Life Processes — Class 10 Science PYQs

(A) / Both, Assertion (A) and Reason (R) are true and Reason (R) is
the correct explanation of the Assertion (A).
1
1

(A)/ Both A and R are true, and R is the correct explanation of A. (1 Mark)

(B) / Ozone shields earth's surface from harmful infra - red radiations. (1)

(B) / Stomata (1 Mark)

(A) / Starch (1 Mark)

(B) / (ii) and (iii)

(D) / $\ce{6CO2 + 12H2O ->[Chlorophyll][Sunlight] C6H12O6 + 6O2 + 6H2O}$ (1 Mark)

(D) Storage of food in roots and stems.
1

• Food:
▪ P – Glucose (½ Mark)
▪ Q – Starch (½ Mark)
• Raw materials: $\ce{CO2}$, $\ce{H2O}$ (½ Mark)
• Conditions: Presence of sunlight, chlorophyll (½ Mark)

(B) / Trypsin digests proteins and lipase digests emulsified fats (1 Mark)

(A)/ Both A and R are true and R is the correct explanation of A. (1 Mark)

(A) Pepsin. (1)

(D) Peristalsis
1

(B) Fats, oils and ghee (1 Mark)

(D)/ It increases surface area for absorption of the food. (1 Mark)

Trypsin is secreted by Pancreas (gland) and it digests proteins.
1/2+1/2
Bile juice is secreted by liver (gland) and it emulsifies fats.
1/2+1/2

• Liver/Pancreas/Small intestine. (1 Mark)
• Bile salts break down big globules of fat into small globules so that an enzyme can act on it / emulsification of fats. (1 Mark)
Lipase enzyme digests emulsified fats into simple form.
• Intestinal juice enzymes finally concert it into fatty acid and glycerol.
In Small intestine. (1 Mark)

(a) Gastric glands secrete the following:
HCl $\rightarrow$ It kills the bacteria that enters the stomach along with food /activates pepsin by providing acidic medium. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
Pepsin $\rightarrow$ It digests the protein ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
Mucus $\rightarrow$ It protects the inner lining of the stomach from the action of the acid under normal condition. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
OR
(b) Saliva: Saliva contains enzyme called salivary amylase that breaks down complex starch to simple sugars. (1 Mark)
Pancreas: It secretes pancreatic enzymes or juices which contains enzymes like trypsin for digestion of proteins and lipase for breakdown of emulsified fats. (1 Mark)
Peristaltic movements: The rhythmic contraction of the muscles of alimentary canal to push the food forward in a regulated manner so that it can be processed properly in each part of the alimentary canal is known as peristaltic movement. (1 Mark) (3 Marks)

(a) Gastric glands secrete the following:
HCl $\rightarrow$ It kills the bacteria that enters the stomach along with food /activates pepsin by providing acidic medium. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
Pepsin $\rightarrow$ It digests the protein ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
Mucus $\rightarrow$ It protects the inner lining of the stomach from the action of the acid under normal condition. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
OR
(b) Saliva: Saliva contains enzyme called salivary amylase that breaks down complex starch to simple sugars. (1 Mark)
Pancreas: It secretes pancreatic enzymes or juices which contains enzymes like trypsin for digestion of proteins and lipase for breakdown of emulsified fats. (1 Mark)
Peristaltic movements: The rhythmic contraction of the muscles of alimentary canal to push the food forward in a regulated manner so that it can be processed properly in each part of the alimentary canal is known as peristaltic movement. (1 Mark) (3 Marks)

(D)/Glucose $\rightarrow$ pyruvate $\xrightarrow{\text{lack of oxygen}}$ Lactic acid + Energy (1 Mark)

(D) Lack of oxygen and formation of lactic acid (1 Mark)

(B) Mitochondria (1 Mark)

u2022 Aerobic Respiration
u2022 Complete breakdown of glucose takes place in presence of oxygen releasing more energy.

A: Cytoplasm
B: Ethanol
C: Carbon dioxide
D: Lactic acid
E: Carbon dioxide
F: Water

(a) Ethanol+ Carbon dioxide + energy (1)
(b) Lactic acid + energy (1)
(c) Carbon dioxide + water + energy (1)

(B) Both A and R are true but R is not the correct explanation of A
1

(A) Alveoli $\rightarrow$ Trachea $\rightarrow$ Larynx $\rightarrow$ Pharynx $\rightarrow$ Nostril (1 Mark)

• The main function of the diaphragm is to flatten during inhalation,
which expands the chest cavity and draws the air into the lungs
/ helps in breathing. (1)
• It is located at the base of chest cavity. (1)

The lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released. (2)

(A) / Both Assertion (A) and Reason (R) are true and (R) is the correct explanation of (A). OR (C)/ Assertion (A) is true but Reason (R) is false. (1 Mark)

(D) / Contraction of Left Ventricle. (1 Mark)

(D) / Mammals (1 Mark)

(D) / Aorta takes oxygenated blood from heart to body parts. (1 Mark)

