CBSE Class 10 Science — Life Processes

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

Identify the part that controls the closing and opening of the stomatal pore in leaves of plants. Select the correct option.

Choose the equation of reaction that correctly represents anaerobic respiration in muscles:

Select the incorrect statement from the following:

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

Assertion (A): The peristaltic movements occur all along the gut. Reason (R): The lining of the gut has muscles that contract rhythmically to push the food in regulated manner.

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.

Assertion (A): In case of iodine deficiency in our diet, there is a possibility that we might suffer from goitre. Reason (R): One of the symptoms of goitre is swelling of neck.

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

Briefly mention the steps in double-circulation through human heart.

Why the lungs always contain a residual volume of air?

Given below is a diagrammatic representation of cross-section of a leaf: [figure] (i) Identify 'P' in the given diagram and write down its role in plants. (ii) Write down a balanced equation of process of photo-synthesis.

Give differences between the following: (a) Nephron and neuron (b) Sensory nerve and motor nerve (c) Consumers and decomposers

Kidneys help to regulate the volume of fluid and various metabolites waste products in the body. Normally, kidney filter about 180 L of fluid daily but the volume actually excreted out is only a litre or two a day. Patients with kidney failures can be saved by dialysis and kidney transplant. (a) Write the structure and function of Bowman's capsule. (b) Although kidneys filter a large amount (about 180 L daily) of fluids, still the excretion from the body is only about a litre or two. Why? (c) What is excretion? Why is it necessary for any living organism? OR (c) State two similarities between lungs and kidneys.

Kidneys help to regulate the volume of fluid and various metabolites waste products in the body. Normally, kidney filter about 180 L of fluid daily but the volume actually excreted out is only a litre or two a day. Patients with kidney failures can be saved by dialysis and kidney transplant. (a) Write the structure and function of Bowman's capsule. [1] (b) Although kidneys filter a large amount (about 180 L daily) of fluids, still the excretion from the body is only about a litre or two. Why? [1] (c) What is excretion? Why is it necessary for any living organism? [2] OR (c) State two similarities between lungs and kidneys. [2]

The essential element taken up from the soil by the plants to synthesize proteins is :

The opening and closing of stomata is regulated by:

Select TRUE statements about lymph from the following : A. Lymph vessels carry lymph through the body and finally open into larger arteries. B. Lymph contains some amount of plasma, proteins and blood cells. C. Lymph contains some amount of plasma, proteins and red blood cells. D. Lymph vessels carry lymph through the body and finally open into larger veins. The true statements are :

One-cell thick blood vessels are known as:

Listed below are the steps of nutrition in Amoeba. Select the correct sequence of these steps : (i) Diffusion of simple nutrients into cytoplasm (ii) Food vacuole formation (iii) Formation of finger like temporary extensions of cell surface (iv) Complex substances broken to simpler ones (v) Undigested material thrown out of the cell surface

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

The gastric glands present in the wall of the stomach release:

The basic filtration unit of the excretory system in human beings is:

In aerobic respiration, the steps are : breakdown of glucose to pyruvate and its further conversion to carbon dioxide. Both processes respectively occur in -

In human alimentary canal, the digestive juice secreted by the gastric glands are:

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

Assertion (A): In large animals, oxygen can reach different parts of the animal's body easily. Reason (R): Respiratory pigments take up oxygen from the air and carry it to body tissues.

Assertion (A): Xylem tissue moves water and minerals obtained from the soil by the roots. Reason (R): Xylem tissue is found only in the roots of a plant.

Assertion (A) : All organisms can make organic compounds like sugar and starch from inorganic substances using radiant energy of the sun. Reason (R) : The organisms which can produce food by photosynthesis are called producers.

Assertion (A): Animals will not get energy if they eat (consume) coal as food. Reason (R): Specific enzymes are needed for the breakdown of a particular food.

"Plants use a variety of techniques to get rid of waste material." Justify this statement giving any four ways.

(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.

State the main function of veins in human circulatory system. Why do they not need thick walls?

(a) Write the name and one function of respiratory pigment found in human beings. (b) Why do lungs always contain a residual volume of air? (c) Why is ATP known as energy currency of the living beings?

The digestion of food in human alimentary canal is a complex process. State the enzyme/salt present in the following and mention their function in the process of digestion: (i) Saliva (ii) Bile Juice (iii) Pancreatic Juice

On the basis of the characteristics of the processes given in the brackets in each case, differentiate between the following: (a) Products of breakdown of pyruvate in aerobic and anaerobic respiration in human beings (product(s) of the processes) (b) Respiration and photosynthesis in plants (gas released) (c) Respiration in terrestrial animals and fishes (organs involved)

Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood, to the human heart. Also name that chamber of the heart which receives deoxygenated blood and state how deoxygenated blood from this chamber is sent to lungs for oxygenation.

(a) (i) "The length of the small intestine in various animals depends on the food they eat." Justify the statement. (ii) Discuss the role of the pancreas and bile juice in the digestion of food in human beings. (iii) How is the small intestine designed to absorb digested food? OR (b) (i) State the role of rings of cartilage present in the throat. (ii) Discuss the role of the ribs and diaphragm when air is taken in during the breathing cycle. (iii) Why do we get muscle cramps during heavy exercise? Explain.

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. [1] (b) Write chemical equation involved in the above process. [1] (c) (i) State in proper sequence the events that occur in synthesis of food by desert plants. [2] 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. [2]

The process in which transport of soluble products of photosynthesis takes place in plants is known as :

In human beings, when the process of digestion is completed, the (i) proteins, (ii) carbohydrates, and (iii) fats are respectively finally converted into:

Which of the following statement(s) is (are) true about human heart ? (a) Right atrium receives oxygenated blood from lungs through pulmonary artery. (b) Left atrium transfers oxygenated blood to left ventricle which sends it to various parts of the body. (c) Right atrium receives deoxygenated blood through vena cava from upper and lower body. (d) Left atrium transfers oxygenated blood to aorta which sends it to different parts of the body.

In human respiratory system, when a person breathes in, the position of ribs and diaphragm will be :

Which of the following statement (s) is (are) true about human heart? (a) Right atrium receives oxygenated blood from lungs through pulmonary artery. (b) Left atrium transfers oxygenated blood to left ventricle which sends it to various parts of the body. (c) Right atrium receives deoxygenated blood from different parts of the body through vena cava. (d) Left atrium transfers oxygenated blood to aorta which sends it to different parts of the body.

Assertion (A): In the human heart ventricles have thicker muscular walls than atria. Reason (R): Ventricles have to pump the blood into various organs.

Assertion (A): Oxygen is essential for all aerobic forms of life. Reason (R): Free oxygen atoms combine with molecular oxygen to form ozone.

Photosynthesis takes place in the leaves and the food prepared by it reaches other parts of the plants. Name the process involved and explain it.

(a) We need to water the soil in plants on a regular basis. But it ultimately reaches the leaves of the plant. Explain how this takes place. OR (b) Name the type of nutrition exhibited by Amoeba. Explain how food is taken in and digested by this organism.

(a) Sometimes while running, the athletes suffer from muscle cramps. Why? How is the respiration in this case different from aerobic respiration? OR (b) Write the other name given to lymph. State its two functions.

We water the soil but it reaches the topmost leaves of the plants. Explain in brief the process involved.

(i) Why is respiratory pigment needed in multicellular organisms with large body size ? (ii) Give reasons for the following : (a) Rings of cartilage are present in the throat. (b) Lungs always contain a residual volume of air. (c) The diaphragm flattens and ribs are lifted up when we breathe in. (d) Walls of alveoli contain an extensive network of blood vessels.

