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Biology > Module Five - Heredity > Flashcards

Module Five - Heredity Flashcards

Reproduction Cell Replication DNA and Polypeptide Synthesis Genetic Variation Inheritance Patterns in a Population

1
Q

what is sexual reproduction?

A
  • involves two parents
  • offspring with mix of parent’s genes
  • offspring differ from parents
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2
Q

what is asexual reproduction?

A
  • involves one parent

- offspring are genetically identical to each other and the parent

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3
Q

what is the gene pool?

A

the genetic material of all organisms in a population

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4
Q

why is reproduction important?

A
  • is a fundamental evolutionary process

- ensures continuity of life

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5
Q

what are the advantages of sexual reproduction?

A
  • offspring contain a mix of parental genes, introducing genetic variation
  • variations that are better suited to the environment have higher chance of surviving in changing environments
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6
Q

what are the disadvantages of sexual reproduction?

A
  • demands more energy and time
  • required to find a mate
  • mating
  • requires a lot of investment in a small amount of offspring
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7
Q

what does sexual reproduction require?

A
  • female (ova) and male gametes (sperm)

- meiosis

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8
Q

what is meiosis?

A
  • type of cell division that takes place in reproductive organs
  • results in FOUR different daughter cells
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9
Q

what is a haploid?

A
  • has HALF the amount of chromosomes

- 23 chromosomes for human haploids

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10
Q

what is a diploid?

A
  • has the ENTIRE amount of chromosomes

- 46 chromosomes for human diploids

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11
Q

how are gametes produced?

A
  • through meiosis
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12
Q

what are somatic cells?

A
  • non-reproductive body cells
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13
Q

what is a zygote?

A
  • a fertilised egg

- is a diploid

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14
Q

how many chromosomes do humans have?

A

46 chromosomes

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15
Q

what process is the reciprocal of meiosis?

A

fertilisation - fusion from haploid to diploid

meiosis - reduction from diploid to haploid

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16
Q

what is external fertilisation?

A

occurs outside the body

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17
Q

what is internal fertilisation?

A

occurs inside the body

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18
Q

what type of environment is best suited for external fertilisation?

A
  • aquatic environments

- moist environments

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19
Q

what are examples of external fertilisation?

A
  • earthworms
  • fish
  • frogs
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20
Q

what type of organism generally performs internal fertilisation?

A

terrestrial organisms

  • reptiles
  • mammals
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21
Q

what are the advantages of external fertilisation?

A
  • wide dispersal of young

- reduces competition for food and living space

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22
Q

what are the disadvantages of external fertilisation?

A
  • little to no parental care
  • many eggs end up not fertilised
  • dehydration
  • exposure to external elements
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23
Q

what are the advantages of internal fertilisation?

A
  • protection from external elements
  • fewer eggs are required for successful offspring
  • more parental care
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24
Q

what are the components of a flower?

A
  • carpel : stigma, style, ovary
  • stamen : anther, filament
  • petals
  • sepal
  • receptacle
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25
Q

which part of the flower is male?

A

stamen

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26
Q

which part of the flower is female?

A

carpel

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27
Q

how does pollination occur in plants?

A

male gametes in the pollen go from the anther to the stigma

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28
Q

what is cross-pollination?

A

pollen from one plant pollinating another plant

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29
Q

what is self-pollination?

A

pollen from the same plant pollinating the plant

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30
Q

what is fertilisation in plants?

A

the sperm cell that was transferred by the pollen fuses with the egg inside the ovule

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31
Q

what are the advantages of self-pollination?

A
  • requires less energy as there is no need to produce structures to attracts pollinators
  • can grow in areas with very few animals and insects
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32
Q

what are the advantages of cross-pollination?

A
  • genetic recombination

- higher chances of survival in the case of environmental change

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33
Q

what are some of the vectors of pollination?

A

wind, water, animals

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34
Q

what are the structural requirements for wind pollination in plants?

A
  • long anthers
  • large amounts of pollen produces
  • large feathery stigma
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35
Q

how does pollination by animals occur?

A

pollinators search for a meal, such as nectar, which is when pollen rubs on their bodies to be carried to another plant

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36
Q

what are the structural requirements for animal pollination in plants?

