1. Write comprehensive notes on any TWO of the following: (5,5)
Everyday Science Paper 2000
TIME ALLOWED: 3 HOURS MAXIMUM MARKS: 100
NOTE: Attempt any TEN questions. All questions carry equal marks. Illustrate your answer with diagram where necessary.
(a) Contribution of Muslim scientists in the field of biology.
(b) Water pollution.
2. Describe the various type of movements of the earth? What are the effects of these movements? Draw simple diagrams to illustrate your answer. (4,6)
3. Explain the following using suitable examples. ( 2 each)
(a) Feedback mechanism of human system.
(With thanks to dr.atifrana)
Homeostatic Feedback Mechanisms
Many endocrine glands are linked to neural control centers by homeostatic feedback mechanisms. The two types of feedback mechanisms are negative feedback and positive feedback. Negative feedback decreases the deviation from an ideal normal value, and is important in maintaining homeostasis. Most endocrine glands are under the control of negative feedback mechanisms.
Negative feedback mechanisms act like a thermostat in the home. As the temperature rises (deviation from the ideal normal value), the thermostat detects the change and triggers the air-conditioning to turn on and cool the house. Once the temperature reaches its thermostat setting (ideal normal value), the air conditioning turns off.
An example of negative feedback is the regulation of the blood calcium level. The parathyroid glands secrete parathyroid hormone, which regulates the blood calcium amount. If calcium decreases, the parathyroid glands sense the decrease and secrete more parathyroid hormone. The parathyroid hormone stimulates calcium release from the bones and increases the calcium uptake into the bloodstream from the collecting tubules in the kidneys. Conversely, if blood calcium increases too much, the parathyroid glands reduce parathyroid hormone production. Both responses are examples of negative feedback because in both cases the effects are negative (opposite) to the stimulus.
Positive feedback mechanisms control self-perpetuating events that can be out of control and do not require continuous adjustment. In positive feedback mechanisms, the original stimulus is promoted rather than negated. Positive feedback increases the deviation from an ideal normal value. Unlike negative feedback that maintains hormone levels within narrow ranges, positive feedback is rarely used to maintain homeostatic functions.
An example of positive feedback can be found in childbirth.
The hormone oxytocin stimulates and enhances labor contractions. As the baby moves toward the vagina (birth canal), pressure receptors within the cervix (muscular outlet of uterus) send messages to the brain to produce oxytocin. Oxytocin travels to the uterus through the bloodstream, stimulating the muscles in the uterine wall to contract stronger (increase of ideal normal value). The contractions intensify and increase until the baby is outside the birth canal. When the stimulus to the pressure receptors ends, oxytocin production stops and labor contractions cease
(d) Carbon cycle
4. What is excretion? Name the excretory organs in man. Describe the structure and function of human kidney for the excretion of urine. (1,2,7)
5. Describe the Principle, construction and working of a telephone? (2,4,4)
6. What are latitudes and longitudes? How can the central line of latitude be used to find the location of a place? (4,6)
7. Differentiate between:
(a) Cardiac Muscles and Skeletal Muscles.
(b) Haze and Smog.
(c) Enzyme and Hormone.
(d) Sedimentary Rocks and Igneous Rocks.
(e) Producers and Consumers.
8. Define the following terms: ( 1 each)
(a) RAM, (b) Byte (c) Mouse (d) Icons (e) Software (f) Control Unit (g) LAN (h) Modem (i) ALU (j) Registers.
9. Discuss the structure of a typical animal cell in detail. 10)
Kindly have a look at the following link
10. Fill in the blanks with appropriate words: ( 1 each)
(a) Monomer of proteins are Amino Acids
(b) Water transport in plants occurs within Xylem.
(c) Underground horizontal stems are called Rhizomes.
(d) In the eye, only Retina
contains receptors for light energy.
(e) Plant hormones
control plant responses to environmental stimuli.
are often called the power houses of the cell.
(g) The rate at which a current changes direction is called its Drift velocity
. (Please Confirm)
(h) The energy of electrons at the negative terminal of a battery is called
is the smallest planet of the solar system.
(j) Diamond is an allotropic form of the element Carbon
11. Which are plastics? Name their different types and processes by which they are manufactured. Discuss the impact of the use of plastics on the environment.
What is plastic?
Plastic is a common name for Polymers: materials made of long strings of carbon and other elements. Each unit in a string is called a monomer, and is a chemical usually derived from oil.
