explain the mechanism of synaptic transmission.
7.Discuss some important historical milestones in development of molecular biotechnology.
8.write short notes on : a) Gene Targeting b) ELISA Test c) Molecular Farming d) Genetic Engineering
SET-2
1) write a general account on viral characteristics and how are they classified on the basis of their genomes?
2) What are Meristems? Explain in detail.
3) Discuss about the cycling of matter in an ecosystem.
4) Describe the double helix structure of DNA.
5) Describe the structure and functions of animal cell.
6) What important features do all sensory receptors have in common?
7) Define biopesticides? What are the various microorganisms useful for production of biopesticides.
8) Write short notes on : a) fate of transgenes b) molecular farming c) monoclonal antibodies d) microbial enzymes.
SET-1 1.write short notes on: a) bacterial shapes diversity b) bacterial reproduction
2.write short notes on: a) Auxins b) Gibberlins
3.what is meant by energy flow in ecosystem?
4.write about: .a) .nitrogenous bases in DNA b.differences between DNA and RNA
5.Explain in brief the organs and organ systems present in the human body and describe their major functions.
6.Discuss various neurotransmitters and explain the mechanism of synaptic transmission.
7.Discuss some important historical milestones in development of molecular biotechnology.
8.write short notes on : a) Gene Targeting b) ELISA Test c) Molecular Farming d) Genetic Engineering
SET-2
1) write a general account on viral characteristics and how are they classified on the basis of their genomes?
2) What are Meristems? Explain in detail.
3) Discuss about the cycling of matter in an ecosystem.
4) Describe the double helix structure of DNA.
5) Describe the structure and functions of animal cell.
6) What important features do all sensory receptors have in common?
7) Define biopesticides? What are the various microorganisms useful for production of biopesticides.
8) Write short notes on : a) fate of transgenes b) molecular farming c) monoclonal antibodies d) microbial enzymes.
pepoldpaperjntu
awaharlal Nehru technological university hyderabad(
Process engineering principles mtech 1st semester final exam paper(2010)
1) a) what is the role of bioprocess engineering in biotech industry. Explain with the help of suitable examples
b) discuss methods of dimensional anlysis in details
2) a) draw a neat sketch of u- tube manometer and explain its working principle
b) write the units of heat capacity , pressure in si and cgs system
3) derive the mathematical expression for bernoulis equation and give its limitations
4) a) draw the neat sketch of venturimeter and give its working principle
b) discuss the working principle of rotameter
5) a) discuss conduction, convection, radiation
b) derive the relationship between overall and individual heat transfer coefficients. Give their significance
6) a) discuss film and nucleate boiling
b) write about evaporation
7) a) what is ficks law of diffusion
b) what is mass transfer coefficient and give their relationship between individual and overall mass transfer coefficient
8) write a short note on
a) distillation
b) absorption
c) liquid liquid extraction
keywords : mtech jntu papers, mtech biotechnology papers, process engineering principles paper, mtech pep papers
jntu mtech papers 2010,
Process engineering principles mtech 1st semester final exam paper(2010)
1) a) what is the role of bioprocess engineering in biotech industry. Explain with the help of suitable examples
b) discuss methods of dimensional anlysis in details
2) a) draw a neat sketch of u- tube manometer and explain its working principle
b) write the units of heat capacity , pressure in si and cgs system
3) derive the mathematical expression for bernoulis equation and give its limitations
4) a) draw the neat sketch of venturimeter and give its working principle
b) discuss the working principle of rotameter
5) a) discuss conduction, convection, radiation
b) derive the relationship between overall and individual heat transfer coefficients. Give their significance
6) a) discuss film and nucleate boiling
b) write about evaporation
7) a) what is ficks law of diffusion
b) what is mass transfer coefficient and give their relationship between individual and overall mass transfer coefficient
8) write a short note on
a) distillation
b) absorption
c) liquid liquid extraction
keywords : mtech jntu papers, mtech biotechnology papers, process engineering principles paper, mtech pep papers
jntu mtech papers 2010,
immunology
The basis of adjuvanicity is often the recognition of these signals by receptors on accessory cells.
DEPOT EFFECTS
: Free antigen usually disperses rapidly from the local tissues draining the injection site.
The function of repressory is to this by providing a long-lived reverse of antigen.
Most common type of this type of adjuvants used in are aluminium compounds(phosphate or hydroxide)
Incomplete adjuvant in which the antigen is incorporated in the phase of a stabilized water in paraffin oil emulsion ,usually produces higher and far more sustained antibody levels.
However because of long lastingof oil in tissues and occasional production of sterile this adjuvant is not used in vaccines except for anti cancer vaccines.
ex: ISA 720, ISA 51
ACTIVATION OF ANTIGEN-PRESENTING CELLS.
: Under the influence of the adjuvants macrophages from which provide sites for with antibody forming cells.
All adjuvants virtually deliver antigen to antigen presenting cells and stimulate then by improving immunogenicity through an increase in antigen.
Ribi adjuvant is commonly used formulation in experimental work in a water –in-oil emulsion incorporating MLA and
Effectson lymphocytes
: In mice alum tends to stimulate helper cells of the Th2 family where as complete adjuvant favours the Th1 subset.
Complete is made from incomplete antigen by adding myco bacterial component.
IL-2 has an adjuvant activity in unresponsive leprosy peatients and a single on dialysis peatients effectively reduced their to hepatitis B surface antigen.
THUCOSAL ADJUVANTS
: The need for adjuvants which stimulate mucosal immunity is being met by exploiting the of ecoli heat (LT)
Cholera toxin to largest cells.
LT is immunogenic through oral route non toxic through in glycine (LTR192G) used as mucosal adjuvant.
CPG dinucleotides motifs have been shown to act as effective mucosal adjuvants ,stimulating the immune system by interacting withTLR9 and there by promoting Th1 responses.
HAPTENS:
It is also quite possible that some of the antibodies with in this mixture of antibodies may be directed towards epotopes that are also found in other antigens.
Such antibodies are said to be cross reactive against the other antigen to which they also bond.
