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Genetics- Fall 2022 > Chap 2- Meiosis and Mitosis > Flashcards

Chap 2- Meiosis and Mitosis Flashcards

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Biology 101 flashcards
1
Q

In living organisms, what is the genetic material made up of?

A

Nucleic acid DNA

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2
Q

What units are DNA organized into? What do these units do?

A

DNA is organized in units called genes. Genes direct metabolic activities of cells.

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3
Q

What does the transmission of genetic material in Eukaryotic cells involve?

A

Meiosis and Mitosis

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4
Q

What is Mitosis?

A

The production of two different cells (2n). The two cells contain the same number of chromosomes and chromatid as their parent.

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5
Q

What is Meiosis?

A

The production of gametes. Half the number of chromosomes are produced (n).

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6
Q

When are chromosomes visible as condensed structures?

A

During Meiosis and Mitosis

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7
Q

What is chromatin?

A

It is uncoiled chromosomes that diffuse network with the nucleus.

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8
Q

What are the two main type of cells?

A

Eukaryotic (bacteria, archae) and Prokaryote (Protisist, plants, fungi, animal)

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9
Q

What are the common features shared in cells?

A

DNA, Plasma membrane, ribosome

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10
Q

What are cells surrounded by? What is its purpose?

A

Cells are surrounded by a semipermeable membrane. It’s purpose is to protect/ create a boundary, delimit the cell from its environment, surround by a covering (glycocalyx),

(Plants have a cell wall composed of cellulose).

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11
Q

What is glycocalyx?

A

Defines the biochemical identity of each cell

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12
Q

What does the nucleus contain?

A

DNA (proteins into thin fibers- chromatin) and nucleolus (rRNA synthesized and assembled)

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13
Q

During Mitosis and Meiosis, what happens to chromatin?

A

It coils and condenses to form chromosomes

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14
Q

What is the eukaryotic cell enclosed by, except nucleus?

A

Cytoplasm

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15
Q

What is the purpose of cytoskeleton?

A

Provides structure to cytoplasm.

Maintains shape, mobility, and anchors organelles

Made up of microtubules and microfilaments

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16
Q

What is the purpose of the endoplasmic reticulum (ER)>

A

compartmentalizes the cytoplasm

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17
Q

What is the purpose of smooth ER?

A

Site of lipid synthesis

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18
Q

What is the purpose of Rough ER?

A

Studded with ribosomes, sites of protein synthesis

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19
Q

What is the purpose of Golgi Apparatus?

A

Receives, refines, and distributes products from the ER.

( Like an EMT picking up, making sure, and leaving the injured to the ER )

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20
Q

What is the purpose of mitochondria?

A

The site of cell respiration, found in both plants and animal cell

It is also the site of ATP synthesis

POWERHOUSE OF THE CELL.

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21
Q

What is the purpose of chloroplast in plant, algae and some protozoan?

A

The site of photosynthesis

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22
Q

What do mitochondria and chloroplast both contain?

A

DNA similar to prokaryotic DNA

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23
Q

Where are centrioles in the cytoplasm located?

A

In the centrosome in animal cells

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24
Q

What is the purpose of centrioles?

A

To organize spindle fibers for movement of chromosomes during meiosis and mitosis

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25
Q

When do somatic cells contain the same number of chromosomes?

A

for members of the same species

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26
Q

Where do chromosomes exist?

A

In homologous pairs in diploid organisms

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27
Q

What are homologous chromosomes?

A

Similar copies of each other; One chromosome of the homologous pair is from the father (via the sperm) and the other from the mother (via the egg)

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28
Q

Alleles

A

different versions of the same gene

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29
Q

What is karyotype?

A

The creation of a photographed, cutting and matching a mitotic chromosome

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30
Q

What is each chromosome structurally made up of?

A

Two sister chromatids connected at the centromere

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31
Q

What is the purpose of Mitosis?

A

Asexual reproduction for many single-celled organisms such as protozoan, fungi, algae.
In multicellular, it is responsible for wound healing, cell replacement, and growth

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32
Q

What happens in mitosis for genetic material?

A

It divides into two nuclei (karyokinesis)

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33
Q

After karyokinesis, what follows?

A

cytoplasmic division (cytokinesis)

34
Q

What is the cell composed of?

A

Interphase (G1, S, G2) and mitosis

35
Q

Where does the S phase occur?

A

In the nucleus, where DNA is duplicated

36
Q

Where do G1 and G2 occur?

A

In the cytoplasm

37
Q

By the end of G2, what occurs?

A

Cell has doubled in size (DNA duplicated, mitosis initiated)

38
Q

Where is G0?

A

In G1- cells withdraw from the cell cycle and enter nondividing, metabolically active state

39
Q

What happens in G1 Phase?

A

The first “gap” phase. Size and protein content of the cell increase and prepare for S phase. Many regulatory proteins are made and activated.

40
Q

What occurs in S phase?

A

“Synthesis” phase, entire DNA in the nucleus of the cell is replicated

41
Q

What occurs in G2 Phase?

A

Second “gap phase”, cell prepared for mitosis and cytokinesis

42
Q

What occurs in G0 phase?

A

No active preparation taking place but within G1, in a way. This phase is present in all cell types that do not actively divide.

Example: Muscle, eye, nerve cells, etc.

43
Q

What are sister chromatids?

A

Two parts of each chromosome. They are identical and visibly connected at centromere

44
Q

What is cohesion?

A

Protein complex that holds sister chromatids together. Formed during S phase.

45
Q

Stages in mitosis?

