wrong Flashcards
(26 cards)
explain the advantages of lipid droplet and micelle formation
droplets increase surface areas (for lipase/enzyme action)
*so faster hydrolysis/digestion (of triglycerides/lipids)
*micelles carry fatty acids and glycerol/monoglycerides through membrane to intestinal epithelial cel
what is the function of the golgi apperatus
modifies processes tryglycerides, combines tryglcerides with proteins, packaged for release/ exocytosis
Sodium ions from salt (sodium chloride) are absorbed by cells lining the gut. Some of these cells have membranes with a carrier protein called NHE3.
NHE3 actively transports one sodium ion into the cell in exchange for one proton (hydrogen ion) out of the cell.
Use your knowledge of transport across cell membranes to suggest how NHE3 does this.
co-transport;
*uses (hydrolysis of) ATP;
*sodium ion and proton bind to the protein;
*protein changes shape (to move sodium ion and/or proton across the membrane)
How does insulin decrease blood glucose levels
- activation of enzymes to convert glucose to glycogen
- vesicles containing glucose carrier chanels fusing with the cell suface membrane so more glucose can be absorbed
- insulin binding with receptors on the cell surface membrane which changes the tertiary shape of the cell surface membrane to increase glucose absorbed into cells
What happens if blood glucose increases (what does the body do to bring it back to normal)
Beta cells in the isles of langahans secrete insulin
Liver cells become more permeable by becoming more permeable by encorporation of vesicles containing glucose carrier proteins, binding of insulin to receptors that changes the tertiary shape of glucose channel protein so more glucose can be absorbed and secreting an enzyme involved in the conversion of glucose to glycogen
so glucose is removed
Describe how ultrafiltration occurs in a glomerulus.
Ignore references to podocytes
1. High blood/hydrostatic pressure;
Ignore references to afferent and efferent arterioles
Ignore ‘increasing/higher blood pressure’ as does not
necessarily mean high
2. Two named small substances pass out eg water, glucose,
ions, urea;
Accept correct named ions
Accept mineral ions/minerals
Accept amino acids/small proteins
Ignore references to molecules not filtered
3. (Through small) gaps/pores/fenestrations in (capillary)
endothelium;
Accept epithelium for endothelium
4. (And) through (capillary) basement membrane;
Exercise causes an increase in heart rate. Describe the role of receptors and of the nervous system in this process.
- Chemoreceptors detect a fall in blood pH
- They send impulses to the medulla
- More impulses are sent to the SAN
- By the sympathetic nervous system
Describe gluconeogenesis (and why its useful during exercise)
Gluconeogenesis is the synthesis of glucose molecules from non-carbohydrate molecules
Glucagon triggers this by activating an enzyme in the liver that causes the conversion by enzymes of fatty acids and amino acids into glucose which are released into the bloodstream to increase glucose
More glucose in the blood means more glucose is transported into the mitochondria which provides ATP for aerobic respiration
How could you reduce transmission of a disease using sterile male mosquitos
The sterile males are not able to reproduce
They compete with the other fertile male mosquitos for courtship and food
What is the equation for capture recapture to find the size of a population?
Population= number in first population x number in second sample/ number marked in second sample
Explain why trained mice can carry out prolonged exercise longer than the control mice.
The trained mice can produce more ATP
Anaerobic respiration delayed as they can aerobically respire for longer
Less lactate built up
Describe why it is important to keep the chloroplast suspension the same water potential as the chloroplast
So osmosis does not occur]
So cells don’t shrink/burst
Explain why DCPIP decolourises the test tube containing chloroplast and light from blue to colourless
Reduction of DCPIP by electrons from light dependant reaction
Explain how chemicals which inhibit the decolourisation of DCPIP could slow the growth of weeds
less/ no ATP produced
less/no NADP produced
less GP converted to GP
Explain why an increase in shoot biomass can be taken as a measurement of net primary productivity
represents dry mass
NPP=GPP-R
application of very high concentrations of fertiliser to the soil causes plants to wilt. explain why.
2 marks
Reduces water potential of soil surrounding root
The water potential of the plant is higher in the root than the soil
so causes water to move out of the plant into the soil via osmosis
- arbuscular mycorrhiza fungi (AMF) are fungi which grow on and into the roots of plants. AMF can increase the uptake of organic ions such as phosphate.
(a) suggest one way in which an increase in the uptake of phosphate could increase plant growth.
1 mark
used to make DNA for plant growth
suggest how transcription factors can reprogramme cells to form iPS cells
Attach to promotor regions to stimulate/ inhibit transcription
to detect the amount of RNA in a tissue sample. Explain the role of reverse transcriptase
converts mRNA to cDNA
What is a gene pool
compete collection of allels within a population
why would multiple primers have to be produced to detect the prescence of different RNA viruses
as the base sequence of each virus differs so different complimentary primers are required
Describe sympatric speciation
Occurs in the same habitat
mutations cause different flowering times
isolated reproduction so change in allele frequencies
Disruptive natural selection
until the two populations can no longer breed to produce fertile offspring
Donepezil inhibits the action of acetylcholinesterase. Explain how donepezil could improve the communication between nerve cells
less acetyl choline is broken down
so more acetyl choline can diffuse across the synaptic cleft and bind to receptor on the post synaptic membrane
More Na+ can enter the post synaptic neurone to reach thresh hold for an action potential
Why can the age a disease can be inherited vary
epigenetics/ environment/ smoking/ diet/exercise
acetylation/ methylation of histones
