Saturday, December 26, 2009

cell biology - objective questions- btechbiotechnology- jntu syllabus-2-1

unit- 1

1)a protective structure called a cell wall made of cellulose.
2)The cell was first discovered by Robert Hooke
3)Hooke's description of these cells (which were actually

non-living cell walls) was published in Micrographia.
4)# Mitochondria and chloroplasts have their own genetic material,

and reproduce independently from the rest of the cell.
5)The cell is the fundamental unit of structure and function in

living thing.
6)The idea that cells were separable into individual units was

proposed by Ludolph Christian Treviranus
7)cells come from pre-existing cells by division.
8)Credit for the first compound (more than one lens) microscope is

usually given to Zacharias Jansen,
9)Cells that lack a membrane-bound nucleus are called prokaryotes

10)size of an animal mitochondrion (about 1-2µm in diameter and 10

µm long

11)bacterial cells divide by binary fission.
12)A eukaryote is an organism whose cells contain complex

structures inside the membranes.
13)Cell division in eukaryotes involves separating the duplicated

14)Eukaryotic cells include a variety of membrane-bound structures,

collectively referred to as the endomembrane system.
15) Robert Brown reported the discovery of the nucleus.
16)Bacteria serve as decomposers and agents of fermentation,
17)Eukaryotic DNA is divided into several linear bundles called

18)The defining membrane-bound structure that sets eukaryotic cells

apart from prokaryotic cells is the nucleus.
19)brain of cell is nucleus
20)nucleus of prokaryotes is circuloid in nature

21)The cell membrane is the biological membrane separating the

interior of a cell from the outside environment.
22)The cell membrane surrounds all cells and it is semi-permeable

in nature.
23)cell membrane contain biological molecules, primarily proteins

and lipids,
24)cellular processes include cell adhesion, ion channel

conductance and cell signaling
25)cell wall plays mostly a mechanical support role rather than a

role as a selective boundary
26)fluid mosaic model given by S. J. Singer and Garth Nicolson
27)The cell membrane consists primarily of a thin layer of

amphipathic phospholipids
28)Proteins in the cell membranes may be integral or peripheral.
29)The cytoskeleton is a cellular "scaffolding" or "skeleton"

contained within the cytoplasm that is made out of protein
30)microtubule-associated proteins (MAPs) are proteins that

interact with the microtubules of the cellular cytoskeleton
31) MAPs bind to the tubulin subunits that make up microtubules to

regulate their stability
32)Microtubules have a diameter of 25 nm and length 200 nanometers

to 25 micrometers.
33)Microtubules are polymers of a- and ß-tubulin dimers.
34)Microtubules are nucleated and organized by the microtubule

organizing centers
35)the term cytoskeleton was first introduced by French

embryologist Paul Wintrebert
36)Microfilaments are the thinnest filaments of the cytoskeleton
37) microfilaments are also called as actin filaments
38)Important component in filament formation is the Arp2/3 complex
39)cilia and flagella help in the process of locomotion
40)An example of a eukaryotic flagellated cell is the sperm cell,
41)Bacterial flagella are helical filaments that rotate like screws
42)The bacterial flagellum is made up of the protein flagellin.
43)Bacterial flagella are motorized by a flow of H+ ions
44)Along with cilia, flagella make up a group of organelles known

as undulipodia.
45)Intraflagellar transport (IFT), the process by which axonemal

subunits, transmembrane receptors, and other proteins are moved up

and down the length of the flagellum.


46)the nucleus referred to as the "control center"
47)nucleus contains most of the cell's genetic material,
48)The nuclear envelope (NE) is a double lipid bilayer that

encloses the genetic material
49) nuclear membrane also known as the perinuclear envelope,

nuclear membrane, nucleolemma or karyotheca
50)Nuclear transport is movement through the pores
51)The nuclear envelope separates the cell's genetic material from

the surrounding cytoplasm.
52)Nuclear pores, provide aqueous channels through the envelope
53)The endoplasmic reticulum (ER) is an eukaryotic organelle that

forms an interconnected network of tubules, vesicles, and cisternae

within cells.
54)The surface of the rough endoplasmic reticulum (RER) is studded

with protein-manufacturing ribosomes giving it a "rough" appearance
55)golgi complex was named afterCamillo Golgi
56)The primary function of the Golgi apparatus is to process and

package macromolecules, such as proteins and lipids,
57)The Golgi is composed of membrane-bound stacks known as

