Question 1

Which of the following statements best describes the main structural 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

Which of the following is a major ecological significance of prokaryotes?

Accepted Answer

They recycle nutrients by decomposing organic matter and fixing nitrogen.

Question 3

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

Accepted Answer

Water will leave the cell, causing it to shrink.

Question 4

Which of the following best explains why carbon is able to form such a wide variety of macromolecules?

Accepted Answer

Carbon has four valence electrons, allowing it to form up to four covalent bonds.

Question 5

Which type of bond is primarily responsible for the unique properties of water, such as high surface tension and cohesion?

Accepted Answer

Hydrogen bonds

Question 6

A scientist observes that a protein loses its function when exposed to high temperatures. Which level of protein structure is most directly affected by this change?

Accepted Answer

Tertiary structure

Question 7

Which of the following is true about enzymes?

Accepted Answer

Enzymes lower the activation energy, speeding up chemical reactions.

Question 8

Which process describes the movement of molecules from an area of high concentration to an area of low concentration without the use of energy?

Accepted Answer

Simple diffusion

Question 9

Gram-positive and gram-negative bacteria differ in their cell wall structure. Which feature is unique to gram-negative bacteria?

Accepted Answer

An outer membrane containing lipopolysaccharides

Question 10

Which equation correctly represents the complementary base pairing in DNA?

Accepted Answer

$$A = T, \ C = G$$

Question 11

DNA replication is described as 'semi-conservative.' What does this mean?

Accepted Answer

Each new DNA molecule contains one old strand and one new strand.

Question 12

Which enzyme is responsible for synthesizing new DNA strands during replication?

Accepted Answer

DNA polymerase

Question 13

A mutation occurs in a gene coding for an enzyme. Which of the following is a possible consequence?

Accepted Answer

The enzyme may lose its ability to catalyze reactions.

Question 14

Which statement best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 15

Which of the following best describes the role of RNA polymerase in transcription?

Accepted Answer

It unwinds the DNA double helix and synthesizes a complementary RNA strand.

Question 16

The genetic code is described as 'redundant.' What does this mean?

Accepted Answer

Multiple codons can code for the same amino acid.

Question 17

Which of the following is NOT a function of prokaryotes in the human body?

Accepted Answer

Causing all infectious diseases

Question 18

Which of the following best describes facilitated diffusion across a cell membrane?

Accepted Answer

Movement of molecules through membrane proteins down their concentration gradient without energy input

Question 19

Which of the following is a real-world example of gene expression regulation?

Accepted Answer

Lactose intolerance due to lack of lactase enzyme production

Question 20

A patient is exposed to a chemical that damages DNA. Which cellular process is most likely to be affected first?

Accepted Answer

DNA replication

General Biology Study Notes: Cells, Macromolecules, Cell Membrane, DNA, and Genes (midterm)

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