Small organic molecules are typically poor immunojens when rejected on their own ,the immune system appears unable to recognize these structures efficiently .
Not with standing this immunologists have found that such molecules can be made visible to the immune system by cooalant coupling to a carrier protein (such as albumn) which in itself immunogenic .such molecules are celled haptens.
ex:In aminobenzene sulphonate.
Immunization with free hapten produces no antibodies to the hapten.
Immunization with hapten group linke to a protein carrier generates antibodies that react with high affinity to hapten alone or linked to a molecule other than the carrier.
Here hapten-antigen.
Hapten protein complex-immunogen.
IMMUNOLOGY
Although antibodies can be raped against practically any organic substances . some molecules antibody responses much more readily than others.
Thus rejection of the average antigen into an animal will almost always the production of a mixture of antibodies that are directed against different epotopes with antigens.
For practical and economical reasons prophylate immunization should the minimum no.of and the least amount of antigen.
Non living organism and especially purified products frequently require which by definition is a substance recorporated into or rejected simultaneously with antigen which the immune response.
Bacterial structures provide the major source of immune because they provide danger signals of .
DEPOT EFFECTS
: Free antigen usually disperses rapidly from the local tissues draining the injection site.
The function of repressory is to this by providing a long-lived reverse of antigen.
Most common type of this type of adjuvants used in are aluminium compounds(phosphate or hydroxide)
Incomplete adjuvant in which the antigen is incorporated in the phase of a stabilized water in paraffin oil emulsion ,usually produces higher and far more sustained antibody levels.
However because of long lastingof oil in tissues and occasional production of sterile this adjuvant is not used in vaccines except for anti cancer vaccines.
ex: ISA 720, ISA 51
ACTIVATION OF ANTIGEN-PRESENTING CELLS.
: Under the influence of the adjuvants macrophages from which provide sites for with antibody forming cells.
All adjuvants virtually deliver antigen to antigen presenting cells and stimulate then by improving immunogenicity through an increase in antigen.
Ribi adjuvant is commonly used formulation in experimental work in a water –in-oil emulsion incorporating MLA and
Effectson lymphocytes
: In mice alum tends to stimulate helper cells of the Th2 family where as complete adjuvant favours the Th1 subset.
Complete is made from incomplete antigen by adding myco bacterial component.
IL-2 has an adjuvant activity in unresponsive leprosy peatients and a single on dialysis peatients effectively reduced their to hepatitis B surface antigen.
THUCOSAL ADJUVANTS
: The need for adjuvants which stimulate mucosal immunity is being met by exploiting the of ecoli heat (LT)
Cholera toxin to largest cells.
LT is immunogenic through oral route non toxic through in glycine (LTR192G) used as mucosal adjuvant.
CPG dinucleotides motifs have been shown to act as effective mucosal adjuvants ,stimulating the immune system by interacting withTLR9 and there by promoting Th1 responses.
HAPTENS:
It is also quite possible that some of the antibodies with in this mixture of antibodies may be directed towards epotopes that are also found in other antigens.
Such antibodies are said to be cross reactive against the other antigen to which they also bond.
Small organic molecules are typically poor immunojens when rejected on their own ,the immune system appears unable to recognize these structures efficiently .
Not with standing this immunologists have found that such molecules can be made visible to the immune system by cooalant coupling to a carrier protein (such as albumn) which in itself immunogenic .such molecules are celled haptens.
ex:In aminobenzene sulphonate.
Immunization with free hapten produces no antibodies to the hapten.
Immunization with hapten group linke to a protein carrier generates antibodies that react with high affinity to hapten alone or linked to a molecule other than the carrier.
Here hapten-antigen.
Hapten protein complex-immunogen.
IMMUNOLOGY
Although antibodies can be raped against practically any organic substances . some molecules antibody responses much more readily than others.
Thus rejection of the average antigen into an animal will almost always the production of a mixture of antibodies that are directed against different epotopes with antigens.
For practical and economical reasons prophylate immunization should the minimum no.of and the least amount of antigen.
Non living organism and especially purified products frequently require which by definition is a substance recorporated into or rejected simultaneously with antigen which the immune response.
Bacterial structures provide the major source of immune because they provide danger signals of .
heatexchangers
heat exchanger
A heat exchanger is a device built for efficient heat transfer from one medium to another
Heat transfer also known as heat flow as transfer of thermal energy is the movement of heat from one place to another
When an object is at adifferent temperature from its surroundings heat transfer occurs so that the body and the surroundings reach the same temperature at thermal equilibrium
Such heat transfer always occurs from a region of high temperature to another region of lower temperature
So, a heat exchanger is a component that allows the transfer of heat from one fluid ( liquid or gas) to another fluid
Heat transfer is usually required
To heat a cooler fluid by means by a hotter fluid
To reduce the temperature of a hot fluid by means of a cooler fluid
To boil a liquid by means of a hotter fluid
To condense a gaseous fluid by means of a cooler fluid
To boil a liquid while condensing a hotter gaseous fluid
In aheat exchanger the media may be separated by asolid wall , as that they never mix or they may be in direct contact.
In heat exchangers wher the media is separated by a solid wall , the heat is transferred from the hot fluid to the metal isolating the two fluids and then to the cooler fluid
The basic design of a heat exchanger normally has two fluids of different temperatures separated by some conducting medium
Types of heat exchangers
Based on the direction of flow , heat exchangers are of 3 types
1) parallel flow: in parallel flow heat exchangers the two fluids enter the heat exchanger from the same end with a large temperature difference
As the fluids transfer heat , hotter to cooler , the temperature of the two fluids approach each other
Thus they have a large temperature difference at the inlet and a small temperature difference at the inlet and a small temperature difference at the outlet .
---------------àfluid 1
--------------àfluid 2
2) counter flow : this exists when the two fluids flow in opposite directions . each of the fluids enter the heat exchangers at the opposite ends because the cooler fluid exits the counter flow heat exchanger , the cooler fluid will approach the inlet temperature of the hot fluid .
