biology paper 1 - questions i get frequently wrong

what do amylase break down

what do amylase break down

break down starch into sugars. they do this in the pancrease and salivary glands

why isnt pancrease produced in the stomach

because the stomavch has a low ph which will dentaure the enzyme

what is the immune system defense for pathogens

pathogens have antigens

this triggers antibodies to be produced by lymphoctyes

this leads to the destructuon of pathogens

memory lympthocyes are also produced

this causes a secondary response in event of an infection from the same pathogen

what is a vaccination

dead or weak pathogen with surface antigens still present

how is a signal transmitted at a synapse

a synapse is a gap between two neurones. neurones transmit electrical impulses.

when an impulse reaches the end of the first neurone a chemical impulse called a neurotransmitter is released and is diffused across the synapse .

the neurotransmitter binds to receptors onto the next neurone which triggers and electrical impluse into the next neurone,

how do painkillers work

they prevent neurotransmitters from binding to receptors in the next neurone. this means the electrical impulse is not triggered and the signal is not recieved by the cns. this means the person does not feel pain

what do protease break down

they break down proteins into amino acids. its produced in the pancrease and small intensene

what do lipase break down

they break down lipids into fatty acids and glycerol produced in pancrease and small intensine

what is the test for starch

iodine solution. if starch is present then it will change from orange brown to blue black

what is the test for reducuing sugars

the benedict reagent. its a blue solution that you heat up in a water bath. the hgih the conc the higher the colour change. it changes to brick red

what is the test for lipids

the emulsion test. you shake the substance with ethanol and then pour it into water. if any lipids are present they will percipate and become a milkly emulsion

what is the test for proteins

birut test. add potassium hydroxide to make the solution alkaine. then add copper sulfate ( blue) and if no protein is in it it will stay blue. if it is in it. it will turn purple

describe the stages of medicine devolpemt

1- pre-clinical stage : the drug is tested in a lab on cells and animals. toxicity and efficacy is tested

2- clinical - tested on humans/ patients

3- double-blind trials - two groups one is given the placeboo effect.

how can insulin be geneticly engineered from bacteria cells

• Cut the insulin gene using a restriction enzyme that leaves sticky ends. Cut the plasmid DNA with the same restriction enzyme to leave complementary sticky ends. Join the gene and the plasmid using ligase. Insert the recombinant plasmid back into the bacteria.

how were aniamls classified before and what was the problem with it

• according to similar obserbale characteristics

  the problem was organism not closely linked may look alike if they are not in the same enviroment

• some closely related species may not look alike if they live in different habitiats e.g worker ants and queen ants

why has the classification system changed

due to biochemistry process

microscopes

and DNA AND RNA ANALYS

what are the 5 kindgoms

• animal

• plant

• fungi

• prokyratic

• protist

what is taxonomy

the classification of organism into taxa

• phylum

• kindgom

• genus

• species

• class

• order

• family

• domain

what are the 3 domains

archea - exomphiles

bacteria - true bacteria

eukrayan