AP BIOLOGY

LABORATORY REVIEW

MITOSIS AND MEIOSIS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Why do the sex cells contain half the number of chromosomes are the organisms body cells?
A
Sex cells of 2 parents combine during reproduction to produce an offspring with a full set of chromosomes.
B
All organisms go through this process.
C
Sex cells are found in the reproductive organs.
D
When cells undergo meiosis, two sex cells are produced.
Explanation: 

Detailed explanation-1: -Gametes are reproductive cells, such as sperm and egg. As gametes are produced, the number of chromosomes must be reduced by half. Why? The zygote must contain genetic information from the mother and from the father, so the gametes must contain half of the chromosomes found in normal body cells.

Detailed explanation-2: -Because meiosis creates cells that are destined to become gametes (or reproductive cells), this reduction in chromosome number is critical-without it, the union of two gametes during fertilization would result in offspring with twice the normal number of chromosomes!

Detailed explanation-3: -Egg and sperm cells have just 23 chromosomes each. That’s half as many chromosomes as regular cells. Through the process of fertilization, egg and sperm join to make a cell with 46 chromosomes (23 pairs), called a zygote. For each chromosome pair, one homologous chromosome came from each parent.

Detailed explanation-4: -Answer and Explanation: It is important that human sperms and eggs have only 23 chromosomes because this way when fertilization occurs, it will form one full diploid cell, which will then divide via mitosis to form a full organism.

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