OCR GCSE Biology A Key Terms

The unique three-dimensional folding of a protein which is essential for its biological function.

The non-living physical factors in an ecosystem, such as temperature, light intensity, and water.

The non-living chemical and physical parts of the environment, including the atmosphere, soil, water, and fossil fuels.

A non-living, physical or chemical component of the environment that affects organisms, such as temperature, light, or soil pH.

Non-living physical or chemical parts of the environment, such as temperature, light, and water availability, that affect organisms.

The natural detachment and shedding of plant parts, such as dead leaves and ripe fruit.

A specific, weakened layer of cells that forms at the base of a leaf stalk under the influence of ethene, causing the leaf to fall.

A measure of the amount of light that a solution absorbs; in beetroot experiments, higher absorbance indicates more membrane damage.

The practice of voluntarily refraining from sexual intercourse.

The total number of individuals of a particular species living in a given area.

The time given to an organism to adjust to a change in its environment before data collection begins.

The process by which the eye's lens changes shape to focus on near or distant objects.

How close a measurement is to the true value of the quantity being measured.

A specific example of a chemical neurotransmitter used in the nervous system.

Organisms that are adapted to thrive in acidic environments, such as soils with a low pH.

Precipitation containing harmful levels of nitric and sulfuric acids, often caused by $SO_2$ emissions.

Traits gained during an organism's lifetime, such as a scar, which are not passed on to offspring.

A cap at the head of a sperm cell containing digestive enzymes to penetrate the egg cell membrane.

Specific protein filaments in muscle cells that slide past each other to cause contraction and relaxation.

The minimum amount of energy required for a chemical reaction to start.

The process of using ATP to move sucrose into the phloem sieve tubes against a concentration gradient.

The specific, indented region on an enzyme where the substrate binds to undergo a chemical reaction.

The movement of mineral ions from a lower concentration in the soil to a higher concentration in root cells, requiring energy from respiration.

The true physical size of a biological specimen before it is magnified.

A nitrogenous base that always pairs with Thymine using two hydrogen bonds.

Specialised connective tissue where excess lipids are stored to provide energy, insulation, and physical protection.

The lower-energy molecule formed when ATP is broken down to release energy, which is subsequently recharged into ATP during respiration.

Glands located above the kidneys that produce adrenaline in response to stress or fear.

A hormone that prepares the body for a 'fight or flight' response by increasing heart rate and boosting delivery of oxygen and glucose to muscles.

Multipotent stem cells found in specific adult tissues that can only differentiate into a limited range of cell types.