Question 1

Which statement best describes the Fluid Mosaic Model of biological membranes?

Accepted Answer

Membranes are fluid and consist of a mosaic of embedded proteins and lipids.

Question 2

A molecule moves from an area of high concentration to low concentration across a membrane without energy input. What process is this?

Accepted Answer

Passive transport (diffusion)

Question 3

Which of the following molecules can freely diffuse across the plasma membrane without the help of a protein?

Accepted Answer

Small nonpolar molecules such as $$\mathrm{O_2$}$$ and $$\mathrm{CO_2$}$$

Question 4

What is the main difference between integral and peripheral membrane proteins?

Accepted Answer

Integral proteins span the membrane, while peripheral proteins are attached to the membrane surface.

Question 5

Which type of membrane transport protein moves two molecules in opposite directions at the same time?

Accepted Answer

Antiporter

Question 6

During osmosis, water will always move from:

Accepted Answer

Hypotonic to hypertonic solutions

Question 7

A red blood cell placed in a hypotonic solution will:

Accepted Answer

Swell and possibly burst due to water entering the cell

Question 8

Which process requires energy input from ATP hydrolysis to move molecules against their concentration gradient?

Accepted Answer

Primary active transport

Question 9

The sodium-potassium pump ($$\mathrm{Na^+/K^+}$$ ATPase) moves sodium and potassium ions in which directions?

Accepted Answer

Sodium out of the cell, potassium into the cell

Question 10

Which statement about the laws of thermodynamics is correct?

Accepted Answer

The total amount of energy in the universe remains constant.

Question 11

Which of the following is an example of exocytosis?

Accepted Answer

A vesicle fusing with the cell membrane to release neurotransmitters

Question 12

What is the role of enzymes in chemical reactions?

Accepted Answer

Enzymes lower the activation energy barrier, speeding up reactions.

Question 13

Which factor can cause an enzyme to denature and lose its activity?

Accepted Answer

Extreme pH

Question 14

Competitive inhibitors affect enzyme activity by:

Accepted Answer

Binding to the active site and blocking substrate binding

Question 15

Which of the following best describes negative feedback in metabolic pathways?

Accepted Answer

The final product inhibits an earlier step in the pathway.

Question 16

Which statement about ATP hydrolysis is correct?

Accepted Answer

ATP hydrolysis releases energy by breaking a bond between phosphate groups.

Question 17

A cell is placed in a hypertonic solution. What will happen to the cell?

Accepted Answer

It will dehydrate and shrink as water leaves.

Question 18

Which of the following is true about exergonic reactions?

Accepted Answer

They release energy as products are formed.

Question 19

Which of the following best describes the role of coenzymes?

Accepted Answer

They are non-protein molecules that help enzymes catalyze reactions.

Question 20

A glucose molecule is transported into a cell against its concentration gradient using the energy from sodium ions moving down their gradient. What type of transport is this?

Accepted Answer

Secondary active transport (cotransport)

Cell Membranes, Transport, Energy, and Enzymes: Study Notes for General Biology

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