10 SA 1 EM 2025-2026 KEY

 

SELF ASSESSMENT TERM 1 MODEL PAPER-2025-2026

 GENERAL SCIENCE - Paper – II     Biological Science

 (English Medium)    Class: X]

 (Max. Marks: 50)      [Time: 2.00 Hrs.

 SECTION – I   6x1=6

1.        Write a balanced chemical equation of Photosynthesis.

        sunlight

  6CO2+12H2O   --→   C6H12O6+6O2+6H2O

                                       Chlorophyll

 

2.        What does this schematic diagram represent?

Double Circulation

 

3. Expand ADP.

ADP – Adenosine Diphosphate

 

 

4. What waste products are stored in the older xylem cells of plants?

Resins, tannins, oils, and gums are stored as waste products in older xylem (heartwood) cells of plants

 

5. We buy salt packets enriched with iodine. Is it the right thing? Why should we take iodine as a part of our food?

Yes, buying iodized salt is correct because iodine prevents goitre and is essential for thyroid hormone production.

 

6. Write a slogan to aware people on "No Tobacco usage".

Slogan: “Say NO to tobacco — Yes to life!”

 

SECTION-II  4x2=8

 

7. What is fermentation? Where do we use this process?

·         Fermentation is the process in which microorganisms like yeast convert sugars into alcohol and carbon dioxide in the absence of oxygen.

·         This process is used in making bread, idli batter, curd, wine, and alcohol.

 

8.

Tropic Movement

Stimulus

Phototropism

Light

Thigmotropism

Touch

Chemotropism

Chemicals

Hydrotropism

Water

Geotropism

Gravity

 

a) What is the response caused by chemicals called? What is the response caused by chemicals called?

Chemotropism.

b) Which type of tropic movement causes tendrils to grow towards the support?

Thigmotropism

9. What are unisexual and bisexual flowers? Explain with examples.

  • Unisexual flowers:
    Flowers that have either stamens (male) or pistils (female) but not both.
    Examples: Papaya, Watermelon, Maize.
  • Bisexual flowers:
    Flowers that contain both stamens (male part) and pistil (female part) in the same flower.
    Examples: Hibiscus, Rose, Mustard.

 

10. Diabetes is a chronic disease. What precautions will you take to control Diabetes of your Grandfather?

  • Give him a balanced diet with less sugar and fewer carbohydrates.
  • Encourage regular walking/exercise every day.
  • Ensure he takes medicines/insulin on time.
  • Monitor blood sugar levels regularly.

 

SECTION-III  5 x 4 = 20

 

11. What are the different types of blood vessels in humans? Write their functions.

Humans have three types of blood vessels: Arteries, Veins, and Capillaries.

Arteries: carry oxygen-rich blood away from the heart to body organs.

They have thick, elastic walls to withstand high pressure.

Veins: carry oxygen-poor blood towards the heart.

They have thin walls and valves to prevent backflow.

Capillaries: help in the exchange of gases, nutrients, and waste between blood and tissues.

 

12. (a) Female Reproductive System



 

 

 

 

OR  12. (b) Neuron



 

13. How to determine whether the tall plant is homozygous tall or heterozygous tall?

To determine if the tall green pea plant is homozygous or heterozygous, cross it with a short plant (tt) and analyze the offspring using a Punnett square.

Punnett Square for TT x tt:

t

t

T

Tt

Tt

T

Tt

Tt

All offspring will be Tt (tall).

 

Punnett Square for Tt x tt:

t

t

T

Tt

Tt

t

tt

tt

Offspring will be 50% Tt (tall) and 50% tt (short).

 

  • If all offspring are tall (Tt), the tall plant is homozygous (TT).
  • If there are both tall (Tt) and short (tt) offspring, the tall plant is heterozygous (Tt).

 

 

14. Advantages of sexual reproduction over asexual reproduction

  • Produces variation among offspring.
  • Variation helps species adapt to environmental changes.
  • Increases chances of survival against diseases and climate changes.
  • Helps in evolution through natural selection.
  • Offspring are genetically different, reducing risks of defects.
  • Leads to formation of more vigorous and healthy generations.