These type of heat exchangers have temperature difference along the heat transfer length . these are used for liquid – liquid condensing and gas cooling applications
Units are usually mounted vertically when condensing vapour and mounted horizontally when handling high concentrations of solids
--------------à
<--------------
3) Cross flow :
This exists when one fluid flows perpendicular to the second fluid
That is one fluid flows through tubes and the second fluid passes around the tubes at 90 degrees.it is generally used as a condenser. These are applicable when one of the fluid changes state .
Eg: steam condenser , the steam existing the turbine enters the condenser shell side , and the cool water flowing in the tube absorbs the heat from the steam , condesing it into water
Large volumes of vapor may be condensed using this type of heat exchangers flow
Among the 3 types of heat exchangers counter current flow is most efficient when compared with other because the average temperature difference between the two fluids over the length of the heat exchanger is maximized.
At the same operating conditions , operating the 3 heat exchangers the counter flow heat exchanger will result in a greater haeat transfer rate than operating in parallel flow
|
---------------
Based on the flow heat exchangers are classified into two types as such
1) single pass heat exchangers - when a heat exchanger fluid passes only once
2) multipass heat exchangers - when a heat exchanger fluid passes more than once
Based on the function heat exchangers are classified into two types
1) regenerative : these heat exchangers use the same fluid for heating and cooling
The same fluid is both cooling fluid and cooled fluid . that is the hot fluid leaving a system gives up its heat to regenerate or heat up the fluid returning to the system.
These are found in high temperature systems where a portion of systems fluid is removed form the main process and then returned.
Because the fluid removed from the main process contain energy , the heat from the fluid leaving the main system is sued to reheat the returning fluid instead of being rejected to an external cooling medium to improve efficiency.
2) non regenerative: the hot fluid is cooled by fluid from a separate system and the enrgy removed is not returned to the system.
The most commonly used heat exchangers are
1) plate heat exchangers
2) shell tube heat exchangers
Plate heat exchangers :
Thes consists of thin plates joined together with a small amount of space between each plate typically mainatained by a small rubber gasket .
This consists of plates inside tubes to separate hot and cold fluids.
These set of tubes is called the tube bundles and can be made up of several types of tubes .
Shell and tube exchangers are typically used for high pressure applications
Several thermal design features should be t5aken into account when designing the tubes in this type of heat exchangers .
Tube diameter , tube thickenss, tube length , tube pitch , tube layout , baffle design play a major role.
Shell and tube heat exchangers :
These comprises of multiple tubes through which liquid flows
Set of tubes in a container called shell
The fluid flowing inside the tube is called tube side fluid and the fluid flowing on the outside of the tube is shell side fluid .
The tunes are divided into two sets
First set contains the liquid to be heated or cooled
Second set contain the liquid responsible for triggering the heat exchange
Selection of heat exchangers:
This depends on the heat transfer rate
Size and weight
Cost
Pumping power
Material of construction
keywors: heat . exchangers, heat exchangers, shell and tube heat exchangers, plate heat exchangers, heat transfer equipment
A heat exchanger is a device built for efficient heat transfer from one medium to another
Heat transfer also known as heat flow as transfer of thermal energy is the movement of heat from one place to another
When an object is at adifferent temperature from its surroundings heat transfer occurs so that the body and the surroundings reach the same temperature at thermal equilibrium
Such heat transfer always occurs from a region of high temperature to another region of lower temperature
So, a heat exchanger is a component that allows the transfer of heat from one fluid ( liquid or gas) to another fluid
Heat transfer is usually required
To heat a cooler fluid by means by a hotter fluid
To reduce the temperature of a hot fluid by means of a cooler fluid
To boil a liquid by means of a hotter fluid
To condense a gaseous fluid by means of a cooler fluid
To boil a liquid while condensing a hotter gaseous fluid
In aheat exchanger the media may be separated by asolid wall , as that they never mix or they may be in direct contact.
In heat exchangers wher the media is separated by a solid wall , the heat is transferred from the hot fluid to the metal isolating the two fluids and then to the cooler fluid
The basic design of a heat exchanger normally has two fluids of different temperatures separated by some conducting medium
Types of heat exchangers
Based on the direction of flow , heat exchangers are of 3 types
1) parallel flow: in parallel flow heat exchangers the two fluids enter the heat exchanger from the same end with a large temperature difference
As the fluids transfer heat , hotter to cooler , the temperature of the two fluids approach each other
Thus they have a large temperature difference at the inlet and a small temperature difference at the inlet and a small temperature difference at the outlet .
---------------àfluid 1
--------------àfluid 2
2) counter flow : this exists when the two fluids flow in opposite directions . each of the fluids enter the heat exchangers at the opposite ends because the cooler fluid exits the counter flow heat exchanger , the cooler fluid will approach the inlet temperature of the hot fluid .
These type of heat exchangers have temperature difference along the heat transfer length . these are used for liquid – liquid condensing and gas cooling applications
Units are usually mounted vertically when condensing vapour and mounted horizontally when handling high concentrations of solids
--------------à
<--------------
3) Cross flow :
This exists when one fluid flows perpendicular to the second fluid
That is one fluid flows through tubes and the second fluid passes around the tubes at 90 degrees.it is generally used as a condenser. These are applicable when one of the fluid changes state .
Eg: steam condenser , the steam existing the turbine enters the condenser shell side , and the cool water flowing in the tube absorbs the heat from the steam , condesing it into water
Large volumes of vapor may be condensed using this type of heat exchangers flow
Among the 3 types of heat exchangers counter current flow is most efficient when compared with other because the average temperature difference between the two fluids over the length of the heat exchanger is maximized.
At the same operating conditions , operating the 3 heat exchangers the counter flow heat exchanger will result in a greater haeat transfer rate than operating in parallel flow
|
---------------
Based on the flow heat exchangers are classified into two types as such
1) single pass heat exchangers - when a heat exchanger fluid passes only once
2) multipass heat exchangers - when a heat exchanger fluid passes more than once
Based on the function heat exchangers are classified into two types
1) regenerative : these heat exchangers use the same fluid for heating and cooling
The same fluid is both cooling fluid and cooled fluid . that is the hot fluid leaving a system gives up its heat to regenerate or heat up the fluid returning to the system.