A
  • flower scent
  • colour
  • markings
  • shape
  • nectar
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37
Q

what is germination?

A
  • when a seed lands in soil with sufficient water, oxygen and warmth
  • embryo begins to grow
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38
Q

what is the life cycle of a plant?

A

pollination, fertilisation, seed dispersal, germination

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39
Q

what is seed dispersal?

A
  • seeds from the ovary are dispersed
  • advantageous over wide distances
  • lessens overcrowding and competition for resources (water, nutrients, light)
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40
Q

what are the advantages of asexual reproduction?

A
  • quick process
  • no requirements for a mate
  • being genetically identical is good if the organism is well adapted to the environment
  • good in food shortage scenarios (requires less energy)
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41
Q

what are the disadvantages of asexual reproduction?

A
  • little to no variation

- vulnerable to sudden changes in the environment

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42
Q

what is vegetative propagation?

A
  • underground organs of a plant (roots, stem) can grow into new plants
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43
Q

what are the types of vegetative propagation?

A

runners, rhizomes, suckers, apomixis

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44
Q

what are runners (vegetative propagation)?

A
  • long, thin, modified stems that grow on the surface of the soil
  • along the stem, nodes produce new roots, for a new plant
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45
Q

what are rhizomes (vegetative propagation)?

A

underground, horizontal modified stems

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46
Q

what are some methods of asexual reproduction in animals?

A

budding, binary fission, and spores.

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47
Q

what is reproductive budding?

A

when an adult organism gives rise to a small bud, which separates from the parent and grows into a new individual

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48
Q

what is an example of reproductive budding?

A

yeast

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49
Q

how does reproductive budding work?

A
  1. a small bud grows on the parent cell
  2. as the bud grows, the parent replicates its DNA
  3. nucleus divides into two
  4. one half moves from the parent cell into the bud
  5. bud breaks off once it is big enough
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50
Q

what is binary fission?

A

the splitting of unicellular organisms into two

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51
Q

what undergoes binary fission?

A

unicellular organisms: bacteria and protists

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52
Q

how does binary fission work?

A
  1. a newly divided cell will grow to twice its size
  2. replicates its DNA
  3. splits into two cells with identical genetic material
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53
Q

what are spores?

A
  • tiny unicellular reproductive cells that are produced in great numbers
  • do not have an embryo
  • does not need to with another cell to grow
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54
Q

what organisms release spores?

A

fungi (moulds and mushrooms) and some plants (mosses and ferns)

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55
Q

how do spores work?

A
  • light: easily dispersed over long distances by wind
  • carry genetic material identical to the parent
  • under proper conditions, spores will germinate and grow
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56
Q

what are the three reproductive mechanisms in mammals?

A

internal fertilisation, implantation, and pregnancy

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57
Q

what is internal fertilisation?

A

the union of female and male gametes within the female’s body

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58
Q

what is implantation in mammal’s reproduction?

A
  • the implantation of the embryo on the uterine walls
  • development of the embryo internally
  • increased chance of survival
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59
Q

what is pregnancy in mammals?

A
  • the growth of an embryo within the mammal
  • allows the embryo to be protected from the external environment
  • constant nutrient supply
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60
Q

what are hormones?

A
  • chemical messengers in the body

- coordinates functions such as metabolism and reproduction

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61
Q

what gland secretes hormones?

A

pituitary gland

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62
Q

what does the pituitary gland do?

A
  • secretes hormones

- stimulates other endocrine glands, regulating their hormone releases

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63
Q

what are sex hormones?

A

hormones that specifically affect the growth/function of the reproductive organs.

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64
Q

when does the reproductive cycle begin in humans?

A

during puberty

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65
Q

what are the hormones involved in mammalian reproduction?

A
  • androgens (testosterone)
  • oestrogens
  • progestogens
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66
Q

what is the purpose of oestrogen?

A
  • control the development and functioning of the female reproductive system
    i. e. enlarged breasts, pubic hair and widening hips
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67
Q

what is the purpose of progesterone?

A
  • primary hormone in pregnancy
  • stimulates secretion of milk (lactation)
  • drop in progesterone leads to menstruation
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68
Q

how does oestrogen and progesterone regulate the ovarian cycle?

