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A Biology Mock Study pt2 > Reproduction and Inheritance - GCSE > Flashcards

Reproduction and Inheritance - GCSE Flashcards

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1
Q

where are chromosomes found?

A

in the nucleus of a cell

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2
Q

what does the nucleus contain genetic material in the form of?

A

chromosomes

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3
Q

what are chromosomes?

A

long lengths of DNA coiled up

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4
Q

what is a gene?

A

a short section of DNA

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5
Q

what are human cells?

A

they are diploid. Meaning they have two copies of each chromosome arranged in pairs

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6
Q

how many chromosomes does a human cell nucleus contain?

A
  1. This means the diploid number for a human is 23
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7
Q

what is DNA?

A

it is a long list of instructions of how to put an organism together and make it work

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8
Q

what does all of the DNA in an organism make up?

A

the organism’s genome (a complete set of information in a organism)

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9
Q

what is a gene (in a DNA molecule)?

A

it is a chemical instruction that codes for saying how to make a particular protein

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10
Q

why are proteins important?

A

because they control most processes in the body. They also determine inherited characteristics (eg. eye colour)

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11
Q

why do genes end up controlling our inherited characteristcs?

A

because they control the production of proteins, and therefore they control inherited characteristics as well

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12
Q

what is the name for different versions of the same gene?

A

alleles

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13
Q

what do alleles (different versions of the same gene) give?

A

they give different versions of a characteristic

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14
Q

how can an ordinary cell make a new cell?

A

it can make a simple cell by simply dividing into two. Both new cells are genetically identical to the original cell and both contain exactly the same genetic information

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15
Q

what is it called when an ordinary cell makes up new cells?

A

mitosis

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16
Q

what is asexual reproduction?

A

it is when it only involves one parent, the offspring has identical genes to the parent (there is no variation between the parent and the offspring)

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17
Q

what is it called when some organisms produce offspring using mitosis?

A

asexual reproduction (only one parent)

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18
Q

what does mitosis produce?

A

genetical identical cells (when a cell reproduces itself by splitting to form two cells with identical sets of chromosomes)

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19
Q

what happens when a cell gets a signal to divide?

there are 4 steps

A

1) it needs to duplicate its DNA so that there’s on copy for each new cell. The DNA forms X-shaped chromosomes, each arm of the chromosome is an exact duplicate of the other
2) the chromosomes lines up at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell
3) membrane form around each of the sets of chromosomes. These become the nuclei of the two new cell
4) lastly, the cytoplasm divides

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20
Q

what does sexual reproduction produce?

A

genetically different cells

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21
Q

what is sexual reproduction?

A

it is where information from two organisms (a father and a mother) is combined to produce offspring which are genetically different to either parent

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22
Q

what does sexual reproduction involve?

A

it involves gametes

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23
Q

what are gametes?

A

the sperm cells and egg cells. They are haploid as well.

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24
Q

what does haploid mean?

A

it means half the number of chromosomes in a normal cell

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25
Q

what is the haploid number for humans?

A

23, because each gamete contains 23 chromosomes.

46 chromosomes/2 = 23

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26
Q

what happens at fertilisation?

A

a male gamete fuses with a female gamete to form a zygote. The zygote ends up with the full set of chromosomes (46 chromosomes)

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27
Q

what is a zygote?

A

a fertilised egg

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28
Q

what causes a zygote to be developed into an embryo?

A

the zygote undergoes cell division (by mitosis) and develops into an embryo

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29
Q

how does the embryo inherits features from both parents?

A

it receives a mixture of chromosomes from its mom and dad

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30
Q

what is the order for the fertilisation of gametes?

A

it is random. This produces genetic variation in the offspring

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31
Q

what are gametes produced by?

A

meiosis

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32
Q

what is a meiosis?

A

type of cell division

  • produces 4 daughter cells
  • offspring are different to parents
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33
Q

why is meiosis different to mitosis?

A

because it doesn’t produce identical cells

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34
Q

where does meiosis happens in humans?

A

it only happens in the reproductive organs (ovaries and testes)

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35
Q

what do meiosis produce?

