Biology as Unit 2 Revision
ASBiology and Disease * Causes of disease * Pathogens
Disease suggests a malfunction of the body or mind which has an adverse effect on good health
For a micro-organism to be considered a pathogen it must * Gain entry to the host * Colonise the tissue of the host * Resist the defences of the host * Cause damage to the host tissues
Pathogen Infection Disease
Entry pathways * Gas exchange system * Digestive system
Natural defences * Mucous layer * Production of enzymes * Stomach acid
Ways of causing disease * Damaging host tissues * Producing toxins
* Data and disease
Correlation doesn’t cause causation.
* Lifestyle and health
Risk – A measure of the possibility that damage to health will occur as a result of a given hazard * Probability that a hazardous event will occur * Consequences of that hazardous event
Factors
* Smoking * Diet * Obesity * Sunlight * Physical activity * High blood pressure * High cholesterol
2. Enzymes and the digestive system
* Enzymes and digestion
Oesophagus - transfers food from the mouth to the stomach
Stomach – Stores and digests food
Small intestine – further digestion by enzymes
Large intestine – absorbs water
Rectum – faeces are stored before egestion
Physical breakdown & Chemical breakdown
All chemical breakdown digestion is done by hydrolysis by hydrolase
Carbohydrases – Carbohydrates
Lipases – Lipids
Protease – Proteins * Carbohydrates – monosaccharide’s
Individual molecule – monomer
Repeating molecules – polymer
Single monomer – monosaccharide
Pair of monomers – disaccharide
Large no. of monomers – polysaccharide
Monosaccharides –
General formula (CH2O)n
Best known monosaccharide – C6H12O6
H O H
HO OH
Test for reducing sugars
(Monosaccharide’s and some Disaccharides) * Add benedicts
Disease suggests a malfunction of the body or mind which has an adverse effect on good health
For a micro-organism to be considered a pathogen it must * Gain entry to the host * Colonise the tissue of the host * Resist the defences of the host * Cause damage to the host tissues
Pathogen Infection Disease
Entry pathways * Gas exchange system * Digestive system
Natural defences * Mucous layer * Production of enzymes * Stomach acid
Ways of causing disease * Damaging host tissues * Producing toxins
* Data and disease
Correlation doesn’t cause causation.
* Lifestyle and health
Risk – A measure of the possibility that damage to health will occur as a result of a given hazard * Probability that a hazardous event will occur * Consequences of that hazardous event
Factors
* Smoking * Diet * Obesity * Sunlight * Physical activity * High blood pressure * High cholesterol
2. Enzymes and the digestive system
* Enzymes and digestion
Oesophagus - transfers food from the mouth to the stomach
Stomach – Stores and digests food
Small intestine – further digestion by enzymes
Large intestine – absorbs water
Rectum – faeces are stored before egestion
Physical breakdown & Chemical breakdown
All chemical breakdown digestion is done by hydrolysis by hydrolase
Carbohydrases – Carbohydrates
Lipases – Lipids
Protease – Proteins * Carbohydrates – monosaccharide’s
Individual molecule – monomer
Repeating molecules – polymer
Single monomer – monosaccharide
Pair of monomers – disaccharide
Large no. of monomers – polysaccharide
Monosaccharides –
General formula (CH2O)n
Best known monosaccharide – C6H12O6
H O H
HO OH
Test for reducing sugars
(Monosaccharide’s and some Disaccharides) * Add benedicts