Question 1

Which of the following statements best describes the cell theory as it applies to all living organisms?

Accepted Answer

All organisms consist of one or more cells, and all cells arise only from pre-existing cells.

Question 2

Carbon is a key element in biological molecules. Which property of carbon allows it to form large, complex molecules essential for life?

Accepted Answer

Its ability to form up to four covalent bonds with other atoms.

Question 3

Which of the following is a correct example of a covalent bond in biological molecules?

Accepted Answer

The bond between two hydrogen atoms in a hydrogen molecule ($$H_2).$$

Question 4

Hydrocarbons are commonly found in cells. What is their primary chemical characteristic?

Accepted Answer

They consist only of carbon and hydrogen atoms and are generally nonpolar.

Question 5

Which of the following side groups is correctly matched with its chemical property?

Accepted Answer

Amino group: positively charged at physiological pH

Question 6

Water is essential for life due to its unique properties. Which property of water allows it to moderate temperature in living organisms?

Accepted Answer

High specific heat capacity ($$C = \frac{q}{m \Delta T})$$

Question 7

A phospholipid molecule is described as amphipathic. What does this mean?

Accepted Answer

It contains both hydrophobic and hydrophilic regions.

Question 8

Facilitated diffusion across a cell membrane requires which of the following?

Accepted Answer

A specific transport protein such as an aquaporin

Question 9

When biological organic compounds assemble into polymers, what type of reaction occurs?

Accepted Answer

Dehydration synthesis (condensation) reaction

Question 10

Which level of protein structure is primarily stabilized by hydrogen bonds between backbone atoms?

Accepted Answer

Secondary structure (e.g., alpha helices and beta sheets)

Question 11

Disulfide bonds in proteins are formed between which amino acid residues, and what is their primary function?

Accepted Answer

Between cysteine residues; to stabilize protein structure

Question 12

Which of the following is a covalent modification that can regulate protein function in the cell?

Accepted Answer

Addition of a methyl group to arginine ($$R-CH_3$)

Question 13

Which of the following statements about DNA structure is correct?

Accepted Answer

DNA is a double-stranded helix with complementary base pairing ($$A$$ pairs with $$T$$, $$G$$ pairs with $$C).$$

Question 14

Which of the following best explains why the DNA double helix is stable but can be separated during replication?

Accepted Answer

The hydrogen bonds between base pairs ($$A-T$$ and $$G-C) $$are strong enough to stabilize the helix but weak enough to be broken by helicase enzymes.

Question 15

Which of the following is a correct difference between RNA and DNA?

Accepted Answer

RNA contains uracil instead of thymine.

Question 16

Which of the following best describes a phosphodiester bond in nucleic acids?

Accepted Answer

A bond between the 3' hydroxyl group of one nucleotide and the 5' phosphate group of another nucleotide.

Question 17

Which of the following is a correct statement about monosaccharides and polysaccharides?

Accepted Answer

Polysaccharides are polymers made from monosaccharide monomers.

Question 18

Glycogen is stored in animal cells for which primary reason?

Accepted Answer

It serves as a readily available energy source.

Question 19

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids contain only single bonds; unsaturated fatty acids contain one or more double bonds.

Question 20

Which of the following statements about prokaryotes and eukaryotes is correct?

Accepted Answer

Eukaryotes have a nucleus, while prokaryotes do not.

Cell Biology Exam 1 Study Guide: Chemistry of the Cell, Macromolecules, and Cell Structure

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