Gcse Biology Paper 1 Organisation Flashcards
(47 cards)
Tissue
A group of cells with a similar structure and function, which all work together to do a job.
Examples of tissues
- muscle tissue contracts to produce movement
- glandular tissue produces substances such as enzymes and hormones
- epithelial tissue covers organs
Organs
Groups of different tissues, which all work together to perform a specific job.Each may contain several tissues.
Organs systems
Groups of organs working together to do a particular job.The digestive system is an example of it, in which several organs work together to digest and absorb food.Lots of them work together to make an organism.
Stomach
An organ that contains:
- muscle tissue that contracts to churn the contents
- glandular tissue to produce digestive juices
- epithelial tissue to cover the outside and inside of the stomach
Enzymes
-They are biological catalysts
- they speed up chemical reactions in living organisms.
They have a number of properties:
- they are all large proteins.
- each of it catalyses a specific reaction.
Active site
A space within the protein molecule of the enzyme.
Optimum
Where enzymes work best at a specific temperature and pH.
Lock and key theory
model used to explain how enzymes work: the chemical that reacts is called the substrate (key) and it fits into the enzyme’s active site (lock).
Denaturing
Where high temperature and extremes of pH make enzymes change shape.The enzyme cannot work once it has been denatured, because the substrate cannot fit into the active site - the lock and key no longer fit together.
Digestive Enzymes
Produced by specialised cells in glands and in the lining of the gut:- the enzymes pass out of the cells into the digestive system.- they come into contact with food molecules.- they catalyse the breakdown of large insoluble food molecules into smaller soluble molecules.
Examples of digestive enzymes
- Protease: digest proteins
- Lipase: digest lipids (fats and oils)
- Carbohydrase: digest carbohydrates
- These are to produce smaller molecules that can be easily absorbed into the bloodstream.
Amylase
- is produced in the salivary glands and the pancreas
- is a carbohydrase that breaks down starch into sugar (maltose).Used to build new carbohydrates.
Protease
- is produced in the stomach, pancreas and small intestine
- breaks down proteins into peptides or amino acids.Used to build new proteins.
Lipase
- is produced in the pancreas and small intestine
- breaks down lipids (fats) into fatty acids and glycerol.Used to build new lipids.
Bile
- It is a liquid made in the liver and stored in the gall bladder.
- It is alkaline to neutralise hydrochloric acid from the stomach.
- It also emulsifies fat to form small droplets, increasing the surface area for enzymes to act on.
- The alkaline conditions and large surface area increase the rate at which fat is broken down by lipase.
- Does not contain any enzymes, so it does not digest fat molecules. It just breaks up fat droplets into smaller ones.
Good health
A state of physical and mental wellbeing.
Disease
Caused by part of the body not working properly.This can affect physical and / or mental health.Can be divided into two main types:
- communicable- non-communicable
Examples of how different diseases can interact with each other
- viruses infecting cells can be the trigger for cancers, such as cervical cancer.
- diseases of the immune system mean that an individual is more likely to catch infectious diseases, e.g. people with HIV are more likely to get tuberculosis.
- immune reactions triggered by a pathogen can cause allergies, such as skin rashes and asthma.
- if a person is physically ill, this can lead to depression and mental illness.
- poor diet, stress, and difficult life situations can increase the likelihood of developing certain diseases.
Casual mechanism
The process by which a cause brings about an effect.
Risk factor
-They make it more likely that a person will develop a certain disease.
-Non-communicable diseases are often caused by the interaction of a number of factors.
They can be:
- aspects of a person’s lifestyle
- substances in the person’s body or environment
Examples of diseases and their proven risk factors
- Cardiovascular disease: lack of exercise / smoking / high intake of saturated fat
- Type 2 diabetes: Obesity
- Liver and brain damage: Excessive alcohol intake
- Lung diseases, including lung cancer: Smoking
- Skin cancer: Ionising radiation, e.g. UV
- lightLow birth weight in babies: Smoking during pregnancy
- Brain damage in babies: Excessive alcohol intake during pregnancy
Coronary heart disease
-Layers of fatty material build up inside the coronary arteries and narrow them.
- Treatment for it include:
- stents to keep the coronary arteries open.
- statins to reduce blood cholesterol levels and slow down the rate at which fatty materials build up.
Heart valve disease
In some people, heart valves may become faulty, developing a leak or preventing the valve from opening fully.Faulty valves can be replaced using biological or mechanical valves.
