SAT II Biology M : Cell Biology

Study concepts, example questions & explanations for SAT II Biology M

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Example Questions

Example Question #11 : Cell Biology

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

Possible Answers:

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

The electron transport chain is found only in plants.

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

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

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

Correct answer:

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

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.

Example Question #12 : Cell Biology

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?

Possible Answers:

Autocrine

Exocrine

Endocrine

Paracrine

Correct answer:

Autocrine

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).

Example Question #13 : Cell Biology

Which of the following organisms undergo photosynthesis? 

I. Blue-green algae

II. Cyanobacteria

III. Ferns

 

Possible Answers:

I and II only

III only

I, II, and III

I and III only

II and III only

Correct answer:

I, II, and III

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.

Example Question #14 : Cell Biology

1. Chromosomes begin to condense

2. Centrioles separate and begin to form a mitotic spindle as they move towards opposite sides of the cell

3. The nucleolus breaks down

During which phase of cell division do the given processes occur?

Possible Answers:

Anaphase

Prophase

Interphase

Metaphase

Telophase

Correct answer:

Prophase

Explanation:

During prophase, the cell will begin to condense its chromosomes to prepare for separation during anaphase. The pair of centrioles in the cell will also separate and begin to move towards opposite ends of the cell, while remaining attached to each chromosome by a microtubule. These fibers form the mitotic spindle, which organizes and repositions the chromosomes during cell division. During this phase, the nuclear envelope and nucleolus also break down and disappear.

Example Question #1 : Mitosis And Meiosis

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

Possible Answers:

spindle fibers shorten

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

the cytoplasm divides into two daughter cells

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

chromosomes condense

Correct answer:

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

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. 

Example Question #1 : Mitosis And Meiosis

During which phase of meiosis does crossing over occur?

Possible Answers:

Prophase II

Anaphase II

Metaphase I

Prophase I

Anaphase I

Correct answer:

Prophase I

Explanation:

Crossing over occurs during Prophase I. During Prophase I, chromatin condenses and homologous chromosomes come together to form a tetrad. At this point, sometimes pieces of the chromatids within the chromosomes break off and exchange DNA. This process is known as "crossing over." This cannot occur in Prophase II because there are no homologous chromosomes in this stage, and therefore there isn't any different DNA to exchange.

Example Question #2 : Mitosis And Meiosis

During which of the following phases of the cell cycle do chromosomes align in the middle of the cell?

Possible Answers:

S

Telophase

Anaphase

G2

Metaphase

Correct answer:

Metaphase

Explanation:

The correct answer is "metaphase." The chromosomes are each attached to spindle fibers at the centromere. When the chromosomes align along the middle of the cell (often called the "metaphase plate"), the cell is in metaphase. Metaphase occurs after prophase (during which the cell grows and replicates its DNA) but before anaphase (when the chromosomes are pulled by spindle fibers to opposite ends of the cell).

Example Question #3 : Mitosis And Meiosis

A new organism from Mars has been discovered, and its genome has . Although these organisms are fluorescent green, their cells undergo meiosis and mitosis in the exact same way that human cells do. 

After one of these cells undergoes meiosis, how many chromosomes will it have?

Possible Answers:

Correct answer:

Explanation:

A somatic (body) cell is always diploid, meaning that it has  chromosomes. When a cell undergoes meiosis, the number of chromosomes in each daughter cell will be half the number in the original parent cell. Each daughter cell produced from meiosis will be haploid, meaning that it will have  chromosomes. 

Example Question #4 : Mitosis And Meiosis

A new organism from Mars has been discovered, and its genome has . Although these organisms are fluorescent green, their cells undergo meiosis and mitosis in the exact same way that human cells do.

After one of these cells undergoes mitosis, how many chromosomes will it have?

Possible Answers:

Correct answer:

Explanation:

A somatic (body) cell is always diploid, meaning that it has  chromosomes. When a cell undergoes mitosis, the number of chromosomes in each daughter cell is the same as the number of chromosomes in the original parent cell. Each daughter cell produced from mitosis is diploid, meaning that it will have  (in this case ) chromosomes.

Example Question #15 : Cell Biology

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

Possible Answers:

M

S

G1

G0

G2

Correct answer:

G1

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.

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