A

controls the production and maturation of gametes in the ovaries

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69
Q

how does oestrogen and progesterone regulate the menstrual cycle?

A

prepares the uterus for implantation of a fertilised egg

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70
Q

what is menstruation caused by?

A
  • a sudden drop in progesterone and oestrogen, when there is no fertilised egg
  • lining in the uterus tears away, exiting the body through the vagina
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71
Q

what is the follicle stimulating hormone (FSH)?

A

helps with the maturation of follicles in the ovaries

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72
Q

what is the luteinising hormone (LH)?

A

promotes final maturation of the ovarian follicle, ovulation and development of the corpus luteum

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73
Q

what is ovulation?

A
  • the release of an egg

- usually occurs on day 14 of the menstrual cycle

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74
Q

when is the follicular phase in the menstrual cycle?

A

from day 1 - day 14

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75
Q

when is the luteinising phase in the menstrual cycle?

A

from day 14 - day 28

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76
Q

what happens during the luteinising phase?

A
  • the burst follicle in the ovary enlarges and changes colour
  • forms the corpus lutuem
  • corpus lutuem secretes progesterone
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77
Q

what hormone does the corpus lutuem secrete?

A

progesterone

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78
Q

how long is the average menstrual cycle?

A

28 days

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79
Q

when does luteinising hormone peak in the menstrual cycle?

A

day 14 (ovulation)

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80
Q

when does follicle stimulating hormone peak in the menstrual cycle?

A

day 14 (ovulation)

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81
Q

when does oestrogen peak in the menstrual cycle?

A
  • day 14 (ovulation)

- day 20 (same time as progesterone)

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82
Q

when does progesterone peak in the menstrual cycle?

A

day 20 (same time as oestrogen)

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83
Q

what are the uterine phases in the menstrual cycle?

A
  • menses (1-4)
  • pre-ovulation (5-13)
  • secretion (16-20)
  • pre-menstruation (21-28)
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84
Q

what are the ovarian phases in the menstrual cycle?

A
  • follicular phase
  • ovulation
  • luteal phase
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85
Q

which uterine phase occurs during the follicular phase in the menstrual cycle?

A
  • menses

- pre-ovulation

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86
Q

which uterine phase occurs during the luteal phase in the menstrual cycle?

A
  • secretion

- pre-menstruation

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87
Q

what occurs during the menses phase in the menstrual cycle?

A

the endometrium breaks down and tears away (period)

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88
Q

what occurs during the pre-ovulation phase in the menstrual cycle?

A

a new endometrium lining forms in the uterus

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89
Q

what occurs during the secretory phase in the menstrual cycle?

A

the corpus luteum secretes progesterone and oestrogen into the bloodstream

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90
Q

what occurs during the pre-menstruation phase in the menstrual cycle?

A
  • degeneration of the corpus luteum

- deterioration of the endometrium

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91
Q

what three glands play a role in the production of sperm?

A
  • hypothalamus
  • pituitary gland
  • Leydig cells
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92
Q

what hormone stimulate the production of testosterone in males?

A

luteinising hormone

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93
Q

what is the role of progesterone in the male reproductive system?

A

maintains the level of testosterone at a high level for the production of sperm

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94
Q

when does fertilisation occur?

A
  • when the haploid nucleus of the egg fuses with that of the sperm
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95
Q

what is the result of fertilisation?

A

formation of a diploid fertilised egg (zygote)

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96
Q

what hormones are secreted during pregnancy?

A
  • oxytocin
  • prolactin
  • prostaglandins
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97
Q

what is the role of prostaglandins during birth?

A

initiates labour

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98
Q

what is the role of oxytocin during birth?

A

promotes coordination contractions of the smooth muscle of the uterus and cervix

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99
Q

what is mitosis?

A

type of cell division where there is the formation of two new identical cells that contribute to growth of an organism

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100
Q

what is meiosis?

A

type of cell division that gives rise to gametes that transmit from one generation to the next

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101
Q

what role does mitosis play?

A
  • growth in multicellular organisms
  • repair of damaged tissue
  • replacement of worn-out cells
  • asexual reproduction
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102
Q

what role does meiosis play?