A

it produces four haploid cells whose chromosomes are not identical

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36
Q

how many divisions does meiosis involve?

A

2

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37
Q

what is the first part of the division of meiosis?

there are 4 steps

A

1) before the cell starts to divide it duplicates its DNA. One arm of each X-shaped chromosome is an exact copy of the other arm
2) in the first division in meiosis the chromosome lines up in pairs in the centre of the cell. One chromosome in each pair came from the organism’s mother and one came from its father
3) the pairs are then pulled apart, so each new cell only has one copy of each chromosome. Some of the father’s chromosomes and some of the mother’s go into each new cell
4) each new cell will have a mixture of the mother’s and father’s chromosome. Mixing up the genes like this is really important because it creates genetic variation in the offspring

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38
Q

what is the second part of the division of meiosis?

2 steps

A

5) chromosomes line up again in the centre of the cell. The arm of the chromosomes are pulled apart
6) you get four haploid gametes. Each gamete only has a single set of chromosomes. The gametes are all genetically different.

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39
Q

what gametes do flowers contain?

A

male and female gametes

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40
Q

what is the name of the male reproductive part of a flower?

A

the stamen

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41
Q

what are the 2 things that the stamen consists?

A
  • anther

- filament

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42
Q

what does the anther contain?

A

pollen grains, which produce the male gametes (sperm)

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43
Q

what is the filament?

A

the stalk that supports the anther

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44
Q

what is the name of the female reproductive part of a flower?

A

the carpel

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45
Q

what are the 3 things the carpel consist of?

A
  • ovary
  • style
  • stigma
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46
Q

what is the stigma?

A

it is the end bit that the pollen grains attach to

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47
Q

what is the style?

A

it is the rod-like section that supports the stigma

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48
Q

what does the ovary contain?

A

the ovary contains the female gametes (eggs) inside the ovules

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49
Q

what does sexual reproduction in plants involve?

A

it involves pollination

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50
Q

what is pollination? and why does it happen?

A

the transfer of pollen from an anther to a stigma. It is so that the male gametes can fertilise the female gametes in sexual reproduction

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51
Q

what is cross-pollination?

A

it is a type of sexual reproduction where pollen is transferred from the anther of one plant to the stigma of another

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52
Q

what do plants that cross-pollinate rely on?

A

they rely on things like insects or the wind to help them pollinate

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53
Q

what is it called when plants need outside help to pollinate?

A

insect pollination

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54
Q

what are 4 different ways that plants are adapted for pollination by insects?

A

1) brightly coloured petals
2) scented flowers and nectaries (glands that secrete nectar)
3) make big sticky pollen grains and thee grains stick to insects as they go from plant to plant
4) the stigma is sticky so that any pollen picked up by insects on other plants will stick to the stigma

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55
Q

other than insect pollination, what is another way for plant pollination?

A

pollination by wind

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56
Q

what are 5 ways in which plants are adapted for plant pollination?

A

1) small, dull petals on the flower
2) no nectaries or strong scents
3) a lot of pollen grains, they are small and light so that they can easily be carried by wind
4) long filaments that hang the anthers outside the flower so that a lot of the pollen gets blown away by the wind
5) a large feathery stigma to catch pollen as it’s carried past by the wind. The stigma often hangs outside the flower too

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57
Q

what happens after the pollen has found its way to the stigma?

A

fertilisation

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58
Q

what is fertilisation?

A

it is when the two nuclei fuse together to make a zygote. This divides by mitosis to form an embryo

59
Q

what are the 4 steps of fertilisation (in plants)?

A

1) pollen grain lands on the stigma of flower, usually with the help from insects or the wind
2) a pollen tube grows out of the pollen grain and down through the style to the ovary and into the ovule
3) a nucleus from the male gamete moves down the tube to join a female gamete in the ovule
4) each fertilised female gamete forms a seed. The ovary develops into a fruit around the seed

60
Q

what does a seed need to start germinating?

A

the right conditions

61
Q

what happens to a seed if it isn’t on the right conditions?

