Reproduction SME flashcards
Mocks (103 cards)
1
Q
Define the term sexual reproduction.
A
Sexual reproduction is the reproductive process during which the nuclei of two gametes fuse to form a zygote and genetically different offspring are produced.
2
Q
Define the term fertilisation
A
Fertilisation is the fusion of gamete nuclei.
3
Q
What are gametes?
A
Front
Sexual & Asexual Reproduction: Differences
What are gametes?
Back
Sexual & Asexual Reproduction: Differences
4
Q
How many chromosomes do human gametes contain?
A
Human gametes contain 23 chromosomes, half of the normal 46 found in other body cells because they only contain one copy of each chromosome.
5
Q
Define the term asexual reproduction.
A
Asexual reproduction is the reproductive process that results in genetically identical offspring from one parent.
6
Q
How do offspring produced by asexual reproduction compare to their parent and each other?
A
Offspring produced by asexual reproduction are genetically identical to the parent and to each other, as there is no fusion of gametes and no mixing of genetic information, resulting in clones.
7
Q
What are the advantages of sexual reproduction?
A
Sexual reproduction allows for genetic variation among offspring, which can increase the chances of survival in changing environments and help in evolution.
8
Q
What are the disadvantages of sexual reproduction?
A
Sexual reproduction requires the production of specialised gametes and the search for a mate, which can be energetically costly and time-consuming.
9
Q
What are the advantages of asexual reproduction?
A
Asexual reproduction is efficient in rapidly producing numerous offspring, requires only one parent, and ensures the preservation of favourable traits.
10
Q
What are the disadvantages of asexual reproduction?
A
Asexual reproduction lacks genetic variation, making offspring vulnerable to changes in the environment. It may also lead to the accumulation of harmful mutations and limit adaptability to new conditions.
11
Q
How does the number of parents differ in sexual and asexual reproduction?
A
Sexual reproduction involves two parents while asexual reproduction involves one parent.
12
Q
What type of cell division is required for sexual reproduction?
A
Meiosis is required for sexual reproduction.
13
Q
Define fertilisation.
A
Fertilisation is the fusion of gamete nuclei, resulting in the formation of a zygote.
14
Q
What is the process of fertilisation in humans?
A
Fertilisation in humans involves the fusion of a sperm cell with an egg cell.
15
Q
What is the result of fertilisation?
A
The result of fertilisation is the formation of a zygote/fertilised egg cell.
16
Q
True or False?
Fertilisation leads to variation in offspring.
A
True.
Fertilisation leads to variation in offspring.
17
Q
Define zygote.
A
A zygote is a fertilised egg cell formed by the fusion of gamete nuclei.
18
Q
What is the significance of variation in offspring?
A
Variation in offspring allows for adaptation to changing environments.
19
Q
What is the main source of genetic variation in offspring in sexual reproduction?
A
The main source of genetic variation in offspring in sexual reproduction is the production of gametes by meiosis, resulting in new combinations of alleles on the chromosomes.
20
Q
State the importance of fertilisation.
A
Fertilisation is important as it leads to the formation of genetically diverse offspring.
21
Q
True or False?
Fertilisation involves the fusion of gametes from the same parent.
A
True or False?
Fertilisation involves the fusion of gametes from the same parent.
22
Q
Define embryo.
A
An embryo is the early developmental stage of a multicellular organism that is produced after cell division of a zygote.
23
Q
Define the term pollination.
A
Pollination is the process of transferring pollen from the anther (male part) to the stigma (female part) of a flower.
24
Q
What are the two main mechanisms of pollination?
A
The two main mechanisms of pollination are insect pollination and wind pollination.
25
True or False?
Pollen is capable of locomotion.
False.
Pollen is not capable of locomotion. It requires a mechanism such as wind, water or insects to transfer it from place to place.
26
Describe how insect-pollinated flowers are adapted for pollination.
Insect-pollinated flowers have structures that allow insects to transfer pollen, such as sticky pollen and nectar-producing glands. They attract insects using brightly coloured petals and attractive smells.
27
Describe how wind-pollinated flowers are adapted for pollination.
Wind-pollinated flowers produce large amounts of lightweight pollen and have exposed stigmas to catch the pollen carried by the wind.
28
What is cross-pollination?
Cross-pollination occurs when pollen is transferred from the anther of a flower to the stigma of a flower from another plant of the same species.
29
What is self-pollination?
