FIRST PREBOARD EXAMINATION : 2024-25

SUBJECT: BIOLOGY
Grade : X Max. Marks: 80
Duration: 2 Hrs
Answer to this paper must be written on the paper provided separately.
You will not be allowed to write during the first 15 minutes.
This time is to be spent in reading the question paper.
The time given at the head of this paper is the time allowed for writing answers.
This paper is divided into two sections.
Section A is compulsory. Attempt any four questions from Section B.
The intended marks for questions or parts of questions are given in brackets [ ]

SECTION A (40 Marks)

(Attempt all questions from this Section)
Question 1
Choose the correct answers to the questions from the given options. (Do not copy the
question, Write the correct answers only.) [15]
(i) Recessive gene is expressed itself in:
(a) Y- linked inheritance (b) Heterozygous condition
(c) F1 generation (d) Homozygous condition
(ii) During an experiment, a biology teacher asked her students to test for starch. Which
chemical they would have used for it?
(a) Carbolic acid (b) Lime water (c) Iodine (d) Soda lime
(iii) The part of the brain which controls heart beat :
(a) Cerebrum (b) Medulla oblongata
(c) Cerebellum (d) Hypothalamus
(iv) Manohar, 65 year old male with chronic kidney disease reports increased urination
especially at night. What is the most likely cause of his increased urine output?
(a) Diabetes mellitus (b) Diuresis
(c) Diuretics (d) Albuminuria
(v) The chief radiation pollutant which raises the risk of thyroid cancer:
(a) Cobalt 60 (b) Uranium (c) Iodine 131 (d) Beta rays
(vi) The complete stoppage of menstruation in females is:
(a) Menarche (b) Ovulation
(c) Menopause (d) Luteal phase
(vii) Tara inserted a safety pin into her left ear to remove ear wax. She felt a sudden pain
with loss of hearing. This was due to:
(a) Rupture of eustachian tube (b) Rupture of ear drum
(c) Rupture of ear ossicles (d) Rupture of cochlea
(viii) The plant Nasturtium is an example for mainly the following phenomenon:
(a) Bleeding (b) Guttation (c) Transpiration (d) Photolysis
(ix) First ancestors of human beings to hunt animals and use fire is:
(a) Homo habilis (b) Neanderthal man
(c) Homo erectus (d) Australopithecus

(x) Population grows by:

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 (a) Population explosion (b) Geometrical progression
(c) Scientific revolution (d) Arithmetic progression
(xi) The stage when no visible change in chromosomes but active synthesis of DNA :
(a) Telophase (b) Interphase (c) Metaphase (d) Anaphase
(xii) Assertion (A): Exosmosis cause shrinkage of the cell.
Reason (R): Exosmosis is the outward diffusion of water through a semi permeable
membrane when the surrounding solution is more concentrated.
(a) Both A and R are True
(b) Both A and R are False
(c) Both A and R are true and R is the correct explanation of A
(d) Both A and R are true but R is not the correct explanation of A
(xiii) The antiseptic property in tears is due to the enzyme:
(a) Ethanol (b) Lysosome
(c) Hydrogen peroxide (d) Lysozyme
(xiv) Harrison cannot discriminate between colours like red and green. This is due to:
(a) Deficiency of Vitamin A (b) Genetic defect
(c) Defective cornea (d) Eye lens loses flexibility
(xv) The hormone secreted by the follicle prior to ovulation:
(a) Oestrogen (b) Luteinizing hormone
(c) Follicle-stimulating hormone (d) Progesterone

