Genetic Variations: Nondisjunction and Crossing Over

How do diploid and haploid cells differ?

• Diploid cells have two sets of chromosomes; haploid cells have one set.
• Diploid cells have one set of chromosomes; haploid cells have two sets.
• Diploid cells are produced by meiosis; haploid cells are produced by mitosis.
• Diploid cells are found in bacteria; haploid cells are found in plants.

Tags

NGSS.HS-LS3-2

Match the following diploid cell number to the correct haploid number.

• 28

• Human: 46

• 20

• Cat: 38

• 19

• Elephant: 56

• 23

• Mouse: 40

• 39

• Dog: 78

Tags

NGSS.HS-LS3-2

What is happening to the genetic information when a sperm and egg go through fertilization?

• The genetic information from the sperm and egg combines to form a zygote with a complete set of chromosomes.
• The sperm and egg remain separate and do not combine.
• The genetic information is destroyed during fertilization.
• Only the egg contributes genetic information to the zygote.

Tags

NGSS.HS-LS3-1

Match the type of cell to the examples of that category.

• Gametes

• Sex Cells

• skin, liver, nerve

• Sperm and Egg

• somatic cells

• Body cells

• sperm, egg

• Somatic Cells

Tags

NGSS.MS-LS3-2

How do the chromosome numbers of the parent cells and daughter cells compare after meiosis?

• The daughter cells have double the chromosome number of the parent cells.
• The daughter cells have half the chromosome number of the parent cells.
• The daughter cells have the same chromosome number as the parent cells.
• The daughter cells have a random chromosome number compared to the parent cells.

Tags

NGSS.HS-LS3-2

What is the role of crossing over during meiosis?

• To increase genetic diversity by exchanging DNA segments between homologous chromosomes

• To ensure chromosomes separate properly during anaphase

• To create identical gametes

• To prevent genetic disorders

What is nondisjunction and what can it lead to?

• A failure of chromosomes to separate properly during anaphase, leading to conditions like Down syndrome

• A successful separation of chromosomes during meiosis

• An exchange of DNA segments between homologous chromosomes

• A process that increases genetic diversity

During which phase of meiosis does crossing over occur?

• Prophase I

• Anaphase

• Metaphase

• Telophase

What characterizes Down syndrome in terms of chromosomes?

• An extra copy of chromosome 21

• A missing chromosome 21

• Normal number of chromosomes

• An extra copy of chromosome 18

What is the result of nondisjuction?

• Improved genetic diversity in populations.
• Higher likelihood of mutations in DNA.
• Abnormal number of chromosomes in gametes or resulting zygotes.
• Increased fertility in offspring.