MCQOPTIONS
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MCQOPTIONS
This section includes 101 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following is not a G-protein coupled receptor? |
| A. | Glycine receptor |
| B. | Adrenergic receptor |
| C. | Glutamate receptor |
| D. | Muscarinic receptor |
| Answer» B. Adrenergic receptor | |
| 2. |
Bacteria do not have which of the following receptors? |
| A. | Adhesion receptors |
| B. | Nuclear steroid receptors |
| C. | Membrane proteins |
| D. | GPCR |
| Answer» C. Membrane proteins | |
| 3. |
Which of the following is involved in extrinsic cell death pathway? |
| A. | Heterotrimeric G protein complex |
| B. | TRADD |
| C. | IRS-1 |
| D. | Protein-kinase A |
| Answer» C. IRS-1 | |
| 4. |
The G protein involved in visual signal transduction is _________ |
| A. | Rhodopsin |
| B. | GTP receptor |
| C. | Arrestin |
| D. | Transducin |
| Answer» D. Transducin | |
| 5. |
Objects are perceived by photo receptors because rods or cones |
| A. | Depolarize |
| B. | Hyperpolarize |
| C. | Repolarize |
| D. | Polarize |
| Answer» C. Repolarize | |
| 6. |
PTB domains bind to ___________ |
| A. | Phosphorylated tyrosine |
| B. | Phosphoryated threonine |
| C. | Phosphorylated serine |
| D. | Phosphorylated cysteine |
| Answer» B. Phosphoryated threonine | |
| 7. |
Which of the following statements is not true about olfactory neurons? |
| A. | Axons of olfactory neurons combine to form olfactory nerves |
| B. | They synapse with cells in olfactory bulb |
| C. | They have receptors that react with odorants dissolved in fluid |
| D. | They are uni-polar neurons |
| Answer» E. | |
| 8. |
Protein kinase A is ____________ |
| A. | Completely inhibited by cyclic AMP |
| B. | Allosterically activated by cyclic AMP |
| C. | Affected by cyclic AMP only under unusual circumstances |
| D. | Activated by covalent binding of cyclic AMP |
| Answer» C. Affected by cyclic AMP only under unusual circumstances | |
| 9. |
A hormone or ligand can be considered as ___________ |
| A. | First messenger |
| B. | Second messenger |
| C. | Third messenger |
| D. | Fourth messenger |
| Answer» B. Second messenger | |
| 10. |
ERF1is a _________ |
| A. | Translation terminating factor |
| B. | Positive regulator |
| C. | Translation promoting factor |
| D. | Enzyme inhibitor |
| Answer» B. Positive regulator | |
| 11. |
In Arabidopsis flg22 binds to _________ |
| A. | FLS2 |
| B. | LPS |
| C. | BAK1 |
| D. | MAPK |
| Answer» B. LPS | |
| 12. |
Which of the following is a short-lived messenger that acts by stimulating a soluble guanylyl cyclase, raising [cGMP] and stimulating PKG? |
| A. | NO |
| B. | NO₂ |
| C. | NO₃⁻ |
| D. | N₂O |
| Answer» B. NO₂ | |
| 13. |
The binding of ligands to many GPCRs leads to ___________ |
| A. | Decrease in concentration of certain intracellular signal molecules called second messengers |
| B. | Increase in concentration of certain intracellular signal molecules called second messengers |
| C. | Decrease in concentration of certain extracellular signal molecules called first messengers |
| D. | Increase in concentration of certain extracellular signal molecules called first messengers |
| Answer» B. Increase in concentration of certain intracellular signal molecules called second messengers | |
| 14. |
Which out of the following statements about sense of smell is not true? |
| A. | Olfactory receptor cells are bipolar neurons, not replaced when damaged |
| B. | The chemicals are received by specific plasma membrane receptors in olfactory receptor cells |
| C. | Olfactory receptors do not adapt quickly |
| D. | The main areas of brain that interpret sense of smell be in the temporal and frontal lobes |
| Answer» D. The main areas of brain that interpret sense of smell be in the temporal and frontal lobes | |
| 15. |
The enzyme activated by cyclic AMP, passing on the hormonal signal is ____________ |
| A. | Protein kinase B |
| B. | Protein kinase A |
| C. | Protein kinase C |
| D. | G protein receptor kinase |
| Answer» C. Protein kinase C | |
| 16. |
In cholera there is uncontrolled secretion of _________ |
| A. | Na⁺ and H₂O |
| B. | K⁺ and H₂O |
| C. | Ca⁺² and H₂O |
| D. | Mg⁺² and H₂O |
| Answer» B. K⁺ and H₂O | |
| 17. |
What is the relationship between olfactory sensors and gustatory sensors? |
| A. | Gustatory hair can also detect odorants |
| B. | Olfactory hair can also detect tastants |
