What is cell division?
Process by which new cells are produced from one cell. Results are 2 cells that are identical to
the original parent cell.
Mitosis:
Define mitosis: Mitosis is the type of cell division giving genetically identical cells with same
number of chromosomes.
Describe the significance of mitosis in a living organisms
Mitosis produces new cells for the growth of an organisms and for the replacement of dead
cells to repair the worn-out parts of the body. Mitosis takes place in any part of a plant or
animal which is producing new cells for growth or replacement.
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Bone marrow produces new blood cell
The epidermal cells of the skin are replaced by mitosis division.
New epithelial cell lining the alimentary canal are produced by mitosis.
Growth of muscles, bones, root, leaf, stem, fruit, etc. result from mitotic cell division.
Asexual reproduction
Explain the stages of the mitosis.
When a cell is not dividing there is not much detailed structure to be seen in the nucleus even if
we treated with special dyes called stain. To produce identical cell, cell division occur. Just
before cell division number of thread like structure appear in the nucleus called chromosomes,
when the nucleus is stained.
Though chromosomes present in the nucleus all time, they show clearly only at the time of cell
division because they become shorter and thicker. Mitosis cell division takes place to produce
identical cell.
Inter phase:
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Cells became larger.
Exact copy of chromosomes is made by replication
Centrioles present near nucleus
Nucleolus and nuclear membrane present
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Prophase
 Chromosomes double (46 to 92)
 Each chromosome now exits as a pair of chromatids joined together by centriomere.
 The centrioles move to the opposite poles of the cell.
Metaphase
The pair of chromatids attached to the spindle fibers at the centriomere.
Anaphase
 The chromatids move upwards and downwards along the spindle.
 The centriomere spilt into 2 and spindle fibers pull to the opposite poles of the cells.
 The separated chromatids now called chromosomes are pulled behind the
centriomeres.
Telophase
The chromosomes reach the poles of the cell, uncoil and loose the ability to be seen clearly.
The spindle fibers disintegrate
Nuclear membrane forms round each set of chromatids.
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Steps in mitosis
1.
2.
3.
4.
5.
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase – Exact copy of chromosome is made each chromosome consists of 2 chromatids.
Prophase- chromosome gets shorter and thicker. Two chromatid is joined by centromere.
Metaphase- all chromosomes are pulled and form a line because spindle fibers attached by
centromere.
Anaphase – Chromosome get pulled apart and spindle fibers contract pulling chromatids to the
opposite poles of the cell.
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Telophase- the 2 chromosome uncoils. Spindle fibers disintegrate. Nuclear membrane forms
and cell starts to divide.
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Asexual reproduction
Define: Process resulting in the production of genetically identical offspring from one parent.
Eg, Budding, binary fission, fragmentation, vegetative propagation.
Budding: in an old potato many small growths (commonly referred as eyes). Each of these
sprouts can be cut from the potato and planted. They will grow into a clone of the original
plant.
Artificial propagation: Many ornamental plants are produced using stem
New leaf begins to develop. Root develops from the cut end of stem.
Vegetative propagation: straw berry plant quickly spread into a large mass of plant (runner).
Define clone: a group of cells or organisms which are genetically identical to each other.
Advantages of asexual reproduction:
Only parent plant is required
Young plants are genetically identical to the parent
Bigger size, fast growing, disease resistant.
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MEIOSIS (REDUCTION DIVISION)
It is a reduction division in which the chromosome number is halved from diploid to haploid (46
to 23)
Define meiosis- It is a reduction division in which the chromosome number is halved from
diploid (46) to haploid (23).
Explain meiosis: During sexual reproduction two gametes (male and female fuse to form the
zygote. Example: human cell have 46 chromosomes
Father (sperm) and mother (egg) have 23 each.
Meiosis is a reduction division in which the chromosome number is halved from diploid to
haploid. Like mitosis, meiosis also has interphase, prophase, metaphase anaphase and
telophase in first meiotic division. Same phases repeated in second meiosis division.
Spermatogenesis
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Oogenesis
Meiosis I
Interphase I
Replication of cell, increase in size of cell
Each chromosome now exit as pair of chromatids, attached at centromeres. Loosely coiled.
