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UNIT 1 BIOLOGY NOTES
3.1.1- Disease may be caused by infectious pathogens or may reflect the
effects of lifestyle
A disease is a disorder of the body, leading to a departure of good health
Acute-sudden onset with rapid changes, chronic is a long-term disease
Pathogens include bacteria, viruses and fungi…

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Pathogens cause disease by damaging host cells (so it can avoid the host's immune
response) and by producing exotoxins or endotoxins which interfere with host cell
metabolism (faster than host's immune response)
Pathogens recognise and attach to host cells due to protein molecules called ligands, and
enter the cell by…

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The digestive system is made up of the mouth, stomach, duodenum, ileum, colon and anus
In the mouth, food is mechanically digested, and mixes with salivary amylase which lubricates
the food. This increases the surface area and allows enzymes to break down the starch. The
food is pushed down in…

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(antibodies), storage (casein-milk, ovalbumin-egg), contractile (myosin), toxins (snake
venom)
A peptide (covalent) bond is formed between two amino acids by a condensation reaction to
form a polypeptide/dipeptide




The primary structure of a protein determines the order/sequence in which amino acids are
arranged
The secondary structure is the way in which…

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Anabolism-building things up from smaller units, catabolism-breaking things down into
smaller units
Enzymes (a tertiary structure) work as biological catalysts, which lower activation energy,
through the formation of enzyme-substrate complexes
Enzymes work using a `lock and key' or `induced fit' action
In the `lock and key' model, the substrate is…

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Carbohydrates are made of C, H and O
A Monomers is called a monosaccharide, dimers are called disaccharides and a polymer is
called a polysaccharide
The general formula for a monosaccharide (or hexose sugar) is
C6H12O6
Glucose + glucose makes maltose, glucose + fructose (pentose
sugar) makes sucrose and glucose…

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This is in most eukaryotic cells, and is bound by a double membrane-the pores allow
molecules to move between the nucleus and cytoplasm
Ribosomal RNA is also made in the nucleolus
The endoplasmic reticulum is the continuation of the outer nuclear membrane-it is made up of
flattened sacs called cisternae…

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Light microscope Colour image can be seen by the Cannot resolve less than 0.2µm
eye
Preparation doesn't produce
artefacts
Enlargement up to x1500

TEM Greater magnification and Specimens must be dead
resolution Black and white image
Can resolve up to half Artefacts produced
Image cannot be seen with the eye…

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facing towards the water and the hydrophobic non-polar tails facing the other way
The addition of other proteins creates a fluid-mosaic structure
Soluble lipids and small molecules (such as oxygen) can pass through unassisted through the
bilayer, and so molecules must therefore be a liquid, gas or in solution
Transport…

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For example in sodium-potassium pumps, the sodium ions bind to the specific binding site,
which triggers the hydrolysis of ATP-causing the phosphate group to become attached,
which causes the protein to change shape and the sodium ions are released
On the other side, a potassium ion binds, causing the phosphate…

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Tamara Abrahams

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Amazing notes thank you so much

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