Section 3 - Genetics - Meiosis, sexual and asexual reproduction Flashcards

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1
Q

Are gametes haploid or diploid cells?

A

Haploid

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2
Q

What is a zygote? Is it haploid or diploid?

A

When a male gate fuses with a female gamete to produce a fertilised egg. It is diploid

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3
Q

In meiosis, how many daughter cells are produced, are they identical and haploid or diploid, and where does it occur?

A

4 daughter cells, not identical to each other, haploid, and happens in reproductive organs; testes and ovaries.

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4
Q

What happens in the 1st division in meiosis?

A
  • Before cell starts to divide, DNA is duplicated with one arm of each X-shaped chromosome an exact copy of other.
  • Chromosomes line up in pairs in centre of cell
  • Pairs pulled apart so each new cell has one copy of each chromosome. Membrane of nucleus break down
  • Cell membrane and cytoplasm divide and two separate cells formed
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5
Q

What happens in the 2nd division in meiosis?

A
  • Chromosomes line up again in centre of cell and arms of chromosomes pulled apart to opposite ends
  • Four daughter cells produced
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6
Q

Difference between sexual and asexual reproduction?

A

Asexual - cells divide by mitosis

Sexual - involves meiosis with genetically different haploid gametes fusing to form a diploid cell at fertilisation

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7
Q

2 advantages of asexual reproduction and how?

A
  • can produce lots of offspring very quickly as reproductive cycle is so fast
  • only one parent needed so organisms can reproduce wherever conditions favourable without waiting for mate
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8
Q

Advantage of sexual reproduction and how?

A

Creates genetic variation so if environmental conditions change then some may survive the change

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9
Q

Disadvantage of asexual reproduction and how?

A

No genetic variation so if environmental conditions unfavourable, whole population may be affected

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10
Q

2 disadvantages of sexual reproduction and how?

A
  • takes more time and energy than asexual so fewer offsprings in lifetime
  • two parents needed so problem if individual isolated
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