Tag: bio-chemistry

Quizzes (82) Questions (1918)

Questions Related to bio-chemistry

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry
Which of the following cellular metabolic processes can occur both in the presence or absence of ${O} _{2}$?

  1. Glycolysis

  2. Fermentation

  3. TCA cycle

  4. Electron transport coupled with chemiosmosis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Glycolysis is an oxidative process in which one molecule of glucose is partially oxidised into two molecules of pyruvate in a series of enzyme catalysed reactions. Glycolysis, the major pathway for glucose metabolism, occurs in the cytosol of cells. It is a unique pathway that occurs aerobically as well as anaerobically and does not involve molecular oxygen.

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Which one of the following hormone never reaches to cytoplasm?

  1. Estrogen

  2. FSH

  3. Progesterone

  4. Testosterone
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

FSH is a proteinaceous hormone. It does not enter its target cells, thus, it never reaches to cytoplasm. Instead, it binds to the receptor present on the cell membrane and activates a membrane bound enzyme that causes conversion of ATP to cAMP. This then alters the activities of enzyme in the cytoplasm.

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry
Last ${e}^{-}$ acceptor during ETS is 
  1. ${O} _{2}$
  2. cyt $a$
  3. cyt ${a} _{2}$
  4. cyt ${a} _{3}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In electron transport chain, there are 7 electron acceptors, which are as follows $Co-Q\rightarrow Cyt\,\, b\rightarrow Cyt \,\,{c} _{1} \rightarrow Cyt \,\,c\rightarrow Cyt \,\,a\rightarrow Cyt \,\,{a} _{3}\rightarrow{O} _{2}$. Oxygen is the ultimate electron acceptor. These electron acceptors are present in a specific sequence along inner mitochondrial membrane.

Multiple choice bio-chemistry respiration in organisms glucose metabolism the need for energy in living organism respiratory function
Which is true about the end products of glycolysis?
  1. $2\,pyruvic \,acid+2ATP+{2NADH} _{2}$
  2. $2\,pyruvic \,acid+{2NADH} _{2}$
  3. $1\,pyruvic \,acid+2ATP+{2NADH} _{2}$
  4. $2\,pyruvic \,acid+1ATP+{1NADH} _{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In glycolysis, two molecules of ATP are consumed during two phosphorylation reactions to form fructose 1, 6-biphosphate. In return, four molecules of ATP are produced by substrate-level phosphorylation (conversion of 1, 3-biphosphoglycerate to 3-phosphoglycerate and phosphoenolpyruvate to pyruvate). Two molecules of ${NADH} _{2}$ are formed at the time of oxidation of glyceraldehyde 3-phosphate to 1, 3-biphosphoglycerate. The net reaction of glycolysis is as follows:

$Glucose+{2NAD}^{+}+2ADP+{2H} _{3}{PO} _{4}\rightarrow2Pyruvate+2NADH+{2H}^{+}+2ATP$

Each NADH is equivalent to 3 ATP, so the net gain in glycolysis is 8 ATP.

So the correct answer is '$2\,pyruvic \,acid+2ATP+{2NADH} _{2}$'.
Multiple choice bio-chemistry respiration in organisms glucose metabolism the need for energy in living organism respiratory function

In glycolysis, glucose molecule is converted into which substance?

  1. Lactic acid

  2. Ethanol

  3. Pyruvate

  4. Amino acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The process by which the glucose (6C compound) is split into two molecules of pyruvic acid (3C compound) is called glycolysis or EMP pathway. It occurs in the cytoplasm. In glycolysis, 4ATP and 2NADH$ _2$ molecules are formed and 2ATP molecules are consumed in hexose phase

So, the correct answer is 'Pyruvate'

Multiple choice bio-chemistry respiration in organisms glucose metabolism the need for energy in living organism respiratory function

For the start of respiration, a living cell requires

  1. Glucose
  2. Glucose + $O _2$
  3. $O _2$

  4. Glucose + ATP
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The mechanism of respiration is initiated by breaking down glucose to pyruvic acid without the help of oxygen. The initial process occurs in the cytosol of cells which requires glucose as well as ATP molecules which provide energy for the process to start. This initial process is known as glycolysis and it takes place in 10 steps in which total 4 ATP molecules are produced and 2 ATP molecules are consumed. Thus, these are the net production of 2 ATP molecules. 

Thus, the correct answer is option D. 

Multiple choice bio-chemistry respiration in organisms glucose metabolism the need for energy in living organism respiratory function

How many ATP are produced in mitochondria on complete oxidation of glucose?

  1. $24$
  2. $30$
  3. $34$
  4. $38$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Name of process   Site  Total ATP formation
 Glycolysis  Cytoplasm  2NADH(i.e. 6ATP)+ 2ATP = 8ATP 
 Conversion of pyruvate to acetyl CoA  Cytoplasm  2NADH = 6ATP
 Kreb's cycle  Mitochondria  6NADH + 2 FADH + 2GTP= 18ATP +4ATP + 2ATP  = 24 ATP

 1 NADH = 3 ATP, 1 FADH = 2 ATP

So, the correct answer is '$24$'

Multiple choice bio-chemistry respiration in organisms glucose metabolism the need for energy in living organism respiratory function

When one molecule of sucrose is subjected to phosphorylation how many ATPs are consumed?

  1. 2

  2. 6

  3. 3

  4. 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During the conversion of fructose-1,6-bis-phosphate to lactate, the pathway generates a total of four molecules of ATP, resulting in a net yield of two ATP per glucose consumed.

correct answer is A.