14 - Meiosis Flashcards

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1
Q

Heredity

A

the transmission of traits from one generation to the next

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2
Q

Gametes

A

Reproductive cells, such as sperm and eggs

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3
Q

Somatic cells

A

All body cells EXCEPT reproductive cells (gametes)

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4
Q

Asexual reproduction

A

A single individual (like yeast or amoeba) is the sole parent and passes copies of all its genes to its offspring WITHOUT the fusion of gametes

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5
Q

Sexual production

A

Two parents give rise to offspring that have unique combinations of genes inherited from the two parents

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6
Q

Sex chromosomes

A

X and Y chromosomes

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7
Q

Autosomes

A

chromosomes that are not involved in determining a person’s sex

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8
Q

Ploidy

A

refers to the number of sets of chromosomes in a cell

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9
Q

Diploid

A

any cell with two chromosomes sets (2n)

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10
Q

Haploid

A

single set of chromosomes (n)

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11
Q

Zygote

A

resulting fertilized egg, diploid cell

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12
Q

Fertilization

A

the union of gametes, culminating in fusion of their nuclei

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13
Q

Meiosis

A

special type of cell division that produces cells with half the chromosome of the parent cell. Occurs in cells of testes and ovaries in humans

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14
Q

Meiosis 1

A

Homologs are separated

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15
Q

Prophase 1

A

Duplicated homologous chromosomes pair up and exchange segments (2n=6)

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16
Q

Metaphase 1

A

chromosomes line up by homologous pairs

17
Q

Anaphase 1

A

The two homologous chromosomes of each pair separate

18
Q

Telophase 1 and cytokinesis

A

Two haploid cells form; each chromosome still consists of two sister chromatids

19
Q

Meiosis 2

A

sister chromatids are separated

20
Q

prophase 2

A
  • spindle apparatus forms
  • chromosomes, each still composed of two chromatids associated at the centromere. are moved by MTs toward metaphase 2 plate
21
Q

Metaphase 2

A
  • chromosomes align at metaphase plate
  • due to crossover in meiosis 1, sister chromatids are not genetically identical
  • kinetochores of the sister chromatids attach to MTs from opposite poles, preparing for their separation
22
Q

Anaphase 2

A

Breakdown of proteins holding sister chromatids together at centromere allows chromatids to separate and move toward opposite poles
- each chromatid has now become an individual chromosome

23
Q

Telophase 2

A
  • nuclei form, chromsomes begin decondensing and cytokinesis occurs
  • four daughter cells are produced, each with a haploid set of (unduplicated chromosomes)
  • Four daughter cells are genetically distinct from one another and from the parent cell
24
Q

Chromosomes

A

structures that carry genetic information

25
Q

Sister chromatids

A

joined copies of the original chromosome

26
Q

Homologous chromosomes

A

(or homologs) are pairs of chromosomes that have the same genes in the same order, but they may have different versions of those genes

27
Q

Duplicated chromosomes

A

chromosomes that have been copied to prepare for cell division

28
Q

Chromatin

A

material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes

29
Q

Crossing over

A

is a process that happens during meiosis where homologous chromosomes exchange pieces of genetic material

30
Q

Synapsis

A

the process during meiosis where homologous chromosomes pair up tightly

31
Q

Chiasmata

A

(singular, chiasma) where crossovers have occurs

32
Q

Independent assortment

A

is a process during meiosis where the pairs of homologous chromosomes are randomly distributed to the daughter cells

33
Q

Random fertilization

A

refers to the idea that any sperm cell can fertilize any egg cell

34
Q

Nondisjunction

A

a mishap, in which the members of a pair of homologous chromosomes do not move apart properly during meiosis 1 or sister chromatids fail to separate during meiosis 2

35
Q

Aneuploidy

A

an abnormal chromosome number

36
Q

Monosomy

A

(2n-1) a type of aneuploidy where a cell is missing one chromosome from a pair. Turner syndrome is a cause of this.

37
Q

Trisomy

A

(2n+1), a condition where a cell has an extra chromosome, resulting in 3 copies instead of 2. This can lead to down syndrome.