GCSE Biology B3-B4.5 Flashcards
Cells
Cells are the basic building blocks of all living organisms. Unicellular and multicellular organisms carry out all the exchanges they need across their cell membranes. Large multicellular organisms contain billions of cells.
Tissues
A tissue is a group of cells with similar structure and function, working together. For example, muscular tissue which contracts to bring about movement.
Organs
Organs are collections of tissue. Each organ contains several tissues, all working together to perform a specific function. For example, the stomach is an organ used in the digestion of food.
Organ system
Organ systems are groups of organs that all work together to perform specific functions. For example, the organ system in the body includes the digestive system, the circulatory system, and the gas exchange system.
‘Lock and Key’ theory
The lock and key theory is a simple model of how enzymes work. The substrate of the reaction to be catalysed fits into the active site of the enzyme. You can think of it like a lock and a key, for the enzyme has a specific shape, which only accepts certain sunstrates. Once its in place, the enzyme and substrate bind together.
Digestive system
Organ system where food is digested and absorbed
Active site
The area on an enzyme where the reactants bind
Amino acids
Molecules made up of carbon, hydrogen, oxygen, and nitrogen that are the building blocks of protein
Amylase
Enzyme that speeds up the digestion of starch into simple sugars
Bile
Neutralises stomach acid to give a high pH for the enzymes from the pancreas and small intestine to work well. It is not an enzyme
Carbohydrates
Molecules that contain only carbon, hydrogen and oxygen. They provide energy for the metabolism and are found in foods such as rice, potatoes and breas
Carbohydrases
Enzymes that speed up the breakdown of carbohydrates into simple sugars
Catalyst
A substance that speeds up the rate of another reaction but is not used up or changed itself
Enzymes
Biological catalysts, usually proteins
Fatty acids
Part of the structure of a lipid molecule
Glucose
A simple sugar
Glycerol
Part of the structure of a lipid molecule
Lipase
Enzymes that speed up the breakdown of lipids into fatty acids and glycerol
Lipids
Include fats and oils and are found in foods such as olive oil, butter, and crisps. They are made up of carbon, hydrogen, and oxygen
Metabolism
The sum of all the reactions taking place in a cell or the body of an organism
Proteases
Enzymes that speed up the breakdown of proteins into amino acids
Proteins
Molecules that contain carbon, hydrogen, oxygen, and nitrogen and are made up of long chains of amino acids. They are used for building the cells and tissues of the body and to form enzymes
What factors affect enzyme reaction?
There are two main factors that affect enzyme reaction. These two factors are temperature and the pH. If the temperature or the pH is too high, the enzyme loses its shape and cannot perform its task anymore, it has become denatured
Denatured
Breakdown of the molecular structure of a protein so it no longer functions
