Meiosis Stages - Difficult Problems Flashcards

Questions and Answers

Match each stage of the cell cycle to the corresponding amount of DNA contained within a cell at that stage.

Metaphase II = 7.3 pg Prophase I = 14.6 pg Telophase I before cytokinesis = 14.6 pg After cytokinesis of meiosis II = 3.7 pg G2 = 14.6 pg G1 = 7.3 pg

Select the reasons why meiosis typically produces genetic variation but mitosis does not.

Gametic chromosomes have a different combination of alleles than parental chromosomes as a result of independent assortment. (correct)

Meiosis produces four genetically different haploid cells. (correct)

Genetic material is exchanged between homologous chromosomes in meiosis during crossing over. (correct)

1n gametes produced in mitosis fuse to produce 2n cells in meiosis.

What fraction in the genome on the pairs of humans would be exactly the same if no crossing over took place? Father and child: ___, Mother and child: _, Full siblings: _, Half siblings: _, Uncle and niece: _, Grandparent and grandchild: ___

Father and child: ½, Mother and child: ½, Full siblings: ½, Half siblings: ¼, Uncle and niece: ¼, Grandparent and grandchild: ¼

How did Mendel use self-pollination and cross-pollination techniques in his experiments with flower color to observe the basic patterns of inheritance?

By cross-pollinating a parental generation of plants with different-colored flowers and allowing the F₁ generation to self-pollinate, Mendel observed the basic patterns of inheritance in the F₂ generation. Signup and view all the answers

What best explains the results of the geneticists' experiments involving obese mice?

The two obesity alleles are recessive to the wild-type alleles but are located at different loci. Signup and view all the answers

In certain salamanders, when a sex-reversed male is mated with a normal female, what is the sex of the offspring likely to be?

Females are the heterogametic sex. Signup and view all the answers

Study Notes

DNA Content in Meiosis Stages

Metaphase II: 7.3 picograms (pg) of DNA
Prophase I: 14.6 pg of DNA
Telophase I Before Cytokinesis: 14.6 pg of DNA
After Cytokinesis of Meiosis II: 3.7 pg of DNA
G2 Phase: 14.6 pg of DNA
G1 Phase: 7.3 pg of DNA

Meiosis vs. Mitosis

Meiosis typically results in genetic variation due to independent assortment of alleles.
Crossing over during meiosis allows for genetic material exchange between homologous chromosomes.
Meiosis produces four genetically distinct haploid cells, whereas mitosis produces identical diploid cells.

Classification of Cells

Haploid Cells: microspore, first polar body, spermatid, megaspore, ovum, secondary oocyte
Diploid Cells: primary spermatocyte, microsporocyte, oogonium, spermatogonium

Genetic Relationship Fractions

Father and Child: ½ shared genetic material
Mother and Child: ½ shared genetic material
Full Siblings: ½ shared genetic material
Half Siblings: ¼ shared genetic material
Uncle and Niece: ¼ shared genetic material
Grandparent and Grandchild: ¼ shared genetic material

Mendel's Experiments

Observed inheritance patterns by cross-pollinating parental plants with different-colored flowers and allowing self-pollination of the F₁ generation to analyze the F₂ generation.

Genetic Cross of Obese Mice

Obesity in mice results from a recessive allele.
F₁ mice are normal size; interbreeding produces normal and obese F₂ mice.
The cross of obese mice from different laboratories produces all normal offspring, indicating the presence of different obesity alleles.

Salamander Sex Determination

In certain salamanders, females can become functional males (sex-reversed males).
Breeding these males with normal females results in approximately 2/3 female and 1/3 male offspring.
Suggests that females are the heterogametic sex in this species.

Description

Test your knowledge on the different stages of meiosis and the corresponding DNA content in diploid cells. Match each stage, including metaphase II, prophase I, and telophase I, with the accurate DNA measurements. Perfect for exam preparation and revision of cell cycle concepts.