Thursday, 17 November 2016
HOW DO ORGANISMS REPRODUCE
Reproduction is a process by which all living organisms give rise to
new organisms similar to themselves (parents).
It is essential for the survival of the species since all living
organisms have a limited life span.
Since the genetic material from one generation is passed in to the
next, it not only maintains the continuity of species but also the continuity
of the parental generation.
It enables a species to increase the total number of individuals.
Types of reproduction:
There are two main forms of reproduction. These are:
1.
Asexual
reproduction
2.
Sexual
reproduction
Asexual reproduction means formation of organisms without the fusion of
gametes. The important features of asexual reproduction are:
i.
It involves only
a single organisms or parent.
ii.
It gives rise to
two or more individuals of the same kind. The individuals formed ate
genetically identical to the parent.
iii.
The cell
divisions are mitotic in nature.
iv.
It is a most
common mode of reproduction in unicellular organism, some plants and lower
multlicellular organisms like sponges and hydra. It is absent in higher
invertebrates and all vertebrates.
Types of Asexual reproduction:
i.
Fission (binary
fission, multiple fission)
ii. Budding
iii. Spore formation iv. Regeneration
v. Vegetative propagation vi. Tissue culture
1. Fission :
Fission means splitting. It occurs in unicellular
organisms. The parent organisms split into two or more equal parts. Each part
then develops as a separate individual. Depending on the number of individuals
formed after splitting of the parent organism, fission is or two types.
a) Binary
fission: The terms binary fissions “splitting of a
single cell into two”.
·
In this method,
first the nucleus elongates and divides into two.
·
Then a
constriction appears in the cell membrane which deepens further, dividing cytoplasm
into two parts.
·
This way the
parent cell divides into two daughter cells.
·
Each part then
grows into an adult organism, similar to the parent.
·
Paramecium also
reproduces by binary fission in the same number as explained in Amoeba in
transverse plane but Euglena and Leishmania (the protozoan causing Kalaazar)
reproduce by binary fission in longitudinal plane.
b) Multiple
fission: Multiple fission means
division of the parent body into a number of daughter organisms.
·
In this the
parent nucleus divides repeatedly.
·
The nuclei move
towards the periphery and each one is surrounded by a small amount of cytoplasm
and cell membranes.
·
Finally each one
of these structure gives rise to a new individual. The multinucleate body gives
give to as many number of daughter individuals as the number of nuclei formed.
·
It is a common
mode of reproduction in malarial parasite (plasmodium), when it invades the RBC
of man.
2. Budding:
In budding the new individual arises as an outgrowth
(bud) from the parent. In can be seen in lower organisms like hydra and yeast.
a) Hydra: In multicellular organisms like hydra, a bulge like
projection as a result of repeated mitotic division grows in the parent body.
·
This bulge is
called the bud.
·
This bud grows
and develops organs like mouth and tentacles around it.
·
It grows to a
full size and develops into a new hydra attached to the parent body.
·
Finally a
constriction at the base separates the new hydra from the parent body.
b)
Yeast: In unicellular organisms like yeast (a fungus)
a bud starts as a small outgrowth from the surface of an adult cell.
As it enlarges the nucleus of the adult cell divides
and then the bud gets pinched off but still remains attached to the parent
cell.
This in turn produces another bud at its tip and the
process continue 3-4 times resulting in a chain of yeast cells.
3. Spore
formation: It is the most common type
of asexual reproduction in majority of fungi and bacteria. The spores develop
in a structure called sporangium. Sporangium develops on slender, erect fungal
nuclei. Each nucleus with a bit of cytoplasm develops into a spore. A spore is
a small microscopic structure with a thick wall.
·
The wall of
sporangium breaks releasing the spores in the air.
·
Sooner or later
under favorable conditions in ground or substratum, each spore germinated into
a hypha and grows into new plants.
E.g.
Rhizopus, mucor, penicillium.
4. Regeneration: The process of getting back a full organism from is
body parts are called regeneration. The simple animals like Hydra and Planaria
show regeneration. This means that in these organisms, whole new organisms can
be reproduced from their cut body parts. In other words or Hydra or planaria
somehow get cut into a number of pieces, then each body piece can grow into a
complete organisms.
Planaria is a flatworm which is found in freshwater ponds and
slow-moving streams. Planaria possesses great power of regeneration. If the
body of planaria somehow gets cut into a number of pieces, then each body piece
can regenerate into a complete Planaria
by growing all the missing parts.
The regeneration of organisms from its cut body parts occurs by the
process of growth and development. This happens as follows: the cell of cut
body part of the organisms divide rapidly to make a ‘ball of cell’. The cell
present in the ‘ball of cell’ move to their proper places within the ball where
they have to inform various organs and body parts of the organisms. The cells
then change their shape (or become specialized) to form different types of
tissues. These different tissues form various organs and body parts of the
organism. In this way a complete organisms is regenerated.
The complex multicellular organisms (like mammals) cannot give rise to
complete individuals from their cut body parts through the process of
regeneration.
Regeneration can be used to reproduce only those organisms which have
relatively simple body organization consisting of only a few specialized cells
(or tissues). In complex multicellular organisms, specialized cells make up
tissues; tissues make up organs; organs make up organ system; and finally organ
systems make up organisms. Since complex multicellular organisms have a very
high degree of organization in their body, they cannot be reproduced from their
cut body parts by the process of regeneration.
5. Fragmentation-
The breaking up of the body of a simple multicellular into two or more pieces on maturing , each of which subsequently grows to form a complete organisms is called fragmentation.
The organisms likes spirogyra and sea anemone can reproduces by these methods.
The main difference between fission and fragmentation is that in fission , a unicellular organism break up to form two daughter organisms whereas in fragmentation , a multicellular organisms breaks up to form two daughter organisms.
6. Vegetative propagation:
I.
It is the
simplest and a rapid way of producing new plants in number of higher plants.
II.
It is development
of a new plant from a vegetative part of plant like stem, root or leaf.
III.
Plants produced
are identical to the parent plant. Same variety of fruit or flower can be
produced year after year.
Vegetative
propagation can be natural or artificial. A number of ornamental plants,
orchids, plants of economical or medicinal value are grown by artificial
vegetative propagation. A number of flowering plants show natural vegetative
propagation. Some of the common ways the plants propagate naturally are by 1. Stem 2. Root 3. Leaves
1. By stem: Underground stems of potato, onion, banana and garlic
etc.
2. By roots: Roots of certain plants like guava, carrot , sweet
potato and
Dahlias have adventitious buds (adventitious buds are
buds
which are present at points
other than the shoot tip and axil of leaves) on the roots which give out shoots
that develop into new plants.
3. By leaves: In Bryophyllum, the adventitious buds ate present
along the
Notches of the leaves. During favorable conditions
young plantlets develop from these buds. These plantlets fall off; grow roots
into the soil and from independent plants.
Artificial
vegetative propagation:
Artificial vegetative propagation is tried by gardeners and
horticulturists for large scale commercial purposes. Some or the common modes
used are:
1. Cutting 2.Layering and 3. Grafting
1. Cutting: Cutting are short pieces of the plant which could be
a stem, root, leaf or a bulb scale. When these are placed in moist soil with
suitable conditions, they develop roots and shoot and grow into a new plant.
Generally the cutting selected has some buds on them. At times stem cuttings
are dipped into a hormone rooting powder to stimulate rooting.
2. Layering: In this method leaves from one of the branches are
removed from a small portion. This small portion of the branch without leaves called
layer is given a small cut and covered with soil. After two days the layer
develops roots and it can be separated from the parent plant and planted
separately.
3. Grafting: Grafting is used to reproduce fruit tree and roses. In
this method a twig (called the scion) is cut from the plant to be increased. It
is then joined to the stem (called the stock) of a rooted plant. The cut
surfaces are taped together. The graft heals on the rooted plant to give a new
plant. Grafting is useful if plants are difficult to grow from seeds.
Advantages
of vegetative propagation:
1.
It is an easier,
less expensive and rapid way of producing new plants under favorable
conditions.
2.
The plants that
cannot produce viable seeds such as banana, pineapple, orange, grape and
produced by seeds.
3.
Plants produced
by vegetative propagation bear flowers and fruits much earlier than those
produced by seeds.
4.
Vegetative
propagation takes much less time and so is highly suitable for plants that have
small number of seeds, poor seed viability or ling periods of seed dormancy.
5.
Superior quality
fruits or flowers can be produced by method of grafting.
6.
Since vegetative
propagation gives rise to plants that are identical to plants, it can be used
to preserve a stock of preserved varieties.
Sexual
Reproduction in Flowering Plants:
The important features of sexual reproduction are:
1.
It involves two
parents a different sex, like male and female.
2.
