Life Process - MCQ Test, Class 10 Science - Class 10 MCQ

Raw Materials for Photosynthesis

Photosynthesis is the process by which green plants, algae, and some bacteria convert sunlight, water, and carbon dioxide into glucose and oxygen. The raw materials required for photosynthesis are:

A: Carbon dioxide
- Carbon dioxide is an essential raw material for photosynthesis.
- It is obtained from the atmosphere through tiny pores called stomata in plant leaves.
B: Water
- Water is another crucial raw material for photosynthesis.
- It is absorbed by the roots of plants from the soil and transported to the leaves through the stem and xylem vessels.
C: Oxygen
- Oxygen is not a raw material for photosynthesis.
- In fact, oxygen is produced as a byproduct of photosynthesis.
- During the light-dependent reactions of photosynthesis, oxygen is released into the atmosphere as waste.
D: None of these
- The correct answer is "None of these" because all the options mentioned (carbon dioxide and water) are raw materials for photosynthesis.
- Oxygen, while not a raw material, is produced as a byproduct.
In conclusion, the raw materials for photosynthesis are carbon dioxide and water, while oxygen is produced as a byproduct.

Chlorophyll, xanthophylls, and carotene are pigments.
- Definition: Pigments are colored substances that absorb certain wavelengths of light and reflect others. They are responsible for the colors we see in plants, fruits, and flowers.
- Chlorophyll: It is the primary pigment found in plants and algae. It absorbs light energy during photosynthesis, converting it into chemical energy.
- Xanthophylls: They are yellow pigments that are commonly found alongside chlorophyll in plant cells. They help in capturing light energy and also act as antioxidants.
- Carotene: It is an orange pigment found in many fruits and vegetables. It is a precursor of vitamin A and also functions as an antioxidant.
- Roles: These pigments play various roles in plants and organisms, including:
- Absorbing specific wavelengths of light for photosynthesis.
- Protecting plants from excessive light and oxidative damage.
- Providing attractive colors to attract pollinators and seed dispersers.
- Acting as antioxidants to neutralize harmful free radicals.
- Occurrence: Chlorophyll is present in the chloroplasts of plant cells, while xanthophylls and carotene are found in the plastids.
- Types: There are different types of chlorophyll, xanthophylls, and carotene, each with specific absorption properties and colors.
- Importance: These pigments are crucial for the survival and functioning of plants and play a significant role in the food chain as they are responsible for capturing energy from the sun and converting it into chemical energy.
- Applications: Pigments like chlorophyll and carotene are used in various fields, including food coloring, cosmetics, and pharmaceuticals.

The carbohydrate group includes sugars, starch , and cellulose. Starch is the usual form in which carbohydrates are stored as energy by plants. It is a white substance which is found in the foods such as potato.

Fungi has a saprophytic mode of nutrition as fungi takes their food from dead organisms.

Answer:
The essential element for the formation of proteins is nitrogen (N).
Explanation:
Proteins are large, complex molecules that are composed of amino acids. Nitrogen is a crucial component of amino acids, which are the building blocks of proteins. Therefore, nitrogen is essential for the formation of proteins.
Here is a detailed explanation of why nitrogen is essential for protein formation:
1. Amino acids: Proteins are made up of chains of amino acids. Amino acids contain an amino group (-NH2) and a carboxyl group (-COOH). The amino group contains nitrogen, which is necessary for the formation of peptide bonds between amino acids.
2. Peptide bonds: Peptide bonds are formed when the amino group of one amino acid reacts with the carboxyl group of another amino acid, resulting in the formation of a covalent bond. These peptide bonds link amino acids together to form polypeptide chains, which eventually fold into functional proteins. The presence of nitrogen in amino acids is essential for the formation of peptide bonds.
3. Protein synthesis: During protein synthesis, ribosomes in the cells read the genetic code in DNA and use it to assemble amino acids in the correct order to form a specific protein. Nitrogen is necessary for the synthesis of amino acids, which are then incorporated into the growing polypeptide chain.
In conclusion, nitrogen is an essential element for the formation of proteins. It is a crucial component of amino acids and peptide bonds, which are fundamental to protein structure and function.