The monomer is made into polymer by chain-linking reactions. This is like making a daisy chain. Instead of flowers, carbon atoms are joined together. The appearance of the daisy chain will be different if you use different colored flowers, and so will polymers.
There are many different types of plastic, depending on the starting monomer selected, the length of polymer chains, and the type of modifying compounds added. Each plastic has been developed for a special purpose.
There are two main groups of plastics:
soften with heat and harden with cooling.
* Some typical thermoplastics are:
* Acrylic (Perspex)
* Acrylo-nitrile (Nylon)
* Polyethylene (Polythene)
* Poly Vinyl Acetate (PVA)
* Poly Vinyl Chloride (PVC)
* Polystyrene and ABS
* PTFE (Teflon)
are cured or hardened by heat.
Some typical thermosets are:
Manufacture of Plastics
Plastics are made into shapes in many ways
Hot molten plastic is squeezed through a nozzle to make long lengths of special shapes like pipes, spouting and wallboard joining strips. It is also used to make large thick sheets of plastic for fabrication.
2. BLOW EXTRUSION (Fig 1)
This is used for making plastic films and bags. While it is still hot, an extruded tube is blown up like a balloon, with compressed air. This stretches the plastic and makes it thin. The balloon is made long enough to allow the plastic to cool. The end of the balloon is pinched together by rollers, to hold the air in and make it flat. The flat tube is then wound on to a big roll. You can see continuous rolls of plastic bags in a fruit shop.
3. INJECTION MOULDING
Hot molten plastic is squeezed into a mould to make lots of objects all the same. They can be very small like a washer or quite large, like a bowl or a clothes basket. Lots of everyday articles are made this way.
4. BLOW MOULDING (Fig 2)
A little bit of hot soft plastic is squeezed into the end of a mould. Compressed air is used to blow a big bubble inside the plastic. The plastic swells out like a balloon until it fills up the whole mould. Many bottles, toys and money boxes are made this way.
5. ROTATIONAL MOULDING
Plastic powder is scooped into a mould. The mould is rotated over a big gas burner. As the mould gets hot, the plastic melts and sticks to the mould. This method is used for making big hollow things like water tanks and barrels.
6. COMPRESSION MOULDING
This is used for thermoset resins. Dry powder is put in a mould which is squeezed and heated until the plastic is cured. This is used for making ashtrays, cups and plates, and some electrical switches.
7. REACTION INJECTION MOULDING
Two chemicals are mixed together and squirted into a mould. The chemicals react together. This is how they make car bumpers, some disposable cups and plates, and the meat trays you get from supermarkets.
8. VACUUM FORMING ( Fig 3)
A sheet of plastic is clamped in a frame and heated until it is stretchy. Then it is sucked into a mould. This is how they make the inside of your refrigerator, bath and handbasin. It is also used to make a lot of packaging for cosmetics, chocolates, biscuits, some yoghurt containers and some disposable cups.
Some thermoplastics are fabricated like sheetmetal. Sheets of plastic are cut to shape. They can be folded by heating a narrow line through the plastic. When it is soft, the sheet will bend along the heated line. Sheets can be joined together by glueing, or by welding. The join is heated with hot air and a thin filler rod is forced into the gap. These fabrication methods are used to make acrylic signs and displays, and industrial tanks and equipment. Our company, Calibre Plastics Ltd, uses fabricating methods to manufactures laboratory fume cupboards and exhaust fans.
Thin flexible plastic sheets are used for making folders, wallets, swimming pool liners, inflatable toys and raincoats. The seams are welded by ultrasonic vibration.
Impact on Environment
The biggest threat to the conventional plastics industry is most likely to be environmental concerns, including the release of toxic pollutants, greenhouse gas, litter, biodegradable and non-biodegrable landfill impact as a result of the production and disposal of petroleum and petroleum-based plastics. Of particular concern has been the recent accumulation of enormous quantities of plastic trash in ocean gyres.
12. Which of the following statements are False and which are True ( 1 each)
(a) In the circulatory system two pulmonary arteries take blood from the left ventricle to the lungs. (False)
(b) Anaphase is the stage of mitosis during which the daughter chromosomes move towards the poles. (True)
(c) The Motor neurons carry nerve impulses from the central nervous system to the effectors. (True)
(d) Cochlea is a part of the middle ear. (False)
(e) Tides happen due to the moonís gravitational pull. (True)
(f) Heavy water contains salts of Calcium and Magnesium. (False)
(g) All non-metals exist in gaseous state. (False)
(h) A parachute can be used by a spaceman to help in landing on the moon. (False)
(i) The gemstones Ruby and sapphires are composed of Aluminum Oxide. (True)
(j) In a chemical battery chemical energy ions directly converted into mechanical energy. (False)
13. Choose the correct answers. Donít reproduce the questions. ( 1 each)
(i) Speed of the wind is measured by:
(a) Barometer (b) Hygrometer (c) perimeter (d) Anemometer
(e) None of these.
