Tag: cell respiration

Questions Related to cell respiration

Pasteur effect is __________________.

  1. Stoppage of fermentation in presence of oxygen

  2. Increase of fermentation in presence of oxygen

  3. Decrease in fermentation in presence of oxygen

  4. No effect on fermentation


Correct Option: A

Lactic acid is produced in the process of

  1. Fermentation.

  2. HMP.

  3. Krebs cycle.

  4. Glycolysis.


Correct Option: A
Explanation:

Fermentation of carbohydrates such as glucose, lactose, sucrose produces lactic acid.

So the correct option is 'Fermentation.'

The incomplete breakdown of sugars in anaerobic respiration results in the formation of 

  1. Fructose and water

  2. Glucose and $CO _{2}$

  3. Alcohol and $CO _{2}$

  4. Water and $CO _{2}$


Correct Option: C
Explanation:

Anaerobic respiration involves the incomplete breakdown of glucose. It releases around 5% of the energy released by aerobic respiration, per molecule of glucose. In yeast it can be observed, as alcoholic fermentation. A biological process in which molecules such as glucose, fructose, and sucrose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products.

In anaerobic respiration, acetaldehyde is reduced to form alcohol by utilising $NADH _2$ obtained from

  1. Glycolysis

  2. Terminal oxidation

  3. Krebs cycle

  4. Acetylation


Correct Option: A
Explanation:

Anaerobic respiration starts with the process of glycolysis. The NADH2 thus formed from glycolysis are used to further oxidise acetaldehyde to form alcohol and CO2. The NAD formed are then recycled back to be used in glycolysis.

So the answer is 'Glycolysis'.

In anaerobic respiration of muscles, pyruvic acid is changes to.

  1. Alcohol

  2. Acetaldehyde

  3. Acetyl CoA

  4. Lactic acid


Correct Option: D

The energy releasing process in which the substrate is oxidized without an external electron acceptor is called as

  1. Aerobic respiration

  2. Glycolysis

  3. Fermentation

  4. Photorespiration


Correct Option: C
Explanation:

Fermentation is an energy releasing process in which substrate like sugar is oxidized into organic acids or alcohol without an external electron acceptor. The final electron acceptor is either acetaldehyde or pyruvate. Aerobic respiration is a process in which energy is produced in the presence of oxygen. Glycolysis is a process of converting glucose into two molecules of pyruvate. Photorespiration is a process in which RuBisCO enzyme oxygenates RuBP by wasting some amount of energy.

Thus, the correct answer is option C.

Lactic acid is converted into alcohol in a process called as

  1. Fermentation

  2. Aerobic respiration

  3. Respiration

  4. Photosynthesis


Correct Option: A
Explanation:

Fermentation is a process used to produce wine, beer, yogurt etc. Yeast performs fermentation to obtain energy by converting sugar into alcohol. Alcoholic fermentation also referred to as ethanol fermentation, is a biological process in which molecules such as glucose, fructose, and sucrose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products.

Conversion of pyruvic acid into ethyl alcohol is facilitated by enzyme(s)

  1. Carboxylase

  2. Phosphatase

  3. Dehydrogenase

  4. Decarboxylase and dehydrogenase


Correct Option: D
Explanation:
When the pyruvic acid converts into alcohol in the presence of enzymes by bacteria and also exhibited by some in the lack of oxygen.
$2CH _3COOH\rightarrow2CH _3CHO+2CO _2$ is takes place in the presence of decarboxylase which removes carbon dioxide
$2CH _3CHO+2 NADH _2\rightarrow2C _2H _5OH+2NAD$ is takes place in the presence of alcohol dehydrogenase.
So the correct option is 'Decarboxylase and dehydrogenase'.

During lactic acid fermentation

  1. $O _{2}$ is used and $CO _{2}$ is liberated

  2. Neither $O _{2}$ is used, nor $CO _{2}$ is liberated

  3. $O _{2}$ is used, but $CO _{2}$ is not liberated

  4. None of the above


Correct Option: B
Explanation:

Lactic acid fermentation is a biological process by which glucose and other six-carbon sugars are converted into cellular energy and the metabolite lactate. It is an anaerobic fermentation reaction, that occurs in muscle cells. There is no liberation of carbon dioxide in this process.

Which molecule listed below is a product of fermentation of glucose by yeast?

  1. $C _{6}H _{10}O _{5}$

  2. $C _{2}H _{5}OH$

  3. $C _{6}H _{12}O _{6}$

  4. $CH _{3}OH$


Correct Option: B
Explanation:

Beer and wine are produced by fermenting glucose with yeast. Yeast contains enzymes, that catalyze the breakdown of glucose to ethanol and carbon dioxide.