A cell has 4 pairs of chromosomes. After mitotic division, the number of chromosome pairs in the daughter cells would be :
- 8
- 14
- 4
- 48
Answer
4
Reason — After mitotic division, the number of chromosome pairs in the daughter cells remain same.
The nuclear changes that occur during cell division are collectively termed as :
- Karyotype
- Cytokinesis
- Karyokinesis
- Enterokinesis
Answer
Karyokinesis
Reason — Karyokinesis is the collective term used for the different phases involved in the division of nucleus in mitosis.
The point of attachment between two sister chromatids of a chromosome is :
- Centrosome
- Chiasma
- Centriole
- Centromere
Answer
Centromere
Reason — Centromere is the point in chromosome where sister chromatids are attached.
The full compliment of DNA of an organism is :
- Gene
- Genetics
- Genome
- Heredity
Answer
Genome
Reason — A complete set of genes or DNA of an organism is called genome .
When a cell in solution shrinks and loses its shape, then the solution is :
- Isotonic
- Hypertonic
- Hypotonic
- Potable water
Answer
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.
With increase in atmospheric humidity, the rate of transpiration will :
- Increase slowly
- Remain the same
- Decrease
- Increase rapidly
Answer
Decrease
Reason — The rate of transpiration depends on concentration of water vapour in surrounding. It is higher when the surrounding is drier.
In the process of photosynthesis, the substance which is reduced is :
- Glucose
- Oxygen
- Water
- Carbon dioxide
Answer
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.
Which of the following is a growth-retarding hormone ?
- IAA
- ABA
- GA3
- GA2
Answer
ABA
Reason — ABA is a growth-retardant as it inhibits germination and development of plant.
Basophils release which of the following chemicals ?
- Histones
- Factor X
- Histamine
- Stuart factor
Answer
Histamine
Reason — Histamine is released by basophils in response to infection or allergy for inflammation.
Which of the following is an inorganic constituent of urine ?
- Urea
- Uric acid
- Ammonia
- Creatinine
Answer
Ammonia
Reason — Ammonia is an inorganic constituent of urine. Urea, uric acid, and creatinine are organic compounds found in urine.
Which part of the brain controls and coordinates muscular activity and balance of the body ?
- Cerebrum
- Pons
- Cerebellum
- Diencephalon
Answer
Cerebellum
Reason — Cerebellum has controls and coordinates muscular activity and balance of the body.
The pigment which is sensitive to dim light :
- Iodopsin
- Melanin
- Visual violet
- Rhodopsin
Answer
Rhodopsin
Reason — Rhodopsin or visual purple is sensitive to dim light and do not respond to colour.
The hormone which stimulates milk ejection is :
- Prolactin
- Luteinizing hormone
- Oxytocin
- Estrogen
Answer
Oxytocin
Reason — Oxytocin is responsible for let down or ejection of milk.
The process of fertilization of sperm and ovum takes place in :
- Uterus
- Fallopian tubes
- Vagina
- Vulva
Answer
Fallopian tubes
Reason — The process of fertilization of sperm and ovum takes place in fallopian tube and later the embryo is implanted in uterus.
The famous book "The Origin of Species" is written by :
- Jean Baptist Lamarck
- Walther Flemming
- Gregor John Mendel
- Charles Darwin
Answer
Charles Darwin
Reason — The famous book "The Origin of Species" is written by Charles Darwin.
Name the following :
(i) The number of deaths per 1000 of population per year.
(ii) The liquid waste material produced by factories.
(iii) The scattered golgi bodies in plant cells.
(iv) The structures which help in the formation of spindle fibres in plant cells during cell division.
(v) The part of inner ear responsible for dynamic balance.
Answer
(i) Mortality rate
(ii) Effluent
(iii) Dictyosomes
(iv) Microtubules
(v) Semi-circular canals
Arrange and rewrite the terms in each group in the correct order so as to be in a logical sequence beginning with the term that is underlined.
