Genes and Health Flashcards
How are the lungs adapted for gas exchange?
Millions of alveoli, alveoli have a large surface area.
Extensive capillary network
They are surrounded by a number of capillaries which leads to a short diffusion path due to the thinness of walls.
There is a steep concentration gradient between the alveoli and the blood.
Describe Fick’s Law.
Increased surface area and a greater concentration gradient increase rate of diffusion.
Thicker surface areas reduce rate of diffusion.
Rate of diffusion is directly proportional to surface area x concentration difference divided by the thickness of the surface.
Describe primary structure of a protein.
Two amino acids joined as a dipeptide, via a condensation reaction, with a peptide bond.
Describe secondary structure of a protein.
Chain coils into alpha helices caused by hydrogen bonds or folds into beta pleated sheets.
Describe tertiary structure of a protein.
Hydrophobic or hydrophilic R groups.
Disulphide, ionic or hydrogen bonds formed.
Describe globular and fibrous proteins.
Globular proteins are compact and spherical. They are soluble. Hydrophilic groups on the outside.
Fibrous proteins are long chains that are strong and cross-linked. They are insoluble. Hydrophobic groups on the outside.
Describe the phospholipid bilayer.
Phosphate heads are polar and hydrophilic. Fatty acid tails are non-polar and hydrophobic.
Glycoproteins - cell to cell recognition
Glycolipids - stability and cell to c ell recognition
Cholesterol - helps maintain stability
Define diffusion.
Net movement from an area of high concentration to an area of low concentration, until it reaches dynamic equilibrium
Define facilitated diffusion.
Polar molecules and ions cross membranes using protein carriers or channel proteins.
Channel proteins use a signal. Gated channels use a change in potential difference.
Some proteins are carrier proteins where molecules bind to a site, causing the protein to change shape and carry the molecule across the layer.
Define osmosis.
Net movement of water molecules from an area of high concentration to an area of high low concentration through a partially permeable membrane. Continues until isotonic.
Define active transport.
Movement from an area of low concentration to an area of high concentration using energy supplied by adenosine triphosphate.
Define exocytosis.
Release of a substance using vesicles. Used in bulk transport and the vesicles fuses with cell membrane
Define endocytosis.
Taking in a molecule using vesicles. Substance is surrounded by the cell membrane and engulfed in a vesicles.
Describe what happens where there is extra water in the mucus.
Sodium is transported across the basal membrane into the epithets cell and diffuses through sodium channels. Chlorine diffuses down an electrical gradient. Water is then moves out of the mucus into the epithelial cell
Describe what happens hen there is too little water in the mucus.
Chloride ions is transported across the basal membrane and diffuses through an open CFTR channel in to the epithelial cell. Sodium diffuses down an electrical gradient. The bronchus is hypertonic to the epithelial cell so water diffused into the bronchus via osmosis.
Describe what happens in cystic fibrosis sufferers.
CFTR channel is absent or dysfunctional. SO the chloride channel is dysfunctional so chloride is unable to diffuse into the bronchus and sodium channel is permanently open. Water is constantly being removed by osmosis crating thick mucus.
Describe the effect of cystic fibrosis on the digestive system.
Difficult to maintain body mass, high basal metabolic rate, requires 120-140% of daily calorie intake.
Pancreatic duct blocked with mucus, prevents release of digestive enzymes, food is not digested properly, resulting in malabsorption syndrome.
Describe the effect of cystic fibrosis on the reproductive system.
Females are less likely to become pregnant due to a mucus plug in the cervix.
Males may have a mucus plug in the cast deferens or may lack the vas deferens.
Haemoglobin
Globular so can be soluble
Contains haem group to bind oxygen
Has 4 sub units each with a haem so binds more oxygen
Describe DNA.
Made up of a phosphate, deoxyribose sugar and a nitrogenous base of adenine, thymine, guanine or cytosine. This is a nucleotide, with phosphodiester bonds, formed by a condensation reaction.