The correct matching of the given options is:
(1) The red colour of human blood: (D) Hemoglobin
(2) The pigment which absorbs solar energy: (A) Chlorophyll
(3) The largest gland of the human body: (C) Liver
(4) Pumping organ of the body: (B) Heart
Explanation:
- Hemoglobin is the protein found in red blood cells that gives blood its red color.
- Chlorophyll is the pigment found in plants that absorbs solar energy during photosynthesis.
- The liver is the largest gland in the human body and performs various functions such as detoxification, metabolism, and storage of nutrients.
- The heart is the pumping organ of the body that circulates blood throughout the body.
Therefore, the correct matching is 1-D, 2-A, 3-C, and 4-B, which corresponds to option C.

The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats.

Factors affecting photosynthesis:
1. Carbon dioxide concentration in air: Carbon dioxide is an essential component for photosynthesis as it is used by plants to produce glucose. Higher concentrations of carbon dioxide in the air can enhance the rate of photosynthesis, while lower concentrations can limit the process.
2. Temperature: Photosynthesis is influenced by temperature. Most plants have an optimal temperature range for photosynthesis, typically between 20-30 degrees Celsius. Higher temperatures can lead to denaturation of enzymes involved in the process, while lower temperatures can slow down the rate of photosynthesis.
3. Light intensity: Light is a crucial factor for photosynthesis as it provides the energy needed for the process. Higher light intensity can increase the rate of photosynthesis, while low light intensity can limit the process.
Factor not affecting photosynthesis:
4. Wind velocity: Wind velocity does not directly affect photosynthesis. While wind can affect the movement of gases, such as carbon dioxide, it does not have a significant impact on the rate of photosynthesis. As long as the necessary factors like carbon dioxide, temperature, and light intensity are within the required range, photosynthesis can occur efficiently regardless of wind velocity.
In conclusion, wind velocity is not a factor that directly affects photosynthesis. Factors such as carbon dioxide concentration, temperature, and light intensity play crucial roles in determining the rate of photosynthesis.

To determine which of the given options does not respire through lungs, we need to understand the respiration methods of each organism listed.
1. Whale:
- Whales are mammals and respire through lungs.
- They have specialized respiratory organs called blowholes on the top of their heads, which they use to breathe air at the water's surface.
2. Duck:
- Ducks are birds and respire through lungs.
- They have a system of air sacs connected to their lungs, allowing for efficient gas exchange during respiration.
3. Frog:
- Frogs are amphibians and primarily respire through their skin.
- They have lungs as well, but their skin plays a significant role in gas exchange, especially when they are in water or in a moist environment.
4. Tadpole:
- Tadpoles are the larval stage of frogs and respire through their gills.
- They have specialized gills that extract oxygen from the water.
Answer: The organism that does not respire through lungs is the tadpole. Tadpoles respire through their gills, not lungs.

The air passing through the nostrils is filtered by the fine hairs and mucus present in nostrils.

Explanation:
When a leaf of a normal plant is boiled in ethanol and treated with iodine, the color change is due to the presence of starch in the leaf. The iodine reacts with starch to form a complex that has a characteristic color.
Here is a detailed explanation of the color change:
1. Iodine Test for Starch:
- The iodine test is commonly used to detect the presence of starch in a sample.
- Iodine reacts with starch to form a deep blue-black color complex.
2. Process of Boiling the Leaf in Ethanol:
- Boiling the leaf in ethanol helps to remove the chlorophyll present in the leaf.
- Chlorophyll is a green pigment that masks the color change caused by the iodine reaction.
3. Color Change Observation:
- After boiling the leaf in ethanol, the chlorophyll is removed, and the leaf turns pale or translucent.
- When the leaf is treated with iodine, the color change is observed.
4. Interpretation of Color Change:
- If the color changes to pink, it indicates the absence of starch in the leaf.
- If the color changes to black or blue-black, it indicates the presence of starch in the leaf.
- If the color changes to orange, it is not a typical response to the iodine test for starch.
5. Conclusion:
- Based on the given options, the correct answer is Blue black (B).
- The color change to blue-black indicates the presence of starch in the leaf.
Note: It is important to note that the iodine test is specific to starch and may not be accurate for detecting other carbohydrates or compounds in the leaf.

Two Chambered Heart is Found:
The correct answer is option D: Only in fish. Let's break down the explanation:
1. What is a two-chambered heart?
- A two-chambered heart is a type of heart structure that consists of two chambers: one atrium and one ventricle.
- The atrium receives blood from the body and transfers it to the ventricle.
- The ventricle pumps the blood out of the heart to circulate throughout the body.
2. Which animals have a two-chambered heart?
- Fish are the primary group of animals that have a two-chambered heart.
- They have a relatively simple circulatory system where blood flows in a single circuit from the heart to the gills, where it picks up oxygen, and then to the rest of the body before returning to the heart.
3. Other animals with different heart structures:
- Amphibians and reptiles have a three-chambered heart, which consists of two atria and one ventricle.
- The atria receive blood from different parts of the body, while the ventricle pumps oxygenated and deoxygenated blood together, leading to some mixing.
- Birds and mammals have a four-chambered heart with two atria and two ventricles.
- The separation of oxygenated and deoxygenated blood in different chambers allows for more efficient circulation and higher metabolic rates.
4. Understanding the given options:
- Option A: Fish, amphibians, and reptiles - This is incorrect because amphibians and reptiles have a three-chambered heart, not a two-chambered heart.
- Option B: Only in amphibians - This is incorrect because amphibians have a three-chambered heart, not a two-chambered heart.
- Option C: Fish and amphibians - This is incorrect because amphibians have a three-chambered heart, not a two-chambered heart.
- Option D: Only in fish - This is the correct answer as fish are the only animals that have a two-chambered heart.
Therefore, the correct answer is option D: Only in fish.

Muscle cramps are caused by an accumulation of lactic acid in the muscles.

Where does the oxygen liberated during photosynthesis come from?
The oxygen liberated during photosynthesis comes from:
1. Water (H₂O)
- During the light-dependent reactions of photosynthesis, water molecules are split into oxygen, hydrogen ions, and electrons.
- This process is known as photolysis, which occurs in the thylakoid membranes of chloroplasts.
- The oxygen atoms released from water molecules combine to form molecular oxygen (O₂), which is then released into the atmosphere as a byproduct of photosynthesis.
2. Carbon dioxide (CO₂)
- While carbon dioxide is utilized during photosynthesis to produce glucose, it does not directly contribute to the production of oxygen.
- Instead, carbon dioxide is reduced to form carbohydrates, and the oxygen atoms released from water molecules provide the oxygen gas.
Therefore, the correct answer is option A: H₂O, as water is the source of the oxygen liberated during photosynthesis.

Component of blood that transports carbon dioxide and nitrogenous wastes:
The correct answer is Plasma.
Explanation:
Plasma is the liquid component of blood that carries various substances, including carbon dioxide and nitrogenous wastes, in dissolved form.
Here are some key points to understand why plasma is responsible for transporting carbon dioxide and nitrogenous wastes:
1. Plasma is a yellowish fluid that makes up about 55% of the total blood volume.
2. It consists of water, electrolytes, proteins, hormones, nutrients, gases, and waste products.
3. Carbon dioxide is a waste product produced during cellular respiration in tissues and organs. It dissolves in plasma and is transported from the tissues to the lungs, where it is exhaled.
4. Nitrogenous wastes, such as urea, are produced during the breakdown of proteins in the liver. These wastes are also dissolved in plasma and transported to the kidneys for excretion in the form of urine.
5. The dissolved form of carbon dioxide and nitrogenous wastes allows for efficient transport throughout the body.
In summary, plasma plays a crucial role in transporting carbon dioxide and nitrogenous wastes in dissolved form, ensuring proper waste removal and gas exchange in the body.

The energy-rich compound produced through respiration is ATP (Adenosine Triphosphate). Here is a detailed explanation:
Respiration and Energy Production:
- Respiration is a metabolic process that occurs in living cells, where organic molecules are broken down to release energy.
- The primary aim of respiration is the production of ATP, which serves as the energy currency of the cell.
- ATP is a nucleotide composed of the base adenine, the sugar ribose, and three phosphate groups.
Steps in ATP Production:
1. Glycolysis:
- The first step of respiration is glycolysis, which occurs in the cytoplasm of the cell.
- During glycolysis, glucose is broken down into two molecules of pyruvic acid (pyruvate).
- This process generates a small amount of ATP through substrate-level phosphorylation.
2. Krebs Cycle (Citric Acid Cycle):
- If oxygen is available, pyruvic acid enters the mitochondria and undergoes the Krebs cycle.
- The Krebs cycle breaks down pyruvic acid further and generates high-energy electrons.
- These high-energy electrons are carried by coenzymes to the Electron Transport Chain (ETC).
3. Electron Transport Chain (ETC):
- The ETC is located in the inner mitochondrial membrane.
- High-energy electrons from the Krebs cycle are transferred along a series of protein complexes in the ETC.
- This transfer of electrons releases energy, which is used to pump protons (H+) across the membrane.
- The proton gradient drives the synthesis of ATP through ATP synthase.
ATP Production:
- The final step of ATP production occurs in the ATP synthase enzyme.
- ATP synthase uses the energy from the proton gradient to convert ADP (Adenosine Diphosphate) to ATP.
- Each molecule of glucose can generate up to 36-38 molecules of ATP through respiration.
Conclusion:
- The energy-rich compound produced through respiration is ATP.
- ATP is generated through the processes of glycolysis, the Krebs cycle, and the Electron Transport Chain.
- ATP serves as the primary source of energy for cellular activities.