A

prevents the chromosome number from doubling with each generation

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103
Q

how many divisions do cells undergo during meiosis?

A

2

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104
Q

what are the successive divisions of meiosis called?

A
  • meiosis I

- meiosis II

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105
Q

what occurs in meiosis I?

A

diploid divides into two haploid daughter cells (chromosomes halved)

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106
Q

what occurs in meiosis II?

A

the two haploids divide again into four haploid daughter cells

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107
Q

what did Watson & Crick discover?

A

the double-helical structure of DNA

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108
Q

in what year did Watson & Crick discover the double-helical structure of DNA?

A

1953

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109
Q

why is DNA replication vital?

A
  • vital for the continuation of a species

- allows for genetic code to be replicated and passed on

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110
Q

what are the stages of mitosis?

A

interphase, prophase, metaphase, anaphase, telophase, cytokinesis

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111
Q

what occurs during the interphase of mitosis?

A
  • DNA replicates

- DNA begins to seperate into chromosomes

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112
Q

what occurs during the prophase of mitosis?

A
  • nuclear membrane begins to break down

- spindle forms across cells

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113
Q

what occurs during the metaphase of mitosis?

A
  • chromosomes line up across the centre of the cell (each chromosome consists of two identical sister chromatids)
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114
Q

what occurs during the anaphase of mitosis?

A
  • separation of the sister chromatids
  • chromatids become chromosomes
  • spindle fibres pull back, pulling their centromeres to opposite ends of the cells
115
Q

what occurs during the telophase of mitosis?

A
  • spindle breaks down

- nuclear membrane reappears

116
Q

what occurs during the cytokinesis stage of mitosis?

A
  • division of the cytoplasm
117
Q

what is the difference in cytokinesis in plant and animal cell mitosis?

A
  • plant: cell plate is formed between the two cells

- animal: cytoplasm constricts in the centre, pinching them seperate

118
Q

what are the components of a strand of DNA?

A
  • sugar-phosphate backbone
  • nucleotides
  • nitrogenous bases
  • hydrogen bonds
119
Q

what are the four types of nitrogenous bases in DNA?

A

adenine, guanine, cytosine and thymine

120
Q

what are nucleotides in DNA made up of?

A

phosphate group, a sugar and and nitrogenous base

121
Q

what are the nitrogenous pairs in DNA?

122
Q

what holds the two complementary strands of DNA together?

A

hydrogen bonds

123
Q

where is the hydrogen bond located in a DNA strand?

A

between complementary bases

124
Q

what is the role of DNA?

A
  • stores genetic information

- responsible for transmitting inherited information

125
Q

what are the types of RNA?

A
  • messenger RNA (mRNA)
  • ribosomal RNA (rRNA)
  • transfer RNA (tRNA)
126
Q

what does mRNA do?

A

involved in carrying information from DNA from the nucleus to the cytoplasm

127
Q

what does rRNA do?

A

brings mRNA and tRNA together during translation

128
Q

what does tRNA do?

A

assists in ‘translating’ mRNA messages into proteins

129
Q

what are the steps in DNA replication?

A
  1. DNA double helix unwinds
  2. DNA unzips
  3. nucleotides are added against each strand
  4. replication errors are identified and correct
130
Q

what enzyme is responsible for unwinding and unzipping the DNA strand during DNA replication?

131
Q

how does the helicase enzyme unzip the DNA strand?

A

disrupts the weak hydrogen bonds between the complementary bases

132
Q

what enzyme is responsible for producing RNA during DNA replication?

133
Q

which enzyme is responsible for adding nucleotides during DNA replication?

A

DNA polymerase III

134
Q

what do nucleotide units consist of?

A

made of sugar-phosphate-base

135
Q

which end of the DNA strand does DNA replication begin from?

A

the 3 prime end (3’)

136
Q

which end of the DNA strand does DNA replication end on?

A

the 5 prime end (5’)

137
Q

are the two strands in DNA parallel or antiparallel?

A

antiparallel (run in opposite directions)

138
Q

which strand add nucleotides in the same direction of the replication fork opening up?

A

the leading strand

139
Q

which strand add nucleotides in the opposite direction of the replication fork opening up?

