SAT II Biology M : Mitosis and Meiosis

圣udy concepts, example questions & explanations for SAT II Biology M

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Example Questions

Example Question #1 :Cell Functions

Each of the following is a step in mitosisEXCEPT__________.

Possible Answers:

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

spindle fibers shorten

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:

Anaphase II

Prophase II

Prophase I

Metaphase 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 #11 :Sat Subject Test In Biology

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

Possible Answers:

Metaphase

Telophase

Anaphase

G2

S

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 #1 :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 haschromosomes. 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 havechromosomes.

Example Question #1 :Cell Functions

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 haschromosomes. 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.

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