Which of the following is an antibiotic produced by a bacterium? MCQ with Answer and Explanation

Which of the following is an antibiotic produced by a bacterium?
A. Griseofulvin
B. Streptomycin
C. Penicillin
D. Cephalosporin
Answer: Option B
Solution (By JKExamLibrary)
Streptomycin is an antibiotic produced by the bacterium Streptomyces griseus. Penicillin and cephalosporins are from fungi (Penicillium and Cephalosporium). Griseofulvin is a fungal antibiotic. Streptomycin is a broad-spectrum aminoglycoside, effective against gram-negative bacteria and Mycobacterium tuberculosis. It inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Biology Questions

Question #1
The organ that stores urine before excretion is the:
A. Kidney
B. Ureter
C. Urinary bladder
D. Urethra

Correct Answer: Option C


Explanation:
The urinary bladder is a muscular sac that temporarily stores urine received from the kidneys via the ureters, until micturition. The urethra drains urine to the exterior.

This question belongs to: Science Biology
Question #2
The 'Hormone Luteinizing Hormone' (LH) is secreted by the anterior pituitary. In females, the mid-cycle surge of LH directly triggers:
A. Ovulation and the formation of the corpus luteum
B. Menstruation
C. The thickening of the uterine lining
D. The growth of ovarian follicles

Correct Answer: Option A


Explanation:
Luteinizing Hormone (LH) is a gonadotropin secreted by the gonadotroph cells of the anterior pituitary. In females, during the late follicular phase, rising estrogen levels exert positive feedback on the pituitary, causing a massive, sudden surge of LH (the LH surge). This surge directly triggers ovulation (the rupture of the mature Graafian follicle and release of the secondary oocyte) and subsequently stimulates the remaining follicular cells to transform into the corpus luteum, which secretes progesterone.

This question belongs to: Science Biology
Question #3
The valve that prevents backflow from the right ventricle into the right atrium is the:
A. Tricuspid valve
B. Aortic valve
C. Bicuspid valve
D. Pulmonary valve

Correct Answer: Option A


Explanation:
The tricuspid valve (right atrioventricular valve) has three cusps and closes during ventricular systole to prevent regurgitation into the right atrium. The bicuspid (mitral) is on the left side. Aortic and pulmonary valves are semilunar valves at the ventricular outlets.

This question belongs to: Science Biology