These are found in high temperature systems where a portion of systems fluid is removed form the main process and then returned.
Because the fluid removed from the main process contain energy , the heat from the fluid leaving the main system is sued to reheat the returning fluid instead of being rejected to an external cooling medium to improve efficiency.
2) non regenerative: the hot fluid is cooled by fluid from a separate system and the enrgy removed is not returned to the system.
The most commonly used heat exchangers are
1) plate heat exchangers
2) shell tube heat exchangers
Plate heat exchangers :
Thes consists of thin plates joined together with a small amount of space between each plate typically mainatained by a small rubber gasket .
This consists of plates inside tubes to separate hot and cold fluids.
These set of tubes is called the tube bundles and can be made up of several types of tubes .
Shell and tube exchangers are typically used for high pressure applications
Several thermal design features should be t5aken into account when designing the tubes in this type of heat exchangers .
Tube diameter , tube thickenss, tube length , tube pitch , tube layout , baffle design play a major role.
Shell and tube heat exchangers :
These comprises of multiple tubes through which liquid flows
Set of tubes in a container called shell
The fluid flowing inside the tube is called tube side fluid and the fluid flowing on the outside of the tube is shell side fluid .
The tunes are divided into two sets
First set contains the liquid to be heated or cooled
Second set contain the liquid responsible for triggering the heat exchange
Selection of heat exchangers:
This depends on the heat transfer rate
Size and weight
Cost
Pumping power
Material of construction
keywors: heat . exchangers, heat exchangers, shell and tube heat exchangers, plate heat exchangers, heat transfer equipment
plasmids
PLASMID
An extra chromosomal DNA which can replicate independently without any relation to chromosomal DNA is called a plasmid
Plasmids thus does not have any genetic relationships with the organism from which of is collected
Usually plasmids are found in naturally occurring bacteria but are sometimes found in eukaryotic organism like sacchromyces cervicea.
Plasmids are usually considered as transferrable agents or a means of transport too.
Size of a plasmid usually ranges from 1 to over 1000 kb.
Plasmids play a role in the process of bacterial conjugation as well horizontal gene transfer.
Plasmid can only uptake the genetic material through the process of transformation.
Plasmids can aid bacteria in the process of nitrogen fixation too.
Plasmids are the stable genetic elements found not only in bacteria but also in the mitochondria of some plants
Plasmids can be composed of DNA or RNA double stranded or single stranded linear or circular.
Plasmids are used to produce high amounts of proteins as such the plasmids with antibiotic resistant gene is introduced into an organism..
The organisms thus produces the protein which acts against gene thus releasing lots of required proteins.
TYPES OF PLASMIDS
Basically there are two types of plasmids based on the process of replication.
A)Non integrating plasmids B)Integrating plasmids.
NON INTEGRATING PLASMIDS
There are the plasmids which replicate with in the host cell but does not integrate with the bacterial DNA
INTEGARTING DNA
This type of plasmids usually integrate with the bacterial DNA and then starts the process of replication.
Based on the ability to transfer to other bacteria the plasmids are classified into two types.
A)Conjugative plasmids B)Non conjugative plasmids.
CONJUGATIVE PLASMIDS
These plasmids contain a type of genes called tra-genes which perform the process of conjugation.
NON CONJUGATIVE PLASMIDS
These are usually non integrating they cannot initiate the process of conjugation and hence they can only be transferred with the assistance of conjugative plasmids.
BASED ON THE FUNCTION THERE ARE DIFFERENT TYPES OF PLASMIDS
A)Fertility/F-plasmids B)Resistance/R plasmids C)Col plasmids D)Degradative plasmids E)virulence plasmids.
F-PLASMIDS
Contain tra-genes thus help in the process of conjugation.
R-PLASMIDS
Contain genes that are against antibiotics / poisons thus help bacteria to produce pili that forms a bridge during the process of conjugation
COL-PLASMIDS
Contain the genes that code for the bacteriocins and proteins.
DEGRADATIVE PLASMIDS/METABOLIC PLASMIDS
Enables the digestion of unusual substances . EX:Salicylic acid ,toluene etc.,
VIRULENCE OF PLASMIDS
Taurns bacteria into a pathogen .
One or more major classification includes yeast plasmids .
They are of two types A)Yeast integrative plasmid B)Yeast replicative plasmid.
YEAST INTEGRATIVE PLASMID
They rely on the first integrating into host chromosome .They help in studying of solo gene.
YEAST REPLICATIVE PLASMID
They carry the sequence of chromosome with origin of replication into host .This is usually less stable in nature.
TRANSFER OF PLASMIDS
The process of transfer of plasmids involves four major steps they are A)Identification B)Classification C)Purification D)Transfer .
IDNETIFICATION.
The process of identification of the plasmids is based on the digestion with specific endonucleases.
CLASSIFICATION
After digesting with endonucleases plasmids are subjected to get electrophoresis which helps in the process of fragmentation patterns obtained .
PURIFICATION
Purified plasmids DNA can be obtained by the process of centrifugation.
TRANSFER OF PLASMIDS
The last step in transferring the plasmid with the desirable gene into the host .
PROCESS OF PLASMID TRANSFER /PLASMIDS ACTING AS TRANSFERING AGENTS .
Plasmid vectors are one of the best approaches that gave successful stories of gene therapy.
GENE THERAPY.
It is the process in which the gene with required qualities is inserted into the plasmid DNA and then the plasmid DNA is introduced into the host organism where the process of gene expression starts thus yielding good results.
PROCESS OF CLONING INTO PLASMID .
Step-1: Plasmid with gene for antibiotic resistance are selected.
Treat the plasmid with restriction endonucleases i.e., ecori
Same restriction endonucleases is used to cleave the foreign DNA too.
Then forming a wick on plasmid DNA and collecting the required gene sequence from foreign DNA,
HYBRIDIZATION
The foreign DNA sequence are the hybridized at sticky ends of plasmid DNA .
LIGASE
The enzyme ligase is then used to form the sticky ends or opened ends of plasmid DNA ,
Thus forming the recombinant DNA .
DNA INSERTION
Plasmid DNA is then inserted into bacterial cell.
CLONING
The plasmid DNA is then subjected to gene amplification process then producing number of copes.
PLATTING
Bacteria then platted with the antibiotic in the medium only those hybridized plasmids can same and all other will die thus helps in the selection of recombinant.
CULTURING
After the process of selection it is subjected to culturing thus producing required DNA /clones.
HOST RESTRICTION IN PLASMID TRANSFER
After the process of plasmid identification ,purification,and insertion of the required DNA into the plasmid the plasmid must be transferred into any of the bacterial host.
Transfering into the host then continuous the further process of cloning and replication thus increasing the number /quality.
Common host that are used for plasmid transfer are Ecoli and salmonella.
Some times this transfer is restricted some host enzymes thus restricting the plasmid from entering into the host.
Other than those hosts the plasmids cannot be transferred into other hosts as they show the host restriction.
EXAMPLES /CARE STUDY
Genome degradation
In the process of host restriction genome degradation is the important step where the plasmid DNA material may be lost due to the enzymes of restriction released by other hosts that cannot host the plasmid .
ex:
Host restricted salmonella serotypes usually cause the genome degradation of the plasmid DNA is restricted into them.
Hosts even have restriction factor Which prevent the process of replication of plasmid DNA then the process of gene expression prevented in the hosts that restrict the plasmid DNA .
EUKARYOTIC GENE REGULATION.
As the complexity of organisms is increasing the mode of gene regulationmust be complex to control the process of gene expression.
For the process of cell specialization and cell regularity it needs the process of gene regulation for eukaryotic organisms.
The process of gene expression itself is very complex in case of eukaryotic organisms.
Transcription and translation are considered as the basic steps in the process of gene expression.
In eukaryotes because of the presence of nucleus seperates transcription from translation in a way not seen in prokaryotes.
Regulation occur at the following steps thus regulating the process of gene regulation in eukaryotes if included.
A)At the time of transcription B)While RNA processing C)During the process of m RNA longetivity D)Translation.
These are the major steps when the eukaryotic regulation occur.
REGULATION OF TRANSCRIPTION /RNA PROCESSING PROCESS
Steps involved mRNA processing are A)Addition of 5?cap B)Addition of a3?poly(A)tail C)Removal of introns .
Usually the regulation process occur in any of these steps.
The regulation at this step of transcription /RNA processing is divided into two types. A)Whether RNA must process B)Which exons are retained m RNA.
Regulation step at RNA process indicates/ determines whether the m RNA gets translated/ not .
During this type of regulation of RNA does not get processed it will be transported out of nucleus and will not be translated forever.
In the second type of regulation i.e., which exons are retaived affects the function of the protein produced.< br/> Exon shuffling is a process in which some genes have exons that can be exchanged thus by this process the polypeptide produced could have a different function lather than the actual function , this production may some times even cause the premature stopin g of cooling.
REGULATION OF RNA LONGETIVITY
Longetivity is the step of degradation of RNA after being processed i.e., the life time of RNA .
The regulation at this step results in the required gene product to be formed rather than other gene product .
For example of two mRNA?s of same langetivity are present and one is made to degrade an hour late than first one by following the process of gene regulation it results in the production of the required ploypeptide more in amount than the other.
REGULATION OF TRANSLATION
This is one of the major regulatory step in eukaryotes in which although the mRNA is ready because of this step of regulation the expression of the product cannot occur.
ex: Although mRNA is ready in the egg it does not get expressed until it gets matured.
REGULATION OF TRANSCRIPTION
Instead of repressors and operon system that are present in prokaryotes activation /other wise transcriptional factors paly a major role in transcription control /regulation.
Regulation can be brought by
A)Altering the rate at which RNA transcripts processed.
B)Altering the rate at which mRNA gets degraded.
C)Altering the efficiency of translation.
PROMOTER AND ENHANCER ELEMENTS
Transcriptional factors are the important protein complexes that help RNA polymerase in binding to DNA.
There are five major types of transcription factor that palys a role in the gene expression like zinc finger proteins , helix turn helix protein , lucin zipper proteins-binding DNA ,helix loop helix-usually then get dimerized.
Steroid receptors In ligand binding thus regulating the activity.
These transcriptional factors which are named as activators ,promoters, enhancers paly a major role in the regulation of the eukaryotic gene expression.
ENHANCERS
The transcriptional factors whose binding increases the rate of transcription of the gene are called enhancers .
Usually these are located thousand of box pairs away from the gene they control.
Enhancers are usually located upstream ,down stream or even with in the gene they control.
Enhancers binding proteins in addition to their DNA binding site have sites that bind to transcription factors assembled the proteins of the gene .
The length of these enhancer is very short and these enhancers bind to the protein to enhance the transcription levels of genes.
Enhances donot directly act on the promoter region but are bound by activator proteins which usually help in transcribing of genes.
EXAMPLE AND ROLE OF A GENE ENHANCER:
HACNS contributed in evolution keeps in modification in the ankle and foot thus allows human to walk.
Most of the enhancers are located upstream.
Some more enhancers include ECOLI
It is usuallu located 120 bp from the start site contain sites for nitrogen regulatory protein C.
Yeast GAL1 and Gal0 genes
These are some of the enhancers which usually enhance the process of transcription.
SILENCERS:
Quite Opposite factors to enhances are silencers usually on binding of a transcriptional factor to these of causes the gene expression to be repressed .
PROMOTER
These are the regulatory regions located upstream towards 5?region of a gene.
Promoter usually regulates where ,when,and to what level of gene is to be expressed.
Promoter are the regions where the RNA polymerase binds these allowing the process of gene expression to proceed.
In eukaryotes RNA polymerase cannot recognize the promoter by itself then it needs the help of some transcriptional factors which aid in binding to the DNA .