Prophase:I
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Longest pahse and most complex
Chromosomes shorten and become visible in single structure.
Chromosomes from father and mother gamete nuclei come together and pair up.
These are homologous chromosomes (each pair is same length, centromeres are in
same position and same number of genes.
 Chaiasmata (chiasma) are were father and mother chromosomes touch each other and
exchange genes (crossing over). Results genetic recombination.
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Metaphase:
 Nucleus and nucleolus disappear
 Spindle fibres form
 Pair of chromatids attached to the spindle fibres at the centrioles.
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Anaphase-I
The centriomere split into 2 and spindle fibres pulls the chromatids to the opposite poles of the
cells.
This separates the chromosomes into 2 haploid sets of chromosomes in the daughter cell.
Telophase-I
 Each pole has haploid set of chromosomes
 Two haploid daughter cells are formed.
Meiosis-II
Interphase is very short. No DNA replication. Meiosis II is similar to mitosis. Except separation of
both daughter cells.
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Prophase-II
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Prophase II same as in mitosis
Chromosomes condense
Centrioles moves to the opposite poles of the cells
Spindle fibres forms.
Metaphase- II
 Pair of chromosomes attached to the spindle fibres at centromere.
 Chromosomes line in equator.
Anaphase-II
The centriomere splits into 2. The spindle fibres pulls the chromosomes to the opposite poles of
the cells.
Telophase:
Nuclear membrane develops on each daughter cell. Four daughter cells formed in haploid
number.
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Difference in asexual and sexual reproduction.
Asexual
1. cell division by binary fission, spores
vegetative reproduction , artificial propagation
2. one parent
sexual
Sexual reproduction organs present in plants
and animals
2 parent
3. no sex cell
4. no zygote
5. under goes mitosis
Male and female sex cell (haploid gamete)
Fertilization forms diploid zygote
Undergoes meiosis
6. offspring genetically identical to parents
Offspring genetically different to parents
7. Rapid multiplication under favorable Takes long time
condition.
8. bacteria, fungi
Complex living organisms(human).
Sexual reproduction in plant
Flowers are reproductive structures that contain the reproductive organs of plant. The male
reproductive organs are the stamen (which produce pollen) male gametes (anther). The female
reproductive organs are the carpels (female gametes are produced inside the ovules). If both
male and female gametes are present in same plant its known as bisexual (hermaphrodite).
Male gametes and female gametes present in separate plants but belongs to same species its
known as unisexual.
State the function of flowering plants?
Sepals are usually green and look like small leaves. Sepals enclose and protect the flower when
it is in the bud stage. They usually disappear after pollination.
Petals are usually brightly coloured and scented. They produce nectar ( a sugar solution) at the
bases. Colour scented and nectar attract pollinating insects
Stamens are male reproductive organ of the flower. Each stamen is made up of a stalk or
filament and an anther.
Anther: produce pollen grain. Male gametes are present inside the pollen grains.
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Carpels (pistil) are the female reproductive organ of a sticky stigma, connected by style to the
ovary, in which female gamete ovule is present.
Outline the process of pollination and distinguish between self-pollination and cross
pollination.
(new plant generally grows from seed. Flowers turned into fruit. Fruits give back seed. Insects
help pollination. Transferring of pollen grains from anther part of the male organ which is
stamen to the stigma of the female organ which is pistil or carpel.
Define pollination:
Transfer of pollen grains from anther (male organ) to the stigma ( female organ) of a flower.
Define Self-pollination - pollen grains are transferred from anther in the stigma of the same
flower. If a bee carry pollen grains from one flower to an another flower of the same plant is
called self pollination.
Define cross-pollination- pollen grains are transferred from anther of one flower to sigma of
another flower of same species.
Agents of pollination: insects, wind, water, animals (birds)
Insects’ pollination- insects visit flower for nectar and transfer the pollens from anther to the
stigma. Generally insects pollinated flowers are brightly coloured, scented and they are also
rich in nectar.
Wind pollination- some plants have smell flower and petals that are not brightly coloured and
they do not produce nectar. Anther and stigma are exposed to the air. The pollen grains are
weightless, hence easily blown away by wind. Example wheat, maize and rice.
Grasses – Feathery stigma pollen grains floating in the air are trapped by them. Anthers hang
outside the flowers.