A

it will lie dormant until the conditions are right for germination

62
Q

what is germination?

A

when seeds start to grow

63
Q

what are 3 things that need to be on the right conditions for a seed to start germinating?

A
  • water
  • oxygen
  • temperature
64
Q

why does water need to be on the right conditions for a seed to start germinating?

A

water is used to activate the enzymes that break down the food reserves in the seed

65
Q

why does oxygen need to be on the right conditions for a seed to start germinating?

A

it needs to be right for the respiration of the plant, which transfers energy from food for growth

66
Q

why does a suitable temperature need to be on the right conditions for a seed to start germinating?

A

it needs to be right for the enzymes inside the seed to work (this depends on what type of seed it is.

67
Q

what does a developed seed contain?

A

an embryo and a store of food reserves, wrapped in a hard seed coat

68
Q

how does a germinating seed get energy from food stores?

A

1) when a seed starts to germinate, it gets glucose for respiration from its own food store. This transfers the energy it needs to grow
2) once the plant has grown enough to produce green leaves it can get its own food for energy from photosynthesis

69
Q

how do you investigate the conditions needed for germination?
(there are 6 steps)

IMPORTANT

tube 1 - water, oxygen, room temperature (control tube)
tube 2 - no water, oxygen, room temperature
tube 3 - water, oxygen, low temperature
tube 4 - water, no oxygen, room temperature

A

1) take four boiling tubes and put some cotton wool at the bottom of each one
2) put 10 seeds on top of the cotton wool in each boiling tube
3) set up each boiling tube
4) leave the tubes for a few days and then observe what has happened.
5) control all the variables during the experiment. Remember to only change one condition at a time so you know that any effect on germination is due to the change in that one tube
6) tube 2 the only change from the control tube (Tube 1) is lack of water. In tube 3 only the temperature has changed. In tube 4 the only change is the lack of oxygen

70
Q

how should you interpret your observation from “How do you investigate the conditions needed for germination?” experiment?

A

You should only see germination happening in Tube 1 because all the conditions needed for germination are present.

The seeds in the other boiling tubes won’t germinate, this is shows that the seeds need water, oxygen and suitable temperature to germinate

71
Q

what are the two ways plants reproduce asexually?

A
  • naturally

- artificially (cloned)

72
Q

how are plants artificially reproduced (how are they cloned)?

A

1) gardeners can take cutting from good parent plants, and then plant them to produce genetically identical copies (clones) of the parent plant.
2) these plants can be produced quickly and cheaply

73
Q

how are plants naturally reproduced?

A

by growing new plants from their stems

74
Q

how are strawberries naturally reproduced?

A

1) the parent strawberry plant sends out runners - fast growing stems that grow out sideways just above the ground.
2) the runners take root at various points (a short distance away) and new plants start to grow
3) the new plants are clones of the parent strawberry plant, so there’s no genetic variation between them

75
Q

what does the male reproductive system make?

A

it makes sperm

76
Q

what are sperms?

A

they are male gametes

77
Q

where are the sperms made?

A

they are made in the testes ALL THE TIME after puberty

78
Q

sperm mixed with a liquid make up what?

A

it makes up semen which is ejaculated from the penis into the vagina of the female during sexual intercourse

79
Q

what is the urethra - male reproductive system

A

a tube which carries sperm through the penis during ejaculation . Urine also passes through the urethra to exit the body

80
Q

what is the erectile tissue - male reproductive system

A

swells when filled with blood to make the penis erect

81
Q

what is testis - male reproductive system

A

where sperm are made (the plural is testes)

82
Q

what are the glands - male reproductive system

A

where the liquid that’s added to sperm to make semen is produced

83
Q

what is the vas deferens (sperm duct) - male reproductive system

A

muscular tube that carries sperm from testis towards the urethra

84
Q

what is the scrotal sac - male reproductive system

A

it is what hangs behind the penis and contains the testes

85
Q

remember what the male reproductive system diagram looks like –>

A

https://1.bp.blogspot.com/-jsasG6ZCXvM/XT7GKAV3D5I/AAAAAAAAAUw/ZFSsOOQ-iEgbE2bKVmWi9r1afLBCYQqoACLcBGAs/s1600/Screenshot%2B2019-07-29%2Bat%2B6.04.46%2BPM.png

86
Q

what does the female reproductive system make?

