Test Paper

The process by which green plants use energy from the sun to convert carbon dioxide and water into glucose in the presence of green-coloured pigment (chlorophyll) is called photosynthesis. Plants obtain carbon dioxide from the atmosphere through stomata and water is absorbed by the roots from the soil. The process of photosynthesis involves following steps:

1. Light is absorbed by chlorophyll, which splits water (called photolysis) and oxygen is released. This reaction depends on sunlight for activation energy. It takes place in thylakoids of the chloroplasts.
2. Carbon dioxide splits and this carbon is used to make sugars. It occurs in stroma. This reaction does not require light energy.
3. Sugars are formed and they combine to form complex sugars.

Photosynthesis can be represented by the following word equation:

Carbon dioxide + water $\xrightarrow[\text{chlorophyll}]{\text{sunlight}}$ Glucose + Oxygen

Following are the uses of the bacteria:

1. Production of butter and cheese — Some bacteria such as Streptococcus and Lactobacillus are used to produce curd, butter and cheese.
2. Production of vitamins — Many bacteria living in the intestine of humans synthesize vitamins such as vitamin B.
3. Production of medicines — Bacteria are also used in the production of certain antibiotics such as streptomycin and aureomycin.
4. Nitrogen fixation — Some bacteria such as Azotobacter and Clostridium live in the root nodules of leguminous plants and fix atmospheric nitrogen into nitrates.
5. Nitrification — Some bacteria such as Nitrosomonas convert ammonia into nitrates and increase the fertility of soil.
6. Curing of tobacco and tea leaves — Bacteria are used in the curing of tobacco and tea leaves. Curing imparts a characteristic flavour to tobacco and tea leaves.
7. Digestion of food — Some bacteria live inside the digestive tract of animals, especially herbivores and break down cellulose (in grass) and help in digestion.
8. Decay of organic waste — Bacteria are the scavengers of nature and help to keep the environment clean. They act on the dead bodies of plants and animals and break them down into simpler chemical compounds. During decomposition, they release carbon, nitrogen and sulphur into the atmosphere

Based on whether a plant produces flower and seeds or not, the plant kingdom is divided into two categories:

1. Non-seeded plants or Cryptogams — These are the plants that do not produce flowers or seeds. They do not have special male and female reproductive units to produce seeds. So, their reproduction is termed as hidden reproduction. Cryptogams are further divided into three groups — Thallophyta, Bryophyta and Pteridophyta.
2. Seed-bearing plants or Phanerogams — They include the plants that have special organs for reproduction. These plants bear male and female reproductive units to produce seeds. They are further divided into two categories — Gymnosperms and Angiosperms.

Depending upon the presence or absence of oxygen, respiration is of two types — aerobic respiration and anaerobic respiration.

Aerobic respiration — When the oxidation of food (glucose) takes place in the presence of oxygen, it is called aerobic respiration. In this process, glucose is completely oxidized to form carbon dioxide and water. It takes place in mostly higher animals and plants. In aerobic respiration, 38 ATP molecules are released from oxidation of one glucose molecule.

Glucose + Oxygen ⟶ Carbon dioxide + Water + Energy (38 ATP)

Anaerobic respiration — When the oxidation of food (glucose) takes place in the absence of oxygen, it is called anaerobic respiration. In this process, glucose is not completely oxidized to form carbon dioxide and water. Rather, it is oxidized to produce ethyl alcohol or lactic acid and 2 ATP molecules.

Glucose (in absence of oxygen) ⟶ Carbon dioxide + Ethyl alcohol + Energy (2 ATP)

Leaves and young green stems have pores on them. These pores are called stomata. The exchange of gases takes place through these stomata. There are more stomata on the lower surface of leaves. Oxygen and water vapour leave the plant through the stomata while carbon dioxide enters through them. Each stoma has two bean-shaped cells called guard cells. The inner walls of the guard cells are thicker than the outer walls. When the guard cells are full of water, they swell and bulge outwards, opening the stomata. When the guard cells lose water, they lose their turgidity closing the stomata. When the stomata open, the exchange of gases takes place by the process of diffusion.

The process of blood filtration by kidneys and urine formation can be explained in the following steps:

1. Filtration — The renal artery brings the blood containing waste material to the kidneys. It then enters the glomerulus under high pressure. Water and small solutes are filtered in the Bowman’s capsule.
2. Reabsorption — The filtrate passes through the thin walls of the Bowman’s capsule into the urinary or renal tubule. As it passes through the tubule, water and many useful substances are reabsorbed by the renal blood capillaries.
3. Secretion — The remaining liquid, along with waste such as urea, uric acid and so on, is called urine and is collected in the urinary bladder.
4. Excretion — Urine leaves the kidneys and passes into the urinary bladder through the ureters. When the urinary bladder is full, urine is passed out through the urethra.

Following are the symptoms of kidney stones

• severe pain in the sides of the abdomen
• blood in the urine
• nausea and vomiting
• reduced amount of urine excreted
• burning sensation during urination
• persistent urge to urinate

The process of breaking down glucose to release energy is called respiration.

A total of 38 ATP molecules are produced by the oxidation of 1 molecule of glucose.

Each genus is further divided into several species.

The size of a bacteria varies from 0.2 to 100 microns .

Gases are exchanged through small openings on the leaves called stomata.

Bile pigments are formed in the liver by the breakdown of haemoglobin of dead RBCs.

Ureters are narrow tubes that lead out from each kidney.

Blue green algae

Reason — Blue green algae is classified under the Kingdom Monera while Rhizopus and Mucor are classified under Kingdom Fungi.

yeast

Reason — Cocci, spirilla and vibrio are forms of bacteria but yeast is a fungi.

When guard cells are full of water, they stretch outwards, opening the stomata. When they lose water they become less turgid closing the stomata.

Bacteria and fungi were included in the Plant kingdom because they showed some plant like characters like non-motility also a few of bacteria are photosynthetic. Protozoans were placed in the animal kingdom because they showed mobility and heterotrophic nutrition.

Two by-products, carbon dioxide and water are given out during cellular respiration. But only carbon dioxide is considered as a waste product because it is harmful for the body if its concentration increases inside the body.

The organ in the picture is Kidney. The labelled diagram is shown below:

True

False

Corrected statement — Amoeba moves with the help of pseudopodia.

True

False

Corrected statement — In anaerobic respiration, 2 ATP molecules are produced by the oxidation of 1 molecule of glucose.

True

True