Model Question Paper 2

4

Reason — After mitotic division, the number of chromosome pairs in the daughter cells remain same.

Karyokinesis

Reason — Karyokinesis is the collective term used for the different phases involved in the division of nucleus in mitosis.

Centromere

Reason — Centromere is the point in chromosome where sister chromatids are attached.

Genome

Reason — A complete set of genes or DNA of an organism is called genome .

Hypertonic

Reason — In a hypertonic solution the cell loses its shape and shrinks because its cell sap (having low concentration of solute) loses water due to high concentration of hypertonic solution. It is called as exosmosis.

Decrease

Reason — The rate of transpiration depends on concentration of water vapour in surrounding. It is higher when the surrounding is drier.

Carbon dioxide

Reason — In the process of photosynthesis, the substance which is reduced is Carbon dioxide as oxygen is removed from it and the carbon is used in the formation of glucose.

ABA

Reason — ABA is a growth-retardant as it inhibits germination and development of plant.

Histamine

Reason — Histamine is released by basophils in response to infection or allergy for inflammation.

Ammonia

Reason — Ammonia is an inorganic constituent of urine. Urea, uric acid, and creatinine are organic compounds found in urine.

Cerebellum

Reason — Cerebellum has controls and coordinates muscular activity and balance of the body.

Rhodopsin

Reason — Rhodopsin or visual purple is sensitive to dim light and do not respond to colour.

Oxytocin

Reason — Oxytocin is responsible for let down or ejection of milk.

Fallopian tubes

Reason — The process of fertilization of sperm and ovum takes place in fallopian tube and later the embryo is implanted in uterus.

Charles Darwin

Reason — The famous book "The Origin of Species" is written by Charles Darwin.

(i) Mortality rate

(ii) Effluent

(iii) Dictyosomes

(iv) Microtubules

(v) Semi-circular canals

(i) Soil water → Root hair → Pericycle → Xylem

(ii) Xylem vessels → Mesophyll → Sub-stomatal space → Stoma

(iii) Light energy → Thylakoid → Splitting of water molecules → Glucose

(iv) Glomerulus → Loop of Henle → Distal convoluted tubule → Collecting duct

(v) Conjunctiva → Cornea → Vitreous humour → Retina

(i) Odd one — Uterine tubes
Seminiferous tubule, Epididymis, Interstitial cells — Parts of Testis

(ii) Odd one — Testosterone
Progesterone, Oestrogen, Prolactin — Female hormones

(iii) Odd one — Cochlea
Conjunctiva, Cornea, Choroid — Parts of Eye

(iv) Odd one — Cell wall
Visking bag, Cellophane paper, Parchment paper — Semi-permeable membranes

(v) Odd one — Acromegaly
Simple goitre, Myxoedema, Cretinism — Hypothyroidism

(i) Walls of thylakoid.

(ii) Surface of old woody stems.

(iii) Upper left side of abdomen.

(iv) Front of neck, below larynx.

(v) Pelvic cavity.

Mutation is a sudden change in one or more genes, or in the number or in the structure of chromosomes.

Sympathetic nervous system prepares the body for violent action against abnormal conditions while the parasympathetic nervous system is more concerned with re-establishing normal conditions after the violent act is over.

Lysozyme is an enzyme having antiseptic property and it is present in tears. It protects the eyes from bacterial infections.

Two significant roles of Hepatic Portal system are:

1. Glycogenesis — Excess sugar is converted and stored in the liver in the form of glycogen.
2. Detoxification — If any poisonous and harmful material is absorbed through food, they are detoxified in the liver.

(i) Hyperopia

(ii) Two reasons for the above defect are:

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

(iii) Convex lens is used for the correction of Hyperopia. The diagram is shown below:

MTP — Medical Termination of Pregnancy

Atrial systole and Ventricular systole.

Two important roles of the plant hormone ‘Gibberellins’ are:

1. Promote the growth of internodes by cell elongation.
2. Break seed dormancy and initiate germination.

Two important functions of Amniotic fluid are:

1. Protects the embryo from physical damage by jerks or mechanical shocks.
2. Keeps an even pressure all around the embryo.

(i) The parts labelled 1 and 3 are:

• 1 → Cortex
• 3 → Pelvis

(ii) The fluid is urine. Its main nitrogenous constituent is Urea.

(iii) Henle's loops and collecting ducts lie in the medulla of kidneys giving it a striped appearance.

Parturition is the act of expelling the full term foetus from the mother's uterus at the end of gestation.

Placenta is the disc like structure attached to the uterine wall connecting the foetus to the uterus. It helps the foetus to get oxygen and nutrients from mother.

Genotypic Ratio → 1:2:1 Phenotypic Ratio → 3:1

(i) Parts numbered 3 and 4 are:

• 3 → Bicuspid valve
• 4 → Aortic Semilunar valve

(ii) Blood flowing through 1 (Pulmonary artery) is deoxygenated. Blood flowing through 2 (Aorta) is oxygenated.

(iii) Part 5 is pulmonary semilunar valve. It prevents backflow of blood into ventricles.

Sanitary landfills are the places where the wastes are dumped in a ground depression and covered with dirt every day.

Hyaluronidase is an enzyme secreted by acrosome present at the top of the head of sperm. It facilitates entry of the sperm into the egg by dissolving the wall of the ovum.

The nerves which carry impulses from eyes and ear to the brain are optic nerve and auditory nerve respectively.

(i) The stage shown is Telophase as the daughter chromosomes have reached opposite poles, spindle fibres have started to disappear, nuclear membrane is formed and the cleavage furrow has started deepening.

(ii) Parts numbered 1 and 2 are:

• 1 → Chromosome
• 2 → Nuclear membrane

(iii) Anaphase is the stage that comes before Telophase. Diagram showing anaphase is given below:

Guttation is the loss of water as droplets along the margins of leaves through hydathodes.

Reflex action is an automatic or quick or immediate involuntary action in the body brought about by a stimulus. Two types of reflex action are natural reflexes and conditioned reflexes.

Nerve are a bundle of nerve fibres (axons) of separate neurons, enclosed in a tubular sheath while ganglion is the aggregate of the cytons or cell bodies of nerve cells from which the nerve fibres may arise or enter into.

The two kinds of Nucleic Acids found in the human body are:

1. DNA — Deoxyribonucleic acid.
2. RNA — Ribonucleic acid.

(i) Transpiration
Transpiration is the loss of water in the form of water vapour from the aerial parts (leaves and stem) of the plant.

(ii) The aim of the above experiment is to demonstrate the different magnitudes of transpiration from the upper and lower surfaces of dicot leaf.

(iii) Below diagram shows an opened stoma with guard cells and stoma labelled:

Genetics is the study of heredity i.e., transmission of body features (both similarities and differences) from parents to offspring and the laws relating to such transmission.

Turgidity is the state of a cell in which the cell wall is rigid and stretched by an increase in the volume of vacuoles due to the absorption of water. It provides rigidity to soft tissues of plant such as the leaves.

Nephron is the basic structural and functional unit of kidney.

Two main steps of 'urine formation' are:

1. Ultrafiltration
2. Reabsorption

(i) Diabetes insipidus

(ii) Diabetes mellitus

(iii) Myxoedema