Life Processes — Class 10 Science PYQs

Which structure in a leaf is mainly responsible for gaseous exchange ?

Pancreas secretes pancreatic juice which contain certain enzyme that helps in digestion of food.
Choose the correct option from the following :

Assertion (A) : In human beings, the respiratory pigment is haemoglobin present in red blood cells.
Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.

What is the function of diaphragm in human respiratory system ? Where is it present in human body ?

Secretion of less saliva in mouth will effect the conversion of :

The breakdown of glucose has taken the following pathway :
$$\text{Glucose}\stackrel{(a)}{\to }\text{Pyruvate + Energy}\stackrel{(b)}{\to }\text{Lactic acid + Energy}$$
The sites '$a$' and '$b$' respectively are :

(a) Besides minimising the loss of blood, why is it essential to plug any leak in a blood vessel ? Name the component of blood which helps in this process and state how this component perform this function.
OR
(b) (i) The transport system in plants is relatively slower than in animals. Give reasons.
(ii) State the role of phloem in the transport of materials in plants.

The maintenance functions of all living organisms must go on even when they are not doing anything particular. Even when we are just sitting in a class or even asleep, this maintenance job has to go on. These maintenance processes require energy to prevent damage and break-down of cells and tissues, which is obtained by the individual organism from the food prepared by the autotrophs, called producers.
(a) Name and define the process by which green plants prepare food.
(b) Write chemical equation involved in the above process.
(c) (i) State in proper sequence the events that occur in synthesis of food by desert plants.
OR
(c) (ii) Explain giving reasons what happens to the rate at which the green plants will prepare food
(I) during cloudy weather, and
(II) when stomata get blocked due to dust.

The opening and closing of stomata is regulated by :

One-cell thick blood vessels are known as :