Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology 105 > Lectures 4-6 (Meiosis And Mitosis) > Flashcards

Lectures 4-6 (Meiosis And Mitosis) Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
0
Q

Homologous chromosomes

A

Matched chromosomes. Among two homologs of a chromosome, one is paternal the other is maternal. Homologs carry the same genes, but may have different alleles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Chromatin

A

DNA and protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Sister chromatids

A

These compose a chromosome when it replicates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Centromere

A

Holds together sister chromatids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Meta centric chromosome

A

Centromere located near the middle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Acrocentric chromosome

A

Centromere is toward one end or the other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

G1 (gap 1)

A

Cell growth, preparation for DNA replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

S (synthesis)

A

Chromosome duplication including DNA replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

G2(gap2)

A

Cell growth, preparation for mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

M(mitosis and cytokinesis)

A

Nuclear division and segregation if chromatids, cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

G0

A

Cells that are not actively growing or dividing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Prometaphase

A

Nuclear envelope breaks down. Kinetochore micro tubules attach to centromeres. Complex of micro tubules from centrosome forms the mitotic spindle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Prophase

A

Chromosomes condense dramatically. Sister chromatids are attached. Centrosomes move apart toward opposite sides of the nucleus. Nucleoli, sites of ribosome production, begin to disappear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Metaphase

A

Chromosome align in the metaphase plate at equator of the cell. Sister chromatids are attached but kinetochore to opposite poles of the mitotic spindle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Anaphase

A

Centromeric connections between sister chromatids are severed. Kinetochore micro tubules shorten.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Telophase

A

Each chromatid is now considered a chromosome. Chromosomes decondense. A nuclear envelope forms around each set of chromosomes. Nucleoli reappear. Spindle micro tubules disperse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Cytokinesis

A

Initiated during anaphase. Completed after telophase. Cytoplasm divided between two daughter cells. Results in two daughter cells with identical genetic information.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Animals vs plants in cytokinesis

A

In animals a contractile ring forms and forms a cleavage furrow, cell is cleaved in two. In plants a cell plate forms near the equator of cell. Starts in the middle and grows outward. Cell is divided into two. W

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Syncytium

A

Multinucleate cell formed during mitosis without cytokinesis. Happens in early drosophila development. Sperm cell precursors of many animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Somatic Cells

A

Most of the cells of the body. Are either in G0 phase (quiescence) or going through the regular cell cycle. Mutations not passed on.

21
Q

Germ Cells

A

Precursors to gametes. Go through meiosis to produce haploid gametes. Mutations that arise in these cells may be passed to the next generation. (germline mutations)

22
Q

Meiosis I

A

Homologus chromosomes segregate into separate daughter cells. Sister chromatids stay together. Creates two haploid cells.

23
Q

Meiosis II

A

Sister chromatids of each chromosome segregate into separate daughter cells. Creates four haploid daughter cells; each chromosome is just one chromatid.

24
Q

Prophase I

A

Chromosomes shorten, homologs pair, crossing over occurs, chromatids fully condense. Subdivided into 5 subphases: Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis

25
Q

Leptotene

A

Chromosomes begin to condense. Centrosomes begin to move to opposite sides of the nucleus.

26
Q

Zygotene

A

Chromosomes enter synapsis: homologues pair. Synaptonemal complex forms

27
Q

Pachytene

A

Synapsis complete, meiotic recombination (crossing over) occurs: non sister chromatids of homologs exchange genetic material

28
Q

Diplotene

A

Synaptonemal complex dissolves. Crossover points appear as chiasmata; holds non sister chromatids together. Meiotic arrest occurs in many species at this point.

29
Q

Diakinesis

A

Chromatids condense fully. Nuclear envelope breaks down, meiotic spindle begins to form. Non-sister chromatids of homologs remain attached at chiasmata.

30
Q

Synaptonemal Complex

A

Specialized proteins that hold homologs together. Starts in zygotene and is fully complete by pachytene. Recombination nodules along the complex forms for crossing over between non-sister chromatids.