58)The Golgi plays an important role in the synthesis of

59)The phosphorylation of molecules requires that ATP
60)The vesicles that leave the rough endoplasmic reticulum are

transported to the cis face of the Golgi apparatus
61)Lysosomes are spherical organelles that contain enzymes called

acid hydrolases
62)The size of lysosomes varies from 0.1–1.2 µm
63)lysosomes are concerned with programmed cell death, called

64)Peroxisomes are organelles from the microbody family and are

present in almost all eukaryotic cells.
65)Chloroplasts are organelles found in plant cells and other

eukaryotic organisms that conduct photosynthesis.
66)chloroplast have the larger size because its membrane is not

folded into cristae
67)Mitochondria provide the energy a cell needs to move, divide,
68)The intermembrane space is the space between the outer membrane

and the inner membrane.
69)ATP synthase, which generates ATP in the matrix
70)Glycosylation is the enzymatic process that links saccharides to

produce glycans, attached to proteins, lipids, or other organic


71)transport that does not need energy passive transport
72)transport that need energy active transport
73)The four main kinds of passive transport are diffusion,

facilitated diffusion, filtration and osmosis.
74)Facilitated diffusion is the movement of molecules across the

cell membrane via special transport proteins
75) the transport protiens are called as carrier protiens
76)Osmosis is the diffusion of water molecules across a selectively

permeable membrane.
77)In the human body, waste products are removed from the

bloodstream in the kidneys via dialysis, an example of diffusion
78)Active transport is the mediated process of moving particles

across a biological membrane against a concentration gradient.
79)Secondary active transport involves the use of an

electrochemical gradient.
80)transport in one direction at the same time as another substance

is being cotransported in the other direction. called antiport.
81)Symport is the name if two substrates are being transported in

the same direction across the membrane.
82)A proton pump is an integral membrane protein that is capable of

moving protons across the membrane of a cell, mitochondrion, or

other subcellular compartment.
83)Endocytosis is the process by which cells absorb molecules
84)Phagocytosis is the process by which cells ingest food material
85)Pinocytosis is also called as cell-drinking.
86)enzymes involved in the electron transport chain are ubiquinone
87)The term docking refers to the holding of two membranes within a

bilayer's distance of one another
88)lysosomes are referred to as suicidal bags
89)The Fo F1 ATP synthase of mitochondria, in contrast, usually

conduct protons from high to low concentration
90)The permeases are membrane transport proteins,

91)Cell division is the process by which a parent cell divides into

two or more daughter cells.
92)This type of cell division in eukaryotes is known as mitosis
93)Cell division also enables asexually reproducing organisms to

develop from the one-celled zygote,
94)In humans this occurs on average, after 52 divisions,
95)limit of divisions to 52 known as the Hayflick limit
96)An enzyme called telomerase, present in large quantites in

cancerous cells, rebuilds the telomeres
97)cell nucleus into two identical sets in two nuclei in mitosis
98)Mitosis and cytokinesis together define the mitotic (M) phase
99)longer phase of cell cycle intephase
100)Formation of phragosome in proprophase
101)microtubules find and attach to kinetochores in prometaphase
102)Telophase is a reversal of prophase and prometaphase events
103)Cytokinesis is often mistakenly thought to be the final part of

104)meiosis is a process of reductional division in which the

number of chromosomes
105)Meiosis is essential for sexual reproduction and therefore

occurs in all eukaryotes
106)The cell cycle, or cell-division cycle, is the series of events

that takes place in a cell
107)The cell cycle consists of four distinct phases: G1 phase, S

phase (synthesis), G2 phase (collectively known as interphase) and

M phase (mitosis).
108)Resting phase is G0 phase
109)cyclins and cyclin-dependent kinases (CDKs), determine a cell's

progress through the cell cycle.
110)CDKs perform a common biochemical reaction called

phosphorylation that activates or inactivates target proteins


111)cellular differentiation is the process by which a less

specialized cell becomes a more specialized cell type.
112)Differentiation dramatically changes a cell's size, shape,

membrane potential, metabolic activity
113)A cell that is able to differentiate into many cell types is

known as pluripotent.
114)A cell that is able to differentiate into all cell types is

known as totipotent
115)In cytopathology, the level of cellular differentiation is used

as a measure of cancer progression
116)# Hematopoietic stem cells (adult stem cells) from the bone

