Biology · Chemistry

Biomolecules and Enzymes

1,501 Questions

This topic focuses on biomolecules, specifically proteins, enzymes, and amino acids. It includes questions on enzyme structures, protein folding, and catalysis. These concepts are crucial for medical and biology competitive exams.

Enzyme catalysisProtein structuresAmino acid synthesisPolypeptide chainsBiomolecule properties

Biomolecules and Enzymes Questions

Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

Which of the following has higher surface area (SA) to volume (V) ratio?

  1. Red blood cell

  2. Nails

  3. DNA

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

Surface area to volume ratio increases as the size of an object decreases. DNA, being a molecular structure, has a significantly higher surface area to volume ratio compared to cellular structures like red blood cells or macroscopic objects like hair and nails.

Multiple choice biology plant kingdom and the environment around us some important plants uses of plants as medicine medicinal plants

Which one of the following pairs is NOT correctly matched?

  1. Neem - Azadirachtin

  2. PEG- Protoplast fusion

  3. Gybogenesis- Haploids
  4. Wheat- $2$-celled pollen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Wheat pollen is typically shed at a 3-celled stage, not a 2-celled stage, making option D incorrectly matched. The other pairs correctly associate neem with azadirachtin, PEG with protoplast fusion, and gynogenesis with haploids.

Multiple choice evs - i busy at work - our internal organs human lymphatic system lymph and its function lymph and tissue fluid

The major site of protein breakdown to form free amino acids is in the

  1. Kidney

  2. Spleen

  3. Liver

  4. Bone marrow
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
During the digestion of proteins, hydrochloric acid and proteolytic enzymes in the stomach break down the intact protein molecule into amino acids, which are then absorbed through the intestinal wall. Further breakdown of amino acids to form free amino acid like α-keto acids occurs in the liver by a process known as transamination. It occurs in liver.
Multiple choice biology biodiversity and classification monera five kingdoms of living organisms biodiversity and need of classification

Death factor is secreted by 

  1. BGA

  2. Archaebacteria

  3. Fungi

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

Cyanobacteria (Blue-green algae or BGA) sometimes reproduce exponentially to form blooms. Blooming cyanobacteria can secrete death factors in such concentrations that they poison and even kill animals and humans. It can also accumulate in other animals such as fish and shellfish and cause poisonings such as shellfish poisoning.

So, the correct answer is 'BGA'.

Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Bacteria are made up of

  1. Nucleic acid

  2. Only proteins

  3. Nucleic acid and Proteins

  4. Nucleosides

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Nucleic acids constitute the genetic material and help in cellular expressions in bacteria, while proteins are important for constitutive activities in the bacterial cells. 15% of bacterial cell is protein, while 7% nucleic acids (DNA and RNA).
So answer is -'nucleic acid and proteins'.

Multiple choice botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

All the following statements are true about exotoxins except 

  1. They are protein in nature.

  2. Are heat labile.

  3. Produced by Gram + positive bacteria.

  4. Are highly antigenic.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An exotoxin is a toxin secreted by bacteria. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. Exotoxin is secreted during lysis of the cell. 

Multiple choice evs production of food from animals dairy farm management cattle farming uses of animals contribution of louis pasteur discoveries by louis pasteur discovery of microorganisms

Casein is a protein present in milk. Which group of protein is associated with casein?

  1. Nucleoprotein

  2. Chromoprotein

  3. Phosphoprotein

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

  • A phosphoprotein are a group of conjugated proteins, like casein, in which the protein molecule is bound to phosphoric acid. 
  • Casein is a phosphoprotein. These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 20% and 45% of the proteins in human milk.

Therefore, the correct answer is option C.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of the following act as a local messenger?

  1. Carrier protein

  2. Glycoprotein

  3. Phospholipid

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

Messenger proteins (or signaling proteins) carry messages or signals. They provide a means by which cells in one part of the body communicate with cells in another location. In some cases, these proteins can carry a signal from one cellular location to another. The signals can trigger/modulate the immune response, promote cell development/differentiation, alter cell metabolism, or stimulate cell growth. Carrier proteins help specific molecules or ions pass through the plasma membrane. They do not extend through the membrane. They bond and drag the molecules through the bilipid layer and release them on the opposite side. 

Therefore, the correct answer is option A.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Insulin receptors are.

  1. Extrinsic proteins

  2. Intrinsic proteins

  3. G-proteins

  4. Trimeric proteins
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Insulin receptors are extrinsic proteins. They are made up of an alpha and a beta subunit that are held together by disulphide bonds. Insulin, which is a polypeptide hormone, binds to the extracellular face of the α-subunits.
Thus, the correct answer is 'Extrinsic proteins.'
Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of the following prevents the accumulation of product?

  1. Positive feedback inhibition

  2. Negative feedback inhibition

  3. Anticoagulation

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • A feedback mechanism for multistep reactions is a biological occurrence wherein the output of a system amplifies the system (positive feedback) or inhibits the system (negative feedback).
  • For example, Release of estrogen from the ovaries stimulates the secretion of GnRH from Hypothalamus which in turn stimulates the secretion of LH from anterior pituitary.when the levels of LH reaches above the normal levels in the blood it stimulates the release of progesterone from corpus luteum which causes the inhibition of the release of GnRH from the hypothalamus which in turn leads to inhibition of release of LH(product) from anterior pituitary and prevents the accumulation of LH(product)in blood. Hence negative feed back.
  • Hence Negative feedback inhibition prevents the accumulation of product.
  • So, the correct answer is 'Negative feedback inhibition'.