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Genes and Health: Cystic Fibrosis
Mucus in the lungs
Lungs allow rapid gas exchange between the atmosphere and the blood
Air drawn into the trachea due to low pressure in the lungs (caused by diaphragm)
Trachea ­ two bronchi ­ bronchioles ­ alveoli (sites of gas exchange)
Mucus produced by…

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Protein Structure
General Structure
All composed of the same basic unites ­ amino acids
20 different amino acids
Plants can make all these amino acids, animals can only make some
Animals obtain the other amino acids through diet; essential amino acids

Amine group; -NH2
Carboxylic acid group; -COOH
Hydrogen; -H…

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Conjugated Proteins:
These have another chemical group associated with their polypeptide chain

Globular Proteins:
Polypeptide chain is folded into a compact spherical shape
Soluble; due to hydrophilic side chains
Enzymes are globular proteins
3-D shape is crucial to ability to form enzyme substrate complexes and catalyse reactions
within cells &…

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Glycoproteins; protein molecules with polysaccharides attached
Some proteins span the membrane whilst others are only on the outer/inner layer
Membrane proteins have hydrophobic areas (these are inside the bilayer)
Some proteins are fixed whilst other move around in the fluid (fluid mosaic model)

Old structure; three layer protein-lipid sandwich…

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Human; red fluorescent
Immediately after fusion the coloured labels remained in their respective halves
After 40 minutes at 370C there was a complete intermixing of proteins
Only possible by diffusion through membrane; proved fluidity of membrane

Unsaturated Phospholipids:
The more unsaturated; the more fluid the membrane
`kinks' in hydrocarbon tail…

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Hydrophilic molecules
Insoluble in lipids
Cross the membrane by either diffusing through water-filled pores within channel proteins
that than span the membrane
Different channel proteins for transporting different molecules (each has a specific shape for
a specific ion/molecule)
Some may be opened or closed depending on a signal (hormone or…

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Substances taken into the cell by the formation of vesicles
Part of cell surface membrane engulfs the material to be transported
Substance can also be absorbed by attaching to a receptor in the membrane then

Water Regulation; unaffected lungs
Cells that line the airways produce mucus
Water in…

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Sodium ions diffuse out of the tissue fluid and move down the gradient, passing between
cells into mucus
Movement of ions into mucus draws water out of the cells by osmosis until solutions outside
cell are isotonic (same concentration of water molecules)

People with CF:

CFTR protein may be missing…

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Digestive System
People with CF have a high basal metabolic rate
Pancreatic duct becomes blocked with sticky mucus, stop the release of digestive enzymes
Lower concentration of enzymes in the small intestine reduces the rate of digestion
Food is not fully digested so less nutrients are absorbed
Energy loss in…




Thank you



This is a well presented and detailed set of notes with useful annotated colour diagrams that cover various topics such as protein and lipid structure, cell membranes, transport through membranes, DNA, RNA, cystic fibrosis and inheritance.  It would be a useful exercise to make as set of flashcards of the key terms mentioned in the notes, to be downloaded and used as a self-test.

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