Difference between insect pollination and wind pollination.
Aquatic pollination- in aquatic plants (sea grass) the pollination is carried out by water. As
water currents slowly carry pollen grains of other flowers.
Suggest in two ways in which plant may prevent pollination.
 Individuals flowers may produce all male or female plants.
 Individuals plants have anther and stigma, but maturing at different times.
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 Distance between the male and female parts of the flowers would reduce chances of
fertilization.
Name the process that follows pollination.
Fertilization
Describe how insect is adapted for pollinating flowers.
Insects, bees, butterflies, flies, moths etc. (even humming birds, and bats pollinate some
flowers). Lupin and wall flower example of insect pollinating flower.
Insects visit the flower for nectar and transfer the pollen from anther to the stigma.
Generally,insects pollinated flowers are brightly colored, scented and the y also rich in nectar.
Bee feed nectar present in the petals. When the bee lands on the petal of the flower. Weight of
bee pushes down the petal. As a result, long stamen push the pollen out from the anther. Bee
has the hair body which collects sticky pollen grains from the flower then flies to another
flower.
(if the flower is older than the first one it already has lost its pollen). When the bees weight
pushes down the petal, stigma comes out and touches the insect body, picking up the pollen
grains on its sticky surface.
Difference between self-pollination and cross pollination.
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Describe how flowers are adapted for insect pollination.
Insect pollinated flowers have brightly coloured petals, scent and produce nectar.
Describe the difference between the insect pollination and wind pollination
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Describe the growth of the pollen tube and its entry into the ovule followed by fertilization.
Pollination is the process by which pollen grains from the anther transferred to the stigma for
the fusion of male and female gametes.
Thousands of pollen grains released from anthers of flowers, but a tiny fraction reach the
stigma of another flower of the same species. (the pollen grains of the same plant from anther
has to transfer to the stigma of the same species. Then only it will start produce pollen tube)
Pollen grains produces pollen tube. At the tip of the pollen tube enzymes are secreted, that
digest the tissue of the style by using enzymes cellulose and the male gametes travel down to
the ovary. Chemicals guide the pollen tube to enter into the ovule through a tiny hole called
micropyle. Haploid male gametes fuse with female gametes which results in fertilization to
form zygote. Zygote undergoes mitosis to produce embryo, which grow into new individuals.
Describe the structure of the seed in terms of the embryo ( radicle, plume and cotyledons and
testa.
During the early stages of fertilization, some parts of the plant are no longer needed such as
sepals, petals, and stamens often dry and fall off. Once fertilization has occurred a number of
changes take place on the ovule and ovary. The ovule becomes the seed and the ovary will
become a fruit. Different flowers produce different types of fruits, but in all cases the following
4 changes take place. The zygote develops into an embryonic plant with small root (radicle
grow down) and shoot plumule grows up. The outer contents of the ovule develop into
cotyledons. Cotyledons present inside the seed. This cotyledons store food for the young plants
(when seed germinates).
In dicot plants food made in the leaves of the parent plant is carried in the phloem to the
cotyledons. In monocot plant, the food is stored in a special tissue called endosperm which is
the outside the cotyledons.
In both monocot and dicot the outside layer of the ovule becomes thicker and harder and
forms a seed coat or testa. The ovary wall becomes the fruit coat.
Difference between monocot and dicot
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Distinguish between ovary and ovule
The ovary is the female reproductive organ, found in plants and animals. It is the organ which
produces eggs or female gametes. The ovary becomes fruits.
Ovule: The ovule is present inside the ovary of a flower. The ovule is found only in flower. Inside
the ovule female gametes egg is present. After fertilization, the ovule becomes the seed.
Describe the disperse of seeds by wind and animals and water.
Seeds are dispersed far away from the parent plant. This helps to prevent competition for
space, food etc. seeds are carried to new habitats where conditions may be favorable for
growth. Seeds may be dispersed by any of 2 methods
Wind dispersal: seeds dispersed by wind are very small or light or their fruits have wings or a
parachute. Example Dandelion fruit
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Dandelion fruit has a fine hair like structure which catches the wind and act like a parachute.
