Medical Biochemistry II PAPER A (MBMB 2200) | MCQ Quiz | OmpathStudy Kenya

Question 1

The molecule that serves as the major source of readily available fuel for neurons and blood cells is

Accepted Answer

Glucose — Glucose is the primary energy source for neurons and red blood cells. Neurons have limited ability to use alternative fuels, and RBCs lack mitochondria, making glucose essential for their ATP production via glycolysis. ---

Question 2

Ammonia is an effective and important urinary buffer for which of the following reasons

Accepted Answer

The walls of the renal tubules are impermeable to NH4+ — NH3 diffuses into tubular fluid where it combines with H+ to form NH4+. The tubular membrane is impermeable to NH4+, effectively trapping it in urine and facilitating acid excretion. ---

Question 3

Which of the choices below is not a fate of carbohydrate taken into the body

Accepted Answer

Conversion to a nucleic acid — While carbohydrates can provide ribose for nucleic acid synthesis, they are not directly converted to nucleic acids. The other options are all direct metabolic fates of carbohydrates. ---

Question 4

The amount of potassium excreted by the kidney will decrease if

Accepted Answer

Circulating aldosterone levels increase — Aldosterone promotes Na+ reabsorption and K+ secretion in the distal nephron. However, when aldosterone levels increase, it also enhances overall K+ conservation mechanisms, leading to decreased K+ excretion. ---

Question 5

An increase in the concentration of plasma potassium causes increases in

Accepted Answer

Secretion of aldosterone — Hyperkalemia directly stimulates aldosterone secretion from the adrenal cortex, which promotes K+ excretion in the distal nephron to restore K+ homeostasis. ---

Question 6

Glomerular filtration rate would be increased by

Accepted Answer

A decrease in the concentration of plasma protein — Decreased plasma protein concentration reduces oncotic pressure, decreasing the force opposing filtration and thereby increasing GFR. ---

Question 7

The greatest amount of hydrogen ion secreted by the proximal tubule is associated with

Accepted Answer

Reabsorption of bicarbonate ion — About 80-90% of filtered bicarbonate is reabsorbed in the proximal tubule via H+ secretion, making bicarbonate reabsorption the major mechanism of proximal H+ secretion. ---

Question 8

Urinalysis is comprised of all of the following except

Accepted Answer

All of the above — This is a trick question. Urinalysis includes all listed components: macroscopic (physical), chemical (dipstick), and microscopic analysis. ---

Question 9

Glycogen is formed in the liver during the

Accepted Answer

Absorptive state — Glycogenesis (glycogen synthesis) occurs during the absorptive state when glucose is abundant after eating, allowing storage of excess glucose as glycogen. ---

Question 10

Which of the following is a normal consequence of the activation of the heat-promoting center

Accepted Answer

Vasoconstriction of cutaneous blood vessels — Heat-promoting center activation causes vasoconstriction of skin blood vessels to conserve body heat by reducing heat loss

Medical Biochemistry II PAPER A (MBMB 2200) | MCQ Quiz | OmpathStudy Kenya

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