F214 Flashcards
C6H12O6 + 6O2 –> 6CO2 + 6H20 is the equation for aerobic respiration - why is this an over simplification?
Because ATP is also made by oxidative phosphorylation
Enzymes such as Rubisco and coenzymes such as NAD are used
Glucose is not the only substrate
Explain how type 1 diabetes is caused
B cells in the islets of langerhans don’t function properly, stops producing or produces Ineffectively the insulin needed to turn glucose into glycogen for storage so there is a build up of glucose in the blood
Can be hereditary
Can be triggered by a virus or other environmental factor
Factors increasing a persons risk of developing type 2 diabetes
Increases with age Hereditary/ genetic More common in males More common in Afro/caribbeans Obesity/overweight/ fat around abdomen High/ frequent intake of sugar Lack of physical activity High blood pressure Excessive alcohol intake
Describe the fate of Pyruvate in anaerobic respiration in muscles cells
Pyruvate is converted into lactate
Pyruvate accepts hydrogen atoms from reduced NAD and is catalysed by lactate dehydrogenase there is no oxygen to act as final acceptor so link reaction/ krebs can’t take place
Limited amount of ATP is made
Suggest how a seal is adapted to respire for a long time under water
Haemoglobin has a higher affinity to oxygen - more oxygen in blood for respiration
Large nostrils to take in air
Keep nostrils closed under water to prevent air from escaping
Lungs have High vital capacity
Has low respiratory rate
Has lots of haemoglobin
Describe a Schwann cell
Schwann cell wraps around axon of neurone, produces myelin and causes electrical insulation which speeds up transmission of action potentials as only Saltatory conduction can occur at nodes of ranvier
Describe the relationship between myelinated axons and speed of conduction
Myelination produces greater speed of conduction, unmyelinated needs larger axon to produce same speed
Describe the relationship between axon diameter and speed of conduction
The wider the axon the quicker the speed of conduction
Suggest why the increase in temperature results in an increase of speed of conduction
Increased kinetic energy so ; ions diffuses into axon quicker, faster movement of vesicles containing neurotransmitters at synapses neurotransmitter is broken down more quickly
Outline the events following the arrival of an action potential at a synaptic cleft
Action potential arrives, causing polarity to increase which causes Na+ channels to open and for Na+ to diffuse into the cell. This increases positivity more and stimulates Ca2+ channels to open. The presence of Ca2+ causes vesicles containing the neurotransmitter acetylcholine to fuse to the membrane and release the neurotransmitter by exocytosis into the synaptic cleft. Acetylcholine diffuses across synapse ad fuses to complementary receptors on the post synoptic membrane which causes Na+ channels to open ECT. The enzyme acetylcholinesterase breaks acetylcholine down into choline and acetyl co A
Name the process by which fluid passes from the glomerulus into the renal tubule
Ultra- filtration
Name the tissues that line the proximal convoluted tubule
Cuboidal epithelium cells
Name the pigment at the reaction centre of photo system 1 and 2
Chlorophyll A
Name the three parts of an ATP molecule
Adenine, ribose, phosphate (x3)
Explain the role of ATP in the cell
Universal energy molecule
Phosphates can be released by hydrolysis, releasing 30kj of energy
Energy released for metabolic reactions ie glycolysis in respiration
Describe the way in which an endothermic animal, such as a mammal, normally prevents its body temperature from decreasing when the external temperature decreases
Thermoreceptors are stimulated and impulses are sent to the hypothalamus
Increased metabolic rate
Vasoconstriction - less blood running near surface of skin so less heat lost by conduction
Shivering to generate heat
Erector muscles contract to raise hairs which trap warm air
Release of adrenaline
Name the process which turns amino acids into ammonia
Deamination
A pregnancy testing kit contains a testing ‘stick’ to detect a hormone in the urine. Explain how the stick detects this pregnancy hormone.