Sycamore:
Sycamore has a wing with a large surface area. When a fruit drops off the tree. It spins, slowly
down. If caught by the wind the seed will be carried away from the parent plant reducing
competition for nutrients water and light.
Water dispersal: Coconut disperses through water.
Animal dispersal:
Fruits such as tomato, black berry are eaten by birds and animals because they are brightly
colored juicy and nutritious. in this method, the fruit has hooks (example Burdrock has hooks).
This hook catch in the fur of animals. Animals move from place to place taking fruit. Eventually
the seed or fruit drops off. This disperse seed away from the parent plant. Example mango,
tomato eaten by animals undigested seeds are passed out through faeces. Faeces provides
nutrients when the seed germinate.
Explain germination of seed. State the environmental condition that affects germination of
seed suitable temperature, water and oxygen.
Seeds start to germinate under the suitable condition that is in the presence of water,
temperature, sunlight.
Germination includes the following steps
1. water activates enzymes stored in the seed. Water enters through the micropyle and
activates enzymes and converts insoluble stored food to soluble food. 2. Enzymes start to digest
the starch stored in the seed into sugar. 3. Sugars produced is taken to the embryo and used as
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an energy source for growth. 4. The radicle (root) grows first fixing the seed into the soil where
it can absorb more water. 5. The shoot grows vertically. 6. Once the shoot grows, first leaf
grows. 7. Now plant is ready for photosynthesis to make food.
State the environmental condition that affect germination of seed.
Water: micropyle allows water to enter, water activates the enzymes, which is important for
the embryo to grow.
Oxygen: important for aerobic respiration to produce energy.
Temperature: Optimum temperature 28®C to 37®C. Enzymes inactive at low temperature.
Enzymes active at high temperature.
Enzymes: Hydrolase break down the insoluble food stored in the seed, into soluble food.
Example glucose, amino acid.
Light: Most seed germinate in the presence of light. Light is important for photosynthesis, when
the shoot appears.
Human reproduction
Reproduction is the process of producing new individuals. In human male sex sperm called male
gametes. In human female sex called egg or ova called female gametes.
The fusion of male gametes sperm and female gametes ovum is called fertilization. The cell
formed after the fusion of the male gametes and female gametes called zygote. Zygote
undergoes cell division to produce embryo. Embryo develops into new individuals.
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The male animal always produces a large number (millions) of sperm, while the female
produces a smaller number of eggs. (some animals such as fish, frog many eggs are fertilized
and then are large number of offspring).
In human only one egg is fertilized at a time, if two egg being fertilized produces (non-identical)
twins.
Female Reproductive System
Explain how female reproductive system of human is adapted for sexual reproduction.
Female reproductive system is located under the stomach. It consists of following parts.
Ovary:
The eggs are female gametes produced in the ovary by meiosis. Female reproductive system is
composed of pair of ovaries. The ovary has the dual function of producing sex gametes and
secreting female sex hormone. The ovary consists of 2 regions.
1. Cortex
2. Medulla
Cortex: The outer cortex contains thousands of developing follicles. Each follicle contains an
egg.
Medulla: Inner medulla composed of connective tissue, blood vessels and mature follicle.
Oviducts (Fallopian tubes)
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There are two funnel shaped opening of the oviduct. One on each side connected to an ovary.
The release of egg from the ovary to the fallopian tube (12 cm) is called ovulation. The tiny egg
(only about the size of full stop), swept into the funnel shaped opening of the fallopian tube by
the movement of cilia to reach the uterus.
Uterus (womb)
Uterus is the place where a bay (fetus) develops if the egg is fertilized. Uterus is only about
80mm long. The walls of the uterus have two layers. The inner lining is a soft spongy layer
containing blood vessels. This blood vessel supply food and oxygen to the developing embryo.
The outer layer is mostly muscular tube the vagina. By which baby passes out of the mother’s
uterus during birth. Vagina receives the male penis during sexual intercourse.
Cervix
Its muscular tissue present at the base of the uterus. Cervix separates the uterus from vagina.
Cervix secretes mucus to help sperm swim.
Male reproductive system
Explain how male reproductive system of human is adapted for sexual reproduction.
The male reproductive system is located under the stomach. It consists of the following parts
Testis
Male human has two testes. Sperms are produced in the male reproductive organ called testis
by meiosis division. Male sex hormone testosterone also produced in testis.
