Cell Functions

Help Questions

SAT Subject Test in Biology › Cell Functions

Questions 1 - 10
1

Which of the following organisms undergo photosynthesis?

I. Blue-green algae

II. Cyanobacteria

III. Ferns

I, II, and III

III only

I and III only

II and III only

I and II only

Explanation

While the photosynthetic process differs slightly among these organisms, cyanobacteria, algae, and ferns (along with all other plants) all undergo photosynthesis-the process of using sunlight to synthesize food from carbon dioxide and water.

2

Which of the following statements about the electron transport chain is true?

The electron transport chain is found on the inside of the inner mitochondrial membrane.

The electron transport chain is used to transport soluble proteins from one organelle to the next.

The electron transport chain uses glucose as its final electron acceptor.

The electron transport chain produces glucose as an energy source for the cell.

The electron transport chain is found only in plants.

Explanation

The electron transport chain is found on the inside of the inner mitochondrial membrane. It is not used to transport proteins; instead, it generates ATP to be used as an energy source by the cell. The electron transport chain is found in plants and animals (though the one found in plants operates very differently than the one found in animals). Oxygen is the final electron acceptor, not glucose.

3

Which of the following types of transport require ATP?

The Na+/K+ pump releasing 3 sodium ions outside of the cell and 2 potassium ions into the cell

Glucose moving into the cell, down its concentration gradient, through a channel

Water moving from an area of low solute concentration to an area of high solute concentration

Water moving down its concentration gradient through an aquaporin

Sodium ions moving from an area of high concentration to an area of low concentration through a voltage-gated sodium channel

Explanation

The Na+/K+ pump is active transport and therefore requires ATP. Since the pump is moving ions against its concentration gradient, it requires ATP to change the conformation of the pump to release the ions. All of the other forms of transport are either diffusion (moving down its concentration gradient) or facilitated diffusion (moving down its concentration gradient with the help of a channel or carrier).

Good tip: Pumps are used for active transport while carrier proteins or channels are used for facilitated diffusion which is a type of passive transport.

4

For each molecule of glucose, how many ATP are produced by the Citric Acid Cycle?

2 ATP

1 ATP

4 ATP

3 ATP

6 ATP

Explanation

Each molecule of glucose produces 2 pyruvate molecules. Each of these pyruvate molecules go through the citric acid cycle and produce 1 ATP each, resulting in 2 ATP total.

5

Each of the following is a step in mitosis EXCEPT __________.

homologous pairs separate and are pulled toward opposite poles of the cell

chromosomes condense

sister chromatids separate and are pulled toward opposite poles of the cell

the cytoplasm divides into two daughter cells

spindle fibers shorten

Explanation

There are no homologous pairs in mitosis. Mitosis has sister chromatids that separate and result in two identical daughter cells. Meiosis has homologous pairs because it occurs in sex cells and has one chromosome from the father and the other from the mother. These chromosomes pair up in Metaphase I and then separate in Anaphase I. Mitosis occurs in somatic cells so there is only one chromosome made up of two sister chromatids that separate during Anaphase.

6

When cells send a signal, it is often in the form of a secreted molecule. In some cases, a cell will secrete a molecule that binds to a receptor on its own cell surface. What type of signaling is this?

Autocrine

Paracrine

Endocrine

Exocrine

Explanation

When a molecule binds to a receptor on a cell surface, it means that a signal has been received by that cell. In this case, the cell that sent the signal is the same cell that is receiving the signal. Autocrine signaling is the term that describes a cell sending a signal to itself ("auto" in this context means self). Exocrine signaling occurs when a substance is secreted through a gland or duct. Endocrine signaling occurs when a substance is secreted into the bloodstream. Paracrine signaling occurs when a cell sends a signal to nearby cells (often to change the behavior or properties of those cells).

7

Which of the following organisms undergo photosynthesis?

I. Blue-green algae

II. Cyanobacteria

III. Ferns

I, II, and III

III only

I and III only

II and III only

I and II only

Explanation

While the photosynthetic process differs slightly among these organisms, cyanobacteria, algae, and ferns (along with all other plants) all undergo photosynthesis-the process of using sunlight to synthesize food from carbon dioxide and water.

8

With regards to mitosis, which checkpoint is considered the most important?

G1

G2

S

M

G0

Explanation

G1 is considered to be the most important checkpoint in the cell cycle. G1 precedes S and G2, so it decides if the cell is ready to commit the resources to go through the S phase, G2 phase, M phase, and then finally division. S is crucial for the replication of cellular materials and the duplication of DNA, but if the cell cannot pass G1, then it will never reach S phase.

9

When cells send a signal, it is often in the form of a secreted molecule. In some cases, a cell will secrete a molecule that binds to a receptor on its own cell surface. What type of signaling is this?

Autocrine

Paracrine

Endocrine

Exocrine

Explanation

When a molecule binds to a receptor on a cell surface, it means that a signal has been received by that cell. In this case, the cell that sent the signal is the same cell that is receiving the signal. Autocrine signaling is the term that describes a cell sending a signal to itself ("auto" in this context means self). Exocrine signaling occurs when a substance is secreted through a gland or duct. Endocrine signaling occurs when a substance is secreted into the bloodstream. Paracrine signaling occurs when a cell sends a signal to nearby cells (often to change the behavior or properties of those cells).

10

For each molecule of glucose, how many ATP are produced by the Citric Acid Cycle?

2 ATP

1 ATP

4 ATP

3 ATP

6 ATP

Explanation

Each molecule of glucose produces 2 pyruvate molecules. Each of these pyruvate molecules go through the citric acid cycle and produce 1 ATP each, resulting in 2 ATP total.

Page 1 of 4
Return to subject