A

the lagging strand

140
Q

which enzyme joins the Okazaki fragments to form one continuous strand?

141
Q

what are the fragments added to the lagging strand called?

A

Okazaki fragments

142
Q

which enzyme ‘proofreads and edits’ the DNA strand during DNA replication?

A

DNA polymerase I

143
Q

which enzyme seals both sides of the DNA strand?

144
Q

what enzyme connects the Okazaki fragments to the lagging strand?

145
Q

what environmental factors cause mutagens?

A

radiation, chemicals, viruses

146
Q

why is a mismatched pair dangerous when it comes to DNA replication?

A

when an incorrect pair is missed by the polymerase, the mistake will be replicated, making the mistake no longer detectable.

147
Q

what does genetic continuity rely on?

A

consistent and correct replication of genetic information

148
Q

how is genetic variation introduced into a population?

A
  • mutation
  • mixing of parental gene
  • introduction of new alleles
149
Q

what is the acronym for the stages of mitosis?

A 
IPMAC
I - interphase
P - prophase
M - metaphase
A - anaphase
C - cytokinesis
150
Q

are humans prokaryotic or eukaryotic?

A

eukaryotic (you-karyotic lol)

151
Q

how many chromosomes are held in a prokaryotic cell?

152
Q

is the chromosome in a prokaryotic cell membrane bound?

A

no, like a noob

153
Q

where is the chromosome located in a prokaryotic cell?

A

floats around the cytoplasm (a dense region called the nucleoid)

154
Q

what is the structure of the DNA in prokaryotic cells?

A
  • not a helix

- two circles of single strands twisted around each other

155
Q

what are plasmids in prokaryotic cells?

A

non-chromosomal DNA

156
Q

how are plasmids advantageous for prokaryotes?

A

provides a select advantage

e.g. resistance to antibiotics

157
Q

why is prokaryotic DNA tightly packaged?

A

prokaryotic DNA is ~1300μm, which needs to fit in bacteria as small as 3μm

158
Q

what is non-coding DNA?

A

DNA that is not used directly to make products (proteins or RNA)

159
Q

how much of human DNA is non-coding?

160
Q

what is coding DNA?

A

DNA that contains sequences that code for products like proteins or RNA.

161
Q

what are non-coding DNA sequences called?

162
Q

what are coding DNA sequences called?

163
Q

is mitochondria DNA (mtDNA) passed down maternally or paternally?

A

maternally (inherited only from the mother)

164
Q

what are the steps for polypeptide synthesis?

A

DNA –> RNA –> protein

165
Q

what are codons?

A

triplets of bases that are used to code instructions for each amino acid in a protein chain

166
Q

what process allows for DNA to produce RNA?

A

transcription

167
Q

what process allows for RNA to produce proteins?

A

translation

168
Q

what is a polypeptide?

A

a molecule made up of a chain of many different amino acids joined by peptide bonds

169
Q

what are the amino acids joined by in a polypeptide chain?

A

peptide bonds

170
Q

what carries out the instructions instead of the DNA for polypeptide synthesis?

A

mRNA (messenger RNA)

171
Q

what is the role of messenger RNA (mRNA) in polypeptide synthesis?

A

carries out a ‘transcribed’ copy of the instructions to the ribosomes

172
Q

what is the role of ribosomes in polypeptide synthesis?

A

‘translates’ the message carried by the mRNA into a product

e.g. protein

173
Q

is the sugar different in RNA and DNA?

A

yes
RNA - ribose sugar
DNA - deoxyribose sugar

174
Q

what is the sugar in RNA?

A

ribose sugar

175
Q

what is the sugar in DNA?

A

deoxyribose sugar

176
Q

how are the nitrogenous bases different in RNA and DNA?

A

RNA has the base uracil (U) instead of thymine (T)

177
Q

what is the role of transfer RNA (tRNA)?

A
  • shaped like a clover
  • had three unpaired bases on one end (anticodons)
  • anticodons connects to its complementary mRNA strand
  • binds with a specific amino acid (according to the anticodon bases)
178
Q

what is the role of ribosomal RNA (rRNA)?

