09 Tys Unit 3.1b Repro In Man
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7/13/09
Unit 3.1B
Structured Qn 1 & 2
Essay Qn 3 & 4
‘09 April TYS HmWk Reproduction in Man
Structured Qn 1
Structured Qn 2
a) A – Placenta; B – Amnion; C – Bladder; D – Vagina b) It protects the fetus against mechanical injury. c) (i) 1. Carbon dioxide
2. Urea (ii) Artery d) (i) Females have XX sex chromosomes (two X chromosomes)
while males have XY chromosomes (one X chromosome) e) (ii) There are 47 chromosomes instead of the normal 46.
a) P: Sperm; Testis
Q: Pollen; Anther
b) R is the tail which enables the sperm to swim up the
vagina, uterus and oviduct to fuse with the egg. S is the pollen tube which grows and tunnels through the style and ovary wall and into the embryo sac to fuse with the ovum. c) Similarities : T is the nucleus and it contains
chromosomes. Differences: T contains only half the number of chromosomes.
Essay Qn 2
Up to 500million sperm are released per ejaculation but
only one ovum is released per menstrual cycle.
Many sperm cells are needed as many of them do not
survive the acidic conditions of the vagina, so a higher number increases the chance of fertilization.
Only one ovum as the uterus can optimally support one
embryo at a time.
Sperm cells are much smaller in size than the ovum,
which adds on their motility.
Although both types of cells carry the haploid number
of chromosomes, the ovum also contains much nutrients required for the early stages after fertilization, adding on its mass and reducing motility.
A sperm cell has a tail which enables it to be motile, while
the ovum is reliant on the cilia in the oviduct to move it.
Sperm cells need to swim up the vagina, uterus and oviduct
to fertilize the egg.
1
7/13/09
Essay Qn 3(a)
Plants produce female gametes in ovules while male
gametes are found in pollen grains.
Pollen grains are a medium of transfer for the male
gametes from the anthers to the stigma for fertilization process.
More pollen grains are produced due to the nature of
pollination (by animal or wind) which can be unpredictable and inconsistent.
Larger number of pollen grains increases the chances of
The female gametes are non-motile and are held within
the ovary. The ovary is much bigger than pollen grains and does not move.
There are much less female gametes as they being
fertilization is dependent on a pollen grain successfully reaching the stigma of the flower they are in.
When the pollen grain reaches the stigma, a pollen
tube will grow to deliver the male gametes for fusion with the female gametes.
successful fertilization.
Essay Qn 3(b)
Does not require fertilization to occur and requires
only one parent.
Not reliant on external agencies such as wind and
animals for pollination.
Daughter plants are genetically similar to the parent
and retain the desirable qualities of the parent.
The parent plant can provide nutrition for the growing
new plant.
Essay Qn 4(a)
Placenta allows dissolved substances such as glucose,
amino acids, mineral salts and oxygen to diffuse from the mother’s blood into the fetus’ blood.
It allows waste material such as urea and carbon
dioxide to diffuse from the fetus’ blood to the mother’s blood for excretion.
It allows antibodies in the mother’s blood to diffuse
into the fetal blood to enable the newborn to have immunity against diseases.
It produces progesterone to maintain the uterine lining
in a suitable state for the duration of the pregnancy.
Essay Qn 4(b)
Cigarette smoke contains nicotine which stimulates release
of adrenaline, increasing heartbeat and blood pressure.
Together with carbon monoxide, they increase the risk of
fatty deposits in the endothelial lining of the blood vessels and risk of plaque formation and atherosclerosis.
Carbon monoxide also reduces the oxygen-carrying capacity
Nicotine can also cause the blood vessels in the
umbilical cord to narrow and reduce the rate of exchange of oxygen, nutrients and waste between mother and fetus.
Carbon monoxide will reduce oxygen delivered to the
fetus and affect its growth.
of blood by binding irreversibly to haemoglobin.
Tar and other irritants also increase the risk of cancer,
bronchitis and emphysema in the mother.
