All Free Biology MCQs with Answers

• A. Menopause starts
• B. FSH secretion is increased
• C. Corpus luteum degenerates
• D. Progesterone secretion is increased

Explanation: Explanation:If fertilization does not take place corpus luteum degenerates and progesterone levels decrease leading to menstruation and…

• A. LH → FSH → Estrogen → Progesterone
• B. FSH → LH → Progesterone → Estrogen
• C. FSH → Estrogen → Progesterone → LH
• D. FSH → Estrogen → LH → Progesterone

Explanation: [A] FSH is produced in the start in menstrual cycle not LH[B] FSH stimulates the production of Estrogen[C] LH is produced first before…

• A. Ethylene
• B. Gonadotrophins
• C. Auxins
• D. Gibberellins

Explanation: Gonadotrophin hormones include FSH and LH, which are released by the pituitary gland under the influence of the hypothalamus.

• A. Somatotropin
• B. Luteinizing Hormone
• C. Testosterone
• D. Spermatogonium

Explanation: LH works with FSH to stimulate estrogen secretion and the rupture of mature follicles to release an egg or ovum.

• A. Uterus, posterior pituitary
• B. Ovaries, uterus
• C. Uterus, anterior pituitary
• D. Ovaries, hypothalamus

Explanation: Uterus: Estrogen enhances and maintains the mucous membrane that lines the uterus.

• A. Only by inhibition of Luteinizing Hormone.
• B. Inhibition of FSH & stimulation of LH.
• C. Inhibition of LH & stimulation of FSH.
• D. Inhibition of both FSH & LH.

Explanation: Luteinizing Hormone is the one which stimulates the ovulation of the follicle.

• A. Estrogen
• B. Progesterone
• C. Luteinizing hormone
• D. Follicle stimulating hormone

Explanation: Option A, estrogen, is the hormone that causes the development and thickening of the endometrial lining.Option B, progesterone, is the…

• A. Products
• B. Metabolites
• C. Substrates
• D. Catabolites

Explanation: Enzymes work by acting on substrates and converting them into products.

• A. Tetany.
• B. Muscle fatigue.
• C. Cramp.
• D. Sciatica.

Explanation: Tetany is the disease caused by low calcium in the blood

• A. I-band shortens
• B. Myosin filaments shorten
• C. Actin filaments shorten
• D. Z-line disappears

Explanation: Option [A] During muscle contraction the following things happen:I band shortensZ lines come closerH zone disappearsHENCE option [A] is…

• A. Sarcolemma
• B. Sarcoplasm
• C. Sarcomere
• D. Muscle fibre

Explanation: The region lying between two Z-bands is called a Sarcomere. Sarcomeres are the functional units of muscle contraction and are composed of…

• A. I-bands shorten
• B. H-zone becomes more visible
• C. Z-lines move further apart
• D. A-bands shorten

Explanation: According to the sliding filament theory, muscle contraction involves the sliding of thin actin filaments over thick myosin filaments…

• A. I-band shortens only
• B. A-band shortens and Z-lines move apart
• C. I-band shortens and Z-lines come close to each other
• D. Actin filament contracts

Explanation: The I- band is the region near the Z - disc where we only have the actin filament.

• A. Cross bridge formation
• B. Cross bridge breaking
• C. Dragging filaments
• D. Shortening of filaments

Explanation: ATP is needed for breaking the bridge between the myosin and the actin.

• A. Extreme fatigue
• B. Muscle contraction
• C. Paralysis
• D. Convulsion

Explanation: Extreme fatigue, or severe tiredness, is an overwhelming sense of exhaustion that isn't relieved by rest.

• A. Actin
• B. Myosin
• C. Tropomyosin
• D. Troponin

Explanation: The thick muscle filament is primarily composed of myosin proteins. In muscle fibers, thick filaments work together with thin filaments…

• A. Two I bands
• B. Two A bands
• C. Two M lines
• D. Two Z lines

Explanation: A sarcomere is the basic structural and functional unit of a muscle fiber, specifically within striated muscle such as skeletal and…

• A. Sarcomere
• B. Sarcolemma
• C. Twitch fibre
• D. Capsule

Explanation: Each muscle fiber is surrounded by the sarcolemma, which also contains the cytoplasm of the cell.

• A. ATP
• B. Creatine-PO4
• C. Myoglobin
• D. Creatinine-P04

Explanation: Creatine-PO4, also known as phosphocreatine, is a muscle component that acts as a store for energy.

• A. Multiple nuclei
• B. Multiple mitochondria
• C. Large amount of myoglobin
• D. Large amount of hemoglobin

Explanation: Skeletal muscle fibers in humans do not contain a large amount of hemoglobin.