Each parent
produces special sex cells called gametes. Male gamete is often referred as
sperm and female gamete as ovum.
3.
The gametes are
haploid and are produced as a result of meiotic division.
4.
The fusion of
male and female gamete results in the formation of a single celled diploid
zygote.
5.
The zygote
undergoes repeated mitotic division and grows into an embryo that gives to
multicellular organisms by cell differentiation.
6.
The organism
formed is genetically different from both the parents and resembles both the
parents in certain features only.
Some
important terms:
Unisexual: It refers to
organisms being either male or female.
Bisexual or
hermaphrodite: It refers to an
individual that has both male and female sex organs.
Gonads: gonads are the reproductive or sex organs that produce
gametes.
Male gonad is called
testis and produced sperms.
Female gonad
is called ovary and it produced eggs or ova.
Gametes: These are specialized cells produced from gonads as a
result of meiotic (reduction division) .These is of two types: sperms and ova
Fertilization:
Fertilization can be defined as the
fusion of a sperm and an egg to give rise to a fertilized egg or zygote.
Zygote: zygote is a singled celled structure formed by the
fusion of a sperm with an egg ovum.
Types of
fertilization:
I.
External fertilization: when the fertilization takes place outside the body of
organism, it is called external fertilization.
In animals like fishes and frogs (amphibians), male
and female come together and discharge their gametes in the surrounding water.
The sperm fertilize the ova in water. This type of fertilization is called
external fertilization.
II.
Internal fertilization: when fertilization takes place inside the body of
female, it is called internal fertilization.
In animals like insects, reptile, birds and mammals
including human beings, the made discharges the sperms inside the body of
female during mating or copulation. The sperm fertilizes the ovum in the
oviduct of female. This type of fertilization is called internal fertilization.
The structure associated with mating is called
accessory sex organs.
Significance
of sexual reproduction:
1.
It promotes
diversity of characters in the offspring since offspring have the genetic
material of both the parents.
2.
There is
increased opportunity for new combination of character to appear in the
offspring. It plays a vital role in the origin of species. At times characters
hidden in the parents get expressed in the offspring.
3.
It results in
variations. The individuals formed are genetically different from both the
parents. Variation is necessary for evolution.
Sexual
reproduction in plants:
Flowers are the reproductive organs in flowering
plants.
Structure of
a flower
A flower is a reproductive part of a plant. Though
flowers differ in color, size and arrangement, their basic plan remains the
same.
Part of a
typical flower:
A typical flower has four whorls arranged around the
receptacle or thalamus – the expanded portion of the stalk.
Whorls: Starting from outside,
the whorl are arranged
Sepals: They are outermost whorl generally green and leaf
like.
They protect the flower bud before it opens.
Petals: They form the second whorl, inner to sepals.
They
are generally large, colored and showy.
They help in
pollination by attracting insects.
Stamens: Stamens are the male reproductive parts. Each stamen has two
Parts, filament and anther.
a)
Filaments are
a long slender stalk.
b)
Anther is a
bilobed flattened structure present at the tip of filament. Each anther has
four pollen sacs which contain pollen grains.
Each pollen grain produces two male gametes.
Carpel or pistil: They form the fourth and the inner most whorl
containing
Female parts. Each carpel has three parts.
a)
Stigma: It
is attached to the style and receives the pollen grains.
b)
Style: it
forms the neck of carpel to which stigma is attached.
c)
Ovary: it is
swollen basal part. It contains ovules. Each ovule contains an egg, the female
gamete.
At maturity,
the pollen grains develop into anthers and egg cell into the ovules.
Pollination:
Pollination is the transfer if pollen grains from an
anther to the stigma. After the pollen grains are shed from the anthers, they
can reach stigma of a flower by a number of means. The flowers could be self
pollinated or cross pollinated.
Types of
pollination
A. Self pollination:
It refers to the transfer of the pollens forms the
anther of a flower, to the stigma of the same flower or to the stigma of
another flower of the same plants.
e.g- china rose, maize
B. Cross
pollination:
It refers to the transfer or the pollens from the anther
of a flower to the stigma of another flower of a different plant of the same
species.
It involves two separates plants and outside agencies
like wind, water, air or insects.
e.g- papaya, mulberry
Agencies of scientific
terms cross pollination
Winds –
Anemophily
Water –
Hydrophily
Insects –
Entomophily
Birds – Orinthiophily
Bats -
Chiropterophily
Fertilization
in plants
After pollination, occurs fertilization in plant. The
main events that lead t fertilization are as given below:
1.