Question 2
(i) Name the following: [5]
(a) The term used for the transmission of genetic constitution of an individual.
(b) The relative concentration of the solutions that determines the direction and
extent of diffusion.
(c) The accessory male gland that pours an alkaline secretion into the semen.
(d) The process of conversion of several glucose molecules into a starch molecule.
(e) The number of individuals per square kilometre at any given time.
(ii) Given below is the cross section of the eye. Study the given diagram and fill in the
blanks: [5]
The wall of the eyeball is composed of three concentric layers. They are
outer (a) , middle (b) and inner (c) . The white
portion on the front of the eye is visible through the (d) . It
bulges out and becomes transparent in the front region where it covers
the coloured part of the eye; this part is called the (e) .
(iii) Read the statements given below and name the structure: [5]
(a) Water conducting tissue in vascular plants.
(b) The packing tissues between the coils of the seminiferous tubules.
(c) The cap like structure on the top of each kidney.
(d) The openings on the barks of trees through which transpiration occurs.
(e) A sheet of fibres connecting the two cerebral hemispheres.
(iv) 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: [5]
(a) Effector, Motor neuron, Receptor, Sensory neuron
(b) Sperm duct, Epididymis, Urethra, Sperm

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 (c) Stapes, Tympanum, Malleus, Incus
(d) Uterus, Graafian follicle, Ovum, Fallopian tube
(e) Dendrites, Axon, Cyton, Synaptic knob
(v) State ‘true’ or ‘false’, if false rewrite the correct statement: [5]
(a) Diaphragms prevent the entry of sperms into the uterus.
(b) Light reaction takes place in the stroma of chloroplast.
(c) In animal cells, cytokinesis takes place by cell plate formation.
(d) Diabetes insipidus is due to insufficient TSH hormone.
(e) Pedigree chart is a diagram showing the ancestral history of a group of related
individuals.
SECTION B (40 Marks)
(Attempt any four questions from the Section)
Question 3
(i) What is the scientific name of the pea plant that Mendel used for his experiments? [1]
(ii) Define parthenocarpy. Name a phytohormone that can induce parthenocarpy. [2]
(iii) Expand the abbreviation – GMO. Write any one application of genetics. [2]
(iv) State the difference between Micturition and Parturition. [2]
(v) State three objectives of Swachh Bharat Abhiyan. [3]
Question 4
(i) Name the taxonomist who coined the term ‘Homo sapiens’. [1]
(ii) Differentiate between SAN and AVN. ( Location) [2]
(iii) Vitamin K is essential for the process of blood clotting. Give reason. [2]
(iv) Distinguish between light and dark reaction (End products) [2]
(v) Study the picture given below and answer the questions: [3]
(a) Identify and define the type of pollution seen
in the picture.
(b) Mention any two control measures
to minimise this kind of pollution.

Question 5
(i) Name an indicator of moisture that is used in science laboratories. [1]
(ii) Define sex-linked inheritance. Give an example for a genetic disorder due to
‘X’ linked inheritance. [2]
(iii) Mention the surgical contraceptive method of female and explain briefly. [2]
(iv) Define photolysis. Where does it occur? [2]
(v) Kathak is a dance which involves a lot of spinning. The dancers experience
dizziness while spinning. [3]
(a) Name the part of the inner ear responsible for
this dizziness. Give a suitable reason.
(b) Give the collective term for utriculus and
sacculus.

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Question 6
(i) What is the symbol of family welfare in India? [1]
(ii) During Mitosis what is the position of chromatids in Metaphase and Anaphase? [2]
(iii) State Mendel’s Law of Purity of gametes. Give an application of Mendel’s laws. [2]
(iv) Mention the two significances of testes being located in the scrotum. [2]
(v) Given below is an experiment on photosynthesis. [3]

(a) Mention the aim of the above experiment.

(b) Write down the conclusion of the given experiment.

Question 7
(i) What is meant by gestation? [1]
(ii) Spleen acts as a blood reservoir. Give reason. [2]
(iii) Name the two hormones produced by the posterior lobe of the pituitary gland. [2]
(iv) Define the following: [2]
(a) Speciation
(b) Mutation
(v) Draw a neat labelled diagram of a root hair. [3]
Question 8
(i) What are the two main components of haemoglobin? [1]
(ii) Give the biological term used for the following: [2]
(a) Viewing objects in sharp focus.
(b) Induced abortion.
(iii) Differentiate between phenotype and genotype. [2]
(iv) Write the main function of capillary and lymph. [2]
(v) Make a Punnett square and find out the genotypic and phenotypic ratios of F2
generation in the progeny of a genetic cross between a Pure Tall (TT) pea plant
with a Pure Dwarf (tt) pea plant. [3]

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