A

Prophase, Prometaphase, Metaphase, Anaphase, Telophase

46
Q

What occurs in Prophase?

A

Chromosomes: Condense and become chromosomes
Centrosomes: radiate microtubules and migrate to opposite poles
Nuclear envelope: Breaks down

47
Q

What occurs in prometaphase?

A

Microtubules of spindle attach to chromosomes

48
Q

What are kinetochore?

A

Where spindle fibers attach to kinetochore (protein layers) and move chromosomes

49
Q

During Prometaphase/Metaphase, what occurs to the structure of chromatic, etc?

A

-Cohesion is degraded by enzyme separase
- Sister chromatid arms disjoin except at centromere
Enzyme shugoshin prevents degradation of cohesion at centromere

50
Q

What occurs during metaphase?

A

Chromosomes align in the center of the cell

51
Q

What occurs during anaphase?

A

Centromeres split and sister chromatids separate from each other (disjunction); they are no longer chromatids, but daughter chromosomes

52
Q

In anaphase, how do we know complete disjunction has occurred?

A

-Shugoshin degards
-Cohesion complex is cleaved by separase
- Sister chromatids are pulled toward opposite poles of cell

53
Q

What occurs during Telophase?

A

The final stage of two complete sets of chromosome, one set at each pole.

  • Cytokinesis partitions the cytoplasm, (cell plate in plants, furrow in animal)
  • Chromosomes uncoil
    -Nuclear envelope re-forms and so does the nucleolus
    -Spindle fibers disappear

END OF MITOSIS.

54
Q

What is the cell cycle genetically regulated by? What happens if it is not regulated?

A

Three major checkpoints. If not regulated, it can lead to uncontrolled cell division characterizing malignancy.

55
Q

What are kinases?

A

Enzymes that serve as a “master control”

56
Q

What do kinases bind to?

A

Cyclins (protein). It activates them at appropriate times during the cell cycle.

57
Q

What does Meiosis do?

A

reduces the amount of genetic material by half. It produced haploid gametes or spores containing one member of each homologous pair of chromosomes.

58
Q

What does Meiosis maintain?

A

Genetic continuity from generation to generation and gives rise to genetic variation in gametes by crossing over, and unique combination (independent assortment)

59
Q

What does fertilization restore?

A

The diploid number

60
Q

What does Meiosis begin with?

A

A diploid cell (DNA duplicated during interphase, chromosomes made up of sister chromatids)

61
Q

What is the unique full structure of Meiosis?

A

It comprises two division: Meiosis I (Reduction division) and Meiosis II

62
Q

What is the exception for mitotic prophase and Meiosis to not be similar?

A

homologous chromosomes pair up (synapsis)

63
Q

What is the purpose of synapsis?

A

gives rise to a tetrad (two pairs of sister chromatids) with overlapping nonsister chromatids (chiasma)

  • exchange of genetic material through recombination
64
Q

What do the tetrad attach to?

A

spindle fibers

65
Q

What occurs in Prophase I of Meiosis I?

A

-Chromosomes become visible as thin threads. DNA replication is already complete
-Homologous chromosomes continue to condense and undergo synapsis (gene for gene pairing)
-After synapsis tetrads are formed. Each chromosome consists of two sister chromatids
- Chromosomes continue to shorten and thicken and chiasmata b/w non-sister chromatids become apparent
-Nuclear envelope begins to break down and spindle is forming

66
Q

What occurs in Metaphase I of Meiosis?

A

Homologous pairs of chromosomes orient randomly, chiasma are visible holding nonsister chromatids together

67
Q

What does crossing over produce?

A

recombinant chromosomes, combine DNA inherited from each parent
-Begins in prophase I as homologous chromosomes pair up gene by gene
-Homologous portions of two nonsister chromatids trade places
-Contributes to genetic variation by combining DNA from two parents into a single chromosome

68
Q

What occurs in prophase II of Meiosis II?

A

Chromosomes are composed of one pair of sister chromatids attached by a common centromere, nuclear envelope breaks down

69
Q

What occurs during Metaphase II during Meiosis II?

A

Centromere is positioned at the metaphase plate

70
Q

What occurs during Anaphase II during Meiosis II?

A

Centromeres divide; sister chromatids are pulled to opposite poles

71
Q

What occurs during Telophase II during Meiosis II?

A

Cytokinesis results in four haploid gametes with equal cytoplasm, containing a combination of maternal and paternal genes

72
Q

Where does spermatogenesis take place?

A

Testes

73
Q

Where does Oogenesis take place?

A

Ovary

74
Q

What is spermatogonium and what does it become?

A

An undifferentiated germ cell that enlarges to become a primary spermatocyte

75
Q

What does the primary spermatocyte undergo?

A

Meiosis I to produce haploid secondary spermatocytes

76
Q

What does secondary spermatocytes undergo?

A

Meiosis II; producing a total of four haploid spermatids that undergo developmental changes and become highly specialized, motile spermatozoa or sperm

77
Q

What is oogonium and what does it become?

A

An undifferentiated germ cell that enlarges to become a primary oocyte

78
Q

What is polar body?

A

The cell with little to almost no cytoplasm; it will ultimately disintegrate

79
Q

What does secondary oocyte receive?

A

the bulk of the cytoplasm

80
Q

What does the secondary oocyte undergo?

A

Meiosis II, produced two haploid cells
-1st polar body may or may not divide
-All polar bodies will eventually disintegrate with only one function cell remaining

Genetics- Fall 2022 (8 decks)

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