These promoter usually contain specific DNA sequences that are recognized by protein known as transcription factors.
Promoters are processed in both prokaryotes and eukaryotes.
Prokaryotic promoter are the short sequences at -10and -35 positions
These are present upstream from the transcription start site.
Sequence of promoter which is at -10 is called the box with TATAAT nucleotides.
Where are sequence at -35 usually consists of six nucleotides TTGACA.
Eukaryotic promoters cause the DNA to bend back on itself which allows for placement of regulatory sequences.
TATA box lies very close to transcriptional sole in eukaryotes .
Promoters are on broad classified into two types .They are core promoters and proximal promoters
CORE PROMOTER This is placed approximately at -34 ,core promoter acts as a binding site RNA polymer.
PROXIMAL PROMOTER Uusally this is upstream of the gene that tends to contain primary regulatory elements .
It is situated approximately at -250 and is specific for transcription factor binding sites.
REPITITIVE DNA
DNA sequences that are repeated are called repetitive DNA sequences.
These repetitive DNA does not code for any proteins.
Repititive DNA counts 5-1000 nucleotides repeated 100 times .
ex:GGTTA GGTTA GGTTA???????????..
Repititive DNA are classified into three different types
A)Highly repetitive B)Moderately repetitive C)Single copy or (very low copy number)
HIGHLY REPITITIVE
10-15%of DNA of highly repetitive.
These are usually present adjacent to each other and the DNA can integrate very soon.
A-T-T-C-G-A-T-T-C-G- - - - - - - - - - - -
repeats are again classified into A)Satellite DNA B)Mini satellite C)Micro satellite.
satellite DNA : They tend to produce a different frequency of the nucleotides adenine,cytosine ,guanine,and thymine.
mini satellite DNA: Mini satellite usually contain the G-C rich DNA upto a length of 10 bp to 100 bp
micro satellite: These are also called as simple sequence repeats .
Micro satellites are typically neutral and co-dominant .
These are usually used as molecular markers.
USES OF REPEATS
: These are used in finding out the kinshop and parental hereditary paternity
moderately repetitive: Roughly 25-40%of DNA fragments usually repeat.
This include repeats also known as mobile elements/transposable elements
Interspered repeats are broadly classified into two types
A)Short B)Long .
SHORT NUCLEAR ELEMENTS: These are the short DNA sequences that represent the reverse transcribed RNA molecules transcribed by RNA polymerase III into tRNA ,rRNA .
The most common types of SINES are alu sequence
These 280 bp long which does not have any coding sequences .
SINES account for 13% and usually represented as junk DNA.
LONG NUCLEAR ELEMENTS: These are found in large numbers in eukaryotic genomes .
These are transcribed to an RNA using RNA polymeraseIII.
LINES code for enzyme like reverse transcriptase
LINES also code for endonucleases
SINGLE COPY
: This class accounts for 50-60%of mammalian DNA
Gene rearrangement
: A structural ordered of a chromosome because of recombination of genes that causes a change in the order of its loci and results in the formation of new arrangement of sequence of gene is called gene rearrangement.
TYPES OF REARREAGEMENTS INCLUDE
: Deletions,duplications ,inversions are considered as the significant source of gene variation.
deletion: Certain sequences are usually deleted thus in this type of mutations .
Usually one or more nucleotides are removed from the DNA thus alters the reading frame of the DNA
Duplication
: Duplication also called chromosomal duplication /gene amplification no.ofcopies of a single functional sequence DNA is produced using this duplication process.
Inversion
: In an inversion usually the entire section of DNA is reversed.
Deletions and duplications usually result in specific susceptibility to rearrangements and then genomic instability.
It was found that many discase traits consist of genomic rearrangements rather than point mutations of single genes.
Some abnormalities and disregulations result due to gene rearrangements.
DNA rearrangements occurs both by homologoes and non homologous recombination mechanisms .
Homologous recombination is found to be the best way of gene rearrangements .
An extra chromosomal DNA which can replicate independently without any relation to chromosomal DNA is called a plasmid
Plasmids thus does not have any genetic relationships with the organism from which of is collected
Usually plasmids are found in naturally occurring bacteria but are sometimes found in eukaryotic organism like sacchromyces cervicea.
Plasmids are usually considered as transferrable agents or a means of transport too.
Size of a plasmid usually ranges from 1 to over 1000 kb.
Plasmids play a role in the process of bacterial conjugation as well horizontal gene transfer.
Plasmid can only uptake the genetic material through the process of transformation.
Plasmids can aid bacteria in the process of nitrogen fixation too.
Plasmids are the stable genetic elements found not only in bacteria but also in the mitochondria of some plants
Plasmids can be composed of DNA or RNA double stranded or single stranded linear or circular.
Plasmids are used to produce high amounts of proteins as such the plasmids with antibiotic resistant gene is introduced into an organism..
The organisms thus produces the protein which acts against gene thus releasing lots of required proteins.
TYPES OF PLASMIDS
Basically there are two types of plasmids based on the process of replication.
A)Non integrating plasmids B)Integrating plasmids.
NON INTEGRATING PLASMIDS
There are the plasmids which replicate with in the host cell but does not integrate with the bacterial DNA
INTEGARTING DNA
This type of plasmids usually integrate with the bacterial DNA and then starts the process of replication.
Based on the ability to transfer to other bacteria the plasmids are classified into two types.
A)Conjugative plasmids B)Non conjugative plasmids.
CONJUGATIVE PLASMIDS
These plasmids contain a type of genes called tra-genes which perform the process of conjugation.
NON CONJUGATIVE PLASMIDS
These are usually non integrating they cannot initiate the process of conjugation and hence they can only be transferred with the assistance of conjugative plasmids.
BASED ON THE FUNCTION THERE ARE DIFFERENT TYPES OF PLASMIDS
A)Fertility/F-plasmids B)Resistance/R plasmids C)Col plasmids D)Degradative plasmids E)virulence plasmids.
F-PLASMIDS
Contain tra-genes thus help in the process of conjugation.
R-PLASMIDS
Contain genes that are against antibiotics / poisons thus help bacteria to produce pili that forms a bridge during the process of conjugation
COL-PLASMIDS
Contain the genes that code for the bacteriocins and proteins.
DEGRADATIVE PLASMIDS/METABOLIC PLASMIDS
Enables the digestion of unusual substances . EX:Salicylic acid ,toluene etc.,
VIRULENCE OF PLASMIDS
Taurns bacteria into a pathogen .
One or more major classification includes yeast plasmids .
They are of two types A)Yeast integrative plasmid B)Yeast replicative plasmid.
YEAST INTEGRATIVE PLASMID
They rely on the first integrating into host chromosome .They help in studying of solo gene.
YEAST REPLICATIVE PLASMID
They carry the sequence of chromosome with origin of replication into host .This is usually less stable in nature.
TRANSFER OF PLASMIDS
The process of transfer of plasmids involves four major steps they are A)Identification B)Classification C)Purification D)Transfer .
IDNETIFICATION.
The process of identification of the plasmids is based on the digestion with specific endonucleases.
CLASSIFICATION
After digesting with endonucleases plasmids are subjected to get electrophoresis which helps in the process of fragmentation patterns obtained .
PURIFICATION
Purified plasmids DNA can be obtained by the process of centrifugation.
TRANSFER OF PLASMIDS
The last step in transferring the plasmid with the desirable gene into the host .
PROCESS OF PLASMID TRANSFER /PLASMIDS ACTING AS TRANSFERING AGENTS .
Plasmid vectors are one of the best approaches that gave successful stories of gene therapy.
GENE THERAPY.
It is the process in which the gene with required qualities is inserted into the plasmid DNA and then the plasmid DNA is introduced into the host organism where the process of gene expression starts thus yielding good results.
PROCESS OF CLONING INTO PLASMID .
Step-1: Plasmid with gene for antibiotic resistance are selected.
Treat the plasmid with restriction endonucleases i.e., ecori
Same restriction endonucleases is used to cleave the foreign DNA too.
Then forming a wick on plasmid DNA and collecting the required gene sequence from foreign DNA,
HYBRIDIZATION
The foreign DNA sequence are the hybridized at sticky ends of plasmid DNA .
LIGASE
The enzyme ligase is then used to form the sticky ends or opened ends of plasmid DNA ,
Thus forming the recombinant DNA .
DNA INSERTION
Plasmid DNA is then inserted into bacterial cell.
CLONING
The plasmid DNA is then subjected to gene amplification process then producing number of copes.
PLATTING
Bacteria then platted with the antibiotic in the medium only those hybridized plasmids can same and all other will die thus helps in the selection of recombinant.
CULTURING
After the process of selection it is subjected to culturing thus producing required DNA /clones.
HOST RESTRICTION IN PLASMID TRANSFER
After the process of plasmid identification ,purification,and insertion of the required DNA into the plasmid the plasmid must be transferred into any of the bacterial host.
Transfering into the host then continuous the further process of cloning and replication thus increasing the number /quality.
Common host that are used for plasmid transfer are Ecoli and salmonella.
Some times this transfer is restricted some host enzymes thus restricting the plasmid from entering into the host.
Other than those hosts the plasmids cannot be transferred into other hosts as they show the host restriction.
EXAMPLES /CARE STUDY
Genome degradation
In the process of host restriction genome degradation is the important step where the plasmid DNA material may be lost due to the enzymes of restriction released by other hosts that cannot host the plasmid .
ex:
Host restricted salmonella serotypes usually cause the genome degradation of the plasmid DNA is restricted into them.
Hosts even have restriction factor Which prevent the process of replication of plasmid DNA then the process of gene expression prevented in the hosts that restrict the plasmid DNA .
EUKARYOTIC GENE REGULATION.
As the complexity of organisms is increasing the mode of gene regulationmust be complex to control the process of gene expression.
For the process of cell specialization and cell regularity it needs the process of gene regulation for eukaryotic organisms.
The process of gene expression itself is very complex in case of eukaryotic organisms.
Transcription and translation are considered as the basic steps in the process of gene expression.
In eukaryotes because of the presence of nucleus seperates transcription from translation in a way not seen in prokaryotes.
Regulation occur at the following steps thus regulating the process of gene regulation in eukaryotes if included.
A)At the time of transcription B)While RNA processing C)During the process of m RNA longetivity D)Translation.
These are the major steps when the eukaryotic regulation occur.
REGULATION OF TRANSCRIPTION /RNA PROCESSING PROCESS
Steps involved mRNA processing are A)Addition of 5?cap B)Addition of a3?poly(A)tail C)Removal of introns .
Usually the regulation process occur in any of these steps.
The regulation at this step of transcription /RNA processing is divided into two types. A)Whether RNA must process B)Which exons are retained m RNA.
Regulation step at RNA process indicates/ determines whether the m RNA gets translated/ not .
During this type of regulation of RNA does not get processed it will be transported out of nucleus and will not be translated forever.
In the second type of regulation i.e., which exons are retaived affects the function of the protein produced.< br/> Exon shuffling is a process in which some genes have exons that can be exchanged thus by this process the polypeptide produced could have a different function lather than the actual function , this production may some times even cause the premature stopin g of cooling.
REGULATION OF RNA LONGETIVITY
Longetivity is the step of degradation of RNA after being processed i.e., the life time of RNA .
The regulation at this step results in the required gene product to be formed rather than other gene product .
For example of two mRNA?s of same langetivity are present and one is made to degrade an hour late than first one by following the process of gene regulation it results in the production of the required ploypeptide more in amount than the other.
REGULATION OF TRANSLATION
This is one of the major regulatory step in eukaryotes in which although the mRNA is ready because of this step of regulation the expression of the product cannot occur.
ex: Although mRNA is ready in the egg it does not get expressed until it gets matured.
REGULATION OF TRANSCRIPTION
Instead of repressors and operon system that are present in prokaryotes activation /other wise transcriptional factors paly a major role in transcription control /regulation.
