Question

7 multiple choice 10 points
human body cells each have 46 chromosomes in their nuclei. meiosis is necessary in order to ensure that each gamete produced in the human body has -
46 chromosomes
92 chromosomes
23 chromosomes
12 chromosomes
8 multiple choice 10 points
when chromosomes do not separate correctly, this is known as
independent assortment
crossing over
nondisjunction
recombinant genes

Explanation:

• Question 7: Meiosis is a type of cell division that reduces the chromosome number by half. Human body cells (somatic cells) are diploid (\(2n = 46\)). Gametes (sperm and egg) are haploid. Through meiosis, the chromosome number is halved so that when sperm and egg fuse during fertilization, the resulting zygote has the correct diploid number (\(2n=46\)).
• Question 8:
• Independent assortment: Refers to the random distribution of homologous chromosome pairs during meiosis I.
• Crossing - over: Occurs when homologous chromosomes exchange genetic material during prophase I of meiosis.
• Nondisjunction: Is the failure of chromosomes to separate properly during anaphase (either in meiosis I or meiosis II). This can lead to gametes with an abnormal number of chromosomes.
• Recombinant genes: Are the result of crossing - over, where new combinations of genes are formed on chromosomes.

Answer:

• Question 7: C. 23 chromosomes
• Question 8: C. nondisjunction