31
Q

Metaphase I

A

Tetrads (homologous chromosomes) align along the metaphase plate. Each chromosome of a pair attaches to microtubules from one pole. Homologs are attached to opposite poles. Sister chromatids attached to the same pole.

32
Q

Anaphase I

A

Homologous chromosomes are pulled to opposite poles. Centromere of each chromosome does not divide. Chiasmata migrate off ends of chromatids.

33
Q

Telophase I

A

Nuclear envelope forms. Haploid cells. Chromosomes are composed of two sister chromatids. Cytokinesis of cells occurs after telophase I

34
Q

Interkinesis

A

Similar to interphase but generally shorter. No chromosome duplication. Chromosomes may decondense depending on the species.

35
Q

Prophase II

A

Chromosomes re-condense if they decondensed during interkinesis. Centrosomes move toward poles of nucleus. Nuclear envelope breaks down.

36
Q

Metaphase II

A

Chromosomes align on the metaphase plate. Sister chromatids of each chromosome attach to spindle microtubules from centrosome attach to spindle microtubules from centrosomes on opposite poles.

37
Q

Anaphase II

A

Centromeres are severed. Sister chromatids of each chromosome pulled to opposite poles.

38
Q

Telophase II

A

Chromosomes begin to decondense. Nuclear envelopes form around each set of chromosomes. Chromosomes now each composed of one chromatid.

39
Q

Cytokinesis (Meiosis)

A

Cytoplasm of each cell is divided to produce two daughter cells. 4 haploid cells.

40
Q

Anuploidy

A

Abnormal number of chromosomes for one set of homologs

41
Q

Independent assortment of unlinked genes.

A

Orientation of each set of homologs on metaphase plate of meiosis I is independent of orientation of other sets of homologs. Different relative orientations of different sets of homologs can yield different combinations of alleles of unlinked genes.

42
Q

Meiotic Recombination

A

Some gametes carry chromosomes with a mix of maternal and paternal alleles of different genes. Each of the four gametes produced in a meiosis will be unique.

43
Q

Oogenesis in Humans

A

Oogonia (diploid germ cells in ovaries of female embryos) divide by mitosis during fetal stage and enter meiosis I to become primary Oocytes. Arrest in diplotene until after birth occurs. At puberty, one oocyte per month resumes meiosis. At ovulation, meiosis 1 produces a secondary oocyte and first polar body. Secondary ooccyte arrests in metaphase of meiosis II. If oocyte is fertilized, meiosis II is completed. Secondary oocyte produces a mature ovum and second polar body. First polar body usually doesn’t divide.

44
Q

Spermatogenesis

A

Spermatogonia (diploid germ cells found in testes) divide by mitosis throughout lifespan of individual. After puberty, spermatagonia undergo mitosis to produce primary spermatocytes. Primary spermatocytes undergo meiosis to produce two secondary spermatocytes. Secondary spermatocytes undergo meiosis II to produce two spermatids. Spermatids mature to become sperm. Equal number of X and Y sperm are produced.

45
Q

Overview of Meiosis I

A

Homologous chromosomes segregate into separate daughter cells. Sister chromatid stay together. Two haploid cells are created.

46
Q

Overview of Meiosis II

A

Sister chromatids of each chromosome segregate into separate daughter cells. Creates four haploid cells. Each chromosomes is now one chromatid.

47
Q

Meiosis and Mendel’s Law of Segregation

A

Mendel’s law of segregation states that alleles of a gene segregate into separate gametes. This occurs as a result of segregation of homologous chromosomes in Anaphase I of meiosis. Each gamete only gets one homolog of each pair and therefore only one allele of each gene.

48
Q

Meiosis and Mendel’s Law of Independent Assortment.

A

This applies to unlinked genes. Results from the fact that different homologous pairs of chromosomes can line up in different orientations on the metaphase plate in meiosis I

49
Q

Hemizygous

A

Offspring has only one allele of a gene. Generally X-linked genes in males.

Biology 105 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions