Life Processes

What is the function of trachea? Why do the walls not collapse even when there is less air in it?

(a) List three events that occur during the process of photosynthesis. State in brief the role of stomata in this process.

(b) Describe an experiment to show that sunlight is essential for photosynthesis.

(a) List two differences between ‘holozoic nutrition’ and ‘saprophytic nutrition. Give two examples each of these two types of nutrition.

 (b) State the roles of liver and pancreas.

 (c) Name the organ which performs the following functions in humans:

Absorption of digested food

Absorption of water.

 (d) Explain the statement, “Bile does not contain any enzyme but it is essential for digestion.”

For two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:

1. Both A and R are true, and R is correct explanation of the assertion.
2. Both A and R are true, but R is not the correct explanation of the assertion.
3. A is true but R is false.
4. A is false but R is true.

Assertion: Ureters are the tubes which carry urine from kidneys to the bladder.

Reason: Urine is stored in the urethra.

For two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:

1. Both A and R are true, and R is correct explanation of the assertion.
2. Both A and R are true, but R is not the correct explanation of the assertion.
3. A is true but R is false.
4. A is false but R is true.

Assertion: Ventricles have thicker walls than auricles.

Reason: Ventricles have to pump blood into various organs with great pressure.

Read the following and answer any four questions from (i) to (v).

Heterotrophic nutrition is a mode of nutrition in which organisms obtain readymade organic food from outside sources. The organisms that depend upon outside sources for obtaining organic nutrients are called heterotrophs. Heterotrophic nutrition is of three types: saprophytic, parasitic, and holozoic nutrition.

1. In which of the following groups of organisms’ food material is broken outside the body and absorbed?
2. Mushroom, green plants, Amoeba.
3. Yeast, mushroom, bread mould.
4. Paramecium, Amoeba, Cuscuta.
5. Cuscuta, lice, tapeworm.

1. Which of the following is a parasite?
2. Yeast
3. Taenia
4. Amoeba
5. Earthworm

III. Which of the following is an example of saprotroph?

1. Grass
2. Mushroom
3. Amoeba
4. Paramecium

1. Heterotrophic nutrition involves:
2. Production of simple sugar from inorganic compounds.
3. Utilisation of chemical energy to prepare food.
4. Utilisation of energy obtained by plants.
5. All of these.

1. ln Paramecium, food enters the body through:
2. Mouth
3. Pseudopodia
4. Cilia

Cytostome.

Read the following and answer any four questions from (i) to (v).

All living cells need nutrients, O₂ and other essential substances. Also, the waste and harmful substances need to be removed continuously for healthy functioning of cells. So, a well-developed transport system is mandatory for living organisms. Complex organisms have special fluids within their bodies to transport such materials. Blood is the most commonly used body fluid by most of the higher organisms. Lymph also helps in the transport of certain substances.

1. Which of the following does not exhibit phagocytic activity?
2. Monocytes.
3. Neutrophils.
4. Basophil.
5. Macrophage.

1. Amount of blood corpuscles in changed in dengue fever. One of the common symptoms observed in people infected with dengue fever is:
2. Significant decrease in RBC count.
3. Significant decrease in WBC count.
4. Significant decrease in platelets count.
5. Significant increase in platelets count.

III. Why are WBCs called soldiers of the body?

1. They are capable of squeezing out of blood capillaries.
2. They are manufactured in bone marrow.
3. They fight against disease causing germs.
4. They have granular cytoplasm with lobed nucleus.

1. Name the blood cells, whose reduction in number can cause clotting disorder, leading to excessive loss of blood from the body.
2. Erythrocytes.
3. Neutrophils.
4. Leucocytes.
5. Thrombocytes.

1. Which of the following is the correct feature of lymph?
2. It is similar to the plasma of blood but is colourless and contains less proteins.
3. It is similar to the WBCs of blood but is colourless and contain more proteins.
4. It is similar to the RB Cs of blood and red in colour.

It contains more fats.

How do they take up carbon dioxide and perform photosynthesis?

(a) What will happen to guard cells and the stomatal pore when water flows into guard cells.

(b) How do plants transmit information from cell to cell?

What is the role of saliva in the digestion of food?

What is internal energy reserve in plants? Do the animals have the same energy reserve? Justify your answer.

What is excretion? How do unicellular organisms remove their wastes?

What are the different ways in which glucose is oxidized to provide energy in various organisms?

State the function of digestive enzymes.