Saturday, 20 August 2016


All living cells in the world are surrounded by cell membrane. Neither animal nor plant cells are devoid of this. As Robertson says it is not only a unit membrane but also a universal membrane all around the cells and their organelles too.

Now read the following questions and answers and suggest some more questions for the aspirants for competitive exams. Please help us rectify the mistakes and improve the content.


1) Which membrane protects the intracellular environment?
A) Cell membrane or plasma membrane or cytoplasmic membrane
2) Which is the outermost layer of animal cells?
A) Cell membrane
3) What is the gateway for the cell?
A) Cell membrane
4) Which is the security guard of the cell?
A) Cell membrane
5) What are the components of an endomembrane system?
A) Plasma membrane, endoplasmic reticulum (ER),  nuclear membrane, Golgi apparatus, and lysosomes.
6) What is the nature of biomembranes?
A) Quasi-fluid, selectively permeable membranes
7) Who coined the term cell membrane?
A) Nageli & Crammer
8) Who coined the term plasma membrane?
A) JQ Plowe
9) What is the thickness of a cell membrane?
A) 75-100 Angstroms
10) What are the extracellular structures that are in association with cell membrane?
A) Cell wall, glycocalyx, and cytoskeleton
11) Which is the Ectoplast?
A) Cell membrane
12) Where is periplasm present?
A) Between outer and inner membranes of bacteria
13) What is the chief component of outer membrane of bacteria?
A) Lipopolysaccharide
14) What is the chief component of all membranes?
A) Lipoproteins
15) What is the fundamental structure of the plasma membrane?
A) Phospholipid bilayer
16) What are the components of a phospholipid?
A) Glycerol, two fatty acid tails, and a phosphate head
17) What is the backbone of the membrane lipids?
A) Glycerol
18) Why is plasma membrane  amphipathic?
A) It contains both hydrophilic heads and hydrophobic tails
19) How many tails a phospholipid has?
A) 2 tails
20) What is the water loving end of a phospholipid?
A) Polar hydrophilic phosphate head
21) What is the water fearing end of a phospholipid?
A) Non-polar hydrophobic
fatty acid tails
22) Which component of the cell membrane is used for cell recognition and act as receptors and antigens?
A) Glycoprotein
23) Which component of a cell membrane maintains the fluidity of cell membranes?
A) Cholesterol
24) What are the lipids that provide stability and impermeability to plasma membranes?
A) Cholesterols
25) What kind of cells have cholesterol in their membranes?
A) Animal cells
26) How could the cell communicate with the external environment?
A)  Through receptor proteins,  hormones, neurotransmitters and signaling molecules.
27) What kind of proteins are transport proteins in cell membranes?
A) Globular proteins
28) What are the communication proteins in cell membranes?
A) Glycoproteins
29) What kind of organisms have multiple plasma membranes?
A) Prokaryotes
30) What is the reason for the flexibility of cell membranes?
A) Lipids
31) What are the double membranous organelles?
A) Nucleus,  mitochondria & plastids (chloroplasts)
32) What are the single membranous organelles?
A) Endoplasmic reticulum, Golgi apparatus,  Lysosomes,  microbodies,  vacuoles,  etc
33) How is the vacuolar membrane called?
A) Tonoplast
34) What is the maximum limit for optical microscopes?
A) 0.25 milli microns or 250 nano meter
35) What kind of structure is exhibited by plasma membrane under electron microscope?
A) Trilamellar structure
36) What is the major component of cell membranes?
A) Proteins
37) What kind of lipids are dominant in plasma membrane?
A) Phospholipids
38) Why are the biomembranes amphipathic?
A) Due to polar hydrophilic heads and nonpolar hydrophobic tails
39) What kind of carbohydrates are common in cell membranes?
A) Oligosaccharides
40) Who gave the lipid model of plasma membrane?
A) Overton
41) Who discovered the bilipid layer in plasma membrane?
A) Gorter & Grendel
42) Who gave the lamellar or sandwich model of plasma membrane?
A) Danielle and Davson
43) Who gave the unit membrane concept?
A) Robertson
44) Who gave the fluid mosaic model of plasma membrane?
A) Singer & Nicholson
45) Who described the cell membrane as "protein icebergs floating in a sea of lipids?"
A) Singer & Nicholson
46) What kind of proteins give elasticity and mechanical support to cell membrane?
A) Structural proteins
47) What are the three kinds of proteins as per their location in plasma membrane?
A) Extrinsic, intrinsic and transmembrane proteins
48) What are the proteins on the outer or inner surface of the plasma membrane?
A) Extrinsic or peripheral proteins
49) What are the proteins located inside the plasma membrane?
A) Inrinsic or integral proteins
50) What are the proteins that extend from outside to inside of the plasma membrane?
A) Transmembrane or tunnel proteins
51) What is the cause for the asymmetry of the plasma membrane?
A) Glycoproteins and glycolipids
52) What is the major driving forces in the formation of lipid bilayers?
A) Hydrophobic effect
53) What is the cell coat in some cells?
A) Glycocalyx
54) Who proved the fluidity of plasma membrane?