(i) Soil water, Xylem, Pericycle, Root hair
(ii) Xylem vessels, Stoma, Mesophyll, Sub-stomatal space
(iii) Light energy, Thylakoid, Glucose, Splitting of water molecules
(iv) Glomerulus, Collecting duct, Loop of Henle, Distal convoluted tubule
(v) Conjunctiva, Retina, Vitreous humour, Cornea
Answer
(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
Match the items given in column I with the most appropriate ones in column II and rewrite the correct matching pairs.
| Column I | Column II |
|---|---|
| (i) Thylakoids | Photorespiration |
| (ii) Starch formation | Photo-chemical phase |
| (iii) ATP | Photosynthesis |
| (iv) Autotrophs | Photolysis of water |
| (v) Light reaction | Polymerisation |
| Phagocytosis | |
| Phosphorylation |
Answer
| Column I | Column II |
|---|---|
| (i) Thylakoids | Photolysis of water |
| (ii) Starch formation | Polymerisation |
| (iii) ATP | Phosphorylation |
| (iv) Autotrophs | Photosynthesis |
| (v) Light reaction | Photo-chemical phase |
Choose the odd one out from the following terms and name the category to which the others belong :
(i) Uterine tubes, Seminiferous tubule, Epididymis, Interstitial cells
(ii) Progesterone, Testosterone, Oestrogen, Prolactin
(iii) Conjunctiva, Cornea, Cochlea, Choroid
(iv) Cell wall, Visking bag, Cellophane paper, Parchment paper
(v) Simple goitre, Myxoedema, Cretinism, Acromegaly
Answer
(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
State the exact location of the following structures:
(i) Chlorophyll
(ii) Lenticels
(iii) Spleen
(iv) Thyroid
(v) Uterus
Answer
(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.
Define - Mutation.
Answer
Mutation is a sudden change in one or more genes, or in the number or in the structure of chromosomes.
Distinguish between sympathetic and parasympathetic nervous system on the basis of function.
Answer
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.
What is lysozyme? Write its one important role.
Answer
Lysozyme is an enzyme having antiseptic property and it is present in tears. It protects the eyes from bacterial infections.
Write two significant roles of Hepatic Portal system.
Answer
Two significant roles of Hepatic Portal system are:
- Glycogenesis — Excess sugar is converted and stored in the liver in the form of glycogen.
- Detoxification — If any poisonous and harmful material is absorbed through food, they are detoxified in the liver.
Given below is a simplified diagrammatic representation of a defect of the human eye. Study the figure and answer the following questions.
(i) Identify the defect (technical term).
(ii) Mention two reasons for the above defect.
(iii) Draw a neat and labelled diagram for the “correction of the above mentioned defect” by using a lens. You must mention the name of the lens used.
Answer
(i) Hyperopia
(ii) Two reasons for the above defect are:
- Shortening of the eyeball
- Lens is too flat
(iii) Convex lens is used for the correction of Hyperopia. The diagram is shown below:
Expand the abbreviation - MTP.
Answer
MTP — Medical Termination of Pregnancy
Name two phases of blood circulation in the human body.
Answer
Atrial systole and Ventricular systole.
What are the two important roles of the plant hormone ‘Gibberellins’ ?
Answer
Two important roles of the plant hormone ‘Gibberellins’ are:
- Promote the growth of internodes by cell elongation.
- Break seed dormancy and initiate germination.
Write two important functions of Amniotic fluid.
Answer
Two important functions of Amniotic fluid are:
- Protects the embryo from physical damage by jerks or mechanical shocks.
- Keeps an even pressure all around the embryo.
The diagram given alongside is the longitudinal section of a human kidney. Study the diagram and answer the questions that follow.
(i) Label the parts numbered 1 and 3.
(ii) Name the fluid that passes down from the part numbered as 4. Also write its main nitrogenous constituent.
(iii) Why does part 2 show a striped appearance?
Answer
(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.
Define - Parturition.