Scrotum
Pair of testes present in sac called scrotum. Testes are situated outside the abdominal cavity in
the scrotal sac (scrotum). Sperm develops here (2 to 3 degree Celsius lesser than the body
temperature.
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Epididymis:
The testes consist of mass of sperm producing tubes called seminiferous tubules. These
seminiferous tubules are highly coiled structure called epididymis. Sperm mature in this region
(motile sperm). Epididymis act as temporary store house of sperm. One end of epididymis
connects into muscular sperm duct (vasodeferens).
Vasodeferens or sperm duct.
Transport sperm form epididymis to urethra. Urethra which carries urine from the bladder to
the outside, when sperm passing through the urethra. A value close to stop urine from passing
out at the same time. Sperm ducts meet the urethra where 2 glands are present. In this sperm
mix with seminal fluid.
1. prostate gland
2. Cowper’s gland
Together produce the seminal fluid which contains nutrients.
Seminal vesicle to activate the sperm. So that sperm swim actively and reach the ovum.
 Fructose: produced from seminal vesicles
 Alkaline: secretion from prostate gland
 Semen = sperm + seminal fluid
Function of seminal fluid
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 Provide medium for sperm to swim.
 Activate the sperm
 Neutralize the acidity in the female reproductive organ.
PENIS
Erected during copulation, the vasdeferens conducts the sperm to the base of the penis, where
they combine with the seminal fluid to form semen which is ejected out of the penis.
Structure of sperm and ovum;
The sperm consists of the head containing nucleus, middle piece and tail.
The sperm head consists of a nucleus containing haploid number of chromosome covered of a
membrane enclosed acrosome. This contain hydrolytic enzymes which involved in the
penetration of the oocyte by the sperm immediately prior to fertilization. Middle piece is
enlarged by the presence of mitochondria, which provides energy for movement of the flagella.
Ovum: Has a large nucleus and abundant cytoplasm surrounding it. Ovum is immotile. But it is
moved along the oviduct by sweeping action of cilia and peristalticcontraction wall of oviduct.
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Compare male and female gametes in terms of size, number and mobility.
Sperm consists of the head containing nucleus, the middle piece and tail. The ovum on other
hand is spherical shape surrounded by an inner plasma membrane and outer protein coat. The
ovum has a large nucleus and abundant cytoplasm surrounding it. The sperm which has a small
nucleus and little cytoplasm is very smaller than the ovum.
Millions of sperms produced at each ejaculation. But one ovum released from alternate ovaries
per month. The sperm is capable of movement aided by the tail and energy released by the
mitochondria in the middle piece. The ovum is immotile, its moved along the oviduct by the
sweeping action of the cilia and peristaltic contraction of wall of oviduct.
Describe the menstrual cycle, with reference to the alternation of menstruation and ovulation, the
natural variation in its length and the fertile and infertile phases of the cycle;
 Menstrual cycle in women is recurring process, in which the lining of the uterus is prepared for
pregnancy. If pregnancy does not happen, the lining is shed at menstruation.
 Female reproductive system works on a 28 days cycle. This is known as menstrual cycle.
 Usually one egg is released from an ovary every moth.
 Before the egg, is released the lining of the uterus becomes thick (full of blood capillaries) and
soft.
 Ready to supply the embryo with food and oxygen. If the egg is not fertilized, it is dead by the
time it reaches the uterus.
The menstruation cycle is controlled by 4 hormones
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Estrogen
Progesterone
Follicle stimulating hormone (FSH)
Luteinizing
hormone
(LH)
1. Estrogen and Progesterone produced by ovaries.
2. Follicle stimulating hormone (FSH) and luteinizing hormone (LH) produced by pituitary gland
Menstrual phase (bleeding phase) 1-5 days
If egg is not fertilized, the thick lining of the uterus becomes unneeded and it breaks down and gets out
of the body through the vagina, with the dead egg for 1-5 days. Lining of the uterus was discharged
(uterus decreases, in thickness to minimum). Bleeding takes place due to rupture of the blood vessels
(menstruation is triggered by decrease concentration of progesterone.
