Biology Meiosis POGIL Flashcards

Questions and Answers

In what type of organs are the cells that enter meiosis I found?

The sex cells

What event must take place during interphase before a cell proceeds to division?

DNA replication

What two structures make up a single replicated chromosome?

Sister chromatids

How many replicated chromosomes does the cell contain during prophase?

Four Signup and view all the answers

At which stage in meiosis I do the pairs of homologous chromosomes come together?

Late prophase I Signup and view all the answers

Once the chromosomes have formed a pair, what are they called?

Tetrads Signup and view all the answers

How many replicated chromosomes are in each of the cells produced at the end of meiosis I?

Two Signup and view all the answers

Cells with a full set of chromosomes are referred to as , whereas cells with half the chromosomes are .

diploid, haploid Signup and view all the answers

At which stages of meiosis I are the cells diploid and at which stages are they haploid?

Haploid = Telophase I Signup and view all the answers

Which statement correctly describes the relationship between the cells at the end of telophase I and the original cell?

The new cells have two copies of half the genetic information in the original cell Signup and view all the answers

Will the cells at the end of telophase I be genetically identical to each other?

False Signup and view all the answers

Where did each of the cells come from that started meiosis II?

Meiosis I Signup and view all the answers

Which structures separate during anaphase I in meiosis I?

Homologous chromosomes Signup and view all the answers

Which structures separate during anaphase II in meiosis II?

Sister chromatids Signup and view all the answers

At the end of meiosis II, are the four daughter cells haploid or diploid?

Haploid Signup and view all the answers

Which statement describes the relationship between the cells at the end of meiosis II and the original cell?

The new cells have one copy of half of the genetic information in the original cell Signup and view all the answers

What is the name given to the cells produced at the end of meiosis I in males?

Spermocyte Signup and view all the answers

What is the name given to the cells produced at the end of meiosis I in females?

Secondary oocyte Signup and view all the answers

What cells are produced at the end of meiosis II in males?

Spermatids Signup and view all the answers

What do spermatids eventually become?

Mature sperm Signup and view all the answers

Before fertilization, what happens to the secondary oocyte?

Proceeds to meiosis II Signup and view all the answers

During fertilization, which two cells come together?

Mature sperm and secondary oocyte Signup and view all the answers

Why does the secondary oocyte divide unevenly during meiosis II?

To get the correct number of chromosomes, enough cytoplasm and organelles to ensure the survival of the zygote Signup and view all the answers

What is the ploidy of the zygote produced by fertilization?

Diploid Signup and view all the answers

What would the ploidy of the zygote be if egg and sperm were produced by mitosis?

Diploid with four sets of chromosomes Signup and view all the answers

Explain the origin of the chromosomes found in the zygote.

Half of the homologous pairs come from one parent and the other pair comes from another parent. Signup and view all the answers

At which stage of meiosis are the chromosomes in Model 4?

Prophase I Signup and view all the answers

What are the crossover points called when homologous chromosomes come together?

Chiasmata Signup and view all the answers

What happens to the chromatids during crossover?

They exchange pieces of chromosome (DNA) Signup and view all the answers

What phrase describes the chromatids after crossing over occurs?

Recombinant Signup and view all the answers

Are the genes on a recombinant chromatid the same as the original chromatid?

True Signup and view all the answers

Are the alleles on a recombinant chromatid the same as the original chromatid?

False Signup and view all the answers

Is either arrangement equally likely during the formation of tetrads in late prophase I?

Yes, it just depends on how the chromosomes pair up Signup and view all the answers

If there were three sets of homologous chromosomes, how many possible arrangements would there be for the tetrads?

8 possible arrangements Signup and view all the answers

Calculate the number of possible genetic combinations due to independent assortment.

8,388,608 Signup and view all the answers

Explain how meiotic events and random fertilization lead to genetic variation.

<ol> <li>Independent assortment causes mixing/scrambling of the homologous pairs. 2) Crossing over causes exchanges of alleles on homologous pairs. 3) Random fertilization unites different combinations of maternal and paternal chromosomes</li> </ol> Signup and view all the answers

Study Notes

Meiosis Overview

Meiosis occurs in sex cells (gametes).
DNA replication is necessary before cell division begins.
Replicated chromosomes consist of two sister chromatids.

Stages of Meiosis I

During prophase I, cells contain four replicated chromosomes.
Homologous chromosomes pair up in late prophase I, forming tetrads.
At the end of meiosis I, two cells are formed, each containing two replicated chromosomes.
Cells are diploid during prophase, metaphase, and anaphase, while they become haploid in telophase after splitting.
The relationship between telophase I cells and the original cell involves each having half the genetic information.

Genetic Variation

Homologous pairs at telophase I are not genetically identical because they carry different alleles for the same genes.
In meiosis II, homologous chromosomes separate first in anaphase I, followed by sister chromatids in anaphase II.
At the end of meiosis II, there are four haploid daughter cells, each with one set of chromosomes.

Male and Female Gamete Production

Males produce spermocyte at the end of meiosis I, which becomes spermatids after meiosis II.
Females yield secondary oocyte at the end of meiosis I, which can proceed to meiosis II.
The process of meiosis II in females results in one ovum and a polar body that degenerates.

Fertilization Process

Fertilization involves the fusion of a mature sperm and a secondary oocyte.
The resulting zygote is diploid, with half of its homologous pairs from each parent.

Impact of Mitosis on Ploidy

If gametes formed by mitosis, the zygote would be tetraploid (four sets of chromosomes).
Each subsequent generation would also double in ploidy.

Chromosomal Dynamics

Each zygote chromosome originates from a homologous pair, with contributions from both parents.
During prophase I, chromosomes may undergo crossing over at points called chiasmata, exchanging DNA segments.
Post-crossover chromatids are referred to as recombinant chromatids; they contain the same genes but potentially different alleles.

Independent Assortment

In late prophase I, chromosomes can arrange in various configurations, leading to multiple genetic combinations.
For three sets of homologous chromosomes, eight tetrad arrangements are possible.
Independent assortment during metaphase I results in 8,388,608 possible genetic combinations due to the orientation of chromosome pairs.

Genetic Variation Outcomes

Independent assortment mixes homologous chromosome pairs.
Crossing over creates new allele combinations.
Random fertilization brings together diverse maternal and paternal chromosomes, contributing to genetic diversity.

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Description

This quiz features flashcards focusing on meiosis, including the types of cells involved, key events in interphase, and the structure of chromosomes. Perfect for reinforcing understanding of meiosis in the context of cell biology. Test your knowledge and prepare for exams with these essential concepts!