(ii) _____________ connects the muscle with the bone.
(a) Cartilage (b) Ligament (c) Tendon
(d) Disc (e) None of these.
(iii) Polio is caused by a:
(a) Bacterial (b) Virus
(c) Fungus (d) Deficiency of vitamin (e) none of these.
(iv) The coldest planet of the solar system is:
(a) Earth (b) Venus (c) Mars (d) Pluto
(e) None of these
Up until recently, it would have been Pluto with an estimated surface temperature between -235 and -210 degrees Celsius, but Pluto has now been relegated the status of a Dwarf Planet. So now, Neptune would be the coldest planet.
(v) ________________ is a vitamin:
(a) Citric acid (b) Tartaric acid (c) Ascorbic acid
(d) Acetic acid (d) none of there
(vi) An eggshell is composed of:
(a) Iron (b) Starch (c) Carbon(d) Protein (e) None of these
(vii) The most abundant element in the earthís crust is:
(a) Nitrogen(b) Silicon (c) Carbon (d) Oxygen
(e) None of these
(viii) The main constituent of Biogas is:
(b) Hydrogen (c) Oxygen (d) Carbon dioxide (e) None of these.
(ix) Stalagmites are deposits of :
(a) Calcium oxide (b) Calcium sulphate (c) Calcium hydroxide (d) Calcium carbonate
(e) Mixture of all salts.
(x) Gigantism is the result of: (Please confirm)
(a) Hypothyroidism (b) Recessive gene (c) Hyper pituitarism
(d) Vitamin D deficiency (e) None of these.
14. What are the causes of Earthquakes: How have earthquakes helped in deciphering the internal structure of the earth? (4,6)
15. What is the endocrine system? Write the names and function of any eight endocrine glands. (2,8)
The endocrine system is an integrated system of small organs which involve the release of extracellular signaling molecules known as hormones. The endocrine system is instrumental in regulating metabolism, growth and development, tissue function, and plays a part also in mood. The field of medicine that deals with disorders of endocrine glands is endocrinology, a branch of the wider field of internal medicine.
List of endocrine glands and their hormones
a. Gonadotropin Releasing Hormone (GnRH)
--Stimulates FSH and LH secretion by pituitary
b. Thyrotropin Releasing Hormone (TRH)
--Stimulates TSH secretion by pituitary
c. Corticotropin Releasing Hormone (CRH)
--Stimulates ACTH secretion by pituitary
d. Prolactin Inhibiting Factor (PIF)
--Inhibits prolactin secretion by pituitary
e. Melanocyte Stimulating Hormone Release Inhibitory Hormone (MIF)
--Inhibits MSH secretion by pituitary
f. Somatostatin (SST)
--Inhibits GH secretion by pituitary
h. Growth Hormone Releasing Hormone (GHRH)
--Stimulates GH secretion by pituitary
B. Posterior Pituitary
a. Oxytocin (OT)
--Stimulates milk letdown; uterine contractions
b. Antidiuretic Hormone (ADH)
i. Also called Vasopressin (AVP)
--Increases renal water absorption; vasoconstriction
C. Anterior Pituitary
a. Follicle Stimulating Hormone (FSH)
i. Also called follitropin
--Female: Increases ovarian follicular growth
and estradiol synthesis
--Male: Initiates spermatogenesis
b. Luteinizing Hormone (LH)
i. Also called lutropin
--Female: Ovulation; Corpus luteum (CL) formation;
--Male: Testicular androgen synthesis
c. Prolactin (PRL)
--Milk synthesis; Progesterone synthesis
in C.L. of some species
d. Thyroid Stimulating Homone (TSH)
--Stimulates Thyroid hormone synthesis and secretion
e. Adrenal Corticotropic Hormone (ACTH)
i. Also called Corticotropin
--Stimulates Adrenal Steroidogenenesis
f. Growth Hormone (GH)
i. Also called somatotropin (ST)
--Stimulates hepatic somatomedin biosynthesis
a. Thyroxine (T4)
--Increase growth; differentiation; calorigenesis
b. Triiodothryonine (T3)
--Same as Thyroxine
c. Calcitonin (CT)
--Decrease blood calcium
