GCSE Biology B3-B4.5

Question 1

Cells

Answer 1

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.

Question 2

Tissues

Answer 2

A tissue is a group of cells with similar structure and function, working together. For example, muscular tissue which contracts to bring about movement.

Question 3

Organs

Answer 3

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.

Question 4

Organ system

Answer 4

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.

Question 5

‘Lock and Key’ theory

Answer 5

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.

Question 6

Digestive system

Answer 6

Organ system where food is digested and absorbed

Question 7

Active site

Answer 7

The area on an enzyme where the reactants bind

Question 8

Amino acids

Answer 8

Molecules made up of carbon, hydrogen, oxygen, and nitrogen that are the building blocks of protein

Question 9

Amylase

Answer 9

Enzyme that speeds up the digestion of starch into simple sugars

Question 10

Bile

Answer 10

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

Question 11

Carbohydrates

Answer 11

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

Question 12

Carbohydrases

Answer 12

Enzymes that speed up the breakdown of carbohydrates into simple sugars

Question 13

Catalyst

Answer 13

A substance that speeds up the rate of another reaction but is not used up or changed itself

Question 14

Enzymes

Answer 14

Biological catalysts, usually proteins

Question 15

Fatty acids

Answer 15

Part of the structure of a lipid molecule

Question 16

Glucose

Answer 16

A simple sugar

Question 17

Glycerol

Answer 17

Part of the structure of a lipid molecule

Question 18

Lipase

Answer 18

Enzymes that speed up the breakdown of lipids into fatty acids and glycerol

Question 19

Lipids

Answer 19

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

Question 20

Metabolism

Answer 20

The sum of all the reactions taking place in a cell or the body of an organism

Question 21

Proteases

Answer 21

Enzymes that speed up the breakdown of proteins into amino acids

Question 22

Proteins

Answer 22

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

Question 23

What factors affect enzyme reaction?

Answer 23

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

Question 24

Denatured

Answer 24

Breakdown of the molecular structure of a protein so it no longer functions

Question 25

Plasma

Answer 25

The clear yellow liquid that carries dissolved substances and blood cells around the body

Question 26

Red blood cells

Answer 26

Cells that carry oxygen throughout the body

Question 27

White blood cells

Answer 27

Part of immune system. They engulf pathogens and make antibodies and antitoxins

Question 28

Platelets

Answer 28

Fragments of cells in the blood that play a vital part in the clotting mechanism of the blood.

Question 29

Urea

Answer 29

The waste product formed by the breakdown of excess amino acids in the liver

Question 30

Arteries

Answer 30

Blood vessels that carry blood away from the heart. They usually carry oxygenated blood and create a pulse. They are under high pressure and have thick lumens

Question 31

Veins

Answer 31

Blood vessels that carry blood towards the heart. They usually carry deoxygenated blood and have valves to prevent the back flow of blood

Question 32

Capillaries

Answer 32

Smallest blood vessels. Run between individual cells and have walls that are one cell thick.

Question 33

Double circulatory system

Answer 33

The circulation of blood from the heart to the lungs is separate to the circulation of blood from the heart to the body

Question 34

Name all parts of the heart

Answer 34

Right ventricle, Right atrium, Vena Cava, Pulmonary artery, Aorta, Valves, Pulmonary vein, Left atrium, Left ventricle, Coronary artery

Question 35

Stent

Answer 35

A metal mesh placed in a blocked or partially blocked artery. They are used to open the blood vessel by the inflation of a tiny balloon

Question 36

Statins

Answer 36

Drugs used to lower blood cholesterol levels and improve the balance of high to low density lipoproteins in the blood

Question 37

Leaky valves and artificial Valves

Answer 37

Heart valves are under a lot of pressure, as a result they can become leaky or become stiff which leads to eventual death. Doctors can replace them with mechanical ones which are made out of titanium and polymers, but you need to use medicine on a daily basis. Or, a doctor could replace it with a biological valves need no medicine but last only 12-15 years

Question 38

Artificial Peacemakers

Answer 38

Resting rhythm of a heart is around 70bpm this is controlled by a group of cells in the right atrium called natural peacemakers. When they stop working a device called and artificial peacemaker can be used to correct irregular heart rates. It sends strong electrical signals to stimulate a proper heart beat

Question 39

Artificial Hearts

Answer 39

When a persons heart fails they need to wait for a donor but usually die while waiting. Scientists have created a temporary heart which gives a diseased heart time to rest and recover. However, this is still new, and cost and resources mean they are not yet widely used. Matthew Green had an artificial heart for 2 years