Ch. 10 Flashcards

1
Q

What are homologous chromosomes?

A
  • a pair of chromosomes of the same length and centromere position
  • passes genes for the same characters at corresponding loci
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2
Q

What are loci?

A

specific places along the length of a chromosome where a given gene is located

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3
Q

What are autosomes?

A

chromosomes not directly involved in determining sex

not sex chromosomes

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4
Q

What are sex chromosomes?

A

chromosomes responsible for determining the sex of an individual

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5
Q

How many autosomes and sex chromosomes do humans posses?

A
  • 44 autosomes (22 pairs)
  • 2 sex chromosomes (1 pair)
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6
Q

What are diploid cells?

A

cells containing 2 sets of chromosomes

denoted as 2n

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7
Q

What are haploid cells?

A

cells containing one set of chromosomes

denoted as n

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8
Q

What is the purpose of meiosis?

A

to produce gametes w/ half the genetic complement of the parent cells

gametes = sperm and eggs

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9
Q

What happens in prophase I?

A
  • chromosomes become visible
  • nuclear envelope breaks down
  • crossing over occurs
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10
Q

What happens in metaphase I?

A

paired homologous chromosomes line up across the center of the cell

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11
Q

What happens in anaphase I?

A

homologous chromosomes separate and are paired to opposite ends of the cell

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12
Q

What happens in telophase I?

A
  • 2 daughter cells are formed
  • each contains only 1 chromosome of the homologous pair
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13
Q

What happens in prophase II?

A
  • chromosomes condense
  • spindles form in each new cell
  • spindle fibers attach to chromosomes
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14
Q

What happens in metaphase II?

A

centromeres of chromosomes line up randomly at the equator of the each cell

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15
Q

What happens in anaphase II?

A

sister chromatids separate and move to opposite poles

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16
Q

What happens in telophase II?

A
  • nuclear envelope reforms
  • cytoplasm divides
  • 4 daughter cells form
17
Q

What is independent assortment?

A

the independent segregation of genes during the formation of gametes

18
Q

What is crossing over?

A
  • the exchange of genetic material between homologous chromosomes
  • results in a mixture of parental characteristics in offspring
19
Q

What is random fertilization?

A

the combination of each unique sperm w/ each unique egg increases genetic variability

20
Q

What is recombination?

A

contributes to genetic variation by shuffling parental DNA and creating new combinations of variants

21
Q

When does independent assortment occur?

A

metaphase I

22
Q

When does crossing-over occur?

A

prophase I