The muscle type that is under voluntary control is:
A. Smooth muscle
B. Visceral muscle
C. Cardiac muscle
D. Skeletal muscle
Answer: Option D
Solution (By JKSSB Mock Tests)
Skeletal muscle, attached to bones, is striated and under conscious (voluntary) control. Smooth and cardiac muscles are involuntary. Skeletal muscles are responsible for locomotion and posture.
Explanation:
Ciliated pseudostratified columnar epithelium (with goblet cells) lines the trachea and bronchi; the cilia beat in coordinated waves to move mucus and trapped particles out of the airways. Squamous epithelium is flat (alveoli), cuboidal in kidney tubules, transitional in urinary bladder.
Consider statements about mitochondria: 1. They have a single membrane. 2. They contain their own circular DNA. 3. They are the site of aerobic respiration. Which are correct?
Explanation:
Mitochondria are double-membrane-bound organelles, possessing an outer smooth membrane and a highly folded inner membrane forming cristae. They contain their own circular DNA and 70S ribosomes, making them semi-autonomous. They are the primary site of aerobic respiration and ATP production. Statement 1 is incorrect as they have two membranes.
Explanation:
Smooth endoplasmic reticulum (SER) lacks ribosomes and is the site of lipid synthesis, including phospholipids and steroids. It also detoxifies drugs and poisons. Rough ER synthesizes proteins, Golgi modifies and packages molecules, lysosomes degrade waste. SER is abundant in cells producing steroid hormones.
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