A

forms a structural part of ribosomes

179
Q

when does transcription occur in polypeptide synthesis?

A

when RNA polymerase binds to a section in DNA and begins building RNA, to make a complementary RNA strand

180
Q

what is the coding strand?

A
  • the antisense strand

- complementary to the non-coding strand, so has the same code as the mRNA being made

181
Q

what is the non-coding strand?

A
  • the sense strand

- has the genetic information to make a protein

182
Q

what occurs during the transcription process in polypeptide synthesis?

A
  • the sense strand of DNA acts as a template for the mRNA
  • mRNA molecule is exactly the same code as the antisense strand, but U replaces T
  • proofreading also occurs here
183
Q

what occurs during the translation stage in polypeptide synthesis?

A
  • occurs when the ribosomes matching tRNA to the mRNA according to their complementary bases
  • the amino acids on the tails of the tRNA are linked with one another
  • tRNA detaches from the mRNA, leaving a growing polypeptide chain
184
Q

what is a locus?

A

position of a gene on a chromosome

185
Q

what is a genome?

A

the total amount of genetic material can hold in each of its cells

186
Q

what are phenotypes?

A

observable physical characteristics of an organism

187
Q

what are alleles?

A

different forms of the same gene

188
Q

what are homologous chromosomes?

A

carry genes for the same traits in the same position but may have differing alleles

189
Q

what is a genotype?

A

the genetic blueprint of an organism

190
Q

what is gene expression?

A

switching on or off of genes to make the required proteins and other products

191
Q

how do environmental factors affect gene expression/phenotype?

A

the environment can chemically modify DNA

192
Q

what are some examples of environment affect phenotypes?

A
  • colour change in hydrangeas according to acidity of the soil
  • stunted growth of children with a lack of nutrients
193
Q

how can identical twins be different?

A

have the game genotypes but differing phenotypes due to difference in environment

194
Q

how many different structures are there in proteins?

195
Q

what are the levels of protein structure?

A
  1. primary
  2. secondary
  3. tertiary
  4. quaternary
196
Q

what is the structure of a protein in the primary level of structure?

A
  • basic structure of a protein

- linear chains or polypeptides

197
Q

what is the structure of a protein in the secondary level of structure?

A
  • three-dimensional arrangement of the polypeptide chain (arranged in a helix or pleats)
198
Q

what is the structure of a protein in the tertiary level of structure?

A
  • an even more complex three-dimensional structure

- further folded than secondary level

199
Q

what is the structure of a protein in the quaternary level of structure?

A
  • made of up of multiple polypeptide chains

- very complex three- dimensional structure

200
Q

what are five main types of protein?

A

structural, enzymes, communication, transport/storage, sensory

201
Q

what are structural proteins?

A
  • found in connective tissues such as skin, cartilage, bone, tendons and ligaments
  • responsible for forming the cytoskeleton (maintains shape of cells)
    i. e. support and movement
202
Q

what are enzymes?

A
  • involved in all biochemical processes of cellular metabolism
  • catalyse reactions
    i. e. enzymes and hormones
203
Q

what are communicative proteins?

A
  • in charge of cell communication, signalling and biological recognition
  • some proteins form channels in cell membranes to carry substances essential for cell functions
  • hormones, neurotransmitters (communicate messages to trigger responses to the environment)
    i. e. signalling and biological recognition
204
Q

what are transport/storage proteins?

A
  • known as ligand-binding proteins
  • bind to or carry or store chemicals in the body
  • must be able to bind easily and drop off the chemical where it is needed
    e. g. haemoglobin with oxygen
205
Q

what are sensory proteins?

A
  • proteins that change their shape or biochemistry activity in response to stimuli
    e. g. dilating of pupil
206
Q

what is the study of a set of proteins in an organism called?

A

proteomics

207
Q

what is the difference between variance and variability?

A

variation - evident in individuals

variability - different forms of a gene within a population

208
Q

describe variability in terms of genetics.

A
  • relates to the different forms of a gene in a POPULATION

- total of all alleles present in the gene pool of a poulation

209
Q

what are the factors that causes variation during sexual reproduction?

A

mutation, fertilisation and meiosis

210
Q

what is a homologous pair in a cell?