(Proliferative phase )Follicular phase – infertile phase
 This phase starts with end of the bleeding. The graffian follicle develops and matures in the
ovary. This process is initiated by FSH.
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 Estrogen is secreted as a result in lining of the uterus starts to build up again. The lining of the
uterus becomes thicker with increased blood supply to receive a fertilized egg.
Ovulation (fertile phase)
At the end of the follicular phase, pituitary gland secretes the luteinizing hormone to release egg from
the ovary.
High level of estrogen (increased level of estrogen) is triggered by the pituitary gland. Due to high
concentration of estrogen ovulation occurs. (release of egg from ovary to oviduct).
Luteal phase (17-28 days)
The amount of FSH, LH estrogen decreases. But progesterone maintains the good constant level of the
lining of the uterus to ensure implantation if fertilization took place.
If the egg is not fertilized the amount of progesterone decreases. This cause damage to thelining of the
uterus and decrease by shedding.Thus, menstruation cycle takes place.
Explain the role of the hormones in controlling menstrual cycle.
FSH: Follicle stimulating hormone: It stimulates the growth of Graafian follicles in the ovary.
Luteinizing hormone: It plays an important role in causing ovulation. It is involved in the development of
corpus luteum.
Estrogen: repairs the lining of the uterus and stimulates the development of sexual characteristics.
Progesterone: Helps in controlling menstrual cycle, keep the lining of the uterus ready for implantation
and pregnancy.
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Describe early development of zygote, simply in the terms of the formation of a ball of the cells that
becomes implanted in the walls of uterus?
After ovulation, the egg last up to 3 days in oviduct, after it is released from the ovary egg travels down
from ovary to oviduct and into the uterus. After copulation millions of sperms reach the fallopian tube.
Sperms are highly fertile for 12- 24 hours. If egg is present in the oviduct, fusion of male gametes and
female gametes, takes place is known as fertilization. The sperm tail is left behind and the head which
contains the nucleus, move towards and then fuses with the nucleus of the ovum.
Egg and sperm were haploid cells with 23 chromosomes. Fertilized egg is called zygote with 46
chromosomes. The egg undergoes cell division and produces a ball of cells. It is called an embryo. Ball of
cells move slowly down the oviduct and reaches the uterus. After 7 days’ fertilization, the tiny embryo
sink (embedded) into the lining of the uterus. This is called implantation. The embryo continues to grow
and produces new cells which form tissues and organs. After 8 weeks when all organs are formed the
embryo is called fetus.
State the function of amniotic fluid in detail.
As the embryo grow, the uterus enlarges, the embryo is enclosed in a water filled sac called amnion (the
membrane that enclose the amniotic fluid). As water cushion to fetus, allow it to move freely. Reduce
temperature fluctuation, lubricate the vagina during birth. This fluid protects the embryo from damage
and unequal pressures.
The oxygen and food are obtained from the mother’s blood by means of structure called placenta.
Describe the functions of the placenta and umbilical cord in relation to exchange of nutrients gases
and excretory products?
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Placenta is a temporary organ is found only in mammals. Placenta contains mixture of maternal cells
from lining of uterus and embryonic cells. But these cells from two genetically individuals (1 mother +
fetus). Soon after the ball of cells reaches the uterus, some of the cells develop into organs the
remaining cells forms disc like structure called placenta.
The placenta is linked to the fetus via umbilical cord which contains umbilical artery and a vein. The
umbilical artery carries carbon dioxide, (deoxygenated blood) and waste (urea) from the fetus. The
umbilical vein caries oxygen (oxygenated blood) glucose, amino acid, fatty acids, salts, vitamins,
hormones, antibody from mother to the fetus.
There is no direct communication between mother’s blood system and fetus blood in the placenta. (the
fetus and mother can have different blood groups. If this blood groups are mixed that triggers clotting
(clumping). The mother’s blood is at high pressure than the fetus blood and it its connected to the
mother circulatory system directly its blood vessels would burst.
Food and oxygen diffuse across thin membrane blood into the fetus blood and carbon dioxide and
nitrogenous wastes diffuses out of the fetus blood into the mother’s blood supply. Antibodies are small
enough to cross the placenta. This give the baby a passive immunity that can protect from pathogens
(bacteria and virus). Potentially harmful substances such as bacteria, virus, drugs, alcohol and nicotine
can pass this fetus.
