revision

Platelets stick to damaged wall of blood vessel

Thromboplastin is released from damaged tissue and from platelets

There is calcium ions and vitamin k in the plasma

Platelets stick to eachother and the damaged wall forming a platelet plug

fibrin mesh traps blood cells, forming a clot.

Prothrombin turns into thrombin ( an enzyme that catalyses the conversion of fibrinogen into fibrin)

Fibrinogen (soluble) turns into fibrin (insoluble)

Normal situation.

Na+ ions are pumped out of the cell at the basal end. Na+ ions enter the cell at the opical end through the na+ channel. The Na+ pump produces a high conc of na+ ions outside the cell at the basal end. water moves out of the cell at the basal end. As water is lost from the cell at the basal end, water moves into the cell from the opical end, drawing water out of the mucus.

The CF Situation.

Na+ ions are pumped out of the cell via the basal end. The CFTR channel is not functioning/present. so is not able to regulate the na+ channels. Na+ ions continue to enter the cell at the opical end through the open Na+ channel. No cl- secretion takes place. water enters the cell by osmosis making the mucus sticky.

Globular Protein.

Can be single chains, 2 or more chains can form a helix or b pleated sheets. spherical in shape. Soluble. Functions; enzymes biological transport eg insulin. structural role within cells eg; cell membrane componants.

Examples; Haemoglobin, insulin,lactose.

Fibrous Protein.

Form rod or wire like shape.

Helix of b pleated sheets.

primary or secondary structure.

No soluble, functions; membrane proteins, construct connective tissue eg tendons.

eg; collagen or eleastin.

Monohybrid inheritance is where and individual inherits a charesteristic which is deturmined by a single gene with two alleles. An example of a disease inherited this way is Cystic Fibrosis.

Pre-implantation genetic diagnosis.

IVF embryo tested before put into womb.

Remove cell from an embryo made of 8 or 10 cells. the DNA is analysed and a decision is made as to whether to put it back into the womb or not.

The gas exchange System.

Sticky mucus forms in the lungs due to non functioning CFTR channel.

Sticky mucus cannot be cleared by beating cillia.

The musuc traps bacteria+increase the change of infection. Sticky mucus blocks airways making gas exchange in the alveoli less efficient.

The Digestive System.

The pancreatic duct become blocked by mucus. The release of a digestive enzyme into the small intestine from the pancreas is reduced. Food is not fully digested in the gut, it takes too long to pass through the small intestine therefore not all the nutrients is absorbed. Molecules that are successfully broken down have to pass across the thick mucus layer to reach the villi.

In females sticky mucus collects in the cervix and mucus plug develops. Sperm cannon get through the mucus. So the chance of fertilisation is reduced.

Males often lack sperm ducts or if present they become partially blocked by mucus.