Photosynthesis Questions and Answers ICSE Class 10

1 Mark Questions

Question 1 : Name the process of conversion of ADP into ATP during photosynthesis.

Answer : Photophosphorylation is the process of conversion of ADP into ATP during photosynthesis.

Question 2 : State the exact location of the chloroplast.

Answer : Chloroplasts are mainly found in the mesophyll cells located between the upper and lower epidermis of the leaves.

Question 3 : Differentiate between the following pair on the basis of what is mentioned in bracket?

Photolysis and photophosphorylation. (definition).

Answer : The difference is given below.

Photolysis Photophosphorylation
It is a process of splitting of water molecule into 2H+ + 4e- + 1/2 O2 in the presence of sunlight by activated photosynthetic pigments. It is a process of formation of ATP from ADP and inorganic phosphate by the utilisation of energy released by electrons emitted during photolysis of water.

Question 4 : Expand the following biological abbreviation – NADP.

Answer : Nicotinamide Adenine Dinucleotide Phosphate is the full form of NADP.

Question 5 : NADP is expanded as

a) Nicotinamide Adenosine Dinucleotide Phosphate

b) Nicotinamide Adenine Dinucleotide Phosphate

c) Nicotinamide Adenine Dinucleolus Phosphate.

d) Nicotinamide Adenosine Dinucleoulus Phosphate

Answer : b) Nictotinamide Adenine Dinucleotide Phosphate.

Question 6 : State the main function of thylakoids.

Answer : The function of thylakoid is to trap the light energy and to transform this energy into chemical energy forms, i.e. ATP and NADPH to be used in dark reaction.

Question 7 : Differentiate between the following pair on the basis of what is mentioned in the bracket.

Stoma and stroma. (describe its structure).

Answer : 

Stoma Stroma
Stoma is the opening of the stomata through which transpired water and respiratory gases pass through. Stroma is the part/region in the chloroplast (matrix), where dark reaction of the photosynthesis takes place.

Question 8 : Name the part of the chloroplast where the light reaction of photosynthesis takes place.

Answer : Light reaction  of photosynthesis takes place in the grana/thylakoids of the chloroplast.

Question 9 : Give one point of difference between the following on the basis of what is given in the bracket?

Light reaction and dark reaction. (site of occurrence).

Answer : Light reaction : Light reaction occurs in the thylakoids/grana of the chloroplast.

Dark reaction : Dark reaction occurs in the stroma of the chloroplast.

Question 10 : Give the biological/technical term for the process of conversion of several molecules of glucose to one molecule of starch.

Answer : Polymerisation is the biological term used for the process of conversion of several molecules of glucose to one molecule of starch.

Question 11 : Why is sleeping under a tree at night not advisable?

Answer : Sleeping under tree at night is not advisable because plants respire at night due to which the atmosphere surrounding the tree is rich in CO2 which is harmful to us.

Question 12 : Name the cell organelle responsible for photosynthesis.

Answer : Chloroplast is the cell organelle responsible for the photosynthesis.

Question 13 : State whether the following statement is true or false. If false, write the correct form of the statement by changing the first or last word only.

Photosynthesis occurs in all the cells of the plant.

Answer : The given statement is false. The correct statement is respiration occurs  in all the cells of the plant.

Question 14 : Explain the term photolysis in photosynthesis.

Answer : Photolysis in photosynthesis is the splitting of water molecules into hydrogen ions and hydroxyl ions in the presence of chlorophyll and light.

Question 15 : Complete the following statement by filling in the blanks with the appropriate word from the choices given in bracket and rewrite the complete statement.

The site of light reaction in the cells of a leaf is …………. (grana, cytoplasm, stroma).

Answer : Grana is the site of light reaction in the cells of a green leaf of a plant.

Question 16 : Name the ground substance present in a chloroplast.

Answer : Stroma is the ground substance present in the chloroplast.

Question 17 : Mention any three adaptations found in plants to favour the process of photosynthesis.

Answer : i) Presence of more stomata to allow rapid exchange of gases like CO2 and O2.

ii) Arrangement of chloroplasts on the upper surface of leaves so as to receive maximum amount of light.

iii) Large surface area of leaves for absorbing maximum light.

Question 18 : Write true or false. Correct the false statements by changing the last word only. Plants that manufacture their own food are called heterotrophs.

Answer : The given statement is false. The correct statement is : Plants that manufacture their own food are called autotrophs.

Question 19 : Rewrite the completed explanation by inserting a key word in the space indicated by ‘^’. Photolysis is the splitting of water molecules into hydrogen ions and hydroxyl ions present in the presence of ‘^’ and light.

Answer : Photolysis in photosynthesis is the splitting of water molecules into hydrogen ions and hydroxyl ions in the presence of chlorophyll and light.

Question 20 : Give the technical term.

The process of conversion of ADP to ATP during the first phase of photosynthesis.

Answer : Photophosphorylation is the process of conversion of ADP into ATP during photosynthesis.

Question 21 : Account for the given below briefly.

Animals owe their existence to chlorophyll.

Answer : Animals owe their existence to chlorophyll because plant with chlorophyll produces the food used by all the living organisms.

Question 22 : Name of the following:

Cytoplasmic organelle that help in the manufacture of starch.

Answer : Chloroplast is the cytoplasmic organelle that help in the manufacture of glucose and starch.

Question 23 : The dark reaction of photosynthesis is light independent. Write true or false.

Answer : The statement is true.

Question 24 : Give reason-Green leaves are thin and broad.

Answer : Green leaves are thin and broad so as to provide the large surface area for trapping light and easy gaseous exchange for photosynthesis to occur.

Question 25 : Give the exact location and one function of thylakoids.

Answer : Location : Thylakoids are found in chloroplast.

Function : The function of thylakoid is to trap the light energy and to transform this energy into chemical energy forms, i.e. ATP and NADPH to be used in dark reaction.