Model Question Paper 1

Fibrinogen

Reason — Thrombin reacts with soluble fibrinogen in presence of calcium ions to form insoluble fibrin.

Polycythaemia

Reason — Polycythaemia is a condition of abnormal rise of erythrocytes in blood.

Glomerulus

Reason — Glomerulus has afferent arteriole and narrow efferent arteriole due to which high pressure is exerted and ultrafiltration occurs.

Afferent arteriole

Reason — Blood enters the glomerulus through afferent arteriole and leaves through efferent arteriole.

Hypothalamus

Reason — Hypothalamus is the centre for thermal regulation in the body.

Corpus callossum

Reason — Corpus callossum is a sheet of fibres connecting the two cerebral hemispheres.

After image

Reason — The image seen by us persists for one-tenth of a second. This is known as after image. In movies, pictures are projected on a screen at the rate of about 24 pictures per second which gives an illusion of life-like continuous movement.

Chewing

Reason — Chewing is an action which can be controlled by us.

Adrenal

Reason — Adrenal glands are like caps on top of each kidney.

Liver

Reason — Liver secretes bile through duct hence, it is not an endocrine gland.

Seminiferous tubule

Reason — Sperms are produced in Seminiferous tubule in testis.

Demography

Reason — Demography is the term given to statistical study of human population.

Nucleosome

Reason — Nucleic acid along with histone protein form nucleosome which is the basic structural unit of human chromosome.

3:1

Reason — The phenotypic ratio in F₂ generation of a monohybrid cross is 3:1 because of segregation of genes which leads to recessive homozygous condition.

Cutin

Reason — The waxy substance of cuticle layer consists of cutin and polysaccharides.

(i) Centriole

(ii) Genotype

(iii) Chromoplast

(iv) Hypertonic

(v) Photosynthesis

(i) Prophase → Metaphase→ Anaphase→ Telophase

(ii) Kidney → Ureter→ Urinary bladder→ Urethra

(iii) Right ventricle → Pulmonary artery→ Lungs→ Pulmonary vein

(iv) Ear pinna → Auditory canal→ Ear ossicles→ Membranous labyrinth

(v) Stimulus → Receptor→ CNS→ Effector

(i) Odd one : Chromosome
Chloroplast, Chromoplast, Leucoplast — Plastids

(ii) Odd one : Adrenaline
Adenine, Thymine, Cytosine — Nitrogenous base

(iii) Odd one : Thrombokinase
Thrombocytes, Leucocytes, Erythrocytes — Blood cells

(iv) Odd one : Urochrome
Urea, Uric acid, Ammonia — Constituents of urine

(v) Odd one : Oesophagus
Wisdom teeth, Vermiform appendix, Ear pinna — Vestigial organs

(i) Testis

(ii) At origin of urethra from bladder (in males)

(iii) Retina of eye

(iv) Between left auricle and left ventricle.

(v) Cyton

The phenomenon of the suppression of growth of lateral buds by apical buds is called apical dominance.

The average life of erythrocytes is about 120 days and that of leucocytes is 14-15 days.

Phytohormones or plant hormones are naturally occurring small organic molecules. For example : Auxins.

Significance of transpiration:

1. Maintains the temperature of plant.
2. Transpirational pull helps in absorption of water and mineral by roots.

(i) Thigmotropism is the phenomenon depicted. It is the directional growth movement of plant parts in response to touch stimulus.

(ii) X → Stem tendril, Y → Leaf tendril

(iii) Stem tendrils (X) and leaf tendrils (Y) enable the plant to climb up a support.

Nicotinamide Adenine Dinucleotide Phosphate

The two main phases of photosynthesis are:

1. Light phase
2. Dark phase

Adaptation of the eye is the process by which the eyes adjust to changes in light levels, allowing us to see clearly in both bright and dim environments. Its two kinds are:

1. Light adaptation
2. Dark adaptation

Two important functions of human ovaries are:

1. They produce eggs.
2. They secrete the reproductive hormones, Oestrogen and Progesterone.

(i) The given organelle is Chloroplast. Photosynthesis occurs in this organelle.

(ii) The labelled guidelines are:

• 1 → Stroma
• 2 → Thylokoid
• 3 → Granum

(iii) Balanced chemical equation representing the process of photosynthesis is given below:

$6\text{CO}_2 + 12\text{H}_2\text{O} \xrightarrow[\text{chlorophyll}]{\text{light energy}} \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{H}_2\text{O} + 6\text{O}_2 \uparrow$

Pollution is the addition of any such constituent to air, water or land which deteriorates the natural quality of the environment.

Stomata are present on leaves whereas lenticels are present on stem and other plant parts except leaves.

Jean Baptiste de Lamarck and Charles Robert Darwin.

Vasectomy in males and tubectomy in females.

Below labelled diagram shows the anaphase stage of mitosis in an animal cell with two pairs of chromosomes:

A population is defined as a group of individuals of the same species living and interbreeding within a given area.

The choroid layer provides nourishment to the eye. It contains a dark black pigment (melanin) which prevents the light rays from reflecting and scattering inside the eye.

Cochlea contains organ of Corti which contains sensory cells for hearing.

Gametes must be produced by meiosis so that the number of chromosomes in them is halved (n). It is so because when two such gametes fuse to form a zygote the original number of chromosomes is restored (2n). If the gametes are formed by mitosis their chromosome number will remain 2n and after fusion the resulting zygote will have 4n chromosomes which is not a normal condition for a species.

(i) Beta cells and Alpha cells of the islets of Langerhans produce Insulin and Glucagon, respectively.

(ii) The main function of Glucagon is to raise the blood glucose levels by stimulating the breakdown of glycogen to glucose in the liver.
The main function of Insulin is to maintain the levels of glucose (sugar) in the blood.

(iii) The Islets of Langerhans

A karyotype is a visual representation of an individual's chromosomes, arranged and organized in a specific pattern.

The two main causes of long sightedness are:

1. Shortening of the eyeball.
2. Lens is too flat

Two important roles of vitreous humour are:

1. It helps in keeping the shape of the eyeball.
2. It protects the retina and its nerve endings.

Diagram of the cross section of spinal cord showing a reflex action is given below:

Evolution is a slow and continuous process whereby complex forms of life have emerged from simpler forms through millions of years.

Two ways to control vehicular air pollution are:

1. Use of efficient engines.
2. Use of unleaded petrol and CNG (Compressed Natural Gas) in automobiles.

Law of Independent Assortment, states that when there are two pairs of contrasting characters, the distribution of the members of one pair into the gametes is independent of the distribution of the other pair.

Abnormalities caused due to hypersecretion of growth hormone in humans are:

1. Gigantism
2. Acromegaly

(i) The process is osmosis. Osmosis is the movement of water molecules from their region of higher concentration (dilute solution or with a lower solute concentration) to their region of lower concentration (concentrated solution or with a higher solute concentration) through a semi permeable membrane.

(ii) Cell sap acts like sugar solution and cell membrane acts like parchment paper.

(iii) The control setup is shown below: