Glossary

An A-Z of keywords and phrases, all of which are relevant to the post-16 biology curriculum.

 

A B C D E F G H I J K L M N O P Q R S T U V W Y Z
Ketogenic diet

A high-fat, low-carbohydrate diet that mimics prolonged starvation. The use of fat as the body’s preferential energy source leads to a build up of ketone molecules (which contain a carbonyl group, C=O, bonded to two other carbon atoms). This diet is sometimes used to reduce the number of seizures suffered by children with epilepsy.

Ketones

Compounds that are produced in the liver when fat is respired under starvation conditions (when levels of carbohydrate in the blood are low) or when the body has insufficient insulin to trigger cells to take up glucose from the blood (for example, in type 1 diabetes). At high levels, ketones can be harmful, causing vomiting, hyperventilation and breath that smells like pear drops.

Kin selection

Natural selection favouring the survival of relatives rather than an individual itself.

Knockout

A technique that inactivates an individual gene.

Krebs cycle

A step in cellular respiration that occurs in the mitochondrial matrix after the link reaction. It completes the oxidation of acetyl CoA and precedes the electron transport chain.