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As level Biology notes










































By Jonathan Curtis



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Contents

Section 1.1: Causes of Disease Pathogens
Section 1.2: Epidemiology
Section 1.3: Lifestyle and Health
Section 2.1: Enzymes and Digestion
Section 2.2: Carbohydrates ­ Monosaccharides
Section 2.3: Carbohydrates ­ disaccharides and polysaccharides.
Section 2.4 ­ Carbohydrate digestion
Section 2.5 ­ Proteins
Section 2.6 ­ Enzyme action
Section 2.7 ­ Factors…

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Section 10.3 ­ Starch, glycogen and cellulose
Section 10.4 Plant cell structure
Section 11.1 ­ Replication of DNA
Section 11.2 ­ Mitosis
Section 11.3 ­ The cell cycle
Section 12.1 ­ Cellular organisms
Section 13.1 ­ Exchange between organisms and their Environment
Section 13.2 ­ Gas exchange in single celled…

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Section 1.1: Causes of Disease Pathogens

Health ­ A state of physical and mental wellbeing, free from disease.

Disease ­ An abnormal condition of an organism that impairs bodily functions and
is associated with specific symptoms.

Noninfectious ­ Sometimes called disorders and can be caused by a broad range
of…

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Interfaces are adapted for absorption but also make it easier for pathogens to pass through.
Gas exchange ­ airborne pathogens

Digestive System ­ Disease in contaminated food or water.

Defences

Gas exchange ­ thick/sticky mucus traps pathogens. Celia that is on the epithelial cells work
together to remove microbes.

Digestive…

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Section 1.2: Epidemiology

Is the study of patterns in diseases and the various factors that effect the spread of disease.

A correlation is different causal link.

Strong, positive correlation







Weak correlation







Negative Correlation







How to prove a link

Wide samples must be used.

Data must be analysed over long periods…

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Demographic Transition

Explains how the population changes over time e.g. from high birth rate.

Section 1.3: Lifestyle and Health

Risk ­ A measure of probability that damage to health will occur as a result of a
given hazard.

We need to look at probability that a hazard will occur as…

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Genetics can cause approximately 5% of cancers. Tumour producing genes
(oncogenes).

Lifestyle factors can expose you to more carcinogens.

More you smoke, higher the risk.
Diet ­ low fat, high fibre, fruit etc.

Radiation, uv light and xrays are carcinogens.

Physical activity ­ exercise reduces the risk.

Alcohol ­ increases…

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Cancer cells were looked at and scientist found that mutations occurred in 3 places
in the DNA.
The gene that mutates is called a tumour suppressor gene.

This is still not a causal link because smoking does not defiantly cause cancer, even
though it is very likely to be the…

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Section 2.1: Enzymes and Digestion

Glands produce enzymes that are used to break down large molecules into smaller
ones that are ready for abortion.

The digestive system provides an interface between the body and the environment
because it allows food to pass through it.

Major parts of the digestive system…

Comments

Aparna

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Amazing notes! The best I've ever seen, thank you so much!

Tamara Abrahams

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Really good notes, thanks!

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