Self-pollination occurs when pollen is transferred from the anther of a flower to:
the stigma of the same flower
the stigma of another flower on the same plant
30
What is the importance of pollination in plant reproduction?
Pollination is crucial for plant reproduction as it facilitates the transfer of pollen, leading to fertilisation and the production of seeds and fruits.
31
True or False?
Petals of insect-pollinated flowers tend to be brightly coloured.
True.
Petals of insect-pollinated flowers tend to be brightly coloured to attract pollinator insects.
32
How are anthers adapted in wind-pollinated plants?
Anthers are adapted in wind-pollinated plants by swinging on long filaments outside of the flower to transfer pollen to the wind.
33
Define fertilisation in plants.
Fertilisation is the process in which the nucleus of a male pollen grain fuses with the nucleus of an ovum in the ovary, leading to the formation of a zygote.
34
How does fertilisation occur in plants?
Fertilisation in plants occurs when the pollen grain nucleus fuses with the ovum nucleus, typically in the ovary.
34
Describe the growth of the pollen tube in plants.
The pollen tube grows from the pollen grain towards the ovary, allowing the pollen nucleus to reach the ovum for fertilisation.
34
True or False?
The ovule contains the male gamete.
False.
The ovule contains the ovum, which is the female gamete.
35
What happens after fertilisation in plants?
After fertilisation, the ovule develops into the seed, while the ovary forms the fruit.
36
Why is fertilisation in plants important?
Fertilisation is essential for plant reproduction as it leads to the formation of a zygote, which develops into an embryo plant within the seed.
37
True or False?
Fertilisation occurs when the male and female gametes fuse.
True.
Fertilisation occurs when the nucleus of a male pollen grain fuses with the nucleus of the ovum (gametes) in the ovary.
37
What does the zygote develop into after fertilisation?
After fertilisation, the zygote develops into an embryo plant.
38
Define ovule.
An ovule is a structure within the ovary of a flower that contains the ovum, which is the female gamete.
39
Define germination.
Germination is the start of growth in a seed under suitable conditions of water, oxygen, and warmth. It is characterised by:
The swelling of the seed
Bursting of the seed coat
The emergence of the embryo plant
39
What are the two main structures formed after fertilisation in plants?
After fertilisation, the ovule develops into the seed, while the ovary forms the fruit.
40
What are the three factors required for successful germination?
The three factors required for successful germination are:
Water
Oxygen
Warmth
41
True or False?
Carbon dioxide is necessary for germination.
False.
Carbon dioxide is not necessary for germination, but its presence does not inhibit the process either.
42
Four tubes of different conditions are set up to investigate germination in seedlings. One tube is a control.
What is the purpose of the control tube in the germination experiment?
The control tube contains all the factors required for germination and serves as a baseline for comparison with the other tubes where one of the factors is selectively removed.
43
Four tubes of different conditions are set up to investigate germination in seedlings. One tube has water with a layer of oil on top.
What is the purpose of the oil layer?
The oil layer prevents oxygen from reaching the seeds, selectively removing the oxygen factor to observe its effect on germination.
44
True or False?
Germination can occur if any one of the required factors is absent.
False.
Germination cannot occur if any one of the three required factors (water, oxygen, warmth) is absent.
45
What is the role of carrying out repeats in the germination experiment?
Repeating the experiment ensures that the results obtained are reliable, reducing the impact of random errors and anomalous results when calculating a mean.
46
What is the independent variable in the germination experiment? (CORMMS)
The independent variable is the abiotic conditions in which the seeds are germinating.
This is part of the CORMMS criteria for planning an investigation.
47
What is the dependent variable in the germination experiment? (CORMMS)
The dependent variable is how many seeds in each abiotic condition germinate.
This is part of the CORMMS criteria for planning an investigation.
48
What are control variables in the germination experiment? (CORMMS)
Two control variables in the germination experiment are:
Temperature (for tubes where the temperature is not being investigated as an abiotic factor)
Type of water used (i.e. sterile water)
This is part of the CORMMS criteria for planning an investigation.
49
What is the organism being investigated in the germination experiment?
The organism being investigated in the germination experiment is the same species of seeds.
This is part of the CORMMS criteria for planning an investigation.
50
True or False?
Germination marks the start of growth in a seed.
True.
Germination is the start of growth in a seed, leading to the emergence of the embryo plant.
51
What are cotyledons?
Cotyledons are seed leaves that surround and protect the embryo within the seed.
52
What is the role of cotyledons role during germination?
