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 functions of lipids biomolecules: chemical constituents of living cells biochemistry

Which of the following derived lipids helps in emulsifications and encapsulation?

  1. Lecithins

  2. Cephalins

  3. Carotenoids

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

Lecithin is a group of yellow-brownish fatty substances present in animal and plant tissues.In the pharmaceutical industry, it is used in emulsifications and encapsulation of drugs and is a good dispersing agent. Thus the correct answer is option A.

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

The phospholipid which is mainly found in the white matter of brain and spinal chord is 

  1. Lecithins

  2. Cephalins

  3. Waxes

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

Phosphatidylethanolamines are phospholipids found in all living cells, They are found mainly in the nervous tissue such as the white matter of the brain, nerves, neural tissue and in the spinal cord. 

So, the correct answer is option D.

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

Which of the following lipid is mainly used for membrane biogenesis?

  1. Carotenoids

  2. Terpenes

  3. Phospholipids

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

Membrane biogenesis is structuring/rebuilding/repairing of the cell membrane. As the cell membrane is made of a bilayer of phospholipids embedded with proteins.It is a process carried out by the cell with the help of smooth endoplasmic reticulum (SER) and Golgi apparatus (GA). Where the SER synthesizes lipids which are added with phosphate group and modified to phospholipids by the process of phosphorylation in the GA and transported through vesicles to the cell membrane.

So, the correct answer is 'Phospholipids'

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

Which of the following lipid act as a precursor of bile acids, Vitamin D and steroids?

  1. Phosphoglycerides

  2. Cholesterol

  3. Phospholipids

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

De novo synthesis of cholesterol from acetyl-CoA takes place in the liver. Cholesterol is an essential metabolite for the normal functioning of the endocrine system, regulation of cell membrane processes, and absorption of dietary lipids. They are important structural components of membranes. Cholesterol also serves as precursor for the synthesis of steroid hormones, vitamin D, and bile salts which are important in fat absorption from the small intestine into the blood circulatory system and secretion of liver waste products through feces. Thus the correct answer is option B.

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

Prostaglandins are made from

  1. Steroid

  2. Carbohydrate

  3. Amino acid

  4. Fatty acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Arachidonic acid is a polyunsaturated omega-6 fatty acid. It is present in the phospholipids and helps in the formation of membranes. It is the most abundant fatty acid in the brain. It is a precursor for the synthesis of prostaglandins. The prostaglandins synthesized is PG$ _2$. They are autocrine and paracrine lipid mediators that act upon platelets, endothelium, uterine and mast cells. 
So, the correct answer is option D.
Multiple choice bio-chemistry lipids functions of lipids biomolecules: chemical constituents of living cells biochemistry

Prostaglandins synthesized from

  1. Amino acids

  2. Fatty acids

  3. Carbohydrates

  4. Steroids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Prostaglandins are synthesized by arachidonic acid. Arachidonic acid is a polyunsaturated omega-6 fatty acid. It is present in the phospholipids and helps in the formation of membranes. 
The prostaglandins synthesized is PG$ _2$. They are autocrine and paracrine lipid mediators that act upon platelets, endothelium, uterine and mast cells. It belongs to a class of fatty acid derivative.
So, the correct answer is option B.
Multiple choice bio-chemistry lipids functions of lipids biomolecules: chemical constituents of living cells biochemistry

What is true of membrane lipids and proteins?

  1. None can flip-flop

  2. Both can flip-flop

  3. Proteins can flip-flop but lipids cannot.

  4. Lipids flip-flop but proteins rarely flip-flop
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lipid bilayer of the cell membrane contains hydrophilic head groups facing outward and hydrophobic tails facing each other. The transport of phospholipids and lipid-linked oligosaccharides is difficult to achieve due to this bipolar nature. The transmembrane lipid transporter proteins called flippases transport lipids across cell membrane through transverse diffusion by flipping their orientation. Floppases transport in reverse direction. In mammals, this affects various processes such as blood coagulation, immune recognition, and programmed cell death.Most protein molecules do not flipflop due to their extensive polar regions, which are unfavorable in the hydrophobic core of the membrane.

Option D is correct.

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 coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

Lipase acts on ________________.

  1. Proteins

  2. Fats

  3. Carbohydrates

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

Lipase is a specialized digestive enzyme secreted primarily by the pancreas and in small amounts in the mouth and stomach. Its primary biological function is to catalyze the breakdown of dietary fats (lipids) into glycerol and fatty acids.

Multiple choice zoology excretion in living organisms excretion - animals human excretory system and products excretory system and products excretion - plants excretion in plants

Ketone bodies consist of

  1. Nicotinic acid, folic acid and ascorbic acid

  2. Acetone, beta hydroxybutyryl CoA and if acetoacetic acid

  3. Acetoacetic acid acetone and beta hydroxybutyric acid

  4. Acetic acid, acetone and beta hydroxybutyric acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ketone bodies are byproducts in the metabolism of fat. During starvation or fasting conditions the liver synthesizes glucose through a process called gluconeogenesis. Gluconeogenesis is a metabolic pathway that results in the generation of glucose from fat. During gluconeogenesis, the ketone bodies are formed as byproducts where the product is glucose. The Kerone bodies consist of acetoacetic acid, acetone and beta-hydroxybutyric acid.

So, the correct answer is 'Acetoacetic acid, acetone and beta-hydroxybutyric acid'.

Multiple choice biology human brain and sense organs the brain nervous system in humans central nervous system

Under prolonged starvation, brain receives energy from

  1. Carbodhydrates

  2. Fats

  3. Proteins

  4. Acetoacetate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During prolonged starvation, glucose reserves are depleted, and the liver converts fatty acids into ketone bodies, primarily acetoacetate and beta-hydroxybutyrate, which serve as the major alternative energy source for the brain.

Multiple choice bio-chemistry our health disease and its treatment manifestation and treatment of disease treatment of disease

Statins used for lowering blood cholesterol level are extracted from

  1. algae

  2. bacteria

  3. viruses

  4. yeast
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statins are products of fermentation by yeast Monascus purpureus which resemble mevalovate and are competitive inhibitors of $\beta - hydroxy-\beta - methylglutaryl$ or HMG CoA reductase.This inhibits cholesterol synthesis. Statins are, therefore, used in lowering blood cholesterol, e.g., lovastatin, pravastatin, simvastatin. 

Multiple choice bio-chemistry digestive system of human digestive system- glands mouth and buccal cavity digestive glands

Emulsification of fats is done by .... 

  1. saliva

  2. gastric juice

  3. bile

  4. intestinal juice
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Emulsification of fats is the process of breaking large fat globules into smaller droplets to increase the surface area for enzymatic digestion. This process is carried out by bile salts present in the bile juice secreted by the liver. Bile does not contain digestive enzymes itself, but it is essential for lipid breakdown.

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.