Lecture 4: The alternation of generations Flashcards

1
Q

what are gametes?

A

sexual cells that can fuse to form a diploid zygote

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2
Q

what is a zygote?

A

a cell formed by the fusion of 2 gametes

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3
Q

what are isogametes?

A

complementary gametes that look similar (sperm - small, motile, male & eggs - large, immobile, female)

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4
Q

what are anisogametes?

A

complementary, motile gametes that look different (smaller = male & larger = female)

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5
Q

what is syngamy?

A

the fusion of 2 complementary gametes to form a zygote

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6
Q

what is gonidium?

A

an asexual reproductive cell/ group of cells where reproductive cells are produced

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7
Q

what is a gametangium?

A

sexual tissues in which gametes are formed from

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8
Q

what is a spore?

A

a haploid cell that can give rise to a new individual without syngamy

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9
Q

what is a zygospore?

A

a diploid cell formed by the fusion of 2 gametes

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10
Q

what occurs when the zygospore undergoes meiosis?

A

forms haploid cells that generate gonidia

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11
Q

what is a gametophyte?

A

a haploid plant that produces haploid gametes by mitosis

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12
Q

what is a sporophyte?

A

a diploid plant that produces haploid spores by meiosis

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13
Q

what is a sporangium?

A

the tissues in which haploid spores are formed

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14
Q

what are homospores?

A

spores that are identical in size and morphology BUT will form male or female gametophytes

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15
Q

what is a zoospore?

A

motile spore

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16
Q

what is a sporophyll?

A

a leaf (microphyll) that bears a sporangium

17
Q

what is an archegonium?

A

female parts of the gametophyte (where egg cell is located)

18
Q

what is an atheridium?

A

male parts of the gametophyte

19
Q

how to chlorophytes reproduce?

A

vegetative mitosis

20
Q

what is the process of vegetative mitosis?

A
  1. when under environmental stress, unicellular chlorophytes differentiate to behave as gametes (become motile if not already)
  2. isogametes pair and fuse becoming a zygote
  3. zygotes undergo meiosis becoming genetically recombined haploid cells
21
Q

what occurs as chlorophytes become colonial?

A

gametic dimorphism where male (smaller) and female (larger) gametes are obvious

22
Q

what is oogamy?

A

larger gametes losing the ability to be motile and look like eggs

23
Q

what is volvox?

A

a model colonial chlorophytic cell that has differentiation of somatic and sex cells

24
Q

how do cells lose their immortality?

A

as cells reproduce via meiosis differentiation occurs meaning mother and daughter cells no longer are the same so ‘death’ is introduced

25
what is a characteristic of reproduction in ALL plants?
the alternation of generations between haploid and diploid
26
what are the 2 self sustaining generations in all plant life-cycles?
1. gametophyte is haploid (n) and generates male/female gametes by mitosis 2. gametes fuse forming a diploid (2n) sporophyte that produces haploid spores via meiosis