Tag: biomolecules: chemical constituents of living cells

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Questions Related to biomolecules: chemical constituents of living cells

Multiple choice bio-chemistry lipids functions of lipids biomolecules: chemical constituents of living cells biochemistry

Why tails of lipids in the membrane are towards inner part?

  1. The tails is non-polar hydrocarbon and so, protected with an aqueous environment

  2. The tail is polar hydrocarbon and so, is protected from aqueous environment

  3. The non-polar or hydrophobic hydrocarbon trails of lipid, being on inner side ensure their protection from aqueous environment.

  4. The tail is hydrophilic so, it tends to be located in the aqueous inner side of membrane
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The tails of the lipids are made up of fatty acids. These are non-polar hydrophobic so they tend to arrange away from the cytoplasmic face as well as the extracellular face. So, they avoid aqueous medium by arranging themselves towards the inner part of the cell membrane.

Hence, the correct answer is 'The non-polar or hydrophobic hydrocarbons tails of lipid, being on inner side ensure their protection from the aqueous environment.

Multiple choice bio-chemistry lipids functions of lipids biomolecules: chemical constituents of living cells biochemistry

Which of the following can be traced in phospholipids of brain tissue and soybeans?

  1. Phosphoglycerides

  2. Phosphoinositides

  3. Cholesterol

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

Phosphoinositides make up a small fraction of cellular phospholipids, They play a fundamental role in controlling membrane-cytosol interfaces, regulation of membrane traffic and the permeability and transport functions of membranes. They are found in brain tissue in animals and soybean seeds. Thus the correct answer is option B.

Multiple choice bio-chemistry lipids functions of lipids biomolecules: chemical constituents of living cells biochemistry

Deficiency of EFA causes

  1. Follicular keratosis

  2. Kidney failure

  3. Sterility

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

Essential fatty acids (EFA) are those fatty acids that body cannot produce on its own and therefore must be supplied from the diet. Deficiency of EFA causes many disease conditions like dry and scaly skin, follicular keratosis (hard and dry skin around hair follicles), bumps on back of upper arms, color variation of skin, dry eyes, mouth and throat, menstrual cramps, dry vagina, excessive thirst, eczema, asthma, hay fever, painful joint. In severe cases, it may result in kidney failure and sterility.

Thus, the correct answer is option D. 

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

Sterols are not fats but solid alcohols. These are put as lipids because they form

  1. Fats and fatty acids

  2. Triglycerides

  3. Cholesterol

  4. Ester and fatty acids
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sterols are classified as lipids because they are hydrophobic and soluble in organic solvents. Cholesterol is the most well-known sterol and serves as a fundamental component of cell membranes.

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

At physiological temperature, sterols in biological membranes

  1. Increase their fluidity

  2. Decrease their fluidity

  3. Increase their permeability to water

  4. Decrease their permeability to water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Biological membranes are made up of lipid bilayer. These sterols affects the fluidity and rigidity of the membrane. At physiological temperature, sterols in biological membranes increase their fluidity but makes them more stronger and rigid. Environmental conditions like higher temperatures or unsaturated fatty disrupts close packing of lipids. This results in increase in the fluidity of the membrane. The membranes become more permeable to water. However, at lower temperatures, membranes become rigid. 

So the correct option is 'Increase their fluidity'.

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 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

Steroid is derived from

  1. Cholesterol

  2. Thyroxine

  3. Vitamin A

  4. Fatty acid ester
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. 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.