 

15. What happens if all body functions are controlled only by the brain?

 

·         If all actions of the human body are controlled by brain, our body will get harm in dangerous situations.

·         Some actions may be delayed and our brain could not conduct reflex actions, which require immediate action to a stimulus.

·         For example, when we touch a hot object, we require an immediate response to save our hand. If the brain controls this action, the time taken will be more and our hand will burn.

·         So, it is controlled by spinal cord, the response will be quick, and we may escape the danger.

·         Nerves can not reach the every corner of the body, whereas hormones of endocrine glands can do that.

·         So it's not good that all functions are controlled by brain.

·          

 

SECTION-IV  2 x 8 = 16

 

16. A) Write the procedure of the experiment to prove that chlorophyll is necessary for Photosynthesis?

Aim

To prove that chlorophyll is necessary for photosynthesis

 

Materials

  • Potted plant with variegated leaves
  • Alcohol
  • Water bath
  • Iodine
  • Bunsen burner

 

Procedure

1.        De-starch the Plant: Place the plant in darkness for 3 days.

2.        Photosynthesis: Expose the plant to sunlight for 6 hours.

3.        Prepare the Leaf:

Ø  Pluck a leaf and mark the green areas.

Ø  Boil the leaf briefly.

Ø  Immerse in alcohol in a water bath.

4.        Stain the Leaf: Dip the leaf in iodine solution.

 

Observations

  • Green Areas: Turn blue-black, indicating starch presence.
  • Non-Green Areas: Remain pale, showing no or very less starch.



Inference

  • Starch in green areas means chlorophyll is needed for photosynthesis.

 

(Or)

 

B) Write in detail the procedure you followed to observe spores of Rhizopus in your school laboratory.

Aim:
To observe the growth of Rhizopus on bread.

Materials:
Moist bread slice, petri dish, magnifying glass

is the common bread mould which grows not only in bread but also on a  variety of other organic matter such as fruits, animal dung, and leather  goods, in warm and humid

 

Procedure:

1.        Place a moist bread slice in a cool, dark place for two days.

2.        Observe the bread under a magnifying glass.

Observation:
A white mass of mold (Rhizopus) grows on the bread, later turning black.

Conclusion:
Rhizopus mold produces black sporangia that release spores for reproduction.

 

17.A) Analyse how sex determination takes place in humans.

 

Chromosomes:

  • Humans have 23 pairs of chromosomes, including 1 pair of sex chromosomes.
  • Females: XX chromosomes.
  • Males: XY chromosomes.

 

 Gametes:

  • Females produce eggs, all carrying the X chromosome.
  • Males produce sperm, which can carry either an X or Y chromosome.

 

Fertilization:

  • If an egg is fertilized by a sperm carrying the X chromosome, the child will be female (XX).
  • If an egg is fertilized by a sperm carrying the Y chromosome, the child will be male (XY).

 

Conclusion:

  • The sex of the child is determined by the father, as the sperm contributes either an X or Y chromosome.
  • The mother always contributes an X chromosome.

 



 

 

 

(Or)

 

B) Differentiate nervous and hormonal mechanisms for control and co-ordination in animals.

 

Nervous Mechanisms

Hormonal Mechanisms

Nervous system (brain, spinal cord, and nerves)

Endocrine system (glands and hormones)

Electrical impulses (neurons)

Chemical messengers (hormones in the blood)

Very fast (milliseconds)

Slow (minutes to hours)

Short-term (immediate but brief)

Long-term (effects last longer)

Muscle contraction, reflex actions

Regulation of metabolism, growth, and reproductive functions

Immediate body actions (reflexes, movement, sensory input)

Gradual processes (growth, puberty, metabolism)

Localized and quick

Systemic (affects the entire body)

Easily reversible

Usually takes longer to reverse effects

Reflex actions, voluntary movements

Release of insulin, growth hormone, adrenaline