Biology

Cellular Respiration and Enzymes

1,721 Questions

Explore key concepts of cellular respiration, including glycolysis, the Krebs cycle, and the electron transport chain. These questions also cover ATP production, anaerobic respiration, and essential metabolic pathways. This topic forms a core part of the biology syllabus for many competitive examinations.

Glycolysis and metabolic pathwaysKrebs cycle processesElectron transport chainATP production countAnaerobic respiration products

Cellular Respiration and Enzymes Questions

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

Substrate -level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?

  1. $0\%$
  2. $2\%$
  3. $10\%$
  4. $100\%$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Substrate-level phosphorylation is the direct transfer of phosphate group to ADP to form ATP. It accounts of 100% of the ATP formed by the reactions of glycolysis. The first substrate-level phosphorylation occurs when 1, 3 - diphosphoglyceraldehyde is converted to 1, 3 - diphosphoglyceric acid and 2 NADH$ _2$ are formed, that is 6 ATP are formed. The 1, 3-diphosphoglyceric acid is then dephosphorylated to 3 phosphoglyceric acid producing 2 ATP via substrate-level phosphorylation. The second substrate-level phosphorylation occurs when phosphoenolpyruvic acid is converted to pyruvic acid producing 2 ATP molecules.

Thus, the correct answer is option D. 

Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

Which among the following is the anabolic process?

  1. Glucose converts to lactic acid.

  2. Acetic acid is converted to cholesterol

  3. Glucose converted to pyruvic acid

  4. Glycogen converted to glucose
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Anabolic process involves the synthesis of complex molecules from simple molecules. Cholesterol is a large and complicated molecule. The starting point of cholesterol synthesis is acetic acid.
So, the correct option is 'Acetic acid is converted to cholesterol'
Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

Heterotrophs can metabolize lipids by a process called ___________ into monomers of _____________ and fatty acids.

  1. Hydrolysis; Glycerol

  2. Dehydration synthesis; Glycerol

  3. Hydrolysis; Glycolipids

  4. Dehydration synthesis; Glycolipids
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heterotrophs can metabolize lipids by a process of hydrolysis, where water molecule is added to break down a chemical compound (lipids). 

Lipids on hydrolysis yield fatty acids and glycerol
So, the correct answer is 'Hydrolysis; Glycerol'

Multiple choice zoology bio-geo chemical cycles in nature nutrient cycles- flow of substances carbon cycle biogeochemical cycles - gaseous

Phtotochemical phase does not includes ________________.

  1. Fixation of ${CO} _{2}$
  2. Release of ${O} _{2}$

  3. Photolysis of water

  4. Formation of ATP and NADPH
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Photochemical phase includes photolysis of water and production of assimilatory power (ATP and NADPH). It liberates O2  during photolysis of water. 

The photochemical phase do not include fixation of CO2.

Multiple choice evs food components energy from different food components nutritional requirements of the body need for nutrients simple test for nutrients test for nutrients

Sugars are not as good as fats as a source of energy for cellular respiration, because sugars.

  1. Produce toxic amino groups when broken down

  2. Contain more hydrogen

  3. Usually bypass glycolysis and the Krebs cycle

  4. Contain fewer hydrogen atoms and electrons
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sugars, when broken down, produces toxic amino groups. During Cellular Respiration, sugar is broken down to CO$ _2$and H$ _2$O, and in the process, ATP is made that can then be used for cellular work. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most. In glycolysis, the 6-carbon sugar, glucose, is broken down into two molecules.

So the correct answer is 'Produce toxic amino groups when broken down'.

Multiple choice biomacromolecules biotechnology cell biology and biotechnology biomolecules biology

What is common between NAD and FAD?

  1. Both are coenzymes

  2. Both are derived from proteins

  3. Both acts as oxygen carriers

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nicotinamide Adenine Dinucleotide (NAD) and Flavin Adenine Dinucleotide (FAD) are coenzymes associated with reversible oxidation and decrease reactions. Then, these lessened coenzymes can give these electrons to some other biochemical response ordinarily engaged with a procedure that is anabolic (like the union of ATP).

So, the correct option is 'Both are coenzymes'.

Multiple choice biology respiration and energy transfer respiratory quotient-basic respiration-plants respiratory quotient

R. Q in anaerobic respiration is 

  1. 0
  2. ${\propto }$

  3. 1

  4. > 1
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The respiratory quotient (RQ) is the ratio of $CO _2$ produced to $O _2$ consumed, while food is being metabolized.
RQ = $CO _2$ eliminated / $O _2$ consumed.
The value of RQ is infinity during anaerobic respiration, because $CO _2$ is produced but $O _2$ is not utilized. Thus, option B is correct and other options are incorrect.

Multiple choice biology respiration and energy transfer respiratory quotient-basic respiration-plants respiratory quotient

When the evolution of $CO _2$ is more than the intake of $O _2$, the respired substrate should be

  1. Fatty acid.

  2. Organic acid.

  3. Glucose.

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

The respiratory quotient depends upon the type of respiratory substrate used during respiration. When organic acids are metabolised more carbon dioxide is evolved than oxygen consumed. Hence, the value of RQ is more than one.

Multiple choice biology respiration and energy transfer respiratory quotient-basic respiration-plants respiratory quotient

R.Q. would depend upon

  1. Nature of enzymes

  2. Nature of substrate
  3. Amount of CO$ _2$ released
  4. Amount of O$ _2$ utilised
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Respiratory Quotient (R.Q.) is the ratio of the volume of CO$ _{2}$ released to the volume of O$ _{2}$ consumed in a respiration process. It depends on the nature of the substrate and its capacity of using O$ _{2}$ and releasing CO$ _{2}$. For example, glucose consumes 6 CO$ _{2}$ and releases 6 O$ _{2}$, so its R.Q. is 1.

 Hence, the correct answer is 'Nature of substrate'

Multiple choice biology respiration and energy transfer respiratory quotient-basic respiration-plants respiratory quotient

The most common respiratory substrate is

  1. Glucose

  2. Sucrose

  3. Maltose

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

The various organic substances such as carbohydrates, fats and proteins are respired completely to carbon dioxide and water are called respiratory substrates. Under natural conditions only carbohydrates are used. Glucose being the simplest monosaccharide hexose molecule acts as the chief respiratory substrate. 

Thus, the correct answer is option A. 

Multiple choice zoology respiratory system phases in respiration human respiratory system parts of respiration

Cellular respiration is

  1. Continuous

  2. Intermittent

  3. Performed at intervals

  4. Held when energy is required
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cellular respiration is a continuous process of oxidation of food to produce energy. The energy produced is utilized by human beings to carry out all the life processes such as digestion, excretion, circulation etc. Since these are continuous processes and do not stop, so they require continuous energy. If the energy is produced intermittently it will slow down these processes and affect the individual. 

Thus, the correct answer is option A.