The placenta is linked to the fetus via umbilical cord which contains umbilical artery and a vein. The
umbilical artery carries carbon dioxide, (deoxygenated blood) and waste (urea) from the fetus. The
umbilical vein caries oxygen (oxygenated blood) glucose, amino acid, fatty acids, salts, vitamins,
hormones, antibody from mother to the fetus.
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There is no direct communication between mother’s blood system and fetus blood in the placenta. (the
fetus and mother can have different blood groups. If this blood groups are mixed that triggers clotting
(clumping). The mother’s blood is at high pressure than the fetus blood and it its connected to the
mother circulatory system directly its blood vessels would burst.
Food and oxygen diffuse across thin membrane blood into the fetus blood and carbon dioxide and
nitrogenous wastes diffuses out of the fetus blood into the mother’s blood supply. Antibodies are small
enough to cross the placenta. This give the baby a passive immunity that can protect from pathogens
(bacteria and virus). Potentially harmful substances such as bacteria, virus, drugs, alcohol and nicotine
can pass this fetus.
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Brings blood supply of fetus close to mother’s
Blood from the fetus passes through the umbilical cord in the umbilical artery to the
placenta.
Here it comes close to the mother's blood.
transport O2 + nutrients (amino acids, glucose…) from mother ---> fetus
transport CO2 + wastes (urea… ) from fetus --->mother (through umbilical vein).
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Prevents
mixing
This is really important because the fetus and mother may have different blood groups - any mixing could
result in blood clotting, which could be fatal to both mother and fetus.
Describe the special dietary needs of pregnant woman?
A pregnant woman’s diet is different to that of a normal woman. This is because a pregnant woman
needs extra supplies of nutrient, because she is feeding herself and her baby.
Proteins: should be increased in a pregnant woman’s body. The growing fetus needs plenty of protein to
build new cells.
Carbohydrates: should also increase since the fetus consumes them too and because it is harder to
move when the women are pregnant.
Calcium: is one of the most essential minerals for the fetus growth. This is because it is used in making
the bones. If the mother does not increase her intake of calcium, the fetus will start absorbing calcium
from pregnant woman bones and teeth.
Iron: is needed in large quantities. Iron is used to produce more hemoglobin for the mother and the
fetus.
Drugs: should be avoided. The drugs affect fetus. Drugs can cause unhealthy babies or even early giving
of an abnormal baby.
Describe the advantages of mother’s milk compared with bottle milk?
The best food for a new born baby is mother’s milk, contain all essential nutrients for the baby like
proteins, fats, carbohydrates, vitamins and minerals in easily digestible form. The mother’s milk also
contains antibodies which are needed by the baby, since their immune system has not developed. More
over mother’s feeding milk builds a close bond between the mother and her baby.
If mother cannot feed milk, there is another alternative, which is formula milk powder. Formula milk is
mixed with boiled water and fed to the babies in bottles. Formula milk contains nutrients in harder
digestible form. Formula milk also lacks of antibodies. Bottle feed baby in a greater risk of infection than
a mother’s milk.
Describe the symptoms, signs, effects and treatment of syphilis.
Syphilis is a sexually transmitted diseases (STD) caused by bacterium Treponema pallidum.Treponema
pallidummultiply at the site of entry within 2-10 weeks after infection papule develops at the site of
infection and breaks down to form a chancre. The primary lesion always heals spontaneously.
After 2-10 weeks, secondary lesion appears. These consist of a red maculopapular rash throughout the
body, including the hand, feet and mouth. The secondary lesion also subsides spontaneously.
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Tertiary syphilis is characterized by the development of granulomatous lesions (gummas) in skin, bone
eyes liver and central nervous system.
Treatment: antibiotic like penicillin, erythromycin, tetracycline.
Discuss the spread of HIV and methods by which it may be controlled.
AIDS (Acquired immune deficiency syndrome) is caused by HIV (human immune deficiency virus. This
virus lives in most of body fluids such as blood and reproductive tract. HIV can spread only in certain
body fluid from a person infected with HIV.
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Blood
Semen
Pre-seminal fluids
Rectal fluids
Vaginal fluids
Breast milk.
