As a cell differentiates, It may change shape or may develop different subcellular structures to carry out tasks.
Tissues are made up of cells.
Tissues are a group of cells that work together to do a job.
Organs are made up of tissues.
Organs systems are made up of organs that perform a certain role.
The digestive system has multiple organs that work together to digest foods.
Enzymes are biological catalysts that increase the rate of reaction.
Enzymes are large proteins. Within the protein molecules, their is a space called the active site.
Enzymes work best at a specific temperature and pH known as the optimum
There is a model that is used to explain how catalysts work: the chemical that reacts is called the substrate and fits into the enzyme's active site. This theory is the lock and key theory.
Enzymes can change shape due to high temperature and extremes of pH. This is called denaturing. Enzymes can no longer work when denatured.
The 3 types of digestive enzyme are protease, lipase and carbohydrase. These digest proteins, lipids (fats and oils) and carbohydrates.
Bile is a liquid made in the liver and stored in the gall bladder. It is alkaline to neutralise hydrochloric acid from the stomach.
Amylase is produced in the salivary glands and the pancreas.
Blood is a tissue made of a liquid called plasma.
Plasma is made of red blood cells, white blood cells and platelets.
Red blood cells contain haemoglobin, which binds to oxygen to transport it from the lungs to the tissues and cells.
The heart pumps blood around the body in a double circulatory system.
The four chambers in the heart are the left and right atria, which receive blood from the veins, and the left and right ventricles which pump blood into the arteries.
The natural resting heart rate is controlled by a group of cells located in the right atrium, which act as a pacemaker.
The heart sends blood to the lungs through the pulmonary artery.
Air obtained by breathing reaches the lungs through the trachea.
The trachea divides into the bronchi.
The bronchi divide into bronchioles
The blood is taken to the heart through the pulmonary vein.
Health is a state of physical and mental wellbeing.
There are two main types of disease: communicable and non-communicable.
Communicable diseases can be spread between organisms whereas non-communicable diseases cannot.
The riskfactor is the likelihood of developing a disease due to a number of factors that could affect the person e.g. lifestyle or environment.
Scientists look for a casualmechanism in order to prove that there is a risk factor involved in the likelihood of getting a disease. This is because some risk factors do not necessarily cause disease.
In coronaryheart disease, layers of fatty material build up inside the coronary arteries of the heart and narrow them.
Treatments for this include: stents to keep the coronary arteries open and statins to slow down the rate at which fatty materials build up.
Cancer is a non communicable disease. It is caused by uncontrolled cell division which forms masses of cells known as tumours.
Benign tumours do not spread around the body. Malignant tumours spread in the blood to different parts of the body where they form secondary tumours.
In the leaves, most of the water will evaporate and diffuse out of the stomata (small pores).
The loss of water from leaves is called transpiration.Humidity can affect the rate of this.
The movement of food through phloem tissue is called translocation.
The stomata closes at night because carbon dioxide is not needed for photosynthesis, so closing the stomata reduces water loss.