SECTION ‘B’ (SHORT – ANSWER QUESTIONS)
2.i) Write a note on Placenta. or Write the types of receptors.
Placenta: The tissues that attach the embryo to the wall of uterus IS called the “Placenta”. The placentra is flat pie or disc shaped structure. It contains million of blood-vessels system. Food and oxygen from the mother’s blood diffuse into the embryo through placenta. The carbon dioxide and waste diffuse out throuth the placenta to the mother. Placenta secretes progesteron, human chorionic gonadotrophin and human placental lactogen
Receptors:Receptors are either modified neurons or epithelial cells
which occur either singly or in groups with other cell types. Depending upon the type of energy detected by receptors, they can be classified into following groups.
• Therrnoreceptors: They detect changes in temperature.
• Chemoreceptors: They detect chemicals dissolved in fluid medium
• Mechanoreceptors: They detect sound, motion, position in relation
to gravity, touch, pressure.
• Photoreceptors: They detect visible and ultra violet light.
• Pain receptors: They detect tissue damage.
ii) Write a note on Energy Conservation.
From the last 150 years human beings are using fossil fuel as cheapest source of energy for domestic and industrial uses, but now this source being non renewable is exhausting at one end while on the other hand it has become a very costly Similarly the nuclear power also has its own demerits, the disposal of nuclear waste and safe use of nuclear power plants is also a great problem. Therefore, we have to develop alternate resources for generating electric power such as solar and wind energy. Besides, generation the proper use of present resource has become more important.
It has been estimated that about 75% electricity produced is being wasted through the use of Inefficient modem machines and appliances such as motors, heaters, air conditioners, refrigerators etc. These appliances not only waste electricity but are also responsible for global warming by increasmq the temperature of the earth. We use light bulbs in our homes, streets and factories, a new fluorescent bulb~onsumes 20% of light electric y and is more durable than normal bulb, so we . should choose correct appliance for daily use.)t will not only save money but also electricity.
iii) Write any Four objections on Darwin’s Natural Selection Theory.
Darwin’s theory of Natural selection was so reasonable and well suported by arguments and examples. Thus it was soon accepted by many bioloqrsts, but still have some of the objections which ar as under.
1.Darwin was unalbe to explain the origin of variation.
2.Small variations can not be responsible for origin of new species. He did not mention about natural variation.
3. He did not mention the role of mutation in evolution.
4. He did not explain the presence of vestigial structures in the body of new organism.
iv) Write note on Disc slip or Test tube baby.
Disc Slip: The intervertebral discs may prolapsed forwarct(during bending forward while lifting heavy weight). It causes hemiation of one or more disc which causes pressure on spinal cord and its’ nerves to causing severe pain in that area supplied by the nerve. It is treated with bed rest, pain killer medicine and traction of body. Test tube baby: Approximaately 10 percent of the couples fail to have children, This condition, called infertility , may be due to a number of causes. In some females, however, this is due to the blockage of oviducts so that the sperms cannot reach the egg. This sort of infertility is overcome by a technique called in vitro fertilization. In this procedure some of the oocytes are sucked up from the ovary of that women before ovulation. These eggs are fertilized, outside her body In a laboratory dish, with the sperm taken from her husband. Eggs thus fertilized In vitro are allowed to develop for a few days in thp. laboratory and one is then transferred to her uterus for implantation where It undergoes normal development and the baby is bom the natural way.
v) Define Ectothermic and Endothermic animals with examples.
Ecotherms: Those organisms which absorb heat energy from their enviroment and have behavioral means of thermo regulation. Example: Reptiles (Lizards) amphibia, invertebrates.
Endoderms: Those organisms which generate their own heat energy. They have physiological as well as behavioral means of thermoregulation.
Example: Some fishes, birds·and flying insects.
vi) Write a note on Thymus gland.
It is situated in the upper part of the chest, behind the breast-bone and consists of two lobes that jom in front of trachea. It secretes several hormones including thymosin that stimulates the development and differentiation of T-Iymphocytes after they leave the thymus. The T-cells defend the body against viruses and other Infectious micro-organism.
vii) Write a note on Haemoriialysis. ,
Hemodialysis means ‘Gleaning the blood’. In this procedure blood is circulated through a machine which”‘contains a dialyzer also called an artificial kidney. Dialyzer has .wo spaces separated by thin membrane Blood passes from one side of the membrane and dialysis fluid on the other. The wastes and excess water pass from the blood through the membrane into the dialysis fluid
viii) Write four differences between Bone and Cartilage.
The human skeletal system consists of bones and cartilages of vanous types. Bones and cartilages are supporting connective tissues.
