bio test 8 markers

both produce gametes; both involve mitosis and meiosis; both have cell growth before meiosis; both involve differentiation to produce a specialised gamete; Oogenesis during development of embryo while spermatogenesis starts during puberty Oogenesis eggs are produced in ovaries while spermatogenesis sperm is produced in testes Oogenesis one egg cell per meiosis while spermatogenesis releases 4 sperm cell per meiosis Oogenesis stops at menopause while spermatogenesis goes on until death

4 main stages: Downregulation, Superovulation, Fertilisation, Implantation Drugs used to halt normal menstrual cycle Inject FSH into mother to stimulate egg development; Egg harvested from ovaries Male provides sperm and egg mixed with sperm 2-3 embryos are implanted into uterus pregnancy test is done to see if implantation has occurred

digestion is the breakdown of large molecules into small molecules; Needed to allow diffusion; so foods can be absorbed into the bloodstream/body; so foods can move from bloodstream into cells; hydrolysis is aided by enzymes; hydrolysis requires water; polysaccharides (hydrolysed) to disaccharides/monosaccharides proteins/polypeptides (hydrolysed) to amino acids;

Davson-danielli model proposed 2 layers of protein on either side of a lipid bilayer Micrograph shows proteins in the lipid bilayer and crossing the lipid bilayer

Amphipathic is when something has both hydrophilic and hydrophobic properties Phospholipids have a hydrophilic head which are exposed to water While hydrophobic tails are away from the water

Homeostasis is maintaining the internal environment/conditions within narrow limits Example of this is regulation of blood sugar levels, blood ph Involves negative feedback When there is variation in a certain factor correction mechanisms are triggered Controlled by endocrine and nervous system Insulin secreted by beta cells in pancreas when blood sugar is above normal Insulin lowers blood sugar levels Glucose -> glycogen/fat Glucagon secreted by alpha cells in pancreas when blood sugar is lower than normal Glycogen -> glucose

Calcium ions enter presynaptic neuron This causes the release of acetylcholine from the pre synaptic membrane The neurotransmitter diffuses across the synaptic cleft to the postsynaptic membrane and attaches to a receptor Change in membrane permeability Sodium ions flow into postsynaptic neuron Initiation of an action potential Removal of the neurotransmitter by acetylcholinesterase

HCG secreted during first 8-10 weeks of pregnancy maintains the corpus luteum and prevents degradation Stimulates growth of placenta and uterine enlargement Inhibits menstruation After the corpus luteum is no longer required HCG levels drop Progesterone secreted by placenta throughout pregnancy Maintains the endometrium and thickens the cervix Inhibits production of oxytocin by pituitary gland End of pregnancy progesterone stops being produced as inhibited by oestrogen produced by fetus

atria collect blood (from veins); SA node sends impulses to muscle fibres initiating contraction; blood is pushed to ventricles by contraction of atrial systole; atrioventricular valves are open as atria contract; semilunar valves are closed so that ventricles fill with blood; ventricles contract Atrioventricular valves close preventing backflow blood is pushed out through the semilunar valves into pulmonary artery and aorta; when ventricles relax and semilunar valves close preventing backflow of blood;

used to test for pregnancy via the presence of hCG in urine hCG is a hormone produced by women during fetal development An animal is injected with an antigen and produces antigen-specific plasma cells The plasma cells are removed and fused with tumor cells capable of endless divisions The resulting hybridoma cell is capable of synthesising large quantities of monoclonal antibody

Cells will divide when they reach a certain size Both villi and alveoli are flattened Many alveoli and villi that increase surface area Both villi and alveoli 1 cell thick moist layer covering the (inner) surface of the alveol Therefore shorter distance for diffusion Network of blood capillaries in each villi and alveoli means effective/extensive blood supply bronchioles structures increase the surface area Villi increase the surface area of the intestine to allow digested food to be efficiently absorbed into the bloodstream