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1)Similarities-Mitosis produce new offspring of same species
DifferencesSexual
Involve Two parents
Involve one male and one female gamete
Involve meiosis
Offspring is not genetically identical to parent
Example: human, cat, dog
Asexual
involve only One parent
No gamete involved
Involve mitosis
Offspring is genetically identical to parent
Example: Amoeba, yeast, starfish
2)a) Spermatogenesis
b) Germ cells are found at the seminiferous wall. Germ cells go
through the process of mitosis and form many spermatogonia. This
takes place when boy reach puberty. All spermatogonia will then go
through the process of growth and form primary spermatocyte.
Primary spermatocyte then goes through meiosis 1 and become
secondary spermatocyte. After this, secondary spermatocyte then
goes through meiosis 2 and form spermatid and lastly it will form
sperm through differentiation.
c)Oogenesis
d)Germ cells are found at the epithelium of ovary. Germ cells than
goes through mitosis and form many oogonia. This process takes
during embryo stage. Only one oogonium goes through the process
of growth and the rest of it degenerates. One primary oocyte then
goes through meiosis 1 and form one secondary oocyte and one
polar body. The size of secondary oocyte is bigger than polar body
because of uneven distribution of cytoplasm happens. The secondary
oocyte and polar body goes through meiosis 2 and form one ovum
and 3 polar bodies.
e)Similarities -Goes through the process of mitosis
Goes through the process of meiosis
Differences –
spermatogenesis
oogenesis
thousands of sperms produced only one ovum is produced
no polar body formed
3 polar bodies are formed
occurs during puberty
occurs during embryo stage
sperms are in same size
uneven distribution of cytoplasm occurs
takes place in testis
takes place in ovary
3)a)Follicle stimulating hormone(FSH)
Luteinising hormone(LH)
Oestrogen
Progesterone
b)After menstruation, pituitary gland secretes Follicle stimulating
hormone(FSH) for development of egg follicle. The developing egg
follicle then secretes oestrogen . Oestrogen helps repair and thicken
endometrium. High level of oestrogen stimulates pituitary gland to
secrete luteinising hormone (LH). LH stimulate ovulation and
development of corpus luteum. Corpus luteum then secretes
progesterone. progesterone helps to thicken the endometrium. If
fertilization does not occur, then corpus luteum will degenerate and
level of progesterone will decrease. This causes the endometrium to
break down . Menstruation will occur.
c)The woman will become more emotional and she will mentally
disturb.
The woman may unable to carry a baby due to hormone imbalance
4)Menopause is when your body stops ovulation and this happens at
a certain age after 50-60 years. Menopause affect the woman by
making her very emotional , she might get a headache because of
her uneven level of hormones. She might even get ovary cancer .
5)a)After the development of zygote after fertilisation , the zygote
will go through four days of mitosis . after that, the zygote will form a
morula , and then a blastocyst is form. Blastocyst will then implant to
the uterus. In the blastocyst, the inner cell mass develops into
embryo and the trophoblast sends out villi to the wall and then form
the placenta .
b)Identical twins
Fraternal twins
share one placenta
two different placenta
identical characteristics
non-identical characteristics
involve only one ovum and one sperm
involve two ova and
two sperms
same sex
different sex
one zygote split into two
two zygotes are formed
occurs during the process of fertilisation
6)a)A: Umbilical arteries
B: Umbilical veins
C: Placenta Amniotic fluid
D: Amniotic sac
E: Umbilical cord
b)The placenta needs to be thick to not allow any substances to
enter in
thin wall, to allow diffusion of substances occurs easily.
c)Because when a pregnant mother takes drugs or smoke, those
things is small enough to go through the placenta and into the
foetus. This will then cause the foetus to be disable in the future.
Development of foetus, mentally retarded
d)To exchange the substances between the foetus and the mother
Absorb shock
e) If blood group is incompatible it will cause agglutination. To
prevent microorganism to enter into the foetus. Protects high
pressure from mother
Because the baby unable to withstand high blood pressure.
Separated circulatory system protects the baby from getting invaded
by microorganism.
7)a)i)condom
ii)sperm bank vasectomy/ tubal ligation
iii)oral contraceptive pill
b) the guy must wear the condom during sex
Condom is wear on man’s penis, it helps to prevent sperm from
entering vagina.
c)The hormone is injected into the mother every day. Use the
ultrasound to detect whether ovum is produced, insert a needle
inside to take the ovum out . Then, put the ovum, sperm and culture
medium into the petri dish and let fertilization occur . After embryo
is formed it is placed into the uterus using a catheter and then
pregnancy test is carried out .
d)Sexually transmitted diseases is disease passed through sexually .
To prevent it we must prevent having many sex partners and using a
condom during sex
8)a)only one embryo cell enlarges and form embryo mother sac cell .
Diploid nuclei of mother sac cell goes through meiosis and form 4
haploid cells . Three haploid cell is degenerated and one is left. It
goes through mitosis 3 times and form 8 nuclei . Two synergids , two
polar nuclei , one egg cell and three antipodal cell are formed. Then
2 layers of integuments are formed around the embryo sac and
micropyle which is a small opening
b) After pollen grain lands on the stigma, Stigma then releases sugary
liquid to germinate the pollen. During the germination of pollen,
pollen tube is formed. During formation of pollen tube, generative
nucleus will form 2 male nuclei. This will then have two male nuclei .
When the pollen tube reaches the embryo sac, The tube nuclei will
degenerates . One male nucleus will fuse with the egg cell and form
zygote . After maturation, it will become embryo. The other male
nucleus will fuse with the two polar nuclei and form triploid nucleus,
then it will become endosperm that is food for the embryo. This
process is called double fertilization.
9)a)Growth is an irreversible process which involves increase of
number of cells , size , organ function and complexity .
b)The three stages of growth is cell division , cell elongation and
cell differentiation. In cell divison , cell go through mitosis , it makes
the cell small and identical. In cell elongation, cells increase in size
,for animal cell, it enlarge by assimilation of food , for plant cell to
grow they go through vacuolation . In cell differentiation , cells
differentiates to specialized cell .
c)The parameters which can measure growth are length and
height. The disadvantages of this is that it is not completely accurate
because it did not take into consideration in other dimension. The
next parameter is volume , the disadvantage is we cannot measure it
if its irregular shape. The other parameter is fresh mass , the
disadvantage is the volume of water is keep changing. The last
parameter is dry mass , the disadvantage is that u have to kill the
organism.
10)a)Insects
b)Ecdysis happens at point A, the insects sheds their inelastic and
hard exoskeleton so that they can grow bigger in size. After they
shed their exoskeleton , their body take in air and water , this helps
to expand their body to a bigger size . Their body will then build cells
and tissues in the expanded volume. Over time , their exoskeleton
will then slowly grow harden and the insect will stop growing in size.
11)a)Lateral meristem has two types of meristem which is vascular
cambium and cork cambium. Vascular cambium and cork cambium
helps to strengthen the plant by its diameter. This is because in
primary growth the plants grows in height so it is tall and heavy. So
in secondary growth the plants grow is width to support the weight
of the plant .
Vascular cambium goes through cell division forms a lot of cambial
cells. The cambial cells link together to form cambium ring. The cells
in the cambium ring divides actively and causes primary xylem to be
pushed inwards, while primary phloem is pushed outwards.
Cork cambium divides actively forms cork cells. The inner part of cork
cambium will become secondary cortex, the outer part of cork
cambium will become cork.
b)i)C
ii)F
iii)A
iv)D
v)G