Immediately
after pollination, as pollen grains land in stigma, they give rise to pollen
tubes.
2.
One
pollen tube grows through the style and reaches the ovary where ovules are
located.
3.
Each
pollen tube has two male gametes.
4. Pollen tube enters the ovule through
a small opening called the micropyle.
On
reaching the ovary, the pollen tube releases two male gametes into the embryo sac of ovule.
One male gamete fuses with other male gamete with the
the egg
cell of the ovule. two polar
nuclei in the ovule 
It is known as fertilization or since it is
fusion of 3 nuclei,
Syngamy and produces a it is
known as triple fusion.
fertilized egg or zygote. (Triple fusion produces a (zygote is diploid
in nature 2n). triploid nucleus and
this 3n in nature.
It is called double
Fertilization
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Double fertilization: Since the process of fertilization occurs twice in the
embryo sac, it is called double fertilization. It is unique to flowering
plants.
Double fertilization includes two fusions – syngamy
and triple fusion
i) Male gametes+ egg
cell = Zygote ( syngamy)
ii) Male gamete + 2
polar nuclei =Triploid nucleus ( triplet fusion)
Double
fertilization = Syngamy + Triple Fusion
Results of double fertilization are:
i. Zygote (2n)
divides mitotically and forms the embryo plant.
ii.
Triploid nucleus
(3n) gives rise to a mass of tissues called endosperm of seed. It provides
nourishment to the growing embryo at the time of seed germination.
Summary of changes after
fertilization
1. The ovary develops into the fruit.
2.The ovules
develop into seeds.The seed contain the
embryo or the potential plant. During the formation of fruit, rest of the
flower withers away.
Germination:
If a seed lands where conditions are appropriate, i.e.
water, oxygen and warmth are available, it will start to grow. Germination is
when the embryo begins to grow. The beginning of the growth of seed is called
germination of seeds. Germination begins when the seed absorbs water, swells
and burst through seed coat . The water helps the enzymes to function in the
seed. The enzyme digest the stored food in cotyledons ad make it soluble. The
soluble food makes the radical and plumule present in the seed to grow .
The embryo grows a new root or radical and new shoot
or plumule. The radical and plumule need food for growth and they get this food
from the food store in the cotyledons.
SEXUAL
REPRODUCTION IN ANIMALS
Sexual Reproduction is the fomation of the new
individuals by a process which involves the fusion of male and female gametes.
Reproduction
in human beings
An
animal having male sex cells called sperms in its body is called male.
An
animal having female sex cells called ova in its body is called female.
The
cells involved in sexual reproduction are called gametes. The male gamete is
called sperm and female gamete is called or ovum or egg.
Fusion
of gametes gives rise to a single cell called zygote.
Fertilization-
The
fusion of a male gamete with a female gamete to form a zygote during the sexual
reproduction is called fertilization.
Puberty:
The
age which the sex hormones (or gametes) begin to be produces and the boy and
girl become sexually mature (able to reproduce) is called puberty.
The
testes produce the male sex hormone called testosterone, and the ovaries
produce two female sex hormones, oestrogen and progesterone.
The various changes which occur in boys at puberty are:
Hair
grows under armpits and in pubic regions (genital area) between the thighs. Hair
also grows on other parts of the body like chest and face (moustaches, beard,
etc). Body becomes more muscular due to the development of muscles. The voice
deepens (or cracks). Chest and shoulders broaden. The penis and testes become
larger. The testes start to make sperm.
The various changes which occur in girls at puberty are:
Hair
grows under armpits and in pubic regions (this change is the same as in boys).
Mammary glands (or breasts) develop and enlarge. The hips broaden. Extra fat is
deposited in various parts of the body like hips and thighs. Fallopian tubes,
uterus and vagina enlarge. Ovaries start release eggs. Menstruation (monthly
period) start. Feeling and sexual drives associated with adulthood begin to
develop. All these changes in girls are brought about by the female sex
hormones ‘oestrogen’ and ‘progesterone’ made in ovaries. Please note that the
hormones ‘oestrogen’ is also written and spoken as ‘estrogen’.
Human reproductive system:
The reproduction systems in human beings
become functional (or start functioning) at a definite age called puberty.
The male reproductive system
The
human male reproductive system consists of the following organs: testes,
scrotum, epididymis, vas deferens (or sperm duct), seminal vesicles, prostrate
gland and penis. Testes are the primary reproductive organs in man (or males).
