SECTION I
Answer 1
(a)
(i) Crossing over
(ii) Population
(iii) Passive acquired immunity
(iv) Non-biodegradable wastes
(v) Pons
(b)
(i) C. Wall pressure exceeds turgor pressure
(ii) C. Thylakoids
(iii) C. Renal pelvis
(iv) D. Hypersecretion of growth hormone
(v) C. Calcium
(c)
(i) Odd term: Styrofoam
Category: Biodegradable materials
(ii) Odd term: Pepsin
Category: Nitrogenous bases of DNA
(iii) Odd term: Iris
Category: Parts of human ear (middle ear)
(iv) Odd term: Cortisone
Category: Hormones of the pituitary gland
(v) Odd term: Typhoid
Category: Genetic disorders
(d)
(i) Anti-diuretic hormone (ADH)
(ii) Posterior
(iii) Diabetes insipidus
(iv) Vasopressin
(v) Blood pressure
(e)
(i) At the centre of the chromosome joining the sister chromatids
(ii) Between tricuspid/bicuspid valves and papillary muscles of the heart
(iii) Base of the neck (below larynx)
(iv) Between iris and choroid (composed of ciliary muscles)
(v) Convoluted region near the Bowman’s capsule
(f)
(i) Myopia
(ii) Two possible reasons are
Eye ball is lengthened from front to back.
Lens is too curved.
(iii) Concave lens
(iv)
(g)
(i) Blind spot: Free of rods and cones
(ii) Acrosome: Spermatozoa
(iii) Iris: Colour of eyes
(iv) Addison’s disease: Hypoglycemia
(v) Cushing’s syndrome: Hyperglycemia
(h)
(i) Defend the body against cancerous cells, pathogens and foreign matter
(ii) Produce male sex hormone called testosterone
(iii) Help to regulate the rate of transpiration by opening and closing of stomata
(iv) Equalises air pressure on either sides of the eardrum allowing it to vibrate freely
(v) Responsible for the secretion of the hormones oestrogen and progesterone in females
SECTION II
Answer 2
(a)
(i) 1: Root hair, 2: Soil particle, 3: Xylem vessel, 4: Vacuoles
(ii) Osmosis is the process which enables the passage of water from the soil into root hair.
(iii) Root pressure is responsible for the movement of water.
(iv) Guttation
(v)
(b)
(i) Human skin cell contains 46 chromosomes, whereas human ovum contains 23 chromosomes.
(ii) Sperm duct transports the sperms into the urethra, whereas the fallopian tube transports the egg from the ovary to the uterus.
(iii) Red Cross looks after maternal and child welfare centres, whereas WHO promotes and supports projects for research on diseases.
(iv) Rods contain the pigment rhodopsin, whereas cones contain the pigment iodopsin.
(v) LUBB is produced by atrioventricular valves, whereas DUBB is produced by semilunar valves.
Answer 3
(a)
(i) 1: Pituitary gland, 2: Thyroid gland, 3: Pancreas, 4: Adrenal gland
(ii) Thyroid glands secrete the hormone thyroxine.
Function: Regulates basal metabolism
(iii) The endocrine part is the islets of Langerhans.
(iv) The pituitary gland is called the master gland because it controls several other hormone-releasing glands.
The hypothalamus of the forebrain controls the pituitary gland.
(v) The adrenal gland secretes the emergency hormone adrenaline.
(b)
(i) The apparatus is called Ganong’s Potometer.
(ii) The phenomenon is called transpiration.
(iii) The evaporative loss of water in the form of water vapour from the aerial parts of plants is known as transpiration.
(iv) Two limitations are
It is not easy to introduce the air bubble into the capillary.
The twig may not remain fully alive for a long time.
(v) The air bubble helps measure the rate of transpiration.
(vi) Transpiration occurs through roots.
Answer 4
(a)
(i)
(ii) 1: Cochlear duct
2: Semicircular canal
3: Oval window
4: Endolymph
5: Sensory cells in semicircular canals
(b)
(i) Menopause
(ii) Bilirubin
(iii) Hepatic portal vein
(iv) Inguinal canal
(v) Pollution
(vi) Excretion
(vii) Nucleotides
(viii) Mutation
(ix) Active transport
(x) Pulmonary vein
Answer 5
(a)
(i) Late prophase. The nuclear membrane and nucleolus disappear.
(ii) The next stage is metaphase.
(iii)
Mitosis in Plant Cell
Mitosis in Animal Cell
1. Asters are not formed.
1. Asters are formed.
2. Occurs at the growing tips.
2. Occurs throughout the body.
(iv)
A. Mitosis
B: Meiosis
(b)
(i) Colour blindness is an X-linked disorder caused by a recessive gene.
(ii) The medulla oblongata is responsible for the control of various life processes such as breathing, heartbeat and blood pressure.
(iii) In case of fertilisation of the ovum by a sperm, the corpus luteum persists and continues to secrete progesterone in the body thus maintaining its high levels.
(iv) Mature RBCs lack a nucleus as it increases the surface area to volume ratio, making the absorption of oxygen more efficient.