1 (testing for) human chorionic gonadotrophin / hCG ;
2 hormone small so can pass from blood into filtrate
3 immobilised ,antibodies on stick ;
4 antibodies attached to , marker / dye ;
5 hormone , binds / complementary , to antibody ;
6 (triggers) appearance of colour / line becomes visible
Name the products of the light dependant reaction that are used in the Calvin cycle
ATP
Reduced NADP
Discuss the fate of triosephosphate in the Calvin cycle
Used to make other carbohydrates eg cellulose
Regenerates RuBP so that cycle can continue
Comparison of glycogen and glucagon
- type of compound
- role of compound
- site of production
Type of compound; - Glycogen; carbohydrate - glucagon; hormone Role of compound; - Glycogen; storage of glucose - Glucagon; breakdown of glycogen into glucose (glycogenolysis) Site of production; - Glycogen; liver - Glucagon; alpha cells in he islets of langerhans in the pancreas
Suggest why MS is described as an auto-immune condition
Attacked by the body’s own immune system
Immune system treats body cells as foreign
Compare anaerobic respiration in mammals and yeast
- hydrogen acceptor after glycolysis
- is co2 produced?
- name of final product
H acceptor after glycolysis; Animal - Pyruvate Yeast - ethanal Co2 produced? A - no Y - yes Final product; A - lactate Y - ethanol
Suggest one benefit of anaerobic respiration to a mammal
Allows glycolysis to continue and ATP to be released
A feature of synapses is that they allow transmission in only one direction. State how this is achieved
Only presynaptic neurone releases neurotransmitter (acetylcholine)
Only post synaptic membrane have receptors
State the products of oxidative phosphorylation.
ATP
OXNAD
H20
Explain the roles of coenzymes in the leaf cell
NADP/ FAD can accept hydrogen and carry electrons to the electron transport chain
Coenzyme a carries acetyl group to link reaction
Explain the likely effect on the blood cells if the water potential of the plasma was allowed to increase significantly
Water potential outside of cell will be higher so water will osmosis into the blood cells
Cells may burst
ADH does not stay in the blood indefinitely.
Suggest where ADH is removed from the blood and describe what then happens to the ADH
molecule.
In the liver, adh is hydrolysed and deaminated, goes through the orinthine cycle to create urea
In the kidney - not selectively reabsorbed so excreted in urine
Outline the hormonal and nervous mechanisms involved in the control of heart rate.
1 adrenalin(e) increases , heart rate / stroke volume / cardiac output ; 2 cardiovascular centre in medulla oblongata ; 3 idea of nervous connection to , SAN / sino-atrial node ; 4 (which) controls frequency of waves of , 5 vagus / parasympathetic , nerve decreases heart rate ; 6 accelerator / sympathetic , nerve increases heart rate ; 7 high blood pressure detected by , stretch receptors / baroreceptors ; 8 low blood pH / increased levels of blood CO2 , detected by chemoreceptors ;
Compare secretion and excretion
Similarities; require ATP, involved in homeostasis.
Differences; excretion - removal of waste from the body, potentially harmful/toxic waste.
Secretion- useful products which are used in cell communication
Role of the hepatic artery
Supplies the liver with oxygenated blood from the heart - oxygen needed for aerobic respiration
Role of hepatic portal vein
Carries oxygenated blood to the liver which is rich in the products of digestion - some of which are toxic compounds
Hepatic vein
This is where blood leaves the liver and rejoins the vena cava
Bile duct
Bile is secreted from the liver
Bike has digestive and excretory functions
Bile duct carries bile from the liver to the gall bladder where it is stored until needed for the digestion of fats in the small intestine
Inter-lobular vessels
Branches from the hepatic artery and hepatic vein enter
Sinusoid
A special chamber where blood from the hepatic artery and hepatic portal vein mix
Lined by liver cells so molecules can be removed from the blood and pass molecules into the blood
They empty into the interlobular vessels
Hepatocytes
Their metabolic functions
Liver cells
Very dense cytoplasm
Have a simple cuboidal shape with microvilli on the surface
They have many metabolic functions;
- protein synthesis
- transformation and storage of carbohydrates
- synthesis of cholesterol and bile salts
- detoxification
Kupffer cells
Specialist macrophages
Move about sinusoids to breakdown and recycle old blood cells
One of the products of this breakdown is bilirubin which is excreted in the bile and gives the brown pigment in faeces