The role of cotyledons during germination is to provide food reserves to the developing seedling until it can photosynthesise and produce its own food.
53
Describe the process of germination in a seed.
During germination, the seed absorbs water, causing the seed coat to split. The embryo plant then grows, with the emergence of the plumule (shoot) and radicle (root).
54
How do cotyledons support the growth of a germinating seed?
Cotyledons store food reserves that provide nourishment to the developing seedling until it can produce its own food through photosynthesis. They supply the energy required for growth during the early stages of germination.
55
What structures emerge during germination?
During germination, the plumule (first shoot) and radicle (first root) emerge from the seed.
56
What are the roles of the plumule and radicle in germination?
The plumule develops into the shoot system, while the radicle grows into the root system.
57
True or False?
Cotyledons are part of the embryo plant within the seed.
True.
Cotyledons are part of the embryo plant contained within the seed, providing nourishment and support during the early stages of growth.
58
What is the role of water in the process of germination?
Water is essential for germination as it triggers the activation of enzymes within the seed, leading to the breakdown of stored nutrients.
It also causes the seed coat to split, allowing the embryo plant to emerge and initiate growth.
59
What role does the seed coat play during germination?
The seed coat protects the embryo plant within the seed and regulates the entry of water. During germination, it splits open to allow the emerging plumule and radicle to grow and initiate the development of the seedling.
60
Define asexual reproduction in plants.
Asexual reproduction in plants involves the production of offspring from a single parent, resulting in genetically identical offspring, known as clones.
61
How do runners contribute to natural asexual reproduction in plants?
Natural asexual reproduction in plants involves the growth of side branches called runners, which produce small plantlets at their ends. These plantlets develop roots upon touching the soil and eventually become independent plants.
61
True or False?
Asexual reproduction in plants produces genetically unique offspring.
False.
Asexual reproduction in plants results in genetically identical offspring, which are exact copies of the parent plant.
62
How are cuttings used in artificial asexual reproduction?
Artificial asexual reproduction in plants involves removing a section of a healthy parent plant with a new bud. This cutting is then placed in water or soil until new roots grow, resulting in a genetically identical offspring, or clone, of the parent plant.
63
What is the purpose of taking cuttings in artificial asexual reproduction?
The purpose of taking cuttings is to produce genetically identical plants quickly and cheaply, allowing gardeners to propagate desirable traits from healthy parent plants.
64
True or False?
Artificial asexual reproduction in plants is a natural process.
False.
Artificial asexual reproduction in plants is a process controlled by humans, involving techniques such as taking cuttings to propagate desirable traits from parent plants.
65
How do runners contribute to natural asexual reproduction in plants?
Runners develop roots upon touching the soil, eventually becoming independent plants that are genetically identical to the parent plant.
66
What is rooting powder, and how is it used in artificial asexual reproduction?
Rooting powder contains plant growth regulators/rooting hormones, that stimulate the growth of new roots on plant cuttings.
67
How does natural asexual reproduction compare to artificial asexual reproduction in plants?
Natural asexual reproduction occurs without human intervention (such as through runners) while artificial asexual reproduction involves human-controlled methods (such as taking cuttings) to propagate desirable traits from parent plants.
68
What term describes the offspring produced through asexual reproduction?
The offspring produced through asexual reproduction are known as clones, which are genetically identical to the parent plant.
69
True or False?
The male reproductive system includes the penis, testes, and urethra.
True.
The male reproductive system consists of several structures, the male reproductive system includes the penis, testes, and urethra among others.
70
What is the function of the testes in the male reproductive system?
The testes are responsible for the production of sperm cells. They also secrete the hormone testosterone, essential for the development of male reproductive organs and secondary sexual characteristics.
71
True or False?
The prostate gland secretes a fluid that nourishes and protects sperm.
True.
The prostate gland produces a milky fluid that contributes to semen volume. This fluid contains enzymes and nutrients that support sperm motility, as well as substances that help neutralise the acidity of the female reproductive tract.
72
What is the role of the sperm duct in the male reproductive system?
The sperm duct delivers sperm cells to the urethra where it is mixed with fluids/semen before being passed out of the penis during ejaculation.
73
How is the male reproductive system involved in sexual reproduction?
The male reproductive system produces and delivers sperm cells to the female reproductive system during sexual intercourse.
74
Define the term ovary.
The ovary is part of the female reproductive system which contains ova (egg cells) ready to mature and be released during ovulation.
75
What is the role of the cervix in the female reproductive system?
