Movement of any molecule through a protein channel

Movement of solutes from lower to higher concentration using ATP

Uptake of liquid droplets by vesicles

MDCAT Biology MCQs with Answers – All 16 Units – Page 6

Question 101 Cell Structure and Function

In the fluid mosaic model, what does the word ‘mosaic’ refer to?

Correct answer B. Proteins scattered among the phospholipid molecules

Open question

Question 102 Cell Structure and Function

What is the main role of cholesterol in animal cell membranes?

Correct answer D. Regulating membrane fluidity and stability

Open question

Question 103 Cell Structure and Function

Which membrane components act mainly in cell-to-cell recognition?

Correct answer A. Glycoproteins and glycolipids

Open question

Question 104 Cell Structure and Function

Which substance crosses the phospholipid bilayer most readily by simple diffusion?

Correct answer B. Oxygen

Open question

Question 105 Cell Structure and Function

Which feature distinguishes facilitated diffusion from active transport?

Correct answer A. Facilitated diffusion moves substances down a concentration gradient without using ATP

Open question

Question 106 Cell Structure and Function

For each ATP molecule used, how does the sodium-potassium pump move ions?

Correct answer D. 3 Na⁺ out of the cell and 2 K⁺ into the cell

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Question 107 Cell Structure and Function

What is osmosis?

Correct answer C. Net movement of water from higher water potential to lower water potential through a partially permeable membrane

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Question 108 Cell Structure and Function

What happens to red blood cells placed in distilled water?

Correct answer B. They swell and burst (haemolysis)

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Question 109 Cell Structure and Function

What is observed when a plant cell is placed in a concentrated salt solution?

Correct answer A. The protoplast shrinks away from the cell wall

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Question 110 Cell Structure and Function

What name is given to the uptake of solid particles into a cell by engulfing them in a vacuole?

Correct answer A. Phagocytosis

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Question 111 Cell Structure and Function

By which process do pancreatic cells release digestive enzymes?

Correct answer D. Exocytosis

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Question 112 Cell Structure and Function

What is the main function of rough endoplasmic reticulum?

Correct answer C. Synthesis and transport of proteins for secretion or membranes

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Question 113 Cell Structure and Function

Which function is carried out by smooth endoplasmic reticulum in liver cells?

Correct answer D. Detoxification of drugs and poisons

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Question 114 Cell Structure and Function

Which organelle forms the acrosome of a sperm cell?

Correct answer B. Golgi apparatus

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Question 115 Cell Structure and Function

Where in a mitochondrion does the electron transport chain operate?

Correct answer B. Inner membrane folded into cristae

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Question 116 Homeostasis

In which part of the nephron does ultrafiltration of blood take place?

Correct answer D. Glomerulus and Bowman's capsule

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Question 117 Homeostasis

Which structural feature mainly creates the high hydrostatic pressure in glomerular capillaries?

Correct answer C. The efferent arteriole is narrower than the afferent arteriole

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Question 118 Homeostasis

Which substance is normally absent from the glomerular filtrate of a healthy person?

Correct answer C. Plasma albumin

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Question 119 Homeostasis

In which region of the nephron are almost all filtered glucose and amino acids reabsorbed?

Correct answer C. Proximal convoluted tubule

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Question 120 Homeostasis

Which feature of proximal convoluted tubule cells best suits them for selective reabsorption?

Correct answer D. Microvilli and many mitochondria

Open question