Meiosis Flashcards

1
Q

TRUE OR FALSE: An unequal number of chromosomes come from the male and female parents. (32 male, 14 female)

A

FALSE: An equal number of chromosomes come from the male and female parents (23 each).

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2
Q

What are homologous chromosomes?

A

Chromosomes that come from the male and female parent (23 from each) - they are homologous because they match up when they get together in the daughter cell

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3
Q

Each male chromosome has a ____________ chromosome from the female parent.

A

corresponding

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4
Q

What are diploid cells?

A

Cells that contain both sets of chromosomes. Contain 2 complete sets of inherited chromosomes, and 2 complete sets of genes

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5
Q

What do diploid cells contain?

A

2 complete sets of inherited chromosomes, and 2 complete sets of genes

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6
Q

What letter if used to represent the diploid number of chromosomes?

A

N

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7
Q

What are haploid cells?

A

Cells with only a single set of chromosomes, and therefore a single set of genes.

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8
Q

What do haploid cells contain?

A

A single set of chromosomes; a single set of genes

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9
Q

When are cells haploid in meiosis?

A

They are haploid starting telophase 1, and all the way until the end of meiosis

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10
Q

What is meiosis?

A

The process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

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11
Q

How many parts does meiosis have (how many times does PMAT happen)?

A

2 parts (goes through PMAT two times)

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12
Q

What are the phases of meiosis 1 (list)?

A
  1. Prophase 1
  2. Metaphase 1
  3. Anaphase 1
  4. Telophase 1
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13
Q

What are the phases of meiosis 2 (list)?

A
  1. Prophase 2
  2. Metaphase 2
  3. Anaphase 2
  4. Telophase 2
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14
Q

What occurs after meiosis is over?

A

Fertilization

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15
Q

What happens during prophase 1?

A

The chromosomes pair up in a structure called the tetrad, which contains 2 chromosomes. As the tetrads are formed, the homologous chromosomes undergo a process called “crossing over”.

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15
Q

What occurs prior to meiosis 1, but doesn’t occur again before meiosis 2?

A

Interphase (replication specifically)

15
Q

What is a tetrad?

A

A structure formed when chromosomes pair up in prophase 1. In this structure, 2 chromosomes (aka 4 chromatids) pair up.

15
Q

Describe the process of crossing over

A
  1. The chromatids of the homologous chromosome cross over one another
  2. The crossed-over sections (which contain alleles) are exchanged
  3. New combinations of alleles are produced
16
Q

What is the result of crossing over?

A

New combinations of alleles are produced (genetic variety)

17
Q

When does crossing over occur in meiosis?

A

It occurs in prophase 1

18
Q

What happens during metaphase 1?

A

Spindle fibers form and attach to each tetrad. Paired homologous chromosomes line up across the center of the cell.

19
Q

What happens during anaphase 1?

A

As the cell moves into anaphase 1, the homologous pairs of chromosomes separate. Spindle fibers pull each homologous chromosome pair toward opposite ends of the cell.

20
Q

What happens during telophase 1?

A

The separated chromosomes cluster at the opposite ends of the cell. A nuclear membrane forms around each cluster of chromosomes. Following telophase 1, in cytokenesis, the cell divides into 2 daughter cells

21
Q

Are the cells at the end of meiosis 1 haploid or diploid?

A

Haploid

22
Q

What is the result of meiosis 1?

A

2 daughter cells, haploid, genetically unique

23
Q

Does interphase occur before meiosis 2?

A

no

24
Q

What happens during prophase 2?

A

The cell’s chromatids (2 in each cell) become visible. The chromosomes DO NOT pair to form tetrads, because the homologous pairs were already separated during meiosis 1.

25
Q

TRUE OR FALSE: tetrads aren’t formed during meiosis 2

A

TRUE: The chromosomes DO NOT pair to form tetrads during prophase 2, because the homologous pairs were already separated during meiosis 1.

26
Q

What happens during metaphase 2?

A

Chromosomes line up in the center of the cell

27
Q

What happens during anaphase 2?

A

The paired chromosomes separate

28
Q

What happens during telophase 2?

A

The nuclear envelope forms; during cytokenesis, the cells divide

29
Q

What is the result of meiosis 2?

A

The result of meiosis 2 is 4 haploid daughter cells

30
Q

What are gametes?

A

The haploid cells produced by meiosis 2; important to heredity

31
Q

What are the gametes in males called?

A

sperm

32
Q

What is the egg in females called?

A

oocyte

33
Q

What occurs after meiosis is done? What does that result in?

A

Fertilization occurs after meiosis is done. A sperm attaches to the oocyte, and the chromosomes of each cell are matched. This results in the zygote

34
Q

What is a zygote?

A

The cell that is created after an egg is fertilized

35
Q

What are some differences between meiosis and mitosis?

A

Meiosis: Mitosis:
Genetically unique Genetically identical
Creates reproductive cells Creates other cells
Goes through PMAT 2x Goes through PMAT 1x
Changes the # of Doesn’t change the
chromosomes # of chromosomes
in the original cell in the original cell

36
Q

What is the result of meiosis in male and female organisms?

A

4 sperm cells in males; 1 egg (oocyte) and 3 polar bodies in females