(C) A is true but R is false. (1)

(D) Body $\rightarrow$ Right Atrium $\rightarrow$ Right ventricle $\rightarrow$ Lungs (1 Mark)

(B) (i) -Red blood ; (ii)-oxygen (1 Mark)

I. (i) 2-chambered
(ii) Amphibians/Reptiles
(iii) Double circulation
II. Double circulation

• Oxygenated blood from lungs comes to left atrium which pushes it to left ventricle $\rightarrow$ (½ Mark)
• Left ventricle contracts to push blood into aorta, to be sent to body parts $\rightarrow$ (½ Mark)
• Deoxygenated blood from body parts is collected and sent to right atrium $\rightarrow$ (½ Mark)
• Right atrium pushes it to right ventricle, to be sent to lungs for oxygenation. (½ Mark)

(a) Some waste is stored in leaves that fall off/wastes may be stored in cellular vacuoles/other wastes are stored as resins and gums in old xylem/ may excrete some waste into soil via roots. (1 Mark)
(b) Mammals and birds have high energy needs to maintain their body temperature. Therefore, mixing of blood is prevented by separation of right and left side of heart and thus they have double circulation. (2 Marks)

(D) / The guard cells have swelled due to inflow of water

(A) / Entry of water into guard cells. (1 Mark)

(D) / Organic substance from leaves to the other parts of the plant. (1 Mark)

(C)/ Guard cells (1 Mark)

(C) it transports food to different parts of the plant body. (1)

• Necessary- It helps in transport of water and minerals from roots to leaves / It helps in temperature regulation. (1 Mark)
• Evil - It results in loss of water. (1 Mark)

Translocation of food and other substances takes place through sieve tubes of phloem by utilising energy. This increases osmotic pressure of the tissue causing water to move into it. (1 Mark)
This pressure moves the material in the phloem to tissues which have less pressure, which allows the phloem to transport food according to the plant needs. (1 Mark)

OR
When water flows into the guard cells they swell and causing stomatal pore to open. (1 Mark)
When water flows out the guard cells shrink causing stomatal pore to close. (1 Mark)

(i) Night- root pressure : The effect of root pressure is more at night for transport of water because of concentration difference between root and the soil. (½+½ Mark)
(ii) Day-transpiration pull: During the day, the evaporation of water molecule from the cell of a leaf creates a suction (transpiration pull) which pull water from xylem cells of the root. (½+½ Mark)

u2022 Root pressure: Cells in the contact of the soil actively take up ions and creates a difference in concentration between roots and soil, water moves from soil to root to eliminate this difference.
u2022 Transpirational pull: Water lost through transpiration from aerial parts of plants, creates a suction which pulls water column from xylem cells of roots.

(B)/ Both A and R are true but R is not the correct explanation of A

(C) / A cluster of thin-walled capillaries richly supplied with blood. (1 Mark)

(C) Glomerulus (1)

(A)
$\bullet$ Kidneys are located in the abdomen. ($\frac{1}{2}$ Mark)
$\bullet$ Nephrons ($\frac{1}{2}$ Mark)
(B)
(i) Amount of water in the body. ($\frac{1}{2}$ Mark)
(ii) Amount of dissolved wastes that need to be excreted. ($\frac{1}{2}$ Mark)
(C)
$\bullet$ Urea content is high in structure 'Q' whereas the concentration of useful substances such as glucose and amino acids and salt is less as they will be reabsorbed back into the blood. (2 Marks)
OR
$\bullet$ Diabetic person may not have insulin so the sugar level in the blood rises. Hence, there will be more glucose in structure Q of table-II. (2 Marks)

(A)
$\bullet$ Kidneys are located in the abdomen. ($\frac{1}{2}$ Mark)
$\bullet$ Nephrons ($\frac{1}{2}$ Mark)
(B)
(i) Amount of water in the body. ($\frac{1}{2}$ Mark)
(ii) Amount of dissolved wastes that need to be excreted. ($\frac{1}{2}$ Mark)
(C)
$\bullet$ Urea content is high in structure 'Q' whereas the concentration of useful substances such as glucose and amino acids and salt is less as they will be reabsorbed back into the blood. (2 Marks)
OR
$\bullet$ Diabetic person may not have insulin so the sugar level in the blood rises. Hence, there will be more glucose in structure Q of table-II. (2 Marks)

(i) The purpose of making urine is to filter out waste products from the blood. (1 Mark)
(ii) Urea and Uric acid. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
(iii) (a) Amount of water reabsorbed by nephron depends on.
• Quantity of water in the body. (1 Mark)
• Quantity of dissolved waste to be excreted from the body (1 Mark)
OR
(b) The urine in summer is usually less in quantity because
• Lot of water is lost by sweating. (1 Mark)
• Water from kidney is reabsorbed to maintain the normal concentration of water in the blood. (1 Mark) (4 Marks)

