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Flashcards in Paper 2 Deck (33):

Exercise increases heart rate explain how receptors and the nervous system are involved

•Increased muscle respiration
•Higher conc of co2 in blood
•Chemoreceptors in artery detects this
•Nervous impulses to sympathetic nervous system in the medulla oblongnata
•Increased frequency of nervous impulses to SAN
•Higher frequency of waves of excitation released
•Higher heart rate


Suggest an advantage of AMPK during exercise

It allows fatty acids into mitochondria to be used as respiratory substrate


Why would releasing sterile males would reduce the chance of the spread of infection in humans

Sterile males will compete with fertile males for resources and females

Carrying capacity of ecosystem for population does not increase

Overall smaller breeding population

Fewer chances of disease transmission


Explain how scientists would use the mark release capture method to determine population size

Collect your sample

Mark them using labels or pens that would not cause any harm


Wait for a period of time

Collect a second sample

Calculate how many marked and unmarked species were caught and record data

Population size is worked using the following equation:

2nd sample previously marked/1st sample X 2nd sample


Explain why the treatment was not effective

Sterile males do not outcompete fertile males

Sterile population becomes insignificant

So sterilisation is not permanent


Explain why transgenic mosquitoes were released in week batches

Because the have a short lifespan

This would maintain population as they die out and the allele will become extinct as it will not be passed on


Explain difference between staining

Untrained mice have less myoglobin which is found in slow twitch muscle and contains stores of oxygen for aerobic respiration


Group b could last longer than group a explain why

Trained mice have a more slow twitch muscle so they are aerobically able to respire

Providing more atp than untrained mice as they mainly anaerobically respire so they have more atp for muscle contraction and therefore exercise longer. Which limits amount of Latic acid build up


What was the average diameter of each cell

Area/pi= R2

The square root of R2 = R

R x 2= Diameter

Diameter/15= mean

Mean from mm to um is x1000= 84.10


Suggest why water potential was the same

There was no water potential gradient that would draw water into Chloroplasts by osmosis

And potentially cause them to burst


Explain why tube 1 was set up

To show that there was no colour change without chloroplasts

To show chloroplasts were having the effect


Explain results in tube 3

As chloroplasts photosynthesise the produce NADP

DCPIP accepts the electrons to regenerate NADP

Causing it (NADP) to become reduced and changing colour


What does reverse transcriptase do

Catalyses condensation reactions to form phosphodiester bonds between nucleotides


Why did the PCR stop

All the free floating nucleotides has been used up to make new dna strands


What is meant by phenotype

Observable characteristics of an organism determined by genetic and environmental factors


What type of gene interaction is the diagram displaying



Work out offsprings genotypes phenotypes and phenotype ratio


Phenotypes: white:green:yellow

Ratio 2:1:1


Work out percentage that heterozygous Bb using hardy Weinberg



Why shouldn’t pancreas transplant be used for people with type 2 diabetes

Type 2 can be treated with regular exercise and diet

There’s no need to risk for surgery

Beta cells still produce insulin but insulin receptors are damaged so would be ineffective


Tick the box that incorrectly describes role of insulin

D~ activates glycogeneisis reactions


Describe how transcription factors turn adult skin in iPS

Negative transcription factors are used to stop expression of specialised genes

Positive transcription factors are used to activate expression of genes


Evaluate use of IPS cells in humans

Transplant was successful in mice as after first week there was similar blood glucose levels to non diabetic. But mice showed more fluctuations than non diabetic group

Although done on mice there could be possible unknown side affects in humans or treatment may not be effective in humans

As transplant cells maybe rejected by immune system

More trials are needed and a larger sample size to see trend as glucose levels were going up gradually after transplant in diabetic mice


What is a gene pool

All genes in a population


Explain how 2 species of palm trees came about due to sympatric seletion where their flowering times are different

•No gene flow between populations
•Mutation occurs
•increases chance of survival to reproduce
•offspring with beneficial allele produced will reproduce
•allele frequency increases
•mutation occurred in both populations
•populations diverge to the point of being different species as allele frequency changes. So can no longer produce fertile offspring


People develop AD every 30 seconds by what % did the amount of people increase

(1x2x60x24x365.5)/5400000 x 100



Why does inhibition of acetylcholinerase improve nerve communication in AD sufferers

Acetylcholine is not broken down

Allowing it to repeatedly stimulate action potentials

Which makes up for lack of ach the person had


Why was the gene not removed by natural selection

Carriers of allele reproduce before age 49

Gene would be passed on regardless of mutation

As there’s no selection pressure against it


Why was the mutation expressed at different ages

Variance in lifestyle or environment leads to variance in epigenetic gene expressions

Variance in genome of individuals may lead to vulnerability against disease in other ways

Clinical signs appear later or earlier


Why double the sample size and only 74/75 mutations were said to be under threat of developing the disease

Two alleles of each gene both susceptible to mutation


Why test the whole genome and not use probe test for the GAC mutation

GAC triplet will not be unique to mutated allele and probe for that triplet will bind all over the place


How fungi get their nutrients

Decompose dead matter

Satrophytes absorb nutrients

Fungi absorb the nutrients from them through the cell wall


What does DNA polymerase do

Join two strands of dna together


Why are primers used added to pcr

They determine dna fragment to be amplified