L17: Meiotic Cell Division & Sexual Life Cycle

Question 1

Does meiotic cell division produce genetically identical or genetically unique daughter cells?

Answer 1

• genetically unique daughter cells

Question 2

During meiosis how do the daughter cells compare to the parent cell in regards to the number of sets of genes/chromosomes?

Answer 2

• they’re only gonna contain one set of chromosomes instead of 2

Question 3

How many daughter cells are produced? Are they diploid or haploid?

Answer 3

• 4 haploid daughter cells

Question 4

What do the terms diploid and haploid mean?

Answer 4

• diploid means two set of chromosomes coming from each parent and haploid is only one set

Question 5

Which role in your body does meiosis serve?

Answer 5

• to produce gametes for reproduction

Question 6

Which is the only cell type in your body to undergo meiosis?

Answer 6

• ovary and teste germ cells

Question 7

What do daughter cells of meiosis become?

Answer 7

• gametes, sperm/egg

Question 8

Can daughter cells of meiosis divide into new cells?

Answer 8

• no because gametes can’t divide

Question 9

How does meiotic cell division fit into the animal life cycle?

Answer 9

• reproduction and genetic variation

Question 10

How many chromosomes are found in human diploid cells and haploid cells?

Answer 10

• 46 chromosomes in diploid and 23 in haploid

Question 11

What is accomplished during meiosis 1?

Answer 11

• segregate homologous pairs into 2 separate daughter cells

Question 12

What is accomplished during meiosis 2?

Answer 12

• separate chromatids into 4 daughter cells

Question 13

What is a homologue?

Answer 13

• a pair of chromosomes with similar genetic information but not identical

Question 14

Do germ cells have homologues?

Answer 14

• yes because they’re diploid

Question 15

Do gametes have homologues?

Answer 15

• no since they’re haploid

Question 16

What happens during fertilization?
What does fertilization accomplish?

Answer 16

• A sperm and egg gamete combine to restore diploidy and reform new homologous pairs in a bigger cell now called a zygote

Question 17

What is the biological significance of sexual reproduction (meiosis + fertilization)?

Answer 17

• Unique offspring are more likely to survive than clones. sex—> population variation —> adaptation to change

Question 18

What is a homologue? What is a gene locus? What are alleles?

Answer 18

homologue - pair of chromosomes that are similar in genetic information but not identical
gene locus - the location of a gene on a chromosome
alleles - a variant or alternative form of a gene

Question 19

How many gene loci do human cells have? How many homologues due human cells have?

Answer 19

estimated that humans have between 20,000 and 25,000 genes

23 homologue pairs

Question 20

How many alleles per gene locus do human diploid cells possess (at least for autosomes)? Different alleles of a gene locus would be expected to express as different __________________ of a trait.

Answer 20

two alleles at each genetic locus, with one allele inherited from each parent

Different alleles of a gene locus would be expected to express as different VARIATIONS of a trait.

Question 21

What happens in a germ cell dividing by meiosis according to Mendel’s Law of Segregation?

Answer 21

Because the alleles at different gene loci vary on homologous chromosomes, segregating them results in unique cells.
each cell inherits at least one copy of each allele (dominant or recessive)

Question 22

What happens in a germ cell dividing by meiosis according to Mendel’s Law of Independent Assortment?

Answer 22

chromosomes align or arrange themselves in random possible ways along the metaphase plate and migrate randomly towards each pole.

Question 23

What happens during allele cross-over? When dos allele cross-over occur? How does allele cross-over impact the genetic diversity of meiotic daughter cells (gametes)?

Answer 23

Allele cross-over may occur: alleles exchanged among synapsed chromosomes during homologue synapsid (meiosis 1)
generates genetic variation

Question 24

Random homologue orientation prior to segregation is random and independent for each homologue. How does the independent assortment of homologous chromosomes/alleles impact the genetic diversity of meiotic daughter cells (gametes)?

Answer 24

increase in variation

Question 25

You were given a math formula for determining the number of unique combinations of maternal/paternal chromosome combinations in gamete cells due to independent assortment. If you are given the number of homologues found in a germ cell, can you use the formula to determine the number of unique gametes that can be produced via meiosis?

Answer 25

2^number of homologues

ex: fruit flies have 4 homologue pairs
2^4 = 16 homologue pairs