The correct matching of the given statements is:
(1) The tissues transporting water is plants - Xylem
(2) Translocation of food - Phloem
(3) Glomerulus - A part of nephron
(4) Excretory product in amoeba - Amoeba
Explanation:
- Xylem is a specialized tissue in plants that transports water and minerals from the roots to other parts of the plant.
- Phloem is another specialized tissue in plants that transports food (sugar) produced during photosynthesis from the leaves to other parts of the plant.
- Glomerulus is a part of the nephron, which is the functional unit of the kidney responsible for the filtration of blood and formation of urine.
- Amoeba is a single-celled organism that excretes its waste through the process of diffusion, so there is no specific excretory product.
Therefore, the correct matching of the given statements is 1-C, 2-B, 3-D, 4-A, which corresponds to option D.

Saliva contains the enzyme amylase, also called ptyalin, which is capable of breaking down starch into simpler sugars such as maltose and dextrin that can be further broken down in the small intestine. About 30% starch digestion takes place in the mouth cavity.

Glycolysis is a process that takes place in the cytoplasm of the cell where glucose (6-carbon compound) break into pyruvate/pyruvic acid(3-carbon compound).so the final product of glycolysis is pyruvate/pyruvic acid.

Photosynthesis and Carbon Dioxide

Photosynthesis is the process by which green plants, algae, and some bacteria convert sunlight, water, and carbon dioxide into glucose (a sugar) and oxygen. During this process, carbon dioxide undergoes certain changes. Let's explore the different possibilities:
Option A: Reduced
- Carbon dioxide is reduced during photosynthesis.
- Reduction refers to the gain of electrons or a decrease in the oxidation state of an atom or molecule.
- In photosynthesis, carbon dioxide is reduced to glucose.
- This reduction process involves the transfer of hydrogen ions and electrons from water molecules to carbon dioxide, resulting in the production of glucose.
Option B: Oxidized and Reduced Simultaneously
- This option is not correct. Carbon dioxide cannot be oxidized and reduced simultaneously during photosynthesis.
Option C: Dehydrated
- Dehydration refers to the removal of water from a substance.
- Although water is involved in photosynthesis, carbon dioxide is not directly dehydrated during this process.
- Water molecules are split to provide electrons and protons for the reduction of carbon dioxide.
Option D: Oxidized
- This option is not correct. Carbon dioxide is not oxidized during photosynthesis.
In conclusion, the correct answer is option A: Carbon dioxide is reduced during the process of photosynthesis.

Answer : B

Renal artery brings oxygenated blood to the kidneys from the aorta which arises out of heart but this blood is not pure and has nitrogenous waste in it while renal vein carries deoxygenated but filtered blood to the heart from where it is again pumped to the entire body.
 

To find out how much air a healthy person can inhale in one breath, we need to consider the average lung capacity. The average lung capacity for a healthy adult is around 4-6 liters. Therefore, the correct answer is option B: 6 liters.
Here is a detailed explanation:
1. Lung capacity: Lung capacity refers to the maximum amount of air that can be inhaled or exhaled during a breath. It is influenced by factors such as age, sex, height, weight, and overall health.
2. Tidal volume: Tidal volume is the amount of air that is inhaled or exhaled in a normal breath. On average, a person at rest inhales and exhales about 500 milliliters (0.5 liters) of air with each breath.
3. Inspiratory reserve volume: Inspiratory reserve volume is the additional amount of air that can be inhaled after a normal breath. It is estimated to be around 3 liters.
4. Expiratory reserve volume: Expiratory reserve volume is the additional amount of air that can be exhaled after a normal breath. It is also estimated to be around 3 liters.
5. Residual volume: Residual volume is the amount of air that remains in the lungs even after a maximum exhalation. It is about 1-1.5 liters.
6. Total lung capacity: Total lung capacity is the sum of tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. On average, it is around 4-6 liters.
7. Therefore, a healthy person can inhale up to 4-6 liters of air in one breath.
In conclusion, the correct answer is option B: 6 liters.