(i) The purpose of making urine is to filter out waste products from the blood. (1 Mark)
(ii) Urea and Uric acid. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
(iii) (a) Amount of water reabsorbed by nephron depends on.
• Quantity of water in the body. (1 Mark)
• Quantity of dissolved waste to be excreted from the body (1 Mark)
OR
(b) The urine in summer is usually less in quantity because
• Lot of water is lost by sweating. (1 Mark)
• Water from kidney is reabsorbed to maintain the normal concentration of water in the blood. (1 Mark) (4 Marks)

(a)
• Bile emulsifies fats for their digestion.
$\frac{1}{2}$
• It makes medium alkaline for further digestion by pancreatic
and small intestinal enzymes.
$\frac{1}{2}$
2
(b) Glucose, water, salt, amino acid
1

(A)
$\bullet$ Kidneys are located in the abdomen. ($\frac{1}{2}$ Mark)
$\bullet$ Nephrons ($\frac{1}{2}$ Mark)
(B)
(i) Amount of water in the body. ($\frac{1}{2}$ Mark)
(ii) Amount of dissolved wastes that need to be excreted. ($\frac{1}{2}$ Mark)
(C)
$\bullet$ Urea content is high in structure 'Q' whereas the concentration of useful substances such as glucose and amino acids and salt is less as they will be reabsorbed back into the blood. (2 Marks)
OR
$\bullet$ Diabetic person may not have insulin so the sugar level in the blood rises. Hence, there will be more glucose in structure Q of table-II. (2 Marks)

(A)
$\bullet$ Kidneys are located in the abdomen. ($\frac{1}{2}$ Mark)
$\bullet$ Nephrons ($\frac{1}{2}$ Mark)
(B)
(i) Amount of water in the body. ($\frac{1}{2}$ Mark)
(ii) Amount of dissolved wastes that need to be excreted. ($\frac{1}{2}$ Mark)
(C)
$\bullet$ Urea content is high in structure 'Q' whereas the concentration of useful substances such as glucose and amino acids and salt is less as they will be reabsorbed back into the blood. (2 Marks)
OR
$\bullet$ Diabetic person may not have insulin so the sugar level in the blood rises. Hence, there will be more glucose in structure Q of table-II. (2 Marks)

(i) The purpose of making urine is to filter out waste products from the blood. (1 Mark)
(ii) Urea and Uric acid. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
(iii) (a) Amount of water reabsorbed by nephron depends on.
• Quantity of water in the body. (1 Mark)
• Quantity of dissolved waste to be excreted from the body (1 Mark)
OR
(b) The urine in summer is usually less in quantity because
• Lot of water is lost by sweating. (1 Mark)
• Water from kidney is reabsorbed to maintain the normal concentration of water in the blood. (1 Mark) (4 Marks)

(i) The purpose of making urine is to filter out waste products from the blood. (1 Mark)
(ii) Urea and Uric acid. ($\frac{1}{2}$ + $\frac{1}{2}$ Mark)
(iii) (a) Amount of water reabsorbed by nephron depends on.
• Quantity of water in the body. (1 Mark)
• Quantity of dissolved waste to be excreted from the body (1 Mark)
OR
(b) The urine in summer is usually less in quantity because
• Lot of water is lost by sweating. (1 Mark)
• Water from kidney is reabsorbed to maintain the normal concentration of water in the blood. (1 Mark) (4 Marks)

(a)
• Amount of water in the body (1)
• Amount of dissolved wastes that need to be excreted. (1)
(b) Plants use different methods for excretion
• Some of their wastes are stored in dead tissues
• Many plant waste products are stored in cellular vacuoles
• Waste products may be stored in leaves that fall off
• Other waste products like resins or gums are stored in old xylem (Any two points) (½+½)

(a) • Structure $\rightarrow$ Bowman’s capsule is a cup shaped end of a coiled tube (nephron) (½ Mark)
• Function $\rightarrow$ Bowman’s capsule collects the filtrate from the blood. (½ Mark)
(b) Most of the water, salt, glucose, amino acids are selectively reabsorbed from the filtrate into the blood as the urine flows along the tubular part of nephron. (1 Mark)
(c) • Excretion is the process of removal of metabolic wastes/ nitrogenous waste/ urea/uric acid from the body. (1 Mark)
• It is essential for survival of a living organism as the excretory products are toxic and harmful to the organism. (1 Mark)
OR
(c) • Both lungs and kidneys remove metabolic waste / Lungs remove carbon dioxide gas ($\ce{CO2}$) from the blood while kidneys remove nitrogenous wastes like urea from the blood. (1 Mark)
• Both lungs and kidneys have thin-walled blood capillaries involved in exchange of gases and filtration of blood respectively. (1 Mark)

(D) / Flowers can store some waste products
1
1

Plants use different strategies for excretion.
• Some of their wastes are stored in dead tissues.
• Many plant waste products are stored in cellular vacuole.
• Waste products may be stored in leaves that fall off.
• Other waste products like resins and gums are stored in old xylem.
• Plants also excrete some of the waste substances into the soil around them. etc.
(any four points) (2 Mark)