E. Adrenal Cortex
--Stimulate carbohydrate metabolism; sympathetic function
--Increase sodium retention
F. Adrenal Medulla
i. Classically called Adrenalin
--Modulate effects on nerve, muscles, cellular secretions,
i. Classically called Noradrenalin
--Similar to Epinephrine
a. Estradiol (E2)
--Stimulates female sexual development and behavior
i. Produced by follicle
b. Progesterone (P or P4)
--Stimulate uterine and mammary gland growth; maternal behavior
i. Produced by Corpus Luteum and Follicle
--Relaxation of pubic symphysis and dilation of uterine cervix
i. Produced by Corpus Luteum
d. Inhibin and Activin
--Regulate FSH release
i. Produced by follicle
a. Chorionic Gondadotropin (CG)
--CL progesterone synthesis
b. Placental Lactogen (PL)
--Immunoprotection; fetal growth and development; mammary development
c. Female Sex Steroid Hormones
a. Testosterone (T or T4)
--Male sexual development and behavior
b. Inhibin and Activin
--Regulate FSH secretion by pituitary
c. Mullerian Inhibiting Factor (MIF)
Also MRF, AMH, AMF, MIH etc.
--Mullerian duct regression
--Regulates seasonal breeders
a. Thymosin and Thymopoetin
--Stimulates proliferation and differentiation of lymphocytes
--Decreases blood glucose; stimulates protein, glycogen,
and fat synthesis
--Increases blood glucose; stimulates gluconeogenesis,
lipolysis, and glycogenolysis
c. Somatostatin (SST)
--Inhibits secretion of other pancreatic islet hormones
d. Pancreatic Polypeptide (PP)
--Modulates secretion of other pancreatic islet hormones
M. Gastrointestinal Tract
--Increases HCl secretion by stomach
--Stimulates pancreatic acinar cell fluid (bicarbonate) secretion
c. Cholecystokinin (CCK)
--Stimulates pancreatic acinar cell enzyme secretion;
gall bladder contractions
d. Gastric Inhibitory peptide (GIP)
--Decreases HCl secretion by stomach
--Increases insulin secretion
e. Vasoactive intestinal peptide (VIP)
--Stimulates intestinal secretion of electrolytes;
smooth muscle relaxation
f. Glucagon-like peptide-1 (GLP-1)
--Increases insulin secretion
--Stimulates gastric acid secretion
h. Neurotensin (NT)
i. Substance P (SP)
j. Gastrin Releasing peptide (GRP)
--Stimulates Gastrin secretion and acid secretion
N. Parathryroid Gland
a. Parathyroid Hormone (PTH)
--Increase blood calcium
--Decreases blood phosphate
--Activates vitamin D
O. Skin, Liver, Kidney
a. Vitamin D3
--Increases blood Calcium; intestinal and renal calcium absorption
a. Angiotensin II (AII)
--Stimulates vasoconstriction; aldosterone secretion; and thrist
a. Erythropoietin (EP)
--Initiates Angiotensin II from liver
c. Vitamin D
--Increases blood Calcium; intestinal and renal calcium absorption
R. Most all Tissues (Eicosinoids)
a. Prostaglandins (PGF2alpha and PGE2)
--Luteolysis, Vasoconstriction, Ovulation (PGF2alpha)
--Vasodilation, Ovulation (PGE2)
b. Prostacyclins (PGI2)
--Decrease Platelet Aggregation
c. Thromboxanes (TXA2)
--Increase Platelet Aggregation
d. Leukotrienes (LTE4)
--Vasoconstriction and permeability
S. Various Tissues (Growth Factors)
a. Epidermal Growth Factor (EGF)
--Stimulates epithelial cell profliferation
b. Fibroblast Growth Factor (FGF)
--Stimulates fibroblast proliferation
c. Nerve Growth Factor (NGF)
d. Somatomedins or
--Insulin-like Growth Factors (IGF-I, II)
--Cellular growth and development; Initiation of lactation; etc.
a. Atrial Natriuretic factor (ANF)
--Stimulates renal salt and water diuresis
U. Various neural tissues (Misc.)
a. Endorphins and Enkephalins
V. Adipose tissue
--Regulates Fat Deposition
This material is intended, but not promised or guaranteed to be accurate
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