marrow that give rise to red blood cells, white blood cells, and

117)Mesenchymal stem cells (adult stem cells) from the bone marrow

that give rise to stromal cells, fat cells, and types of bone cells
118)# Epithelial stem cells (progenitor cells) that give rise to

the various types of skin cells
119)Muscle satellite cells (progenitor cells) that contribute to

differentiated muscle tissue
120)Dedifferentiation is a cellular process often seen in more

basal life forms such as worms and amphibians
121) In mammals, the zygote and the embryo during early stages of

development are totipotent
122)Pluripotent stem cells undergo further specialization into

multipotent progenitor cells
123)Germ line cells are any line of cells that give rise to gametes
124) artificial skin is an example of stem cell aplication
125)a hollow sphere of cells, called a blastocyst
126) stemcells and meristematic cells in plants constitute

pleuripotent cells
127)inner cell mass will go on to form virtually all of the tissues

of the human body
128)multipotent progenitor cells that then give rise to functional

129)dedifferentiation is an aberration of the normal development

cycle that results in cancer
130)RNA molecules are an important type of intracellular

differentiation control signal.


131)Cell signaling is part of a complex system of communication

that governs basic cellular activities and coordinates cell actions
132)Errors in cellular information processing are responsible for

133)Cells communicate with each other via direct contact called

juxtacrine signaling
134)Cells communicate over short distances paracrine signaling

135)Cells communicate over large distances and/or scales endocrine

136)The Notch signaling mechanism is an example of juxtacrine

137)Endocrine signals are called hormones
138)Hormones are produced by endocrine cells and they travel

through the blood to reach all parts of the body.
139)Paracrine signals target only cells in the vicinity of the

emitting cell
140)Neurotransmitters are ligands that are capable of binding to

ion channel proteins
141)Ligand-gated ion channel receptors are a class of receptor that

may occur both at the cell-surface or intracellularly.
142)Cell-surface receptors are integral transmembrane proteins and

recognize the vast majority of extracellular signaling molecules.
143) eukaryotic cells, most intracellular proteins activated by a

ligand/receptor interaction possess an enzyme caled tyrosine kinase
144)cAMP is derived from adenosine triphosphate (ATP) and used for

intracellular signal transduction
145)cAMP is synthesised from ATP by adenylyl cyclase
146)In the species Dictyostelium discoideum, the chemotactic

movement of cells is organized by periodic waves of cAMP that

propagate through the cell
147)Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide

derived from guanosine triphosphate
148)cGMP is a common regulator of ion channel conductance,

149)chemoreceptor, is a sensory receptor that transduces a chemical

signal into an action potential.
150)Second messengers are molecules that relay signals received at

receptors on the cell surface


151)Cancers are caused by abnormalities in the genetic material of

the transformed cells
152)Carcinoma: Malignant tumors derived from epithelial cells
153)Sarcoma: Malignant tumors derived from connective tissue, or

mesenchymal cells.
154)Lymphoma and leukemia: Malignancies derived from hematopoietic
155)Substances that cause DNA mutations are known as mutagens,
156)he process of cell change in which ,a cell loses its ability to

control its rate of division, and thus becomes a tumour cell, is

called cell transformation.
157)Telomerase is an enzyme that adds specific DNA sequence repeats
158)necrosis, is a form of traumatic cell death that results from

acute cellular injury,
159) telomerase enzyme allows for replacement of short bits of DNA

known as telomeres
160)Embryonic stem cells express telomerase, which allows them to

divide repeatedly and form the individual.
161)SMAC binds to inhibitor of apoptosis proteins (IAPs) and

deactivates them,
162)Cell shrinkage and rounding are shown because of the breakdown

of the proteinaceous cytoskeleton by caspases.
163)The removal of dead cells by neighboring phagocytic cells has

been termed efferocytosis
164)Angiogenesis is a physiological process involving the growth of

new blood vessels from pre-existing vessels
165)Sprouting angiogenesis was the first identified form of

166)Intussusception, also known as splitting angiogenesis, was

first observed in neonatal rats
167)Formation of vascular structures from circulating or

tissue-resident endothelial stem cells is called vasculogenesis
168)spread of a disease from one organ or part to another

non-adjacent organ or part is called metastasis
169)Metastatic tumors are very common in the late stages of cancer.
170)Proto-oncogene: A normal gene which, when altered by mutation,

becomes an oncogene


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