They provide support, surface for the attachment of muscles and protection to many vital organs like brain, heart, eyes etc. and also give a definite form and shape of the body. Moreover the skeleton plays a vital role In locomotion and movements. Following are the some differences between bone and cartilage.
ix) Write a note on Hydrostatic skeleton or Homologous organs.
Hydrostatic skeleton: It is a fluid filled gastrovascular cavity which act as hydrostatic skeleton and qive support and resistance to muscles contraction to cause proper motility.
Example: This type of skeleton is found 10 Annelids (earthworm), Cnidanan (Hydra) and other soft bodied invertebrates (Echinoderms, sea anemone).
Hornoloqus Organs: Many different species show close resemblance in their anatomy i.e. their intemal qeneral structural plan is same, though their external appearance is very different performing different functions. Such remarkably similar structures perform modified functions 10 different species are called homologous organs.
Example: Skeletal system in the wing of bird or bat, fore-limb of Turtle, fore-leg of horse, flipper of whale and arm of man is very Similar intemally havmq same type of bones and muscles though they al are superficially different from each other and perform different functions in different habitats.
Biologists are of the opinion that homology indicates their common
x) How does a Muscle become fatigued?
During a heavy or prolonged exercise when enough Cygenis not available muscle cells receive supply of ATP through fermentation also called anaerobic respiration. During fermentation glucose is converted into lactic acid Instead of carbon dioxide, and water as the case is with normal aerobic respiration. This accumulation of lactic acid in the muscle produces a tiring condition of the muscle known as fatigue.
xi) Differentiate between Parasympathetic and Sympathetic nervous system.
xii) What’ is Abnormal development? Give any three examples.
Deviation In the normal structure and function of an organism under unfavourable condition during embryological development is called as “Abnormal development.”
The branch’ of biology which deals with the abnormal development and their causes IScalled as teratology Some abnormal condition of human being are as follows.
i) Microcephaly: These Individuals born with small skull in proportion to ItS body size. Cause’ Viral infection, folic acid defeciency
ii) Cleft Lip and Palate: The individuals born with the split in upper lip and gap in the roof of muth. Cause’ Viral infection, Antiepueptic drugs. (e g. phenytoin)
iii) Polydactyly: The individual born with excessive number of finger or toes. r.e. more than normal fingers or toes. Cause: It may be heriditary or familial.
xiii) What is the significance of Sexual reproduction?
Reproduction in whtch fusion of nuclei of two gametes of opposite. sexes belonging to same species called “Sexual Reproduction”. Importance of Sexual Reproduction:
i- Sexual reproduction is Important to avoid genetic monotomy in which organism produces asexually throu~h out their lives an
Identical copies of parent
ii- Sexual reproduction is Important to develop an endless variety of organism, because each organism IS develop from unique set of character from both parents.
iii- It help the organism to adopt the changing enviroment or changing habitat of animal.
iv- The genetic variation produced by sexual reproduction is the basis of evolution foundation.
v- The chances of survival in a new species produced by sexually reproduction are very high even they cope with unfavourable environment as well as the outbreak of diseases.
xiv) Differentiate between Nervous coordination and Chemical coordination.
Ans. See on Page # 409.
xv) Write a note on DNA fingerprinting.
Ans: See on Page Ii 409.
xvi) Give any two evidences in favour of Organic evolution.
Following are the two evidences In favour of organic evolution.
1- Evidence from Classification. All the members of a family has resemblance, class, order, genus I.e. they may have evolved from some common ancestor.
2- Evidence from Homology. Resemblance or similarities of the structures of the organism e.g. fore limbs of birds, dog, whale, bat, man etc
SECTION ‘C’ (DETAILED – ANSWER QUESTIONS)
3. Describe the Human female reproductive system ‘with the help of a diagram.
Female reproductive system consists of following organs.
1- External genitalia.
4- Fallopian tubes
External Geuitalla: The external genitalia are collectively known as
Vayina: Vagina IS an elastic, fibro-muscular, tubular structure which
lies between the urinary bladder and the rectum.’ It runs upwards from the vulva to the cervix.
The ength o’ vagina is vanable. Its length is 6 to 10 cm
The vagina wall consists of three layers.
1- Stratified squamous epithelium.
2- Fibro-muscular layer
3- Fibro-fatry tissue.
Functions. It behaves not only as birth eanal but also fur.ctions as specialized receptacle for the penis.
the uterus ;5 a pear shaped muscular organ with a lining of vascular tissue .
