Biology · Chemistry

Lipids, Fats, and Biochemistry

1,130 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 biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

What are lipids?

  1. Composed of fatty acids

  2. Triglycerides

  3. Insoluble in water

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

Lipids are esters of fatty acids and glycerol which form emulsion with water are soluble in organic solvents, example- ghee, butter, carotene, menthol. Fatty acids are long chains of hydrocarbon having an acidic group. Chemically, lipids are diverse and may be acidic or esters but all lipids have a common property that they are hydrophobic and insoluble in water.

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Lipids are insoluble in water because lipid molecules are ______________.

  1. Hydrophilic

  2. Hydrophobic

  3. Neutral

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

Lipids are hydrophobic means water-hating. They are water-insoluble. Lipids are non-polar molecules while water is a polar molecule, so there is no way for water to attach to a lipid molecule. Instead, the non-polar lipids will bind to themselves, which is why oils and fats form droplets on the surface of the water.

Hence B is the correct option. 

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

The structural lipids of cell are 

  1. Phospholipids

  2. Simple lipids

  3. Steroids

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

Phospholipids are a class of lipids that are a major component of all cell membranes as they can form lipid bilayers. Most phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline; one exception to this rule is sphingomyelin, which is derived from sphingosine instead of glycerol. 

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Lipids are insoluble in water, because lipids molecules are ___________.

  1. Neutral

  2. Zwitter ions

  3. Hydrophobic

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

Lipids are hydrophobic means water hating. They are water insoluble. Lipids are non-polar molecules while water is polar molecule, so there is no way for water to attach to a lipid molecule. Instead, the non-polar lipids will bind to themselves, which is why oils and fats form droplets on the surface of water.

Hence C is the correct option. 

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Fats are also known as

  1. Lipids

  2. Proteins

  3. Carbohydrates

  4. Nucleic acids
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Lipids may be broadly defined as hydrophobic or amphipathic small molecules, that originate entirely or in part by carbanion-based condensations of thioesters and/or by carbocation-based condensations of isoprene units. A lipid is considered to be any molecule, that is insoluble in water and soluble in organic solvents. Biological lipids usually refer to a broad grouping of naturally occurring molecules which includes fatty acids, waxes, eicosanoids, monoglycerides, diglycerides, triglycerides, phospholipids, sphingolipids, sterols, terpenes, prenols, fat-soluble vitamins (such as vitamins A, D, E and K) and others. The main biological functions of lipids include their central role in energy storage, as structural components of cell membranes, and as important signaling molecules.
Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Maximum percentage of lipoprotein is present in

  1. Chylomicron

  2. HDL

  3. VDL

  4. VLDL
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A lipoprotein is a biochemical assembly that contains both proteins and lipids. There are several types of lipoproteins, each having different functions, but all essentially are transport vehicles. Lipoproteins are categorized and named mainly accordingly to their density which varies with the ratio of lipids to proteins from largest and highest to smallest and heaviest, the four major classes of lipoproteins are chylomicrons, VLDL, LDL and HDLs.
So the correct answer is 'Chylomicron'.
Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Which of the following is not a lipid?

  1. Wax/ lecithin

  2. Sterol/ cholesterol

  3. Glycerol/ maltose

  4. Lecithin/ Ghee
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Lipids:- lipids are molecules that contain hydrocarbons & make up the building blocks of the structures & function of living cells. e.g. - Fats, oil, waxes, contain vitamins (such as A, D, E, & K), Hormones & most of all cell membranes that is not made up of protein.
Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Which of the following lipid is essential part of good diet?

  1. Oleic acid

  2. Linoleic acid

  3. Stearic acid

  4. Palmitic acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Essential fatty acids are that fatty acid which plays an important role in the biological process and they can be metabolized easily. These acts as a fuel rather getting deposited as fat in the body. The human body cannot synthesize essential fatty acids. Alpha-linolenic acid and linoleic acid are the two essential fatty acid. The essential fatty acids like alpha-linolenic acid and linoleic acid are unsaturated as they have double bonds.
So, the correct answer is option B.
Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Structural lipids of cell membrane are

  1. Simple lipid

  2. Chromolipid

  3. Phospholipid

  4. Steroid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Phospholipids are the structural lipids which have phosphorous attached to the lipids molecules. It is an important constituent of the cell membrane. It is made up of two hydrophobic fatty acid tails and a hydrophilic head consisting of a phosphate group. The two constituents are joined by a glycerol molecule. It can easily form bilayer because of its amphiphilic nature. It has the hydrophobic tail which does not interact with water and a hydrophilic head which can interact with water.
So, the correct answer is option C.
Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Which fatty acid is liquid at room temperature?

  1. Palmitic acid

  2. Stearic acid

  3. Lauric acid

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

Linoleic acid is an unsaturated fatty acid. Unsaturated fatty acids have double bonds that create kinks in the chain, preventing tight packing and keeping them liquid at room temperature.

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Steroids are

  1. Lipids

  2. Proteins

  3. Vitamins

  4. Carbohydrates
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 carbon which is arranged in four fused structure. It is found in plants, animals, and fungi. It is considered as an important class of lipids as they have properties similar to the triglycerides. It also plays important role in defensive mechanism of the body.

So, the correct answer is option A.

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Cerebroside is a

  1. Glycolipid

  2. Sterol

  3. Phospholipid

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

Cerebroside is an important component of muscles and nerve cell membrane. It is also known as galactosylceramide. It is a class of glycolipids which consists of N -acyl sphingosine with glucose or galactose. Its deposition causes Gaucher disease. It is synthesized in endoplasmic reticulum and membranes of Golgi apparatus. It is degraded in the lysosomes. It is also known as galactolipid.

So, the correct answer is option A. 

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids

Hydrolysis of lipid yields

  1. Fats

  2. Fatty acids and glycerol

  3. Mannose and glycerol

  4. Maltose and fatty acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Most common lipids are triglycerides of glycerol and fatty acids. During digestion of lipids they are broken down into constituent fatty acids and glycerols by the action of lipase enzymes.

Hence B is the correct option. 

Multiple choice biology food and it's constituents functions and principal sources of lipids chemical organization in living beings lipids
Choose the correct combination:

$a$ Fatty acid $1.$ Glutamic acid
$b$ Phospholipid $2.$ Tryptophan
$c$ Aromatic Amino Acid $3.$ Lecithin
$d$ Acidic Amino Acid $4.$ Palmitic acid
  1. $a - 1, b - 2, c - 3, d - 4$
  2. $a - 4, b - 3, c - 2, d - 1$
  3. $a - 2, b - 3, c - 4, d - 1$
  4. $a - 3, b - 4, c - 1, d - 2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

a) Palmitic acid is a saturated fatty acid. Its chemical formula is CH$ _3$(CH$ _2$)$ _{14}$COOH. Meat, cheese and diary products are the main source of the palmitic acid. It was first discovered in saponified palm oil. Excess carbohydrate in the body is converted into palmitic acid. 

b) Lecithin is an essential phospholipid which is present in the body. It is composed of choline, fatty acids, glycerol, glycolipids, phospholipids, phosphoric acid and triglycerides.
c) Tryptophan is a aromatic amino acid which acts as a precursor to the neurotransmitter. It helps in biosynthesis of proteins. It also helps in the synthesis of niacin and auxin.
d) Glutamic acid is an acidic amino acid which acts as a important neurotransmitter.
So, the correct answer is option B.