The function of testes is to make the male sex cells (or male gametes) called
sperms and also to make the male sex hormone called testosterone. The secretion
of seminal vesicles and prostrate gland provide nutrition to the sperms and
also make their further transport easier.
The female reproductive system
The
human female reproductive system consists of the following organs: ovaries,
oviducts (which are also called fallopian tubes, uterus and vagina. Ovaries are
the oval shaped organs which are inside the abdominal cavity of a woman near
the kidneys. A woman has two ovaries. Ovaries are the primary reproductive
organs in a woman (or female). The function of ovaries is to make mature female
sex cells ( or female gamates) called ‘ova’ or ‘ eggs’, and also to make the
female sex hormones ( called oestrogen and progesterone).
Menarche and Menopause
Menarche: The
begininning or commencement of menstruation at puberty is termed as menarche.
In other words, the first monthly period or menstruation is called the menarche.
It marks the beginning of the reproductive life of a woman. Normally it occurs
between 11-13 years.
Menopause: At about
the age of 50-55, the ovulation stops and the menstrual cycle is permanently
discontinues. The ovarian as well as uterine cycles stop. This is known as
menopause.
Menopause
is marked by the stoppage of menstrual flow and other cycle events related to
it.
After
menopause the female loses the ability to reproduce.
Menopause also brings about a hormonal
imbalance in the body( decreased oestrogen level), and hence is accompanied by
other changes like loss of bone matter, increased body weight etc.
Reproductive life: The period
between menarche and menopause i.e. between 12-50 years is called the normal
reproductive life of human female.
Fertilization
Fertilization
involves the fusion of a sperm and an ovum and restores the diploid number of
chromosomes. The fertilized ovum formed is called zygote.
In
human beings, the fertilization is internal. During mating, millions of sperms.
About 200,000,000 are deposited in the vagina but only one out of these
fertilizes the ovum. The sperms are highly active and motile but remain fertile
for only about 12-24 hours in the female reproductive tract.
The
sperms released in vagina, move up the uterus and then the fallopian tubes.
Only a very small number of sperms reach the fallopian tubes because the female
reproductive tract is strongly acidic. Finally only one sperm fertilizes an
ovum. Fertilization occurs high up in the fallopian tube. A sperms may
fertilize an ovum if mating takes place during the ovulatory phase.
The
union of a sperm and am ovum gives rise to a zygote.
Fertilization
is marked by the absence of menstrual flow.
Development of zygote after
fertilization
-Immediately after
fertilization, the zygote begins with repeated mitotic division. Also it starts
moving down slowly , along the fallopian tube towards the uterus. In about 4-5
days, as a result of repeated divisions, it becomes a multicellular structure called
an embryo and reaches the uterus.
-At about the 7th
day after ovulation, the embryo gets attached ( embedded ) to the thickened
inner wall of uterus . this is called implantation.
-After
implantation, a special tissue develops between the embryo and the uterine
wall. This tissue is called placenta.
Placenta:
Placenta is a disc- shaped connection between the mother and the embryo
(foetus). When the embryo takes the characteristic human form, it is termed as
foetus till birth.
-It is through
placenta that the foetus exchanges respiratory gases, nutrients and excretory
wastes with the maternal blood. Placenta supplies the foetus everything it
needs for development. ( in the placenta , blood of the mother and the foetus
never mix since exchange always takes place through the membrane. CO2 and wastes move from the foetus to maternal
blood, and O2 and nutrients
from the maternal to foetal blood by diffusion).
Umbilical cord:
it is during the development of embryo, that
along with placenta, develops another structure called umbilical cord.
Umbilical cord is a long and thick cord that runs between the foetus and the
placenta( placenta is attached to the uterus).
-Umbilical cord is
attached to the belly of the foetus. It contains the blood vessels taking
foetal blood to and from the placenta.
Gestation:
Pregnancy
or gestation refers to the condition of carrying developing foetus inside the
uterus till birth. It begins with conception i.e. the fertilization of the ovum
by a sperm, and continues until the birth of the baby.
Duration of pregnancy :
in
human beings, the average duration of pregnancy is about 280 days ( or 40
weeks) i.e. approximately nine months.
It
is calculated from the 1st day of the last menstrual cycle. The
newborn baby after 40 weeks of gestation weighs about 3.5 kg.
Parturition:
On
completion of pregnancy or gestation, the birth of the fully formed foetus is
called parturition.