A) Frye & Edidin
55) How are the fused cells or cytoplasmic hybrids?
A) Cybrids
56) What are the "supra-membrane" structures?
A) Ascaveola, post-synaptic density, podosome, invadopodium, focal adhesion, and
cell junctions
57) What are the specific proteins that make supra-membrane structures?
A) Integrins and cadherins
58) What are the lipid vesicles?
A) Liposomes
59) What is the outermembrane of microvilli?
A) Glycocalyx
60) What are the plasma membrane evaginations or outpushings?
A) Microvilli, ciliary sheath, flagellar sheath, stereocilia
61) What are the plasma membrane invaginations or inpushings?
A) Pores, mesosomes,  lomasomes and transfer cells
62) What are the connections between two adjacent animal cells?
A) Junctional complexes
63) What are the cementing material between two adjacent animal cells?
A) Adherenes
64) What are the fusions between two adjacent animal cells?
A) Occludens
65) What is the spot where two adjacent animal cells join?
A) Macula
66) What is the strip along which two adjacent animal cells join?
A) Zonula
67) What are the intercellular junctional complexes between two plant cells?
A) Plasmodesmata
68) Who discovered plasmodesmata?
A) Strasburger
69) What are the cytoplasmic bridges between two adjacent plant cells?
A) Plasmodesmata
70) What are the plasma membrane invaginations to increase surface area for absorption?
A) Microvilli
71) What are the cell organelles that provide mechanical support to microvilli?
A) Microfilaments
72) Where do you find microvilli in human body?
A) Intestinal epithelium, liver cells, convoluted renal tubules, gall bladder, ureter.
73) What are the non-motile plasma membrane evaginations?
A) Stereocilia
74) Where do you find stereocilia in human body?
A) Epidydymus
75) What are the plasma membrane infoldings that help in replication and respiration in bacteria?
A) Mesosomes
76) What are the plasma membrane infoldings at the junction of two adjacent  eukaryotic cells?
A) Lomasomes
77) What are the fine hydrophilic channels between two adjacent animal cells?
A) Gap junctions
78) What are the plasma membrane evaginations that transfer stimuli between cells?
A) Intercellular bridges
79) What are formed when Intercellular outgrowth fit into one another?
A) Inter-digitations
80) What are the disc shaped thickened areas with tonofibrils between epithelial cells?
A) Desmosomes or Macular adherents
81) What are the desmosomes with microfilaments and intermediate filaments?
A) Terminal bars or Zonulae adherentes
82) What are the semi-disc shaped thickened areas with collagen fibrils between epithelial cells?
A) Hemidesmosomes
83) What are the impermeable fused areas between plasma membranes of adjacent cells?
A) Tight junctions or Zonulae occludentes
84) What is the energy free membrane transport?
A) Passive transport
85) What are the two types of passive transport?
A) Diffusion & osmosis
86) What is meant by membrane permeability?
A)  The rate of passive diffusion of molecules through the membrane
87) What are the molecules that pass through cell membranes due to diffusion?
A) Permeant molecules
88) Which two factors decide permeability of molecules through cell membranes?
A) Electric charge and polarity
89) How is described the movement of particles from their higher  to lower concentration?
A) Diffusion
90) What are membranous  proteins through which movement of water takes place?
A) Aquaporins
91) What is the movement of water from high concentrated to low concentrated solution across the semipermeable membrane?
A) Osmosis
92) Who discovered osmosis?
A) Jean-Antoine Nollet
93) What is the pressure that develops inside the cell due to the osmotic entry of water?
A) Osmotic pressure  (OP)
94) Which apparatus is used to measure osmotic pressure?
A) Osmometer
95) Who invented osmometer?
A) Pfeffer
96) What is the amount of osmotic pressure exerted by a solution?
A) Osmolariry or osmocity
97) What is the tension developed in a system when it is placed in a solution?
A) Tonocity
98) What are the three types of tonocity?
A) Hypotonic, hypertonic and isotonic
99) What kind of solution has low osmotic concentration or osmotic pressure?
A) Hypotonic solution
100) What kind of solution has high osmotic concentration or osmotic pressure?
A) Hypertonic solution
101) What kind of solution has similar osmotic concentration or osmotic pressure as that of the other?
A) Isotonic solution
102) What will happen when a cell is placed in a hypotonic solution?
A) Endosmosis
103) What will happen when a cell is placed in a hypertonic solution?
A) Exosmosis
104) What will happen when raisins are placed in water?
A) Swelling due to endosmosis
105) Which process keeps the plant cells turgid?
A) Endosmosis
106) What is the mechanism to prevent bursting of plant cells due to excess endosmosis?
A) Wall pressure
107) What is the reason for oozing out of water droplets from sliced cucumbers sprinkled with salt?
A) Exosmosis
108) What will happen when both turgor pressure and wall pressure become zero?
A) Plasmolysis
109) What is the process of shrinkage of protoplast from the cell wall?
A) Plasmolysis
110) What is the process of shrinkage of animal cell
A) Crenation
111) What is the first stage of plasmolysis when the protoplast is in still contact with cell wall at all places?