A

two chromosomes that carry the alleles for the same genes

211
Q

what is crossing over?

A
  • the swapping of genes on the maternal and paternal genes

- introduces variation

212
Q

how many stages are in meiosis?

A

two

  1. meiosis I - two daughter cells
  2. meiosis II - four daughter cells
213
Q

where is the centromere?

A

the connection between the two chromatids of a chromosome

214
Q

what is a chromatid?

A

one of two identical halves of a chromosome

215
Q

what is independent assortment?

A

how different genes independently separate from one another when reproductive cells are develop

216
Q

what are the stages of meiosis?

A
  • early prophase
  • late prophase
  • metaphase I
  • anaphase I
  • telophase
  • cytokinesis I
  • metaphase II
  • anaphase II
  • cytokinesis II
217
Q

what occurs during the early prophase in meiosis?

A

chromosomes separate into homologous pairs

218
Q

what occurs during the late prophase in meiosis?

A
  • nuclear membrane breaks down
  • chromosomes splits into chromatids
  • crossing over occurs
219
Q

what occurs during the metaphase I in meiosis?

A
  • chromosomes align in the middle
  • random segregation
  • independent assortment
220
Q

what occurs during the anaphase I in meiosis?

A

chromosome pairs seperate, moving to opposite ends of the cell

221
Q

what occurs during the telophase in meiosis?

A
  • two daughter cells formed

- number of chromosomes are halved

222
Q

what occurs during the cytokinesis I in meiosis?

A
  • daughter cells are not identical

- have half the number of chromosomes

223
Q

what occurs during the metaphase II in meiosis?

A

chromosomes align in the centre

224
Q

what occurs during the anaphase II in meiosis?

A

daughter chromosomes move apart

225
Q

what occurs during the cytokinesis II in meiosis?

A
  • four non-identical daughter cells

- haploid cells

226
Q

what is the genetic consequence of meiosis?

A
  • one cell undergoes two meiotic divisions to make four haploid cells
  • new combinations are the result of both crossing over and random segregation
227
Q

what is the genetic consequence of fertilisartion?

A
  • two haploid gametes fuse to form a diploid zygote

- 50% maternal - 50% paternal

228
Q

what does autosomal mean?

A

a gene is that NOT sex-linked

229
Q

what does recessive mean?

A
  • genes which are expressed in offspring only when inherited from both parents
  • overpowered by dominant genes
230
Q

what does autosomal recessive inheritance refer to?

A
  • not sex-linked
  • recessive gene received both paternally and maternally
  • affected individual must carry TWO of the allele
  • trait skips a generation
231
Q

what is an example of autosomal recessive inheritance?

A

cystic fibrosis

232
Q

what are alleles?

A

different forms of the same gene and occur in pairs in diploids

233
Q

how many alleles of each gene do diploids have?

234
Q

how many alleles of each genes do haploids (gametes) have?

235
Q

define genotype.

A

combination of genes that is present in each cell

236
Q

what does it mean to be homozygous?

A

same alleles of the certain gene

237
Q

what does it mean to be heterozygous?

A

different alleles of the certain gene

238
Q

what does autosomal dominant inheritance refers to?

A
  • not sex-linked
  • affected individual must carry at least ONE of the affected alleles
  • does NOT skip a generation
239
Q

how are females different from males according to their genes?

A

female - XX

male - XY

240
Q

when does sex linkage occur?

A
  • when some genes carried on the X and Y chromosomes code for something that isn’t gender
  • appears more in males
241
Q

what is an example for sex linkage?

A

colour blindness

242
Q

why does sex linkage occur more frequently in males?

A

the male has no equivalent allele on the Y chromosome to mask the defective allele

243
Q

what is incomplete dominance?

A

there is the blending of the two alleles expressed

244
Q

what is co-dominance?

A

both alleles are expressed, creating a new phenotype

245
Q

what is an example of incomplete dominance?

A

a red flower is mated with a white flower to produce a pink flower

red flower + white flower = pink flower

246
Q

what is an example of co-dominance?

A

a red bull is mated with a white bull to produce a spotted red-white bull (roan)

247
Q

what does multiple alleles refer to?

