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Biology > genetic diversity > Flashcards

genetic diversity Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is a mutation

A

a random change in the DNA that alters the sequence of bases.

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2
Q

what 3 things is DNA code

A

it is degenerate so more than one codon can codon for the same amino acid. it is universal so the same codon triple always code for the same amino acid. it is non overlapping so each base is only part of one codon.

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3
Q

what is meiosis

A

is nuclear cell division that results in 4 daughter cells what have half the DNA of the original organism.

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4
Q

what type of cells does meiosis produce

A

haploid cells

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5
Q

stages of meiosis

A

prophase 1, metaphase1, anaphase 1, telophase 1, cytokinesis, prophase 2, metaphase2, anaphase 2, telophase 2, cytokinesis.

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6
Q

what happens in prophase 1

A

the DNA condenses. 2 chromatids joined at centromere. they are arranged in homologous pairs. crossing over may occur. nuclear envelop breaks down.

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7
Q

what happens in metaphase 1

A

they line up along the equator of the cell. spindle fibres attach. independent assortment. means the proportion of paternal and maternal chromosomes that end up on each side is due to chance.

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8
Q

what happens in anaphase 1

A

the spindle fibres pull them to opposite ends of the cell. centromeres do not divide

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9
Q

what happens in telophase 1

A

chromosomes arrive at opposite poles. spindle fibres break down. nuclear envelope form around the 2 groups of chromosomes.

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10
Q

what is cytokinesis

A

division of the cytoplasm. cleavage furrow. 2 haploid cells.

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11
Q

what is prophase 2

A

nuclear envelope breaks down and chromosomes condense.

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12
Q

what is metaphase 2

A

spindle fibres attach and they line up along the equator of the cell.

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13
Q

what is anaphase 2

A

chromatids pull to opposite poles. 4 groups of chromosomes.

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14
Q

what is telophase 2

A

nuclear envelope forma around each group of chromosomes.

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15
Q

what is cytokinesis

A

cytoplasm divides creating 4 haploid cells

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16
Q

why do chromosomes cross over

A

the make more genetic diversity

17
Q

how does crossing over work

A

chromosomes in each pair they twist around each other. chromatids break and the sections re-join.

18
Q

what does crossing over result in

A

the exchange of alleles between homologous chromosomes.

19
Q

causes of variation

A

environmental changes (access to food) and genetic changes (mutations)

20
Q

how is genetic diversity determined

A

by its total number of different alleles.

21
Q

what is natural selection

A

it is the process that organisms with more desired characteristics will survive and reproduce in a habitat

22
Q

how does natural selection drive evolution

A

variation in a population due to mutations. some alleles are favourable which held organisms to survive and reproduce. these are passed onto offspring.

23
Q

example of natural selection in the real world

A

black peppered moths- after the cities became covered in soot, the peppered moths went from black to white as they were able to camouflage.

24
Q

what is normal distribution

A

it is a bell curve

25
Q

what is stabilising distribution

A

individuals with characteristics towards the middle of the range are more likely to survive and reproduce. for example birthweight

26
Q

what is directional selection

A

individual alleles for a single extreme phenotype are more likely to survive and reproduce. for example bacterial resistance.

27
Q

what are extremophiles

A

they are organisms that live best in extreme climates.

28
Q

anatomical adaptions

A

fur, shells, camouflage, teeth, sunken stomata, waxy cuticle, swollen stems

29
Q

behavioural adaptions

A

survival (playing dead),
courtship, seasonal (migration), phototropism (growing towards light), geotropism (roots grow with gravity)

30
Q

physiological adaptions

A

poison production, strong reflexes, homeostasis, toxin production, seed dormancy

31
Q

leaf adaptions

A

small surface area for evaporation, waxy cuticle so waterproof, sunken stomata to reduce water loss, rolled leaves to deduce effect of wind, long roots to get lots of water, less stomata so less places to lose water from.

32
Q

why cant antibiotics completely eradicate bacteria

A

as some are resist to antibiotics.

33
Q

aseptic techniques

A

wash hands, light a burner burner, disinfect bench, close windows, flame bottle, flame instrument, only take lid off petri dish when needed

Biology (12 decks)

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