Transmission
The spread of HIV is only possible if these fluids come in contact with a mucus membrane or
damage tissue. Mucous membrane is found inside the rectum, vagina opening of penis etc.
(sexual intercourse). HIV also spread from HIV infected women to her child during pregnancy or
breast feeding.
HIV also spread by blood transfusion, organ or tissue transplant. From an HIV, infected donor.
HIV also spread sharing of injection, needles razors. Etc.
Pathogenesis: The virus lives and multiply in lymphocytes (WBC). The virus could live for years in
the body before it starts showing symptoms of diseases. This disease prevents WBC from killing
bacteria and virus. (WBC count decreases).
Bacteria or virus infection enough to kill the patient.
Prevention:
 There is no cure for AIDA till now.
 It is best to prevent it from spreading by not having sexual intercourse with an infected
person.
 Use condom
 Avoid multiple sexual partner
 Prevent your blood mixing the blood an infected person.
 Don’t share unsterilized needles, that have used by an infected person.
AIDS - transmission and prevention methods
AIDS (Acquired Immune Deficiency Syndrome) is a disease caused by the HIV. HIV can not
live outside the human body. It is an especially fragile virus - much less tough than the cold
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virus.
It is transported in body fluids. You can only become infected with HIV through direct
contact of your body fluid with those of someone with the virus.
How HIV affects the immune system
The HIV virus attacks some types of lymphocyte (white blood cells) in the blood stream.
Lymphocytes produce antibodies ---> attack the antigens on invading microbes.
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Some lymphocytes are stored in lympho nodes ---> protection against future infection.
HIV prevents this immunity being retained, so the AIDS sufferer has no protection
against diseases such as tuberculosis (TB) and pneumonia.
Methods of transmission:
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unprotected sexual intercourse with infected person
drug use involving sharing needle used by infected person
transfusion of infected blood
infected mother to fetus
feeding a baby with milk from an infected mother
unsterilised surgical instruments
Prevention
condom for sexual intercourse
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refuse sexual intercourse
screen blood (for transfusion)
use sterilized needles
feed baby with bottled powdered milk (if mom has HIV)
use sterilized surgical instruments.
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methods
Describe the following methods of birth control nature, chemical (spermicidal)
mechanical, hormonal and surgical.
Natural method:
The most successful method of family planning is not having sexual intercourse at all. This
method is 100% successful in preventing pregnancy.
Rhythm method
1. by understanding menstrual cycle and avoid intercourse at the time of ovulation
(fertile period) 12-16 days.
2. During or soon after ovulation a women’s temperature rises about 0.5®C.
3. After infertile period a woman’s temperature returns to normal. During ovulation
type of mucus secreted by the cervix and vagina.
Artificial method of family planning.
Condom: A thin rubber sheath is placed on the erect penis before sexual intercourse. The condom
traps the sperms and prevents them from reaching the uterus.
Diaphragm: Thin rubber disc placed in the vagina before sex intercourse, covers the cervix and
stops sperms entering the uterus.
Intra-uterine device: it is small copper or plastic inserted in the uterus. It prevents implantation of
a fertilized ovum. (98% effective) small risk for uterine infections.
Chemical (spermicidal): (cream, gel)
Spermicides placed in the vagina. Spermicidal cream that kills or immobilize sperms. (its important
that it is quite useless to use spermicidal cream after sexual intercourse has taken place, because
by that time many sperms may reached oviduct.
The contraceptive pill:It contains the hormones estrogen and progesterone which prevents the
ovulation. The pills need to be taken each day for 21 days between menstrual period. Sometimes
this contraceptive pill may increase the risk of cancer of the breast and cervix.
Surgical method – sterilization
Vasectomy: In man sperm ducts are cut and the end sealed. This means that his semen contains
secretion of the prostate gland and seminal vesicle, but no sperms. So cannot fertilize the ovum.
(testes continue to produce sperm and testosterone. Sperms are removed by white cells as fast
they form. Testosterone ensure that there is no loss o masculinity.
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Laparotomy: Woman oviducts are tied, blocked or cut by surgical method. The ovaries are
unaffected. Sexual desire and menstruation continue as before. So not sperm can reach to fertilize
an ovum.
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