2
Unit 3.1B
Structured Qn 1 & 2
Essay Qn 3 & 4
‘09 April TYS HmWk Reproduction in Man
Structured Qn 1
Structured Qn 2
a) A – Placenta; B – Amnion; C – Bladder; D – Vagina b) It protects the fetus against mechanical injury. c) (i) 1. Carbon dioxide
2. Urea (ii) Artery d) (i) Females have XX sex chromosomes (two X chromosomes)
while males have XY chromosomes (one X chromosome) e) (ii) There are 47 chromosomes instead of the normal 46.
a) P: Sperm; Testis
Q: Pollen; Anther
b) R is the tail which enables the sperm to swim up the
vagina, uterus and oviduct to fuse with the egg. S is the pollen tube which grows and tunnels through the style and ovary wall and into the embryo sac to fuse with the ovum. c) Similarities : T is the nucleus and it contains
chromosomes. Differences: T contains only half the number of chromosomes.
Essay Qn 2
Up to 500million sperm are released per ejaculation but
only one ovum is released per menstrual cycle.
Many sperm cells are needed as many of them do not
survive the acidic conditions of the vagina, so a higher number increases the chance of fertilization.
Only one ovum as the uterus can optimally support one
embryo at a time.
Sperm cells are much smaller in size than the ovum,
which adds on their motility.
Although both types of cells carry the haploid number
of chromosomes, the ovum also contains much nutrients required for the early stages after fertilization, adding on its mass and reducing motility.
A sperm cell has a tail which enables it to be motile, while
the ovum is reliant on the cilia in the oviduct to move it.
Sperm cells need to swim up the vagina, uterus and oviduct
to fertilize the egg.
1
7/13/09
Essay Qn 3(a)
Plants produce female gametes in ovules while male
gametes are found in pollen grains.
Pollen grains are a medium of transfer for the male
gametes from the anthers to the stigma for fertilization process.
More pollen grains are produced due to the nature of
pollination (by animal or wind) which can be unpredictable and inconsistent.
Larger number of pollen grains increases the chances of
The female gametes are non-motile and are held within
the ovary. The ovary is much bigger than pollen grains and does not move.
There are much less female gametes as they being
fertilization is dependent on a pollen grain successfully reaching the stigma of the flower they are in.
When the pollen grain reaches the stigma, a pollen
tube will grow to deliver the male gametes for fusion with the female gametes.
successful fertilization.
Essay Qn 3(b)
Does not require fertilization to occur and requires
only one parent.
Not reliant on external agencies such as wind and
animals for pollination.
Daughter plants are genetically similar to the parent
and retain the desirable qualities of the parent.
The parent plant can provide nutrition for the growing
new plant.
Essay Qn 4(a)
Placenta allows dissolved substances such as glucose,
amino acids, mineral salts and oxygen to diffuse from the mother’s blood into the fetus’ blood.
It allows waste material such as urea and carbon
dioxide to diffuse from the fetus’ blood to the mother’s blood for excretion.
It allows antibodies in the mother’s blood to diffuse
into the fetal blood to enable the newborn to have immunity against diseases.
It produces progesterone to maintain the uterine lining
in a suitable state for the duration of the pregnancy.
Essay Qn 4(b)
Cigarette smoke contains nicotine which stimulates release
of adrenaline, increasing heartbeat and blood pressure.
Together with carbon monoxide, they increase the risk of
fatty deposits in the endothelial lining of the blood vessels and risk of plaque formation and atherosclerosis.
Carbon monoxide also reduces the oxygen-carrying capacity
Nicotine can also cause the blood vessels in the
umbilical cord to narrow and reduce the rate of exchange of oxygen, nutrients and waste between mother and fetus.
Carbon monoxide will reduce oxygen delivered to the
fetus and affect its growth.
of blood by binding irreversibly to haemoglobin.
Tar and other irritants also increase the risk of cancer,
bronchitis and emphysema in the mother.
2
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