Odisha BSE Madhyama Science key terms

The process by which green plants use sunlight, water and carbon dioxide to make glucose and release oxygen. It takes place mainly in the chloroplasts of leaf cells, using the green pigment chlorophyll.

The green pigment found in chloroplasts that absorbs sunlight for photosynthesis. It captures mainly blue and red light and reflects green light, which is why most leaves look green.

A small green structure inside plant cells where photosynthesis happens. It contains chlorophyll and the enzymes needed to convert light energy into chemical energy stored in food.

Tiny openings, mostly on the underside of leaves, through which gases enter and leave the plant. Carbon dioxide enters and oxygen and water vapour escape, controlled by guard cells.

The loss of water vapour from a plant, mainly through the stomata of its leaves. It pulls water upward from the roots and helps cool the plant on hot days.

The plant tissue that carries water and dissolved minerals upward from the roots to the stem and leaves. Its cells are dead and hollow, forming continuous tubes.

The plant tissue that transports food, mainly sucrose, made in the leaves to other parts of the plant such as roots, fruits and growing tips.

The breakdown of food inside cells to release energy for life activities. Aerobic respiration uses oxygen and gives carbon dioxide and water; it happens day and night in all living cells.

The release of energy from food without using oxygen. In yeast it produces alcohol and carbon dioxide; in hard-working human muscles it produces lactic acid, which causes tiredness and cramps.

The breakdown of sugar by microorganisms such as yeast without oxygen. It is used in making bread, curd and alcoholic drinks, and produces carbon dioxide or alcohol as by-products.

The breaking down of large food molecules into simple, soluble substances that the body can absorb. It happens mechanically by chewing and chemically by enzymes in the mouth, stomach and small intestine.

A protein made by living cells that speeds up a specific chemical reaction without being used up. Examples include amylase, which digests starch, and pepsin, which digests protein.

The movement of digested food, water and minerals through the wall of the small intestine into the blood. Finger-like villi increase the surface area so absorption happens quickly.

Tiny finger-like projections lining the small intestine. They greatly increase the surface area for absorbing digested food and contain blood vessels that carry nutrients away.

The fluid that circulates in the body, carrying oxygen, food, hormones and waste. It is made of plasma and cells: red cells carry oxygen, white cells fight infection, and platelets help clotting.

The red iron-containing pigment in red blood cells. It combines with oxygen in the lungs and releases it in the tissues, giving blood its red colour.

A muscular organ that pumps blood around the body. It has four chambers: the right side sends blood to the lungs and the left side pumps oxygen-rich blood to the rest of the body.

A blood vessel that carries blood away from the heart. Arteries have thick, elastic walls and usually carry oxygen-rich blood, except the pulmonary artery, which carries oxygen-poor blood to the lungs.

A blood vessel that carries blood toward the heart. Veins have thin walls and valves that stop blood flowing backward; most carry oxygen-poor blood, except the pulmonary vein from the lungs.

The removal of harmful waste products made by the body's chemical reactions. The kidneys excrete urea in urine, the lungs remove carbon dioxide, and the skin removes salts and water in sweat.

A bean-shaped organ that filters waste such as urea from the blood and controls the body's water and salt balance. It produces urine, which passes to the bladder.

The microscopic filtering unit of the kidney. Each kidney has about a million nephrons, which filter blood and reabsorb useful substances such as glucose and water.

A fast, automatic response to a stimulus that does not need conscious thought, such as blinking or pulling a hand from a hot object. It is controlled by the spinal cord.

The basic cell of the nervous system that carries electrical messages. It has a cell body, dendrites that receive signals, and a long axon that transmits impulses to other cells.

The tiny gap between two neurons or between a neuron and a muscle. Messages cross the gap by chemical transmitters rather than by direct electrical contact.

A chemical messenger made by an endocrine gland and carried by the blood to a target organ. Hormones control growth, sugar level, reproduction and other slow body processes.

A hormone made by the pancreas that lowers the level of glucose in the blood. Too little insulin causes diabetes, in which sugar appears in the urine.

The word summary of photosynthesis: carbon dioxide plus water, in the presence of sunlight and chlorophyll, gives glucose plus oxygen. It shows the raw materials and products of the process.

The process by which living things produce new individuals of their own kind. It may be asexual, involving one parent, or sexual, involving a male and a female parent.

The transfer of pollen grains from the anther of a flower to the stigma. It may happen within the same flower or between flowers, carried by wind, insects, water or animals.

The joining of a male gamete with a female gamete to form a zygote. In flowering plants the pollen nucleus fuses with the egg inside the ovule; in animals sperm fuses with the egg.

The single cell formed when a male and a female gamete fuse. It divides repeatedly to grow into a new individual and is the first cell of the offspring.

A change in body form during the life cycle of some animals. In complete metamorphosis, as in butterflies, the stages are egg, larva, pupa and adult.

The passing of characters such as eye colour and height from parents to offspring through genes. Genes are carried on chromosomes inside the nucleus of every cell.

A unit of heredity found on a chromosome that controls one or more characters. Genes are made of DNA and are passed from parents to their children.

A thread-like structure in the cell nucleus that carries genes. Human body cells contain 46 chromosomes in 23 pairs, while gametes contain half that number.

Deoxyribonucleic acid, the chemical that makes up genes and carries hereditary information. Its double-helix structure allows it to copy itself accurately before cell division.

A feature or behaviour that helps an organism survive in its habitat. Examples include the camel's hump for storing fat and the streamlined body of a fish.

The process by which organisms better suited to their environment survive and reproduce more successfully, so their useful features become more common over generations.