(a) Give reasons for the following : (i) Alveoli in lungs are richly supplied with blood capillaries. (ii) Respiratory pigment in the blood takes up oxygen and not carbon dioxide. (iii) During anaerobic respiration, a 3-carbon molecule is formed as an end product instead of $\mathrm{CO}_2$ in human beings. OR (b) (i) Name the movements that occur all along the gut in human digestive system. How do they help in digestion ? (ii) Where is bile juice stored in human body ? List two roles of bile juice.

(a) Design an experiment to demonstrate that carbon dioxide is essential for photosynthesis. Write the observation and conclusion of the experiment. OR In the experimental set- up shown above in diagram (I) atmospheric air is being passed into lime water with a syringe while in diagram (II) air is being exhaled into lime water. The time taken for the lime water to turn milky in both the test tubes is different. Give reason. (ii) Draw the diagram of an open stomatal pore and label (I) Guard cells, and (II) Chloroplast on it. Mention two functions performed by stomata.

Kidneys are vital organs for survival. Several factors like infections, injury or restricted blood flow to kidneys reduce the activity of kidneys. This leads to accumulation of poisonous wastes in the body, which can even lead to death. In case of kidney failure, an artificial kidney can be used. An artificial kidney is a device to remove waste products from the blood through dialysis. (a) (i) Name the artery that brings oxygenated blood to the kidney. (ii) Name the cluster the thin-walled blood capillaries present in the Bowman's capsule. (b) In human excretory system name the organ which stores urine. Is this organ under hormonal control or nervous control? (c) (i) List two major steps involved in the formation of urine and state in brief their functions. OR (c) (ii) In which part of the nephron does selective reabsorption take place? List the factors which the amount of water reabsorbed depends on.

Human digestive system is a tube running from mouth to anus. Its main function is to breakdown complex molecules present in the food which cannot be absorbed as such into smaller molecules. These molecules are absorbed across the walls of the tube and the absorbed food reaches each and every cell of the body where it is utilised for obtaining energy. (a) Name the glands present in the buccal cavity and write the components of food on which the secretion of these glands act upon. (b) Two organs have a sphincter muscle at their exit. Name them. (c) What will happen if: (i) mucus is not secreted by the gastric glands. (ii) Villi are absent in the small intestine. OR (c) "Bile juice does not contain any enzyme, yet it has important roles in digestion." Justify the statement.

The process in which loss of water in the form of vapours from the aerial parts of plants takes place is $X$, which helps in $Y$. Here $X$ and $Y$ respectively are:

An organism which breaks down the food material outside the body and then absorbs it is

Sphincter muscles are present at the exit of :

As compared to terrestrial organisms, the rate of breathing in aquatic organisms is:

Consider the following statements about small intestine and select the one which is NOT correct:

Opening and closing of stomata is due to :

During vigorous exercise, the occurrence of cramps in the outer muscles of an athlete is due to the conversion of pyruvate to :

Assertion (A) : The walls of atria are thicker than those of the ventricles. Reason (R) : Ventricles have to pump blood into various organs at high pressure.

Assertion (A) : Amoeba takes in food using finger like extensions of the cell surface. Reason (R) : In all unicellular organisms, the food is taken in by the entire cell surface.

Assertion (A): Blood clotting prevents excessive loss of blood. Reason (R): Blood clotting is due to blood plasma and white blood cells present in the blood.

Assertion (A) : The inner walls of the small intestine have finger like projections called villi which are rich in blood. Reason (R) : These villi have a large surface area to help the small intestine in completing the digestion of food.

(a) Why is it important to prevent oxygenated and deoxygenated blood from mixing in birds and mammals? (b) Which animals can tolerate some mixing of the oxygenated and deoxygenated blood streams? On what factor does the body temperature of these animals depend?

(a) List the events in proper sequence that take place during the process of photosynthesis. OR (b) Explain in brief two ways by which leaves of a plant help in excretion.

Give the name of the enzyme present in the fluid in our mouth cavity. State the gland which produces it. What would happen to the digestion process if this gland stops secreting this enzyme?

