SAT II Biology M : Mitosis and Meiosis
Study concepts, example questions & explanations for SAT II Biology M
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Example Questions
Example Question #3 : Cell Functions
Each of the following is a step in mitosis EXCEPT __________.
sister chromatids separate and are pulled toward opposite poles of the cell
spindle fibers shorten
homologous pairs separate and are pulled toward opposite poles of the cell
the cytoplasm divides into two daughter cells
chromosomes condense
homologous pairs separate and are pulled toward opposite poles of the cell
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 #4 : Cell Functions
During which phase of meiosis does crossing over occur?
Prophase II
Anaphase I
Prophase I
Anaphase II
Metaphase I
Prophase I
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 : Cell Functions
During which of the following phases of the cell cycle do chromosomes align in the middle of the cell?
G2
Metaphase
Anaphase
Telophase
S
Metaphase
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 : Cell Functions
A new organism from Mars has been discovered, and its genome has 
After one of these cells undergoes meiosis, how many chromosomes will it have?
A somatic (body) cell is always diploid, meaning that it has 
Example Question #4 : Cell Functions
A new organism from Mars has been discovered, and its genome has 
After one of these cells undergoes mitosis, how many chromosomes will it have?
A somatic (body) cell is always diploid, meaning that it has 
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