| C. | Olfactory sensors provides information about substance that we are about to taste |
| D. | No relation |
| Answer» D. No relation | |
| 18. |
cAMP and cGMP are derived from ____________ |
| A. | ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively |
| B. | ATP and GTP by the actions of adenylate cyclase and gualnlate cyclase respectively |
| C. | GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively |
| D. | None of the mentioned |
| Answer» C. GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively | |
| 19. |
Which of the following catalyzes the cutting of PIP2 into 2 moles of IP3 and diacylglycerol in cell signaling? |
| A. | Phosphokinase C |
| B. | Phospholipase C |
| C. | Lipokinase |
| D. | Phosphodiesterase C |
| Answer» C. Lipokinase | |
| 20. |
Transcription factor in plants is _________ |
| A. | Serine |
| B. | Threonine |
| C. | WRKY22/29 |
| D. | Leucine |
| Answer» D. Leucine | |
| 21. |
Negative regulator of ethylene response is _________ |
| A. | LPS |
| B. | CTR1 |
| C. | BAK1 |
| D. | MAPK |
| Answer» C. BAK1 | |
| 22. |
When visual stimulus reaches receptors in retina of eye, first process involving absorption of physical energy by receptors is? |
| A. | Reception |
| B. | Transduction |
| C. | Coding |
| D. | Adaptation |
| Answer» B. Transduction | |
| 23. |
Which of the following statements is false about a ligand-gated ion channel receptor? |
| A. | They are present in the cell membrane |
| B. | They consist of five glycoproteins |
| C. | Differences in membrane potential affect whether the channel receptors are open or close |
| D. | Neurotransmitters can act as the chemical messengers for these channels |
| Answer» D. Neurotransmitters can act as the chemical messengers for these channels | |
| 24. |
Which out of the following is not a neurotransmitter? |
| A. | Noadrenaline |
| B. | Cyclic AMP |
| C. | Dopamine |
| D. | Acetyl choline |
| Answer» C. Dopamine | |
| 25. |
Which of the following statements about action potential is false? |
| A. | Na⁺/K⁺ pumps are directly involved in creating the action potential |
| B. | Na⁺ and K⁺ concentrations are not significantly changed during an action potential |
| C. | This includes both positive and negative feedback loops |
| D. | Only a relatively small number of Na⁺ and K⁺ actually diffuse across the membrane |
| Answer» C. This includes both positive and negative feedback loops | |
| 26. |
The receptor channels for which of the following are gated by extracellular ligands? |
| A. | Glycine |
| B. | IP₃ |
| C. | cAMP |
| D. | cGMP |
| Answer» B. IP₃ | |
| 27. |
Which of the following are intracellular second messengers? |
| A. | Acetylcholine |
| B. | Glycine |
| C. | IP₃ |
| D. | Glutamate |
| Answer» D. Glutamate | |
| 28. |
Which of the following is false about phosphorylation by IRS on serine residue? |
| A. | It is an inhibitory phosphorylation |
| B. | It is molecular mechanism for insulin resistance |
| C. | It increases insulin levels |
| D. | Target tissues fail to respond to circulating insulin |
| Answer» D. Target tissues fail to respond to circulating insulin | |
| 29. |
Vision, olfaction and gustation employ _________ |
| A. | Serpentine receptors |
| B. | Enzyme coupled receptors |
| C. | Ligand gated receptors |
| D. | Adhesion receptors |
| Answer» B. Enzyme coupled receptors | |
| 30. |
Which of the following directly phosphorylate tyrosines to start a kinase protein enzymatic cascade? |
| A. | Receptor tyrosine kinase |
| B. | Receptor guanylyl cyclases |
| C. | Receptor serine kinase |
| D. | Receptor threonine kinase |
| Answer» B. Receptor guanylyl cyclases | |
| 31. |
Which of the following serves as a neurotransmitter in adrenergic neurons? |
| A. | Serotonin |
| B. | Epinephrine |
| C. | Dopamine |
| D. | Histamine |
| Answer» C. Dopamine | |
| 32. |
Steroid hormones receptor binds to _____________ |
| A. | Hormone response elements in m-RNA |
| B. | Hormone response elements in DNA |
| C. | Hormone response elements in proteins |
| D. | Ribosomes to stimulate translation |
| Answer» C. Hormone response elements in proteins | |
| 33. |
Mode of action of steroid hormones involve ______________ |
| A. | Stimulation of DNA replication |
| B. | Stimulation of m-RNA transcription |
| C. | Inhibition of protein synthesis |
| D. | Secondary messenger |
| Answer» C. Inhibition of protein synthesis | |
