Biology key terms

A living phloem cell specialised for conducting dissolved organic substances and joined end to end with other sieve tube elements.

A digit that contributes to the stated precision of a measured or calculated value, counted from the first non-zero digit.

An observable feature that suggests a plant is unhealthy, such as leaf spots or stunted growth.

A small sugar molecule, such as glucose, that can be joined to others to make a larger carbohydrate.

An equivalent ratio written using the smallest convenient values, or in a form specified by the question such as $n:1$.

Inheritance in which one gene is chiefly responsible for the feature being considered.

A part of a plant that receives sucrose to use or store, such as a growing shoot or root.

A word or symbol placed before a unit to multiply or divide its size by a stated power of ten.

One of two identical copies of a chromosome after its DNA has been copied.

A unit belonging to the internationally agreed International System of Units, such as the metre, kilogram and second.

A measurement of an object's dimensions, such as its length, area or volume.

A person's ability to form relationships, interact with others and take part in society.

The wearing away and removal of soil by agents such as water.

Any body cell other than a cell involved in producing offspring. A genetic change to a somatic cell is not inherited by the patient's children.

A part of a plant from which sucrose is transported, such as a photosynthesising leaf or a storage organ releasing sugar.

A model that shows where parts are positioned or how they are connected.

A cell whose structures are adapted to enable it to carry out a particular function.

The formation of one or more new species from an existing species.

A group of organisms that can interbreed to produce fertile offspring.

The geographical areas in which a species occurs.

How similar the abundances of the different species in a community are.

The number of different species present in a particular area or sample.

The energy transferred when the temperature of 1 g of a substance rises by 1 °C.

The matching of an enzyme's active site to a particular substrate because their shapes are complementary.

The object or biological material being examined.

A chemical agent that kills or disables sperm.

Nervous tissue running through the vertebral column that carries impulses between the brain and much of the body.