bio general chaps 12,13,14,15 Flashcards
suggest why glucose is phosphorylated at the beginning of glycolysis
so it becomes and unstable
suggest one use of the reduced NAD that is produced in glycolysis
to provide hydrogen atoms
name the type of phosphorylation reaction by which ATP is made during glycolysis
substrate-linked reaction
pyruvate can enter the mitochondria by active transport
describe the main conditions needed for pyruvate to enter the mitochondrion by active transport (3)
- the inner mitochondrial membrane is impermeable to pyruvate
- a carrier protein is needed
- oxygen needs to be available
pyruvate is involved in the link reaction in the matrix of the mitochondrion
Describe the link reaction (3)
- decarboxylation and dehydrogenation of pyruvate
- reduced NAD is produced
- formation of Acetyl coA
name all the bonds that are likely to hold a molecule of rubisco in shape (4)
1.covalent
2.hydrogen
3.disulfide
4.ionic
suggest how rubisco activase can activate rubisco
it stops oxygen from getting to the bundle sheath cells
suggest why the rate of photorespiration increases at high light intensities in C3 plants (2)
it increases the rate of light-dependant stage , so an increase in oxygen is produced
explain why the rate of photosynthesis decreases as a result of photorespiration in C3 plants (2)
-less RuBP to combine with CO2, therefor less GP
state precisely where non-cyclic photophosphorylation occurs in the choloroplast 1
thylakoid membranes
outline the uses of triose phosphate in the mesophyll cells to the leaf (3)
it helps to produce RuBP to further make glucose and sucrose
where is PEP carboxylase located 1
in the mesophyll cells
where is rubisco located 2
C3 plants —–> mesophyll cells
C4 plants —–> bundle sheath cells
name the homeostatic mechanism by which blood glucose concentration is maintained 1
negative feedback
in humans, carbohydrates such as glucose are not the only respiratory substrates
name two non-carbohydrate respiratory substrates in humans 2
lipids and fatty acids
name the location of the receptors in a non-diabetic person that detect a change in blood glucose concentration
pancreas
suggest one advantage of using a biosensor and one advantage of using a dipstick to measure glucose concentration
biosensor- immediate readings
dipstick- easy to use/painless
describe the role played by insulin in the control of blood glucose concentration 5
- insulin binds to the receptors on the liver
- it increases the rate of diffusion of glucose in liver cells
- faster respiration of glucose
4.which activates glycogen synthase - blood glucose concentration decreases
name the structure that acts as a filtration barrier
basement membrane
with reference to the maintenance of the water potential of the blood, explain what is meant by negative feedback 2
- osmoreceptors in the hypothalamus detect a decrease in the water potential
- ADH is released in the blood by the pituary glands so more water is absorbed
suggest and explain why cold diuresis occurs 4
- blood pressure increases in the kindey
- so more ultrafiltration happens
3.therefor an increased volume of urine - ADH concentration in blood decreases
state one change in the internal environment of a mammal that leads to the release of ADH
decrease in water potential of the blood
name the part of the body that releases ADH into the blood
posterior pituitary gland
Describe the main stages of cell signalling involving ACTH 5
- ACTH binds to the receptors on the cell surface membrane of the adrenal gland cells
- G protein is activated
- cyclic AMP is the second messenger and it
5 binds to kinase enzyme
if the conc. of cortisol in the blood inreases above it’s set point, it will inhibit the production of ACTH by the anterior pituitary gland
name this type of mechanism
negative feedback
explain how a tumour develops 2
a tumour develops by uncontrolled mitosis and the abnormal mass of cells formed
state precisely the name and location of the cells where a change in the water potential of the blood would be detected
osmoreceptors in the hypothalamus
describe the homeostatic role of ADH when the water potential of the blood decreases 5
ADH is secreted into the blood by the posterior pituitary glands and then binds to the receptors on the cell surface membrane of collecting duct cells, water moves from collecting duct into the blood and the water potential of the blood rises
suggest how a tumour in the hypothalamus can lead to a person producing a large volume of dilute urine 3
the production of ADH stops
so less ADH is secreted into the blood by the posterior pituitary
so the water remains in the collecting duct
state the role of adipose tissue in thermoregulation
thermal insulation
the hypothalamus in the brain is the control centre for thermoregulation
outline how a change in temp of the external environment results in an impulse arriving at the hypothalamus 2
the thermoreceptors in the skin detect a change and the sensory neurone sends an impulse to the hypothalamus
describe the main conditions that are required for pyruvate to enter the mitochondrion by active transport 3
the inner mitochondrial membrane is impermeable to pyruvate so a carrier protein is needed and oxygen must be available
describe the role of aquaporins in osmoregulation 3
aquaporins are water channel proteins that allow water to be reabsorbed into the blood by increasing cell surface membrane permeability to water
describe the role of the brain in osmoregulation when the water potential of the blood increases above the set point 3
an increase in the water potential of the blood is detected by osmoreceptors in the hypothalamus so less ADH is produced
outline the role of the mitochondrial matrix in respiration 3
- its the site of kreb’s cycle and link reaction
-its the site of production of reduced NAD and FAD
-its where substrate linked phosphorylation happens
explain how a lack of oxygen affects oxidative phosphorylation 4
- the process stops because no electrons are accepted by oxygen
- no electrons move by the ETC
- no H+ ions are pumped into the intermembrane space
-chemiosmosis
describe the functions of the internal membranes of chloroplast in photosynthesis 7
- photoactivation
2.helps to move electrons along the ETC
3.site if photolysis
4.site of light dependant stage
5.gives large surface area
6.ATP synthase to make ATP
7.chemiosmosis