| 34. |
The peptide trigger for the self-incompatibility response that prevents self-pollination is _________ |
| A. | Salicylic acid |
| B. | Jasmonates |
| C. | Brassinosteroids |
| D. | Plant peptide hormones |
| Answer» D. Plant peptide hormones | |
| 35. |
Which of the following converts GTP to cGMP to start its enzymatic cascade? |
| A. | Receptor guanylyl cyclase |
| B. | Receptor adenylyl cyclase |
| C. | Calmodulin |
| D. | Protein kinase-A |
| Answer» B. Receptor adenylyl cyclase | |
| 36. |
Most olfactory receptors are located on the _________ |
| A. | Superior surface of nasal cavity |
| B. | Interior surface of nasal cavity |
| C. | Lateral surface of nasal cavity |
| D. | Medial surface of nasal cavity |
| Answer» B. Interior surface of nasal cavity | |
| 37. |
GPCR is comprised of ___________ |
| A. | 7 transmembrane helices |
| B. | 8 transmembrane helices |
| C. | 9 transmembrane helices |
| D. | 10 transmembrane helices |
| Answer» B. 8 transmembrane helices | |
| 38. |
Ras protein is a ____________ |
| A. | G-protein switch |
| B. | Small monomeric GTPase switch protein |
| C. | Serine-threonine kinase |
| D. | Tyrosine kinase |
| Answer» C. Serine-threonine kinase | |
| 39. |
Which of the following is involved in proline rich motif binding? |
| A. | SH2 |
| B. | SH3 |
| C. | PTB |
| D. | PH |
| Answer» C. PTB | |
| 40. |
Cyclin dependent kinases which control progression through cell cycle checkpoints are totally activated by which of the following? |
| A. | Binding to cyclin, plus phosphorylation by a Cdk activating protein kinase |
| B. | Binding to cyclins |
| C. | Phosphorylation by Cdk activating protein kinase |
| D. | Phosphorylation by a tyrosine kinase |
| Answer» B. Binding to cyclins | |
| 41. |
Passage of a cell through stages of cell cycle is controlled by a protein kinase that phosphorylates many different proteins at appropriate times. |
| A. | Cdk activating kinase |
| B. | Cyclin-dependent kinase |
| C. | Cyclins |
| D. | Tyrosine kinase |
| Answer» C. Cyclins | |
| 42. |
Which of the following occurs in meiosis but not in mitosis? |
| A. | Attachment of spindle fibers to kinetochore |
| B. | Replication of DNA prior to start of cell division |
| C. | Separation of sister chromatids at anaphase |
| D. | Pairing of homologous chromosomes at metaphase plate |
| Answer» E. | |
| 43. |
At which cell cycle checkpoint, cell cycle is halted if cell’s DNA is damaged? |
| A. | G₁ – S |
| B. | S – G₂ |
| C. | G₂ – M |
| D. | G₀ – G₁ |
| Answer» B. S – G₂ | |
| 44. |
Which of the following are stimulated to become membrane associated upon binding of insulin to the insulin receptor? |
| A. | PH-domain |
| B. | PTB |
| C. | SH₃ |
| D. | SH₂ |
| Answer» B. PTB | |
| 45. |
Which of the following statements regarding cyclin-dependent protein kinase is not correct? |
| A. | Their activity is regulated by cyclins |
| B. | They can alter the activity of proteins involve in the progression of cells through cell cycle |
| C. | Their activity fluctuates during cell cycle |
| D. | Each type of cell contains one specific form |
| Answer» D. Each type of cell contains one specific form | |
| 46. |
Which second messenger signals the release of Ca⁺² from endoplasmic reticulum? |
| A. | IP₃ |
| B. | 1, 2 diacyl glycerol |
| C. | cAMP |
| D. | cGMP |
| Answer» B. 1, 2 diacyl glycerol | |
| 47. |
Cdk2/cyclinE functions in ____________ |
| A. | G₂/M transition |
| B. | G₂ |
| C. | M |
| D. | G₁/S transition |
| Answer» E. | |
| 48. |
Which of the following is involved in phospho-tyrosine binding? |
| A. | SH2 |
| B. | SH3 |
| C. | PTB |
| D. | PH |
| Answer» B. SH3 | |
| 49. |
The mutation which cannot give rise to an oncogene? |
| A. | Addition or deletion of a base producing a nonsense message and an inactive protein product |
| B. | A point mutation changing just one amino acid in protein product |
| C. | A translocation, putting gene under control of strong promoter producing over expression |
| D. | A point mutation producing stop codon, premature termination |
| Answer» B. A point mutation changing just one amino acid in protein product | |
| 50. |
The characteristic of malignant other than a benign tumor is? |
| A. | Undergoes metastasis |
| B. | Develops blood supply |
| C. | Cell divides an unlimited number of times |
| D. | Grows without needing a growth signal |
| Answer» B. Develops blood supply | |