Answer
Parturition is the act of expelling the full term foetus from the mother's uterus at the end of gestation.
Differentiate between biodegradable and non-biodegradable wastes.
Answer
| Biodegradable waste | Non-biodegradable waste |
|---|---|
| Biodegradable wastes are substances which can be broken down by microorganisms into harmless and non-toxic substances. | Non-biodegradable wastes are substances which cannot be broken down by microorganisms. |
| Examples: Leaves, dung. | Examples: Plastic, glass. |
What is placenta? Write its one important role.
Answer
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.
Make a Punnett square for the cross between two heterozygous axial flowers. Write the Genotypic and Phenotypic ratios of the offspring.
Answer
| A | a | |
| A | AA | Aa |
| a | Aa | aa |
Genotypic Ratio → 1:2:1 Phenotypic Ratio → 3:1
Given below is the diagram of a human heart showing one phase of contraction. Study the same and answer the following questions.
(i) Label the parts numbered as 3 and 4.
(ii) What is the main difference between the blood flowing through the parts numbered as 1 and 2 ?
(iii) Write one important role of the part numbered as 5.
Answer
(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.
Define — Sanitary landfills.
Answer
Sanitary landfills are the places where the wastes are dumped in a ground depression and covered with dirt every day.
Differentiate between spermatogenesis and oogenesis.
Answer
| Spermatogenesis | Oogenesis |
|---|---|
| Spermatogenesis is the process of production of sperms in seminiferous tubules. | Oogenesis is the process in which the ova producing cells give rise to the mature ovum. |
| Spermatogenesis takes place in testis. | Oogenesis takes place in ovaries. |
What is hyaluronidase ? Write its important role.
Answer
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.
Name the nerves which carry impulses from eyes and ear to the brain.
Answer
The nerves which carry impulses from eyes and ear to the brain are optic nerve and auditory nerve respectively.
The diagram given alongside represents a stage during the mitotic cell division. Study the same and answer the following questions.
(i) Identify the stage. Give reasons to support your answer.
(ii) Label the parts numbered 1 and 2.
(iii) Draw a neat and labelled diagram of the stage that comes before the stage shown in the figure.
Answer
(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:
Explain - 'Guttation':
Answer
Guttation is the loss of water as droplets along the margins of leaves through hydathodes.
What is 'Reflex action'? What are its two main types ?
Answer
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.
Differentiate between 'Nerve' and 'Ganglion' with respect to their composition.
Answer
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.
What are the two kinds of Nucleic Acids found in the human body ? Write their full forms.
Answer
The two kinds of Nucleic Acids found in the human body are:
- DNA — Deoxyribonucleic acid.
- RNA — Ribonucleic acid.
The diagram given below is an experimental set-up to demonstrate a metabolic process in plants. Study same and answer the following questions.
(i) Name and define the physiological process being studied.
(ii) What is the aim of the above experiment?
(iii) Draw a neat diagram of an opened stoma and label the guard cells and stoma.
Answer
(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:
Define - Genetics.
Answer
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.
Distinguish between Autosomes and Sex-chromosomes (2 points).
Answer
| Autosomes | Sex chromosomes |
|---|---|
| They determine the somatic traits. | They determine the sex of an organism. |
| They are numbered as 1 to 22. | They are recognized by the letters XO, XY, ZO, ZW. |
What is meant by turgidity in plant parts ? How does it play an important role ?
Answer
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.
Name the basic structural and functional unit of kidney. Write two main steps of 'urine formation'.
Answer
Nephron is the basic structural and functional unit of kidney.
Two main steps of 'urine formation' are:
- Ultrafiltration
- Reabsorption
Identify the hormonal disorders with the following clues :
(i) Urination is frequent and copious.
(ii) Great deal of urine, loaded with sugar.
(iii) Person becomes sluggish and there is a swelling of the face and hands.
Answer
(i) Diabetes insipidus
(ii) Diabetes mellitus
(iii) Myxoedema