A

it makes ova (eggs)

87
Q

what is the ova?

A

female gametes

88
Q

when is an ovum (egg) produced?

A

it is produced every 28 days from one of the two ovaries

89
Q

after leaving one of the ovaries where does the ovum pass into?

A

it passes into the fallopian tube, this is where it might meet sperm that have entered the vagina during sexual intercourse

90
Q

after the fallopian tube, what happens to the ovum tube if it isn’t fertilised by sperm?

A

the ovum break up and pass out of the vagina

91
Q

after the fallopian tube, what happens to the ovum tube if it is fertilised by sperm?

A

the ovum starts to divide, the new cells will travel down the fallopian tube to the uterus (womb) and attach to the endometrium (uterus lining)

92
Q

what does a fertilised ovum develop into?

A

an embryo

93
Q

what is the fallopian tube (oviduct) - female reproductive system

A

a muscular tube that carries the ovum from the ovary to the uterus

94
Q

what is the uterus (womb) - female reproductive system

A

the organ where an embryo grows

95
Q

what is the ovary - female reproductive system

A

the organ that produces ova and sex hormones

96
Q

what is the edonmetrium (lining of uterus) - female reproductive system

A

it is where an implantation of an embryo would happen so it has a good blood supply

97
Q

what is the cervix - female reproductive system

A

the neck of the uterus

98
Q

what is the vagina - female reproductive system

A

where the sperm are deposited

99
Q

remember what the female reproductive system diagram looks like –>

A

http://www.edplace.com/userfiles/female%20reproductive%20system.jpg

100
Q

what do hormones promote at puberty? what are those hormones

A

sexual characteristics: they are sex hormones. Testosterone in men and oestrogen in women

101
Q

what do the sex hormones in women (oestrogen) trigger/ causes?

A
  • extra hair on underarms and pubic area
  • hips to widen (important)
  • development of breasts (important)
  • menstruation cycle (important)
102
Q

what do the sex hormones in men (testosterone) trigger/ causes?

A
  • extra hair on face and body
  • muscles to develop (important)
  • penis and testicles to enlarge
  • sperm production (important)
  • deepening of voice (important)
103
Q

how many stages does the menstrual cycles has?

A

four stages

104
Q

what is the first stage of the menstrual cycle?

A

day one - menstruation starts. the uterus lining breaks down for about four days (lieee it is 5 but whatevs)

105
Q

what is the second stage of the menstrual cycle?

A

the uterus lining builds up again, from day 4 to day 14 into thick spongy layer full of blood vessels, ready to receive a fertilised egg.

106
Q

what is the third stage of the menstrual cycle?

A

an egg develops and is released from the ovary at day 14 - this is called ovulation

107
Q

what is the fourth stage of the menstrual cycle?

A

the wall is then maintained for about 14 days until day 28- If no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down and the whole cycle starts again.

108
Q

when does an embryo begin to become considered a fetus?

A

when it starts to look human

109
Q

what develops once the embryo has been implanted?

A

the placenta develops, allowing the blood of the embryo and mother get very close to allow the exchange of food, oxygen and waste (the blood doesn’t touch one another BECAUSE BLOOD CAN’T MIX TOGETHER)

110
Q

other than the placenta, what else forms in the early stages of pregnancy?

A

the amnion membrane, which surrounds the embryo and is full of amniotic fluid. Amniotic fluid protects the embryo against knocks and bumps

111
Q

what are alleles?

A

they are different versions of the same gene

112
Q

what control the characteristics you develop?

A

the genes you inherit. Some characteristics can be controlled by a single gene however most are controlled by several genes interacting.

113
Q

how many copies do you usually have of each gene?

A

most of the time you have two copies of each gene, one from each parent.

114
Q

what happens if you inherit different alleles?

