(4)

In the autotropic mode of nutrition, the plants can prepare their own food in the presence of sunlight, carbon dioxide, water and chlorophyll present in the leaves of the plants.

(4)

Only in the presence of sunlight autotrophs can convert carbon dioxide and water into carbohydrates. By covering the leaf by black paper strip the leaf does not get sunlight in the covered part and no photosynthesis takes place and no starch will be present in the leaf thus light is necessary for photosynthesis.

(3)

Due to the presence of starch, when iodine solution was added to rice water, the solution becomes blue-black. Iodine forms starch iodide complex when it comes in contact with the amylose structure of starch. The blue-black colour comes from the starch iodide complex.

(2)

The entry of water into guard cells aids in the opening of guard cells, the guard cell becomes turgid as a result of this. Water going out from guard cells aids in the closing of guard cells, as a result of this the guard cells become flaccid.

(2)

Yeast, mushrooms, and bread mould all exhibit a saprophytic mode of nutrition. They use digestive enzymes secreted outside their body to break down complex organic substances and absorb basic molecules as nutrition.

(2)

Amylase is a starch hydrolase enzyme that catalyses the conversion of starch to simple sugars. As a result, if salivary amylase is lacking in saliva, starch digestion is hampered.

(2)

Bile is a dark green to yellowish brown fluid produced by the liver. It is stored in the gall bladder and it helps in the digestion of fats in the small intestine.

(4)

Food is broken down in the small intestine by enzymes secreted by the pancreas and bile from the liver. Because it contains all of the enzymes required for the digestion of every type of food, the food is finally digested in the small intestine of the alimentary canal.

(4)

Pancreatic juice contains the digestive enzymes amylases, lipases, and trypsin, which are secreted by the pancreas. Amylase degrades starch, trypsin degrades proteins, and lipase degrades emulsified lipids.

(4)

Ptyalin, also known as salivary amylase, is an enzyme that is found in the saliva of humans and some other animals. It begins the process of starch digestion in the mouth. While the pancreas does produce digestive enzymes like trypsin, amylase, and lipase, which are crucial for breaking down proteins, carbohydrates, and fats respectively, it does not produce ptyalin.

(3)

Pepsin enzyme is secreted by the stomach that breaks down proteins into smaller amino acids. Trypsin enzyme is secreted by the pancreas that breaks down proteins

(3)

Bile juice is secreted by the liver and stored in gall bladder. It helps in the breakdown of fats into fatty acids

(4)

Salivary amylase, which is present in saliva, digests carbohydrates such as starch. It is also digested in the pancreas by pancreatic juices.

(3)

Proteins are first broken down in the stomach. Pepsinogen is released by peptic cells in the stomach. Pepsinogen is a proenzyme which is converted into active pepsin. Pepsin breaks down proteins into smaller polypeptides.

(1)

Amylase is the first enzyme in the digestive tract to mix with food. It is secreted in the mouth and acts on starch to break it down into smaller molecules.

(3)

Fermentation is an anaerobic process in which sugar is converted to acids or alcohol in the absence of oxygen. This process occurs in yeast, bacteria, and oxygen-depleted muscle cells in the same way that lactic acid fermentation does, but it takes place in the cytoplasm rather than in the mitochondria.

(4)

Arteries are thick-walled blood vessels that pump blood away from the heart at a high pressure because their walls are highly muscular, they do not have valves.

(2)

Aerobic respiration is the process of breaking down pyruvate into carbon dioxide, energy, and water in the presence of oxygen. This process takes place in the mitochondria of the cell.

(3)

Calcium hydroxide solution is the lime water. When it reacts with carbon dioxide, it forms insoluble calcium carbonate, which remains suspended in water and gives it a milky white colour.

(1)

The pyruvate produced during glycolysis usually enters the Kreb’s cycle as acetyl coenzyme A in the mitochondrial matrix, where it provides a reservoir of chemical energy (ATP, NADH and$FAD{H}_2$). Pyruvic acid can be transformed to lactic acid as one of its potential fates in cellular respiration. Under stressful conditions, this often occurs in the cytoplasm of muscle tissue.

(2)

The air sacs in lungs are known as alveoli. The alveoli are the sites where exchange of the gases takes place. The concentration of oxygen gas in the alveoli is higher than that in the blood during inhalation, therefore it diffuses into the blood. Concentration of carbon dioxide is more in the blood than that in the alveoli during exhalation, thus it diffuses into the alveoli.

(1)

In vascular plants, xylem is a type of tissue that transports water and some nutrients from the roots to the leaves. The other type of transport tissue is phloem, which is responsible for transporting sucrose and other nutrients throughout the plant. The xylem acts as a conducting tissue to transport water and some soluble nutrients such as minerals and inorganic ions from the roots to the rest of the plant.

(3)

Kidneys are the bean shaped reddish brown paired organs in human beings. These are a part of excretory system that helps in the process of urine formation. Thus kidneys help in excretion.

(3)

Urine from the nephron is transported to the collecting duct, where it enters the ureters. Ureters open from kidney into the urinary bladder. The urinary bladder holds urine, and as the volume of urine collected increases, so does the size of the bladder. When the CNS sends a voluntary message to the bladder, the bladder muscles contract and the bladder sphincter relaxes, allowing urine to pass through the urethra.

(2)

For the experiment where $CO₂$ is given out during respiration, KOH solution or pallets are taken in a test tube and placed in the conical flask. KOH absorbs carbon dioxide and prevents it from being utilised by the plant for the process of photosynthesis.