The cervix is a ring of muscle at the entrance of the uterus. It keeps the developing fetus inside the uterus during pregnancy. It expands (dilates) during birth to allow passage of the baby through the vagina.
76
How is the oviduct adapted to carry out its function in the female reproductive system?
The oviduct is a tube connecting an ovary to the uterus. It is lined with ciliated cells which help deliver a mature ovum (egg cell) from the ovary to the uterus. Fertilisation of the ovum by a sperm cell occurs in the oviduct.
77
What is the role of the uterus in the female reproductive system?
The uterus is a muscular bag where a fertilised ovum is implanted which will develop into a fetus during pregnancy.
78
True or False?
The vagina is a muscular tube where a man's penis is inserted during sexual intercourse.
True
The vagina is a muscular tube where a man's penis is inserted during sexual intercourse. It leads to the woman's uterus.
79
What is the menstrual cycle?
The menstrual cycle is the sequence of events that includes the thickening of the uterus lining, ovulation and menstruation; it is controlled by a series of hormones.
80
What is the role of oestrogen in the menstrual cycle?
Oestrogen causes the uterus lining to thicken during the first part of the menstrual cycle. It also interacts with other hormones to bring about maturation of an egg cell.
81
What happens to oestrogen levels during the menstrual cycle?
Oestrogen levels rise from day 1 and peak just before day 14. The peak in oestrogen occurs just before the egg cell is released.
82
True or False?
An increase in progesterone results in the loss of the uterus lining.
False.
A decrease in progesterone levels at the end of the cycle results in the loss of the lining during menstruation.
83
What happens to progesterone levels during the menstrual cycle?
Progesterone levels are low from day 1 – 14 and starts to rise once ovulation has occurred. Levels then decrease towards the end of the cycle.
84
What is the role of FSH (follicle-stimulating hormone) in the menstrual cycle?
FSH is released by the pituitary gland and causes an egg to start maturing in the ovary. It also stimulates the ovaries to start releasing oestrogen.
85
What hormone is released by the pituitary gland when oestrogen levels peak?
When oestrogen levels reach their peak the pituitary gland is stimulated to release LH (luteinising hormone).
86
True or False?
LH causes egg cells to start to mature within the ovaries.
False.
LH causes ovulation to occur. It is FSH that causes an egg cell to begin to mature.
87
What substances does the fetus obtain from the mother's blood during pregnancy?
The fetus gains the following substances from the mother's blood:
Glucose
Amino acids
Fatty acids
Water
Oxygen
Mineral ions
Vitamins
88
True or False?
The mother's blood mixes with that of the fetus at the placenta.
False.
The mother's blood and that of the fetus are separated by a membrane within the placenta.
89
How does the mother's blood exchange substances with the fetus's blood?
Substances are exchanged between the mother's blood and the fetus' blood in the placenta. Here substances cross the placental membrane by diffusion.
90
What waste products are removed from the fetus's blood at the placenta?
The mother's blood receives the following waste products from the fetus at the placenta:
Carbon dioxide
Urea
91
How is the placenta adapted for efficient diffusion?
The placenta is adapted for diffusion by:
Large surface area of contact between the mother's blood and that of the fetus
A short diffusion distance between the mother's blood and the fetus' blood
91
What is the primary mechanism for the movement of molecules across the placenta?
The movement of most molecules across the placenta occurs by diffusion. For some substances active transport may be involved.
92
Where does the embryo develop during human pregnancy?
Embryo development occurs in the uterus after the embryo has implanted into the uterus lining.
93
What is the role of the amniotic fluid during pregnancy?
The role of the amniotic fluid is to protect the developing embryo from being bumped by the movements of the mother's body.
94
What are secondary sexual characteristics?
Secondary sexual characteristics are features that are not present at birth but that develop during puberty.
95
What are the two hormones that control the development of secondary sexual characteristics?
The two hormones that control the development of secondary sexual characteristics are:
Oestrogen (females)
Testosterone (males)
96
Give examples of secondary sexual characteristics that develop in females.
Examples of secondary sexual characteristics that develop in females include:
Breasts develop
Body hair grows
Widening of hips
Menstruation begins
Growth of sex organs
97
True or False?
Secondary sexual characteristics, such as growth of sex organs, voice breaking and growth of body hair, occur in males in response to the hormone oestrogen.
False.
The secondary sexual characteristics in males develop in response to the hormone testosterone. Oestrogen is involved with stimulating development of secondary sexual characteristics in females.
