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genetic inheritance > chapter 2 > Flashcards

chapter 2 Flashcards

1
Q

what is a chromosome?

A

structure within living cells that contain genetic material

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2
Q

what is chromatin?

A

DNA + proteins

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3
Q

what are diploid species?

A

two sets of chromosomes forming a homologous pair

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4
Q

do homologous pairs have the same allele?

A

no, they have the same gene loci but different allele

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5
Q

what chromosome isnt a homologous pair?

A

sex chromosomes

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6
Q

what is asexual reproduction?

A

pre existing cell divides to produce new cells

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7
Q

what is an example of asexual reproduction?

A

wound healing and cell replacement in adult organisms

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8
Q

what is binary fission?

A

bacteria replicated chromosomes then divides into two daughter cells- genetically identical

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9
Q

what is interphase?

A

G1, S and G2

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10
Q

what is G0?

A

non dividing state- cell can enter this stage when it is aging and theres DNA damage, temporary lack of nutrition, or its normal differentiation program

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11
Q

what is senescence?

A

cell aging and DNA damage- permanent

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12
Q

what is quiescence?

A

temporary lack of nutrition and/or growth factors-reversible

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13
Q

what happens during G1 phase?

A

cell prepares to divide, accumulates proteins and reaches a restriction point where the cell MUST complete the cycle

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14
Q

what happpens during S phase?

A

chromosomes are replicated

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15
Q

what are sister chromatids?

A

two copies of a chromosome joined together at the centromere to form an X shape

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16
Q

what happens during G2?

A

cell accumulates the materials that are necessary for nuclear and cell division- checks if there are any mutations or errors with DNA copying

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17
Q

how many chromosomes and chromatids are present during G2?

A

46 chromosomes but 92 chromatids

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18
Q

what are astral microtubules?

A

project towards plasma membrane

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19
Q

what are polar microtubules?

A

project into region between two spindle fibers

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20
Q

what are the stages of mitosis?

A

PPMAT- prophase, prometaphase, metaphase, anaphase, telophase

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21
Q

what happens during prophase?

A

nuclear membranse dissociate and two centrosomes move apart- mitotic spindle begins to form

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22
Q

what happens during prometaphase?

A

centrosomes reach opposite poles, spindle fibers interact with sister chromatids

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23
Q

what happens during metaphase?

A

pairs of sister chromatids align along a plane called the metaphase plate

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24
Q

what happens during anaphase?

A

cohesin bond that holds the sister chromatids together is broken and chromatids are pulled to opposite sides

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25
Q

how many chromosomes are present DURING anaphase?

A

92 chromosomes are now on opposite sides of the cell

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26
Q

what happens to the kinetochore and the polar microtubules as anaphase proceeds?

A

kinetochore microtubules shorten and the polar microtubules lengthen

27
Q

what happens during telophase?

A

nuclear membrane reforms to form two separate nuclei by the formation of a cleavage furrow

28
Q

What is the outcome of mitotic cell division?

A

Produce two identical daughter cells with the same number of chromosomes as daughter cells- genetically identical

29
Q

What is meiosis?

A

The process of two diploid parents making gametes with half the amount of genetic material (haploid)- one chromosome from each homologous pair

30
Q

How many divisions are in meiosis?

A

Two successive divisions to reduce the number of chromosomes from diploid (parent) to haploid (gamete)

31
Q

What happens during prophase I of meiosis?

A

Chromosomes are replicated and undergo synapsis and form the synaptonemal complex and undergo crossing over

32
Q

What is synapsis?

A

Recognition process where homologous chromosomes find each other and align (homologous chromosome 1 with homologous chromosomes 1)

33
Q

What is crossing over?

A

Physical exchange of chromosomes- critical for proper segregation and genetic variation- produce chiasma connection

34
Q

what happens during prometaphase I?

A

Spindle apparatus is complete and chromatids are attached to the kinetochore microtubules

35
Q

What happens during metaphase I?

A

Chromosomes are aligned along metaphase plate- opposite homologous pairs are linked and will be pulled apart

36
Q

What happens during anaphase I?

A

Homologous chromosomes separate from one another but connection holding sister chromatids together does not break

37
Q

What happens during telophase I?

A

Homologous pairs reach poles and nuclear membrane reforms

38
Q

What is the outcome of meiosis I?

A

Produce two non-identical cells, each with half the number of chromosomes but chromosomes are Still in pairs

39
Q

What happens in meiosis II?