A

you will have instructions for two different versions of a characteristic but you only show one version of the two. The dominant allele always wins

115
Q

what are the two alleles that fight together for a characteristic but one still always win?

A

the dominant - winner

and the recessive - loser

116
Q

actually, i was lying before, the recessive allele can win but only with one condition. what is that condition?

A

if both alleles are recessive (think of it from a point of both alleles becoming friends)

117
Q

what is the name for the inheritance of a single characteristic?

A

monohybrid inheritance

118
Q

what is used in genetic diagrams to represent genes?

A

letters. The dominant alleles are always shown with a capital letter and recessive alleles with a small letter

119
Q

what does homozygous mean?

A

it means two alleles with the same for a particular gene (two dominants or two recessive)

120
Q

what does heterozygous mean?

A

it means two different alleles for a particular gene (a dominant and a recessive)

121
Q

what is your genotype?

A

it is the alleles that you have

122
Q

what is you phenotype?

A

the characteristics the alleles produce

123
Q

go to page 114 and 115 to learn about genetic diagrams

A

vai marcela para de ser preguiçosa

124
Q

what do chromosomes control?

A

whether you’re male or female

125
Q

how many pairs of chromosomes in every human body cell?

A

23 matched pairs, in total 46 single chromosomes

126
Q

what is labelled in the 23rd pair of chromosome?

A

XX or XY, they are the two chromosomes that decide whether you turn out male or female

127
Q

what are the chromosomes males have (XX or XY)?

A

males have XY, the Y chromosome causes male characteristics

128
Q

what are the chromosomes females have (XX or XY)?

A

males have XX, the XX combination causes female characteristics

129
Q

why is the male reproductive system that at the end of the day determines the sex of the baby?

A

because all eggs have one X chromosome however the sperm can have either an X chromosome or a Y chromosome. So it really depends if the sperm that fertilised the egg carries an X or Y

130
Q

why are all animals (including humans) bound to be slightly different from each other?

A

they are bound to be slightly different from each other because their genes are slightly different

131
Q

what is the one exception of the rule of all of us having different set of genes?

A

identical twins, because their genes are exactly the same

132
Q

what is most variations in animals caused by?

A

a mixture of genetic and environmental factors

133
Q

what is almost every single aspect of a human (or other animal) affected by?

A

our environment, it can even have a large effect on human growth even before someone is born (ex. a baby’s weight at birth can be affected by the mother’s diet)

134
Q

what are the 4 factors which aren’t affected in any way by the environment?

A
  • eye colour (important)
  • hair colour in most animals (in humans, vanity plays a big part)
  • inherited disorders like haemophilia, cystic fibrosis, etc.
  • blood group (important)
135
Q

what are three factors that can be influenced by both genes or environment?

A
  • health
  • intelligence
  • sporting ability
136
Q

what environmental factors strongly affect plants?

A
  • sunlight
  • moisture level
  • temperature
  • mineral content of the soil
    (environmental variation in plants is much greater as you can see)
137
Q

what is the theory of evolution?

A

life began as simple organisms from which more complex organisms evolved (rather than just popping into existence)

138
Q

is the process of evolution still going on today?

A

yes, some bacteria are evolving to become resistant to antibiotics

139
Q

what does natural selection mean?

A

the survival of the fittest. Over many generations the characteristics that increase survival becomes more common in the population, making the species become better and able to survive. The ‘best’ features are naturally selected and the species become more adapted to its enviroment

140
Q

how did Charles Darwin come up with the theory of evolution?

A

he came up with the theory of evolution through natural selection

141
Q

what does the survival of the fittest mean?

A

organisms with the most suitable characteristics for the environment would be more successful competitors and so would have a better chance of survival

142
Q

what would a surviving organisms have an increased chance of?

A

of breeding and passing on their genes, meaning that a greater proportion of individuals in the next generation will have the better alleles, and so the characteristics, that help survival

143
Q

how can bacterium become less affected by a particular antibiotic?

A

bacteria develop random mutation in their DNA. These can lead to changes in a bacterium’s characteristics.

A Biology Mock Study pt2 (9 decks)

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