Write one specific function each of the following organs in relation with excretion in human beings : (i) Renal Artery (ii) Urethra (iii) Glomerulus (iv) Tubular part of nephron

(a) Name the type of blood (oxygenated / deoxygenated) transported by each of the following mentioning the path (i.e. from one organ (which place) to another (which place)). (i) Vena cava (ii) Pulmonary artery OR (b) With the help of a schematic flow chart, show the breakdown of glucose in a cell to provide energy - (i) in the presence of oxygen (ii) in lack of oxygen

Two green plants are kept separately in oxygen free containers, one in the dark and other in sunlight. It was observed that plant kept in dark could not survive longer. Give reason for this observation.

Name the part of the human excretory system where nephrons are found. Write the structure and function of nephrons.

In the process of digestion of food in human beings, two protein-digesting enzymes are secreted. Name the enzymes along with the glands that secrete them.

Explain the process of transport of oxygenated and deoxygenated blood in a human body.

(a) (i) State the role of ATP in cellular respiration. (ii) What ensures sufficient exchange of gases in plants? (iii) State the conditions on which the direction of diffusion of gases in plant depend upon. OR (b) (i) What is the internal energy reserve in plants and animals? (ii) How desert plants perform photosynthesis if their stomata remain closed during the day?

(A) (i) How does Paramecium obtain its food ? (ii) List the role of each of the following in our digestive system : (a) Hydrochloric acid (b) Trypsin (c) Muscular walls of stomach (d) Salivary amylase OR (B) (i) What is double circulation? (ii) Why is the separation of the right side and the left side of the heart useful? How does it help birds and mammals?

(a) With the help of an activity, explain the action of saliva on the food we eat. (b) Why is bile juice important in the process of digestion?

Which one of the following statements is correct about the human circulatory system?

Anaerobic process (A) takes place in yeast during fermentation. (B) takes place in the presence of oxygen. (C) produces only energy in the muscles of human beings. (D) produces ethanol, oxygen and energy. OR Most of the digestion and absorption of the food takes place in the

Complete the following flow chart as per the given instructions:

(a) State the role played by the following in the process of digestion. (i) Enzyme trypsin (ii) Enzyme lipase (b) List two functions of finger like projections present in the small intestine.

(a) In the process of respiration, state the function of alveoli. (b) Rate of breathing in aquatic organisms is much faster than that in terrestrial organisms. Give reasons. (c) Complete the following pathway showing the breakdown of glucose : Glucose in cytoplasm (6-carbon molecules) $\rightarrow$ (i) (3-carbon molecules + energy) $\xrightarrow{\text{Presence of } O_2 \text{ in mitochondria}}$ (ii) + $H_2O$ + energy

(a) Write the correct sequence of steps followed during journey of oxygen rich blood from lungs to various organs of human body. (b) What happens when the system of blood vessels develop a leak?

OR (a) Name the organs that form the excretory system in human beings. (b) Describe in brief how urine is produced in human body.

(a) Why is there a difference in the rate of breathing between aquatic organisms and terrestrial organisms? Explain. (b) Draw a diagram of human respiratory system and label - pharynx, trachea, lungs, diaphragm and alveolar sac on it.

Give reasons: (a) Ventricles have thicker muscular walls than atria. (b) Transport system in plants is slow. (c) Circulation of blood in aquatic vertebrates differs from that in terrestrial vertebrates. (d) During the daytime, water and minerals travel faster through xylem as compared to the night. (e) Veins have valves whereas arteries do not.

(a) Describe the structure and function of the basic filtering unit of kidney. (b) List two factors on which reabsorption of water from urine depends?

Write two different ways in which glucose is oxidized to provide energy in human body. Write the products formed in each case.

Write three types of blood vessels. Give one important feature of each.

In the experimental set up to show that $CO_2$ is given out during respiration, name the substances taken in the small test tube kept in the conical flask. State its functions and the consequence of its use.