A

Meiosis two is now similar to mitosis but without the extra replication, sister chromatids are already replicated and are now just separated to form 4 haploid cells

40
Q

What two factors affect genetic variation of chromosomes?

A

Crossing over during prophase I and random separation of homologous chromosomes depending on how they line up along the metaphase plate during metaphase I

41
Q

What are the possible combinations in humans?

A

2^23= 8,388,608 possible combinations based on the 23 pairs of chromosomes

42
Q

How do eukaryotic organisms produce offspring?

A

Through sexual reproduction

43
Q

What is gametogenesis?

A

Formation of gametes (haploid) from parents (diploid) which will then fuse through fertilization to form a new diploid organisms

44
Q

What are isogamous species?

A

Produce gametes that are morphologically similar like fungi and algae

45
Q

What are heterogamous species?

A

Produce gametes that are morphologically different- such as sperm, which are small and mobile and eggs, which are very large and in mobile

46
Q

What is spermatogenesis?

A

Production of sperm occurring in the testes, diploid spermatogonial cell divides to produce two cells- one spermatogonial cell and one primary spermatocyte. Primary spermatocyte will go through meiosis I and II to produce four haploid spermatids- mature into sperm cells

47
Q

What is the structure of sperm?

A

Long flagellum and a head with a haploid nucleus- head is capped by an acrosome, which contains digestive enzymes that enable sperm to penetrate through the egg

48
Q

What is oogenesis?

A

Production of egg cells which occurs in the ovaries- diploid oogonia cells produce diploid primary oocytes before birth- primary oocytes initiate meiosis I in utero but stop at prophase 1 until ovulation where they reach metaphase II and will only complete meiosis if fertilized

49
Q

How does primary oocyte activation occur?

A

Monthly; produce two haploid cells through asymmetric division, a large secondary oocyte which will enter meiosis II and a small polar body containing the other half of the chromosomes will undergo apoptosis.

50
Q

What type of oocyte enters meiosis?

A

The large secondary oocyte enters meiosis monthly

51
Q

What are the two life cycles of plants?

A

Haploid gametophyte generation and the diploid sporophyte generation

52
Q

What’s the cycle of plants?

A

Cells in sporophyte undergo meiosis to produce haploid cells called spores, spores will then divide with mitosis to produce the gametophyte, which produces gametes which upon fertilization grow into a plant

53
Q

How does gamete formation occur in flowering plants?

A

In anthers, diploid microsporocyte undergo meiosis to produce four haploid micro spore- undergo mitosis to form a pollen grain which will form two sperm cells.
In ovaries, diploid megasporocytes undergo meiosis to produce four haploid megaspores- undergo mitosis and develop into the embryo sac which will produce an egg cell

54
Q

How does fertilization occur in flowering plants?

A

Begins when pollen lands on stigma, tube cell develops into a pollen tube that makes contact with an ovule- undergo mitosis to produce two haploid sperm; double fertilization occurs when sperm fertilizes egg to create zygote, second sperm units with the central cell to produce am endosperm (3 sets of haploid chromosomes)

55
Q

What is heterogametic sex and homogametic sex?

A

Heterogametic will produce two different types of gametes, two different sex chromosomes and homogametic produce only one type (females having two x)

56
Q

How is sex determined in mammals?

A

Males will produce half the sperm cells with X chromosomes and half with Y, depending on the cell that fertilizes the egg will determine the sex of the zygote.

57
Q

How is sex determined In insects?

A

Some males are X0 and some are XY, Y does not determine maleness. It is the ratio between the X chromosomes and the number of sets of autosomes- if the ratio is 0.5- it will be male and if the ratio is 1 it will be female q

58
Q

What happens if the ratio between x and autosomes isn’t 1 or 0.5?

A

If you have a ratio of 0.67 which is in between both sexes you will have an intersex offspring. Will have both female and male parts

59
Q

what is a homogametic specie?

A

males contain two
Z chromosomes

60
Q

what are heterogametic species?

A

females have one Z and one W chromosome

61
Q

how does sex determination work in bees?

A

maples are produced from unfertilized haploid eggs and females are diploid produced from fertilized eggs

62
Q

what is environmental sex determination for reptiles?

A

sex is controlled by temperatures rather than sex chromosomes

63
Q

what is environmental sex determination in nemo fish?

A

large female fish exhibits dominance which inhibits hormone production and makes males, if female dies, male eggs become females and cycle starts again

genetic inheritance (3 decks)

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