Q: Which formula correctly represents the calculation of the net movement of molecules ($J$) across a membrane by facilitated diffusion?

$J = P \times (C_{out} - C_{in})$

Question 1

Which of the following statements best describes the difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have a nucleus surrounded by a membrane, whereas prokaryotic cells lack a true nucleus.

Question 2

A scientist is studying the plasma membrane's ability to act as a barrier. Which property of the membrane is most responsible for its selective permeability?

Accepted Answer

The amphipathic nature of phospholipids, with hydrophilic heads and hydrophobic tails.

Question 3

Which equation correctly represents the relationship between the rate of diffusion ($R$) and the concentration gradient ($\Delta C$) across a membrane?

Accepted Answer

$R = k 	imes \Delta C$

Question 4

Which of the following best explains why non-polar molecules can easily cross the plasma membrane, while ions cannot?

Accepted Answer

Non-polar molecules are compatible with the hydrophobic interior of the membrane, while ions are repelled due to their charge.

Question 5

A mutation causes a cell to produce fewer transport proteins in its plasma membrane. What is the most likely effect on the cell?

Accepted Answer

The cell will have reduced ability to transport specific molecules that require facilitated diffusion.

Question 6

Which of the following is a covalent bond found in proteins that helps stabilize their tertiary structure?

Accepted Answer

Disulfide bond ($S-S$)

Question 7

Given the abbreviated structural formula $NH_2-CH(R)-COOH$, what does the 'R' group represent in amino acids?

Accepted Answer

The variable side chain that determines the amino acid's properties.

Question 8

Which of the following best describes the process of gene expression in a eukaryotic cell?

Accepted Answer

DNA is transcribed into RNA in the nucleus, and RNA is translated into protein in the cytoplasm.

Question 9

Which of the following statements about phospholipids is correct?

Accepted Answer

Phospholipids form bilayers because their hydrophobic tails avoid water and hydrophilic heads interact with water.

Question 10

A cell is placed in a solution with a higher concentration of solutes than inside the cell. What will most likely happen to the cell?

Accepted Answer

Water will leave the cell, causing it to shrink.

Question 11

Which of the following is an example of a non-covalent interaction important in protein folding?

Accepted Answer

Hydrogen bonding between backbone atoms

Question 12

Which formula correctly represents the calculation of the net movement of molecules ($J$) across a membrane by facilitated diffusion?

Accepted Answer

$J = P 	imes (C_{out} - C_{in})$

Question 13

Which of the following best describes the role of functional groups in determining the properties of amino acids?

Accepted Answer

Functional groups attached to the R group of amino acids determine their polarity, charge, and reactivity.

Question 14

A protein is found to be denatured after exposure to high temperature. Which type of interaction is most likely disrupted?

Accepted Answer

Non-covalent interactions such as hydrogen bonds and hydrophobic interactions

Question 15

Which of the following is a correct statement about the relationship between structure and function in biological molecules?

Accepted Answer

The three-dimensional structure of a molecule determines its interactions and biological function.

Question 16

Which process requires energy input from the cell to move substances against their concentration gradient?

Accepted Answer

Active transport

Question 17

Which of the following is true about the directionality of membrane transport proteins?

Accepted Answer

Some transport proteins are uniporters, moving substances in one direction only.

Question 18

Which of the following best explains why water can cross the plasma membrane despite being polar?

Accepted Answer

Water crosses the membrane via specialized channel proteins called aquaporins.

Question 19

A researcher wants to predict the movement of ions across a cell membrane. Which factor is most important to consider?

Accepted Answer

The charge and concentration gradient of the ions

General Biology Study Guide: Cell Structure, Biochemistry, Membrane Transport, and Proteins

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