Tag: cell membrane

Questions Related to cell membrane

Beta-oxidation mainly takes place in _________.

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

  1. Cytoplasm

  2. Mitochondria

  3. Golgi bodies

  4. None of the above

Show answer
Correct Option: B
Explanation:

In biochemistry and metabolism, beta-oxidation is the catabolic process by which fatty acid molecules are broken down in the cytosol in prokaryotes and in the mitochondria in eukaryotes to generate acetyl-CoA, which enters the citric acid cycle, and NADH and FADH2, which are co-enzymes used in the electron transport.

Which among the following is the anabolic process?

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

  1. Glucose converts to lactic acid.

  2. Acetic acid is converted to cholesterol

  3. Glucose converted to pyruvic acid

  4. Glycogen converted to glucose

Show answer
Correct Option: B
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'

Steroid is derived from

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

  1. Cholesterol

  2. Thyroxine

  3. Vitamin A

  4. Fatty acid ester

Show answer
Correct Option: A
Explanation:
Steroids are the organic molecule which plays an important role in the growth and development of the body. The molecular structure consists of 17 carbons which are arranged in four fused structure. It is found in plants, animals and fungi. Cholesterol which is the derivative of steroid forms an integral component of the cell membrane and alter the membrane fluidity. The also acts as hormone precursor for steroidal hormones.
So, the correct answer is option A.

Misuse of anabolic steroids cause various side-effects in males and females. Which  of the following  side-effects of anabolic steroids is not observed in females?

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

  1. Masculinisation

  2. Breast enlargement

  3. Excessive hair growth on face and body

  4. Deepening of voice

Show answer
Correct Option: A
Explanation:

Masculinisation is a side-effect which is not commonly observed in females due to the intake of anabolic steroids. so, 'the correct option is - masculinisation'. "So, the correct answer is 'A' ".

Which of the following is a major substrate for synthesis of fats?

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

  1. Acetyl- CoA

  2. Pyruvate

  3. Glycogen

  4. None of the above

Show answer
Correct Option: A
Explanation:

Fatty acids are components of the phospholipids that make up the bulk of the lipid bilayers of all cellular membranes. It is synthesized by cytosolic acetyl-CoA  through carboxylation by acetyl-CoA carboxylase into malonyl CoA. This conversion occurs primarily in the liver, adipose tissue and lactating mammary glands, where the fatty acids are combined with glycerol to form triglycerides

So, the correct answer is option A.

Stability of the plasma membrane is enhanced by _________ .

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

  1. cholesterol molecules

  2. phospholipids

  3. glycoproteins

  4. glycolipids

Show answer
Correct Option: A
Explanation:

Cholesterol helps to keep the membrane stable. This stability is maintained  as: At high temperatures, cholesterol reduces membrane fluidity by restraining the movement of phospholipids. At low temperatures, cholesterol gives solidification of the membrane because it prevents the close packing of phospholipids.

So, the correct answer is 'cholesterol molecules'

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

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

  1. Hydrolysis; Glycerol

  2. Dehydration synthesis; Glycerol

  3. Hydrolysis; Glycolipids

  4. Dehydration synthesis; Glycolipids

Show answer
Correct Option: A
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'

Cholesterol content is minimum in

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

  1. Fish

  2. Cow's skimmed milk

  3. Liver

  4. Vegetable oils

Show answer
Correct Option: D
Explanation:

Cholesterol content is minimum in vegetable oils as plant have ergosterol as the major sterol present in them. Cholesterol is present in animals and 20 % of total cholesterol is sythesised in liver.

Animal membranes contain

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

  1. Steroids

  2. Chlorophyll

  3. Prostaglandins

  4. Vitamin A

Show answer
Correct Option: A
Explanation:
Steroids are the organic molecule which plays an important role in the growth and development of the body. It is a four-ring structure. Steroids such as cholesterol form an integral component of the cell membrane and alter the membrane fluidity. It provides the stability to the cell membrane by limiting the membrane fluidity. 
So, the correct answer is option A.

Saturated fatty acid that reduces oil quality is

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

  1. Palmitic acid

  2. Stearic acid

  3. Erucic acid

  4. All the above.

Show answer
Correct Option: C
Explanation:

Fatty Acid Composition of Canola Oil The decrease in the level of erucic acid in rapeseed oil resulted in a marked increase in C18 acids, which make up approximately 95% of all fatty acids present in canola oil. 

Hence C is the correct answer.