The correct match for each term is as follows:
- Tissue fluid: (A) Lymph
- Atria: (C) Chamber of the heart
- Alveoli: (B) A surface for gaseous exchange
- Functional unit of kidney: (D) Nephron
Explanation:
- Tissue fluid is commonly known as interstitial fluid or extracellular fluid. It is derived from blood plasma and surrounds the cells in the body's tissues. This fluid is drained by the lymphatic system and is called lymph.
- Atria are the upper chambers of the heart. They receive blood returning to the heart from the body and the lungs. Therefore, they are correctly matched with Chamber of the heart.
- Alveoli are tiny air sacs present in the lungs. They are the main site for the exchange of oxygen and carbon dioxide during respiration. Hence, they are correctly matched with A surface for gaseous exchange.
- The functional unit of the kidney is the nephron. Nephrons are responsible for filtering and purifying the blood, regulating the body's fluid and electrolyte balance, and producing urine. Therefore, they are correctly matched with Nephron.
Hence, the correct match is option D: 1-A, 2-C, 3-B, 4-D.

During exhalation, ribs move down and inwards, while diaphragm move upwards and relaxes. This reduces the size of the chest cavity and air is pushed out of the lungs.

During photosynthesis, light energy from the sun is absorbed by:
- Chlorophyll: Chlorophyll is the pigment found in the chloroplasts of plant cells. It is responsible for absorbing light energy during photosynthesis.
- Mitochondria: Mitochondria are organelles responsible for generating energy in the form of ATP through cellular respiration. They are not involved in the absorption of light energy during photosynthesis.
- Guard cells: Guard cells are specialized cells found in the epidermis of plant leaves. They control the opening and closing of stomata, but they do not directly absorb light energy during photosynthesis.
- Stomata: Stomata are small openings found on the surface of plant leaves and stems. They allow for the exchange of gases, such as carbon dioxide and oxygen, during photosynthesis. However, they do not absorb light energy.
Therefore, the correct answer is Chlorophyll (C), as it is the pigment that absorbs light energy during photosynthesis.

As one age, arteries lose their elasticity. Consequently, the heart has to pump the blood more forcefully in order to fulfil the need of the body cells.

The common passage for both the digestive and respiratory systems is the oropharynx.
Explanation:
The oropharynx is a part of the throat that is located behind the mouth. It is a common passage for both the digestive and respiratory systems, serving as a connection between the oral cavity and the larynx.
- The oropharynx plays a crucial role in both systems by allowing the passage of food and air.
- It is involved in the process of swallowing, as it serves as a pathway for food to enter the esophagus during digestion.
- In the respiratory system, the oropharynx is responsible for allowing air to pass through to the larynx and then into the trachea.
The other options mentioned in the question are not common passages for both systems:
- The larynx (option A) is a part of the respiratory system and is responsible for sound production and the passage of air into the lungs.
- The esophagus (option B) is a part of the digestive system and is responsible for the transportation of food from the mouth to the stomach.
- The trachea (option D) is also a part of the respiratory system and connects the larynx to the bronchi, allowing air to pass into the lungs.

 Vermiform appendix is considered to be the vestigial part of the human alimentary canal; it is said that human ancestors may have relied upon the appendix for the digestion of cellulose when they lived on a diet that was rich in plant products.

Organ Involved in the Process of Ingestion in Amoeba:
The correct answer is A: Pseudopodia.
Explanation:
Amoeba is a unicellular organism that belongs to the group of protozoans. It captures and ingests its food through a process called phagocytosis. During this process, the following organs are involved:
1. Pseudopodia: Pseudopodia are temporary extensions of the cell membrane that are formed by the cytoplasm of the amoeba. These extensions help in capturing and engulfing the food particles.
2. Tongue: Amoeba does not possess a tongue-like structure for ingestion.
3. Tentacles: Tentacles are long, slender, and flexible structures typically found in organisms like jellyfish or sea anemones. Amoeba does not have tentacles for ingestion.
4. None of these: This option is incorrect as the process of ingestion in amoeba involves the use of pseudopodia.
Summary:
In the case of Amoeba, the organ involved in the process of ingestion is pseudopodia. Pseudopodia are temporary extensions of the cell membrane that help in capturing and engulfing food particles through phagocytosis.

Stomach secretes the enzyme pepsin and pancreas produces trypsin. Both of them breakdown protein.