Meiosis Flashcards

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Questions and Answers

What are somatic cells? Are they haploid or diploid?

Somatic cells are all cells other than sex cells. They are diploid because they have 2 copies of each chromosome.

What are gametes? Are they haploid or diploid?

Gametes are sex cells (eggs and sperm) and they are haploid.

Define haploid. Define diploid.

Haploid cells have one set of chromosomes, while diploid cells have 2 copies of each chromosome.

Compare and contrast asexual and sexual reproduction. Be sure to reference mitosis and meiosis.

Asexual reproduction produces identical daughter cells through mitosis, while sexual reproduction involves meiosis to create genetically unique organisms. Signup and view all the answers

What are homologous chromosomes?

Homologous chromosomes are pairs comprising one chromosome from each parent. Signup and view all the answers

Why must sex cells undergo two successive divisions? Use the words diploid and haploid in your response.

Sex cells undergo two divisions to separate homologous pairs and chromatids, transitioning from diploid to haploid state. Signup and view all the answers

Explain why it is important for gametes to be haploid.

If gametes were diploid, the zygote would have twice the normal number of chromosomes. Signup and view all the answers

Human somatic cells (body cells) contain 46 chromosomes. How many chromosomes would be in a sperm cell? Is a sperm cell haploid or diploid?

A sperm cell has 23 chromosomes and it is haploid. Signup and view all the answers

Human somatic cells (body cells) contain 46 chromosomes. How many chromosomes would be in a human zygote? Is a zygote haploid or diploid?

A zygote has 46 chromosomes and it is diploid. Signup and view all the answers

What structures separate in Anaphase 1? What structures separate in Anaphase 2?

In Anaphase 1, homologous chromosomes separate; in Anaphase 2, sister chromatids separate. Signup and view all the answers

When does crossing over occur? What is the purpose of crossing over?

Crossing over occurs in Prophase 1 to increase genetic variation. Signup and view all the answers

Compare and contrast the end products of meiosis 1 and meiosis 2.

Meiosis 1 results in 2 haploid cells with replicated chromosomes; meiosis 2 results in 4 haploid cells with un-replicated chromosomes. Signup and view all the answers

Define the terms spermatogenesis and oogenesis. How do spermatogenesis and oogenesis relate to meiosis?

Spermatogenesis is the formation of sperm, and oogenesis is the development of egg cells. Both processes occur via meiosis. Signup and view all the answers

Compare and contrast mitosis and meiosis.

Mitosis is a diploid, asexual process; meiosis is haploid and sexual. Signup and view all the answers

What is the function of mitosis?

To split somatic cells or create new cells. Signup and view all the answers

What is the function of meiosis?

To create sex cells. Signup and view all the answers

Location in the body for mitosis?

Mitosis occurs throughout the body in various tissues. Signup and view all the answers

Location in the body for meiosis?

Meiosis occurs in the testes and ovaries. Signup and view all the answers

Number and type of daughter cells for mitosis?

2 diploid daughter cells. Signup and view all the answers

Number and type of daughter cells for meiosis?

4 haploid daughter cells. Signup and view all the answers

Change in chromosome number for mitosis?

Stays the same. Signup and view all the answers

Change in chromosome number for meiosis?

Chromosome number is halved. Signup and view all the answers

Number of phases for mitosis?

One phase. Signup and view all the answers

Number of phases for meiosis?

Two phases. Signup and view all the answers

Number of cell divisions for mitosis?

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Number of cell divisions for meiosis?

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Difference in DNA between parent cell and daughter cell for mitosis?

Identical. Signup and view all the answers

Difference in DNA between parent cell and daughter cell for meiosis?

Genetic variation due to crossing over. Signup and view all the answers

What is nondisjunction?

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly. Signup and view all the answers

Study Notes

Somatic Cells and Gametes

Somatic cells are any cells apart from sex cells, formed through mitosis, and are diploid with two copies of each chromosome.
Gametes are sex cells (sperm and eggs) produced via meiosis and are haploid, containing only one set of chromosomes.

Chromosome Definitions

Haploid cells contain a single set of chromosomes, while diploid cells have two sets, one from each parent.

Reproductive Processes

Asexual reproduction involves mitosis, producing two identical daughter cells and results in no genetic variation.
Sexual reproduction begins with meiosis, providing genetic diversity through the creation of unique gametes.

Homologous Chromosomes

Homologous chromosomes consist of paired chromosomes from each parent that correspond to each other in terms of gene loci.

Division in Meiosis

Two successive divisions in meiosis are essential; homologous chromosomes separate in meiosis I, followed by sister chromatids separating in meiosis II.

Importance of Haploid Gametes

Gametes must be haploid; if diploid, the resulting zygote would have double the normal chromosome count, disrupting genetic stability.

Chromosome Count in Human Cells

Human sperm cells contain 23 chromosomes (haploid), while somatic cells contain 46 chromosomes (diploid).
A human zygote has 46 chromosomes, making it diploid.

Phases of Meiosis

In Anaphase I, homologous chromosomes move apart; in Anaphase II, sister chromatids separate.
Crossing over occurs in Prophase I, enhancing genetic variation by exchanging chromosome segments.

Meiosis Outcomes

Meiosis I results in two haploid daughter cells with replicated chromosomes, while meiosis II produces four haploid daughter cells, each with un-replicated chromosomes.

Reproductive Cell Formation

Spermatogenesis refers to sperm formation, and oogenesis refers to the development of eggs, both processes linked to meiosis.

Comparison of Mitosis and Meiosis

Mitosis is diploid and asexual, resulting in two identical daughter cells; meiosis is haploid and sexual, producing four genetically varied daughter cells.
Both start with DNA replication, but mitosis completes in one round and meiosis in two.

Functions of Cellular Division

The function of mitosis is to generate new somatic cells, while meiosis's function is to create gametes.

Locations of Cell Division

Mitosis occurs throughout the body, while meiosis is limited to reproductive organs (testes and ovaries).

Daughter Cell Characteristics

Mitosis results in 2 diploid daughter cells, maintaining the original chromosome number.
Meiosis produces 4 haploid daughter cells, halving the chromosome number from the parent cell.

Phases and Divisions in Mitosis and Meiosis

Mitosis comprises one phase and involves one cell division; meiosis involves two phases and two cell divisions.

DNA in Daughter Cells

Mitosis yields daughter cells with identical DNA to the parent cell, while meiosis results in genetic variation due to crossing over.

Nondisjunction

Nondisjunction refers to the failure of homologous chromosomes or sister chromatids to separate during meiosis, potentially leading to conditions such as Down syndrome due to abnormal chromosome numbers.

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Description

Test your knowledge on meiosis with these flashcards. Learn about somatic cells, gametes, and their chromosome composition. Perfect for students aiming to understand cell division and reproductive biology.