The muscular part of uterus is called the myometrium
The spongy lining of uterus filled with vascular tissue called as
Endometr urn. This tissue undergoes changes each month In preparation for possible reception of a fertilized egg If the
vurn IS not fertilized, the lining is shed and menstruation occurs.
the waU of the uterus consists of three layers.
Uterus’s subdivided into three parts.
1 Body of uterus
4- Fallopian Tubes:
There are two fallopian tubes .
These tubes are attached to either side of the uterus
The length of each tube ISabout 10 em.
The lumen at the lateral end of the fallopian tube -ope-is In 0 the peritoneal cavity .
The eggs are released into a fallopian tube which serves as an OViduct
Each tube is lined with cilia that serves to move the ovum towards the uterus
Fertilization when occurs, takes place in the fallopian tube in the region of ampulla (the dialated part of fallopian tube) .
The wall of the fallopian tube consists of the follcNlng layers from inside out:
2. Muscle wall
3. Peritoneal covering
There are tw» ovaries in fAmale body, They lie on either side of the
The ovanes are almond shaped
Their, ..g..th IS4 cm breadth is 2 5 cm and thickness 1,5 cm approximately,
They have no peritoneal covering, _
Ovane ~ are attached to the uterus by the ovarian ligament.
Internal Structure: The ovaries have two zones namely,
Cortex: It is the cuter zone and IS filled With special type of cells
Medulla: It is he inner co’ of the ovary, It consists mostly of blood vesels and nerves w ‘h a loosly packed fibrous tissue
Function Ovary performs two major functions:
i. Oogenesis: It IS the process of production of female gametes r.e. ova or egg cells Estimates suggest that there are at birth from 3000 to 30,000 ootential egg cells, each located in a saclike follicle, However only ,50 to 450 of these ever mature,
ii. Hormone Secretion Ovary secretes two major hormones:
Oestrogen + Progesterone These hormones are respons ble for the feminine characters and reprod -ctive changes Ir.lfem’ale At e onest of sexual matunty hormones begin to influence the eggs to mature Witt In the fOI .cle and to be released at the rate 0′ approximately one every four weeks from alternate ovaries,
OR What is Pollutron? Describe Air Pollution.
POLLUTION’ Pollution IS ,.f’ undesrrable (unwanted) change 1:1 the physical, chemical and biological characteristic of environment harmful to human and other related species. Causes: Pollution is caused by some material called pollutant. A pollutant IS any fac ‘r that damage or make the environment unclean Pollutant effects air, water, soil ana may danger the health and lives of all liVing beings Types. Generally pollution may be
from sun which can cause harm to every living being on earth and chloride ions are continuously destroyrnq this protective covering. Major sources of chlonne is a group of gases produced from Industries. This group is CFC (chlaro-floro-carbon) which is widely used as refrigerators and rndustrial foaming agent. Normally, these are inert gases but when accumulated at stratosphere (hlght altitude). They causes chlorine atom to release which react With ozone atom in presence of ultra violet radiation to convert ozone into oxygen. Due to this damage to ozone layer, Itra violet rays reaches to earth surface \ and causes harm to hving orgamsm specially it produces skin cancer.
4. Explain the structure of Nephron and write the regulatory functions of kidney.
The structural and functional unit of kidney is called “Nephron”, There are millions of Nephron in each kidney. Nephron perform excretory function as well as osmoregulation.
STRUCTURE OF NEPHRON: The nephron begins ac a spherical structure calied malpiqhran body. The rnalpiqhran body composed of cup like “Bowman’s capsule” The bowman capsule contain network of capillaries known as “glomerulus” It lies in the cortex of kidney
Proximal Convulated Tubule: It is a coiled tubule arise from bowman capsule. It also hes in cortex II is also attached With capillaries.
loop of Henle: The proximal tubule narrows and descent down in medulla and make U-shaped tube that again comes back in cortex. Ttus tube is known as “loop of henle” It has descending and ascending limb.
Distal Convulated Tubule’ The ascending limb of loop of henle become coiled and lie in cortex it is called as ‘distal convulated tubule”, Collecting Duct: The distal convulated tubule open into a’ common duct called ·collecting duct”. It receives-urine from several nephrons and drains into the pelvis of the kidney.
b) Germ Lrne Cell Therapy. Germ line gene therapy is also In success to treat cystic fiborsis. in this disease patient face to produce mucus due to defect In gene. In this condition liposome (rrucroscopic lipid envelope) would be sprayed (aerosol spary) periodicallv With normal gene on lung ep helra of patient.
l.rposorne pa kages wI! be taken up into the cells of he I[;ng surface
and genes m y e ter the ::hromosome and expressed themselves