All Free Biology MCQs with Answers

4461. Actin and myosin are the basic proteins involved in contractile machinery of our body to which type of proteins do they belong?

• A. Globular proteins
• B. Intermediate protein
• C. Fibrous Proteins
• D. Integral protein

Explanation: Actin and myosin both have filament shape structure

4462. Minimum amount of energy is stored by:

• A. Lipids
• B. Proteins
• C. Nucleic acids
• D. Carbohydrates

Explanation: Nucleic acids are not used to synthesize ATP or store energy in any form.

4463. Which of these labels matches the structure of the partial RNA strand shown?

• A. I.Phosphate; II. Ribose; Ill. Nitrogenous base
• B. I. Phosphate; II. Nitrogen base; III. Ribose
• C. I. Nitrogenbase: II. Phosphate: III. Ribose
• D. I. Ribose: II. Nitrogen base; III. Phosphate

Explanation: Option D is correct, as Ribose: II. nitrogen base; III. Phosphate

4464. The RNA molecules mostly occur as a:

• A. Duplex
• B. Double stranded structure
• C. Single stranded structure
• D. Genetic material

Explanation: A single-stranded structure refers to a molecule that consists of only one chain of nucleotides or monomers, as opposed to the double-stranded structure where two complementary strands are paired together. The context in which "single-stranded" is used often pertains to nucleic acids, such as RNA (ribonucleic acid) or certain types of DNA.

4465. It comprises about 10 to 20% of the cellular RNA:

• A. mRNA
• B. tRNA
• C. rRNA
• D. snRNA

Explanation: Transfer RNA (tRNA) is a type of RNA (ribonucleic acid) molecule that plays a vital role in the process of protein synthesis within cells. tRNA acts as a translator between the nucleotide language of mRNA (messenger RNA) and the amino acid language of proteins. Its primary function is to bring the appropriate amino acids to the ribosome during protein synthesis.

4466. On the surface of _, the mRNA and tRNA interact to translate the information from genes into a specific protein.

• A. DNA
• B. Chromosome
• C. Ribosome
• D. Nucleosome

Explanation: A ribosome is a cellular structure that functions as the site of protein synthesis in both prokaryotic and eukaryotic cells. It plays a crucial role in translating genetic information from messenger RNA (mRNA) into functional proteins. Ribosomes are composed of two subunits, and they are typically found in the cytoplasm of the cell.

4467. Select the molecular formula of lactose.

• A. C11H22O11
• B. C12H22O11
• C. C12H24O12
• D. C11H24O12

Explanation: Option B is correct, as it is the correct molecular formula of lactose.

4468. Which one of the following has no free aldehyde or ketone group?

• A. Fructose
• B. Sucrose
• C. Maltose
• D. Galactose

Explanation: Sucrose is a common disaccharide, meaning it is composed of two monosaccharide sugar units. Specifically, sucrose is made up of one molecule of glucose and one molecule of fructose, joined together by a glycosidic bond. It is often referred to as table sugar and is the most widely used sugar in food and beverage production.

4469. Structural proteins are usually:

• A. Enzymatic
• B. Fibrous
• C. Soluble
• D. Globular

Explanation: Fibrous proteins are a class of proteins characterized by their elongated, thread-like structures. These proteins are often insoluble in water and play key roles in providing structural support and strength to cells and tissues. The structure of fibrous proteins is well-suited for their functions, and they are distinct from globular proteins, which have more compact, spherical shapes.

4470. Keratin and chitin are chemically:

• A. Carbohydrates and are functionally similar
• B. Carbohydrates but functionally different
• C. Proteins and functionally similar
• D. Different but functionally similar

Explanation: Keratin and chitin are chemically different but functionally similar.