A

there may be three or more alleles for a single gene trait

248
Q

what is an example of multiple alleles?

A

blood types

249
Q

how are males and female distinguished in pedigrees?

A

male - square

female - circle

250
Q

how are affect individuals distinguished in a pedigree?

A

individual is usually coloured in

251
Q

how are identical twins distinguished in a pedigree?

A

point connecting both twins to parents with a line between them

252
Q

how are non-identical twins distinguished in a pedigree?

A

point connecting both twins to parents

253
Q

what are punnett squares used for?

A

to see the probability of genotypes and phenotypes

254
Q

what is a pedigree chart used for?

A

used to trace the inheritance of a particular trait through several generation

255
Q

how is the frequency of a certain allele calculated?

A

(number of copies of allele in population)/(total number of the genes in population)

256
Q

what are single nucleotide polymorphisms (SNPs)?

A

important genetic markers that are used to distinguish individuals and to identify disease susceptibility

257
Q

what does STR stand for?

A

short tandem repeats

258
Q

what does SNPs stand for?

A

single nucleotide polymorphisms

259
Q

what is a haplotype?

A

cluster of marker alleles on the same chromosome

260
Q

what is a genetic consequence of mutation?

A

is a change in DNA that may give a rise to new alleles and different phenotypes

261
Q

what is DNA sequencing?

A

the process of determining the nucleic acid sequence (the order of the bases A, T, C and G)

262
Q

what are the three methods of DNA sequencing called?

A
  1. The Sanger Method
  2. The Maxam-Gilbert Method
  3. New-generation technologies
263
Q

what is DNA profiling?

A

scientific technique used to identify and compare individuals by characteristics in their DNA

264
Q

what are short tandem repeats (STRs)?

A

sections of non-coding DNA that are repeated many times over that are unique for every individual

265
Q

what are the steps for DNA profiling?

A
  1. sample is collected
  2. the polymerase chain reaction (PCR) is used to multiple the amount of DNA
  3. gel electrophoresis is used to seperate the the segments
    (smaller segments travel further in the gel)
266
Q

how is gel electrophoresis used in DNA profiling?

A
  • used to separate segments of DNA according to length

- shorter fragments travel further in the gel

267
Q

define population genetics.

A

the study of genetic variation within a population, and changes in frequency of genes and alleles over time

268
Q

what does conservation genetics look at?

A

looks at how genes are inherited in a population, to avoid extinction and maintain biodiversity

269
Q

what are haplotype network maps used for?

A

used to map out different haplotypes in populations

270
Q

what is a haplotype network map?

A

two-dimensional summary of genetic diversity within a group

271
Q

what does each circle represent in a haplotype network map?

A

a unique haplotype

272
Q

what does the size of the circle signify in a haplotype network map?

A

size is proportional to the number of individuals that belong to that haplotype

273
Q

what do the connecting lines between each circle mean in haplotype network maps?

A

the lines connect each haplotype to its closest relative

274
Q

what do the number of bars on each connecting line mean in a haplotype network map?

A

each bar represents that mutational steps between each haplotype
(more bars = more difference in sequence)

275
Q

what is the advantage analysing large scale genetic information?

A

can be used to predict the inheritance of a disease or disorder?

276
Q

what is the Out-of-Africa theory?

A
  • the theory states that Homo sapiens developed first in Africa and then spread around the world
  • all modern people are ultimately people of African descent
277
Q

how does the Maxam-Gilbert method work for DNA sequencing?

A

chemicals are used the identify a specific base

278
Q

how does the Sanger method work for DNA sequencing?

A

DNA is isolated and replicated using PCR

279
Q

how does new-generation technologies work for DNA sequencing?

A

DNA is propelled with a motor protein through a protein nanopore

280
Q

what is conservation manangement?

A

how to avoid extinction by maintaining genetic biodiversity

281
Q

what is the traditional conservation management method?

A

field observations

282
Q

what are the two human migration theories?

A
  1. multiregional hypothesis (MRE)

2. Out of Africa hypothesis

283
Q

what does the multiregional hypothesis (MRE) state?

A
  • suggest gene flow between neighbouring populations

- all humans can be linked back to Homo erectus from Africa

Biology (8 decks)

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