Population control:
Human
population is increasing at an enormous rate. It is estimated to become double
in next 30-35 years. The increase in human population is not only adding to the
already exploding population but is also causing a number of socio-economic problems.
Also the frequent pregnancies have an adverse effect on the health of a woman.
Birth control or fertility regulation methods:
To
control over- population, the best method is the birth control. For this a
number of scientific techniques have been developed to prevent pregnancy. These
methods of birth control can be broadly classified into the following three categories.
1.
Barrier
methods
2.
Chemical
methods
3.
Surgical
methods
Some common birth- control or fertility regulation methods
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s.n
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Birth control
Methods
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Working of the birth- control method
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Examples
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1.
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Barrier methods
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-They prevent the entry of sperm in
the female genital tract. Hence fertilization cannot take place.
-They include physical
devices that act as barriers.
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Condoms –used by male
Diaphragm and cervical caps – used
by females
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2.
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Chemical methods
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-These are specific drugs used by females.
-They are in the form of oral pills and
vaginal pills
-Oral pills also known as birth control pills
or oral contraceptives (OCs) conatain a combination of hormones. They prevent
the production of ova in ovaries by acting on hypothalamus, pituitary and
ovaries. Since ovulation does not occur, pregnancy cannot take place.
-Vaginal pills are chemical spermicides i.e.
kill a large number of sperms.
-Intrauterine contraceptive devices (IUCDs)
like copper T. Copper T is a small plastic device shaped like a letter T,
with a fine copperwire wrapped around it. It is placed inside the uterus by a
qualified doctor. It prevents implantation of ovum in the lining of uterus.
The copper of copper T is slowly and continuously released into the uterus.
Because of the presence of copper t, copper T is considered to be a drug.
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Oral pills also called as oral
contraceptives (OCs) and vaginal pills.
Intrauterine contraceptive devices
(IUCD) like copper T
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3.
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Surgical methods
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-Surgical methods involve birth control by
sterilization.
-They can be performed on either males or
females and are almost 100% effective and are irreversible.
-In males, sterilization involves vasectomy
i.e the removal of a portion of vas deferens from each testis. It prevents
sperms from entering the urethra.
- In females, it involves tubectomy i.e the
removal or ligation (tying ) of a section of each fallopian tube. It prevents
ova from reaching the uterus.
Vasectomy and tubectomy , both prevent contraception permanently.
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Vasectomy in males.
Tubectomy in females.
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Reproductive health and sexually transmitted diseases (STDs)
The
term health includes the physical, mental and social well being of a person.
Reproductive
health includes aspects that ensure a responsible, safe and satisfying
reproductive life.
1. Importance of studying reproductive health
i.
It aims at providing awareness
regarding the fertility regulation methods to both males and females.
ii. It
gives the right, the freedom and choice to control child birth.
iii. It
gives people the ability to prevent and control sexually transmitted diseases
(STDs).
iv. It
helps people to manage disorders related to reproductive system.
2. Sexually transmitted diseases (STDs)
Sexually transmitted diseases (STDs) are
highly infectious diseases that spread form an infected person to a healthy person
by sexual contact.
These
diseases are caused by micro-organisms like viruses, bacteria, protozoans or
fungi that are passed from one human being to another by sexual contact. Most
of these diseases are curable, though there is no definite cure for AIDS( a
sexually transmitted disease) till now. In most cases the common symptoms are
burning sensation at urination and discharge from urethra or genital tract.
Some common sexually transmitted
diseases (STDs)
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Name of sexually transmitted diseases
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Causative organism
(micro- organism)
|
Symptoms
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Gonorrhea
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Bacterial
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-Infects mucous
membranes of the urino genital tract.
-Genital
discharge, painful urination.
-Children born
to afflicted mothers often suffer eye infections.
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Syphilis
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Bacteria
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-Causes sores
and lesions in the genital tract
-Burning
sensation at urination
-Later causes
sores in mouth.
-Can be deadly
if not treated.
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Trichomoniasis
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Protozoa trichomonas
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Vaginal irritation, itchining and discharge
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AIDS
(Acquired Immuno
Deficiency syndrome)
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HIV
(Virus)
Human Immuno deficiency
virus
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-Destroy the
immune system of body.
-Persistent
cough and fever
-Body attacked
by other diseases like pneumonia, T.B. and certain cancers.
AIDS is a life
threating disease. At present there is no vaccine to prevent and there is no
cure. However AIDS is preventable.
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