(a) Mention any two components of blood. (b) Trace the movement of oxygenated blood in the body. (c) Write the function of valves present in between atria and ventricles. (d) Write one structural difference between the composition of artery and veins. OR (a) Define excretion. (b) Name the basic filtration unit present in the kidney. (c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions: (i) form urine. (ii) is a long tube which collects urine from kidney. (iii) store urine until it is passed out.

List the steps of preparation of temporary mount of a leaf peel to observe stomata.

Why do herbivores have longer, small intestine than carnivores?

The rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms. Give reason. State the pathway of air from nostrils to the lungs in human beings.

(a) State the purpose of formation of urine. (b) What will happen if there is no tubular reabsorption in the nephrons of kidney?

The iodine solution is:

Choose the correct set-up to demonstrate that $\text{CO}_2$ is given out during respiration:

Draw a labelled diagram of stomatal apparatus with closed stomatal pore.

While performing an experiment with raisins, a student took the following measurements: Mass of water taken in the beaker = 25 g, Mass of raisins before soaking = 5 g, Mass of raisins after soaking = 8 g, Mass of water left in the beaker after experiment = 21 g. The percentage of water absorbed by raisins is

While performing the experiment of determining the percentage of water absorbed by raisins, the extra water left on the surface of soaked raisins is removed before final weighing. The correct procedure for this is

A student weighed some raisins and recorded the weight as 'x'. She then soaked the raisins in distilled water. After about 2 hours she removed the raisins, wiped them dry and weighed again and recorded that as 'y'. The percentage of water absorbed by raisins may be determined using the relationship

Dry raisins were soaked in water for 2 hours, to determine the percentage of water absorbed by raisins. Before final weighing of swollen raisins, the extra water left on the surface of soaked raisins was removed by :

In the experiment for determining the percentage of water absorbed by raisins, we do the final weighing of the raisins after keeping them dipped in water for about one hour. For the accuracy of the result, the extra water from the surface of the soaked raisins is removed by

Following are the steps involved in the experiment of determining the percentage of water absorbed by raisins which are not in proper sequence: a. Weigh soaked raisins, b. Weigh dry raisins, c. Soak the raisins in water for 2 hours, d. Wipe out soaked raisins gently. The correct sequence of these steps is

While performing the experiment with raisins to determine the percentage of water absorbed by them, a student made following measurements : Mass of water in the beaker = 40g; Mass of raisins before soaking = 5g; Mass of raisins after soaking for 2 hours = 8g; Mass of water left in the beaker after the experiment = 35g. The percentage of water absorbed by raisins is :

To determine the percentage of water absorbed by raisins, raisins are soaked in water for:

During the course of an experiment, 'to determine the percentage of water absorbed by raisins', raisins are weighed

If $W_1$ is the initial mass of raisins and $W_2$ is the final mass after soaking in water, then the percentage of water absorbed by the raisins is

The colour of raisins as used in the experiment, 'to determine the percentage of water absorbed by raisins' was

Raisins are wiped off gently before final weighing with help of:

Instead of room temperature ($25^\circ\text{C}$), if the water used for soaking is $50^\circ\text{C}$, the percentage of water absorbed by raisins will be

Following are the steps involved in the experiment 'to determine the percentage of water absorbed by raisins'. They are not in proper sequence. I. Soak the raisins in fresh water. II. Weigh dry raisins. III. Weigh soaked raisins. IV. Wipe out soaked raisins. The correct sequence of steps is

The set of materials required in the experiment, "to determine the percentage of water absorbed by raisins" is

The step(s) necessary for determining the percentage of water absorbed by raisins is/are:

Name the green dot like structures in some cells observed by a student when a leaf peel was viewed under a microscope. What is this green colour due to?

Explain the process of digestion of food in mouth, stomach and small intestine in human body. Or (a) List the three events that occur during the process of photosynthesis. Explain the role of stomata in this process. (b) Describe an experiment to show that “sunlight is essential for photosynthesis.”