A) Limiting plasmolysis
112) What is the second stage of plasmolysis when the protoplast starts shrinking away from the corners of the cell wall?
A) Incipient plasmolysis
113) What is the unrecoverable stage of plasmolysis where the protoplast is in contact with cell wall only at a few places?
A) Evident plasmolysis
114) What is the reason for plasmolysis of plant cells or crenation of animal cells?
A) Exosmosis
115) What is the process of swelling of shrunken Protoplast in hypotonic solution?
A) Deplasmolysis
116) What are the different applications of plasmolysis?
A) Salt in pickles, sugar in jams, salting of fish, sprinkling salt on weeds, etc
117) Give examples for substances that show lipid matrix solubility and passive transport.
A) Triethyl citrate, ethyl alcohol,  methane
118) What are the passages in cell membranes through which the exchange of oxygen and carbon dioxide takes place?
A) Hydrophilic membrane channels  (tunnel proteins)
119) How is called the fine filtration from blood capillaries under pressure?
A) Ultrafiltration
120) What is the capillaries bunch in which the blood undergo ultrafiltration?
A) Glomerulus
121) Where does para-cellular ultrafiltration take place?
A) Gap junctions
122) Where does trans-cellular ultrafiltration take place?
A) Fenestrarions in cells
123) By which process waste products are removed from blood into isotonic solution?
A) Dialysis
124) What are the proteins that facilitate transport of substances across membranes without energy expenditure?
A) Permeases
125) How is called the occurrence of facilitated and active transport together?
A) Co-transport
126) Which is the downhill process in membrane transport?
A) Passive transport
127) Which is the uphill process in membrane transport?
A) Active transport
128) What kind of membrane transport occurs along concentration gradient?
A) Passive transport
129) What kind of membrane transport occurs against  concentration gradient?
A) Active transport
130) What kind of membrane transport requires energy?
A) Active transport
131) What are the integral proteins that helps active transport?
A) Carrier proteins
132) What is the difference between carrier proteins and permeases?
A) Carrier proteins require ATP but not permeases
133) What are pumps in cell membranes?
A) Active transport systems
135) What are the channels of active transport systems?
A) Gated channels
136) What is the driving force for ionic pumps in membranes?
137) How many Na ions are passed out and K ions pumped in when an ATP molecule is hydrolysed?
A) 3 Na ions & 2 K ions
138) Which ionic pump helps sea birds to excrete salts through their nasal glands?
A) Na-K pump
139) What are the types of secondary active transport?
A) Uniport, Cotransport (Symport) & Countertransport (Antiport)
140) What kind of pump transports only a single particle at a time?
A) Uniport
141) What kind of pumps transport two particles at a time?
A) Symport & Antiport
142) What kind of pump transports two particles at a time to the same side?
A) Symport
143) What kind of pump transports two particles at a time in opposite directions?
A) Antiport
144) What are the integral proteins meant for cotransport?
A) Symporters
145) Give an example for Symport.
A) Na out & Glucose in
146) Give an example for antiport.
A) Na out & Ca in
147) What is the movement of a large quantity of molecules across membranes at a time?
A) Bulk transport
148) What are the carriers of bulk transport?
A) Vesicles
149) What is the inward bulk transport?
A) Endocytosis
150) What is the outward bulk transport?
A) Exocytosis
151) What is cell drinking?
A) Pinocytosis
152) Who discovered pinocytosis?
A) Lewis
153) Name the fibrillar protein required for pinocytosis?
A) Clathrin
154) Name the Contractile protein required for pinocytosis?
A) Actin
155) What are the pinocytotic vesicles?
A) Pinosomes
156) Which vesicle of golgi apparatus absorbs a pinosome content?
A) Receptosome
157) What is cell eating?
A) Phagocytosis
158) What are the phagocytic blood cells?
A) Leucocytes (WBC)
159) What are the phagocytic liver cells?
A) Kupffer's cells
160) What are the phagocytic spleen cells?
A) Reticular cells
161) What are the phagocytic cells of connective tissue?
A) Histiocytes
162) What is the phagocytic vesicle?
A) Phagosome
163) Which cell organelle form a digestive vacuole from pinosomes or phagosomes?
A) Lysosome
164) What is the process of removal of undigested food from cell?
A) Ephagy (Exocytosis)
165) What are the membranous locomotory organelles?
A) Pseudopodia & undulations
166) What are the pseudopodial cells?
A) Amoeba, WBC, macrophages
167) What are the contractile proteins involved in pseudopodia formation?
A) Actin-myosin
168) In what kind of cells locomotory membranous undulations are seen?
A) Fibroblasts
169) Whether the bulk transport is an active or passive process ?
A) Active process
170) Where are antigens located?
A) Surface of cell membrane
171) What is the cell membrane of myocytes?
A) Sarcolemma
172) What is the cell membrane of oocytes?
A) Oolemma
173) What is the cell membrane of axons of neurons?
A) Axolemma
174) What is a hollow droplet of bilayer membrane?
A) Liposome
175) Which is the energized membrane transport?
A) Active transport
176) What are the transport pumps in guard cells of stomata?
A) K-H pumps

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