Multiple Choice QuestionsThe cell membrane of neuron maintains intracellular conditions that differ from those of the extracellular environment. Such difference in intra- and extracellular conditions are critical to the function of the nerve cell as the nerve cell membrane resembles a charged capacitor. Assuming the electric field (E) across a parallel-plate capacitor is uniform and if membrane thickness is 7 nm and potential difference across the membrane is –60 mV, calculate E of the membrane.
6 × 105 Vm–1
7 × 105 Vm–1
8.6 × 106 Vm–1
6.6 × 106 Vm–1
Actinomycin D inhibits the process of transcription in both prokaryotic and eukaryotic organisms. The following statements are made about actinomycin D-mediated inhibition of transcription:
(a) Actinomycin D inhibits transcription from a double stranded DNA template by either E. coli or yeast RNA polymerases.
(b) Actinomycin D inhibits transcription from a single stranded RNA template by eukaryotic viral RNA polymerases.
(c) Actinomycin D inhibits transcription from single stranded x 174 DNA template by E. coli RNA polymerase immediately after viral DNA entry.
(d) Actinomycin D inhibits transcription from double stranded RNA template by eukaryotic RNA polymerase II.
Which of the combinations of the above statements is a true representation of the mechanism of actinomycin D mediated inhibition.
(a) only
(a), (b) and (c)
(a), (b) and (d)
(a) and (d) only
Following table presents bryophyte phyla with their selected characteristics:
In the above table, phyla A, B and C represent.
A-Marchantiophyta, B- Bryophyta, C-Anthocerotophyta
A-Bryopyta, B- Marchantiophyta, C-Anthocerotophyta
C-Bryopyta, B- Marchantiophyta, A-Anthocerotophyta
A-Bryopyta, C- Marchantiophyta, B-Anthocerotophyta
A single protofilaments of microtubule grows at the speed of 2μm/min. Considering that there is no catastrope in the microtubule nucleation and the size of the tubulin unit of the order of 5nm, how many tubulin units are added to the growing microtuble per minutes?
400
1600
3200
5200
Bacteria adopt different stratergies to evade host defense mechanisms. From the lists of various different mechanisms and bacterial strategies against host defense given below, select the option representing all correct pairing.
| Host defense mechanism | Bacterial strategies against host defense |
|
(a) Phagocytosis |
(i) Change of bacterial surface charge, making it more positive |
| (b) Release antibodies, like IgG | (ii) Capsular polysaccharides, such as that of Klebsiella pneumoniae |
| (c) Antibody meditated Agglutination | (iii) Release of soluble proteins like protein A of Staphylococcus aureus |
| (d) Anti-microbial peptides | (iv) Secretion of elastase to inactivate C3a and C5a |
| (a) | (b) | (c) | (d) |
| (i) | (ii) | (iii) | (iv) |
| (a) | (b) | (c) | (d) |
| (ii) | (iii) | (iv) | (i) |
| (a) | (b) | (c) | (d) |
| (iv) | (iii) | (ii) | (i) |
| (a) | (b) | (c) | (d) |
| (iii) | (i) | (iv) | (ii) |
B.
| (a) | (b) | (c) | (d) |
| (ii) | (iii) | (iv) | (i) |
The polysaccharide capsules are effective physical barries that protect the bacteria from being killed. The fact that bacteria capsules are commonly hydrophilic and negatively charged diminishes their removal through phagocytosis, so A will match with X. Cell bound or soluble Protein A is produced by Staphylococcus aurcus. Protein A attaches to the Fe region of IgG and blocks the cytophlic(cell-binding) domain of the Ab so it is again a bacteria strategy to defend against host. Thus, the ability of IgG to act as an opsonic factor is inhibted, and opsonin-mediated ingestion of the bacteria is blocked, so b will match with Y. In Gram-positive bacteria, the major bactorial lipid component, phosphatidylglycerol can be chemically modified by bacterial enzymes to convert the lipid from anionic to caticinc or zwitterionic form. This process leads to increased levels of resistance of the bacteria against polycationic antimicrobial agents so d will match with W. C3a and C5a are anaphylatoxins that get inhibited so do not induce anti body mediated agglutination.
Which one of the following activities is NOT involved in protein folding in the endoplasmic reticulum?
Peptidyl prolyl isomerase
Protein disulphide isomerase
Protein glycosylation
Protein ubiquitination
Given below is a list of bacteria either functioning methanogens or methanotrophs:
A) Methanabacterium sp
B) Methanacoccus sp
C) Methylomonas sp
D) Methylosinus sp
Which of the following options classifies the above list correctly?
Methanogen-A; Methanotrophs- B, C, D
Methanogen-A; Methanotrophs- D
Methanogen-A, B; Methanotrophs- C, D
Methanogen-A, D; Methanotrophs- B, C
The table given below provides a list of groups of Arthropds (A-D) and some features (i-v)
| (a) Onychophorans | (i) includes insects |
| (b) Trilobites | (ii) have cephalothrox and often pincer-like append-age |
| (c) Hexapods | (iii) marine arthropods that disappeared in the Permian extinction |
| (d) Chelicerates | (iv) are considered related to arthropads but have unjoined appendage |
| (v) only arthropod group without antennae |
Which one of the following options represents the correct match between the arthropod groups with these features?
| (a) | (b) | (c) | (d) |
| (iv) | (iii) | (i) | (v) |
| (a) | (b) | (c) | (d) |
| (i) | (iii) | (iv) | (ii) |
| (a) | (b) | (c) | (d) |
| (iii) | (iv) | (ii) | (i) |
| (a) | (b) | (c) | (d) |
| (iv) | (iii) | (v) | (ii) |
Membrane-bound, Golgi-derived structures containing proteolytic enzymes in sperms of sea urchin are called:
Cortical granuels
Micromeres
Acrosomal vesicles
Macromeres
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