Regulation can be brought by
A)Altering the rate at which RNA transcripts processed.
B)Altering the rate at which mRNA gets degraded.
C)Altering the efficiency of translation.
PROMOTER AND ENHANCER ELEMENTS
Transcriptional factors are the important protein complexes that help RNA polymerase in binding to DNA.
There are five major types of transcription factor that palys a role in the gene expression like zinc finger proteins , helix turn helix protein , lucin zipper proteins-binding DNA ,helix loop helix-usually then get dimerized.
Steroid receptors In ligand binding thus regulating the activity.
These transcriptional factors which are named as activators ,promoters, enhancers paly a major role in the regulation of the eukaryotic gene expression.
ENHANCERS
The transcriptional factors whose binding increases the rate of transcription of the gene are called enhancers .
Usually these are located thousand of box pairs away from the gene they control.
Enhancers are usually located upstream ,down stream or even with in the gene they control.
Enhancers binding proteins in addition to their DNA binding site have sites that bind to transcription factors assembled the proteins of the gene .
The length of these enhancer is very short and these enhancers bind to the protein to enhance the transcription levels of genes.
Enhances donot directly act on the promoter region but are bound by activator proteins which usually help in transcribing of genes.
EXAMPLE AND ROLE OF A GENE ENHANCER:
HACNS contributed in evolution keeps in modification in the ankle and foot thus allows human to walk.
Most of the enhancers are located upstream.
Some more enhancers include ECOLI
It is usuallu located 120 bp from the start site contain sites for nitrogen regulatory protein C.
Yeast GAL1 and Gal0 genes
These are some of the enhancers which usually enhance the process of transcription.
SILENCERS:
Quite Opposite factors to enhances are silencers usually on binding of a transcriptional factor to these of causes the gene expression to be repressed .
PROMOTER
These are the regulatory regions located upstream towards 5?region of a gene.
Promoter usually regulates where ,when,and to what level of gene is to be expressed.
Promoter are the regions where the RNA polymerase binds these allowing the process of gene expression to proceed.
In eukaryotes RNA polymerase cannot recognize the promoter by itself then it needs the help of some transcriptional factors which aid in binding to the DNA .
These promoter usually contain specific DNA sequences that are recognized by protein known as transcription factors.
Promoters are processed in both prokaryotes and eukaryotes.
Prokaryotic promoter are the short sequences at -10and -35 positions
These are present upstream from the transcription start site.
Sequence of promoter which is at -10 is called the box with TATAAT nucleotides.
Where are sequence at -35 usually consists of six nucleotides TTGACA.
Eukaryotic promoters cause the DNA to bend back on itself which allows for placement of regulatory sequences.
TATA box lies very close to transcriptional sole in eukaryotes .
Promoters are on broad classified into two types .They are core promoters and proximal promoters
CORE PROMOTER This is placed approximately at -34 ,core promoter acts as a binding site RNA polymer.
PROXIMAL PROMOTER Uusally this is upstream of the gene that tends to contain primary regulatory elements .
It is situated approximately at -250 and is specific for transcription factor binding sites.
REPITITIVE DNA
DNA sequences that are repeated are called repetitive DNA sequences.
These repetitive DNA does not code for any proteins.
Repititive DNA counts 5-1000 nucleotides repeated 100 times .
ex:GGTTA GGTTA GGTTA???????????..
Repititive DNA are classified into three different types
A)Highly repetitive B)Moderately repetitive C)Single copy or (very low copy number)
HIGHLY REPITITIVE
10-15%of DNA of highly repetitive.
These are usually present adjacent to each other and the DNA can integrate very soon.
A-T-T-C-G-A-T-T-C-G- - - - - - - - - - - -
repeats are again classified into A)Satellite DNA B)Mini satellite C)Micro satellite.
satellite DNA : They tend to produce a different frequency of the nucleotides adenine,cytosine ,guanine,and thymine.
mini satellite DNA: Mini satellite usually contain the G-C rich DNA upto a length of 10 bp to 100 bp
micro satellite: These are also called as simple sequence repeats .
Micro satellites are typically neutral and co-dominant .
These are usually used as molecular markers.
USES OF REPEATS
: These are used in finding out the kinshop and parental hereditary paternity
moderately repetitive: Roughly 25-40%of DNA fragments usually repeat.
This include repeats also known as mobile elements/transposable elements
Interspered repeats are broadly classified into two types
A)Short B)Long .
SHORT NUCLEAR ELEMENTS: These are the short DNA sequences that represent the reverse transcribed RNA molecules transcribed by RNA polymerase III into tRNA ,rRNA .
The most common types of SINES are alu sequence
These 280 bp long which does not have any coding sequences .
SINES account for 13% and usually represented as junk DNA.
LONG NUCLEAR ELEMENTS: These are found in large numbers in eukaryotic genomes .
These are transcribed to an RNA using RNA polymeraseIII.
LINES code for enzyme like reverse transcriptase
LINES also code for endonucleases
SINGLE COPY
: This class accounts for 50-60%of mammalian DNA
Gene rearrangement
: A structural ordered of a chromosome because of recombination of genes that causes a change in the order of its loci and results in the formation of new arrangement of sequence of gene is called gene rearrangement.
TYPES OF REARREAGEMENTS INCLUDE
: Deletions,duplications ,inversions are considered as the significant source of gene variation.
deletion: Certain sequences are usually deleted thus in this type of mutations .
Usually one or more nucleotides are removed from the DNA thus alters the reading frame of the DNA
Duplication
: Duplication also called chromosomal duplication /gene amplification no.ofcopies of a single functional sequence DNA is produced using this duplication process.
Inversion
: In an inversion usually the entire section of DNA is reversed.
Deletions and duplications usually result in specific susceptibility to rearrangements and then genomic instability.
It was found that many discase traits consist of genomic rearrangements rather than point mutations of single genes.
Some abnormalities and disregulations result due to gene rearrangements.
DNA rearrangements occurs both by homologoes and non homologous recombination mechanisms .
Homologous recombination is found to be the best way of gene rearrangements .
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