Biology · Chemistry

Lipids, Fats, and Biochemistry

1,009 Questions

Lipids, fats, and biochemistry explore the structure and function of biological molecules. This includes fatty acids, cholesterol, trans-fats, and cellular membranes. Questions on this topic frequently appear in science sections of competitive government exams.

Types of fats and lipidsCholesterol and human bodyFatty acidsCellular membranes

Lipids, Fats, and Biochemistry Questions

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

Beta-oxidation mainly takes place in _________.

  1. Cytoplasm

  2. Mitochondria

  3. Golgi bodies

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. Acetyl- CoA

  2. Pyruvate

  3. Glycogen

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Stability of the plasma membrane is enhanced by _________ .

  1. cholesterol molecules

  2. phospholipids

  3. glycoproteins

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

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

Animal membranes contain

  1. Steroids

  2. Chlorophyll

  3. Prostaglandins

  4. Vitamin A
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

Saturated fatty acid that reduces oil quality is

  1. Palmitic acid

  2. Stearic acid

  3. Erucic acid

  4. All the above.
Reveal answer Fill a bubble to check yourself
C Correct answer
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. 

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

 .......... is the regulatory enzyme in the fatty acid biosynthesis.

  1. Aminoacyl synthetase

  2. Acetyl CoA carboxylase

  3. Peptidyl transferase

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
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 B.
Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

The oil of which one of the following plants is edible and rich in poly unsaturated fatty acids?

  1. Aleurites fordii

  2. Cocos nucifera

  3. Carthamus tinctorius

  4. Ricinus communis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carthamus tinctorius, commonly known as safflower, produces an edible oil that is exceptionally rich in polyunsaturated fatty acids, particularly linoleic acid. The other plants listed either yield oils with different fatty acid compositions or are not primarily known for edible polyunsaturated oil.

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

Cholesterol belongs to which of the following groups

  1. Steroids

  2. Neutral fats

  3. Waxes

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

The steroids are composed of seventeen carbon atoms, bonded in four fused rings: three six-membered cyclohexane rings and one five-membered cyclopentane ring. The steroids differ in the functional group attached to this four-ring core and by the oxidation state of the ring.

Steroids such as cholestrol decrease membrane fluidity. Like lipids, these are highly concentrated energy stores. They are normally metabolized and excreted.
So, the correct option is 'Steroids'.

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

Which one of the following is not a correct statement regarding the design of biological membranes?

  1. Carbohydrate molecules associated with membranes tend to be associated with protein molecules embedded in the membrane

  2. Hydrophobic ends of phospholipid molecules in the outer monolayer of the membrane are exposed directly to the extracellular environment

  3. Cholesterol is a type of lipid frequently found in membranes of animal cells

  4. Protein molecules can be located on the inner and outer surfaces of the membrane as well as traverse the entire thickness of the bilayer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
In a cell membrane, the hydrophobic ends of phospholipid molecules in the outer monolayer of the membrane are sandwiched between the hydrophilic heads of the phospholipid bilayer and are not exposed to the extracellular environment.

So, the correct answer is 'Hydrophobic ends of phospholipid molecules in the outer monolayer of the membrane are exposed directly to the extracellular environment'.
Multiple choice bio-chemistry lipids derived lipids biomolecules: chemical constituents of living cells cell membrane

CPPP which is the important component of sterol is mainly stood for?

  1. Cyclopentanoperhydrophenanthrene

  2. Pentanoperhydrophenanthrene

  3. Cycloperhydrophenanthrene

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CPPP is the abbreviated form of Cyclopentanoperhydrophenanthrene. It is an important component of sterol. Thus the correct answer is option A.