paper 1 Flashcards
(33 cards)
what is the type of tissue in plants that contains stem cells
meristems
what plant does aspirin originate from
willow
why does chlorosis occur
because of a deficiency in magnesium ions
where in the heart is the pacemaker found
in the right atrium
why do bacterial cells cause the cells to burst
water enters the cell by osmosis so no cell wall can withstand the pressure of the water
two affects of aneorobic respiration on the body
muscle fatigue or oxygen debt occurs caused by a build up of lactic acid
weaker muscle contractions because less energy is released
how could anabolic steroids improve an athletes performance
the athlete is faster/stronger because they have more muscle mass so stronger muscle contractions
how do scientists make monoclonal antibodies with a hybridoma
the cell is cloned many identical cells are produced all the cells make the same antibody the antibody is collected and purified
why does bursting of red blood cells cause tiredness
less oxygen carried in blood so less energy released from respiration
differences between sexual and asexual reproduction
sexual- involves gametes joining, ,mixing of genetic information, involves only meiosis
asexual- no fusion of gametes, no mixing of genetic information, involves mitosis
function of mitochondria
site of aerobic respiration
test for protein
biuret reagent
why is a thin layer of onion epidermis used in the microscope practical
to help see the individual cells
how does mimicry help hornet moths to survive
predators are tricked by the colouring so they think it’s a hornet and avoid it
describe how mitosis produces two genetically identical cells
chromosomes are doubled and the replicated chromosomes are pulled apart to each end of the cell the cytoplasm divides to form two the set of each chromosomes are identical to each other
differences between transpiration and translocation
transpiration involves xylem and translocation involves phloem transpiration stream is made up of dead cells whilst translocation are living cells
describe how the alveoli and the villi are adapted to increase absorption
both have a large surface area to maximise diffusion both have one cell thick walls to reduce diffusion distance both have a good blood supply to maintain concentration gradient villi have microvilli to increase the surface area cells of villi contain many mitochondria for active transport
explain how the immune system of animals respond to a vaccination and prevents an outbreak of food poisoning in humans
the white blood cells / lymphocytes produce antibodies against Salmonella antigen antibodies are complementary to Salmonella
specific antibodies bind to antigens
if infected specific antibodies are produced quickly or in large
numbers
so white blood cells or antibodies would kill live Salmonella so fewer salmonella in animals
so number of bacteria never reaches a high enough level for
infection to develop so fewer toxins produced in humans
explain how the human lungs are adapted for efficient exchange of gases by diffusion
many alveoli
provide a large surface area
capillaries are thin
which provides short diffusion path (for oxygen / carbon
dioxide)
breathing mechanism moves air in and out
to maintain a concentration / diffusion gradient
good blood supply
to bring carbon dioxide to the lungs quickly
describe the effects of liver failure on the human body
no bile made
fats / lipids are not emulsified
lactic acid not broken down / oxidised
lactic acid is toxic
proteins / amino acids will not be broken down
amino acids not made into urea
liver does not break down
toxins accumulate in blood
glycogen stores will not be formed
cannot control blood glucose
describe how clinical trials should be carried out
given first to healthy volunteers
to test it is safe or to test for toxicity or to check for
any side effects
then to some patients (with the disease) or people with the
disease
to check for any side effects
(control variables)
explain how the human lungs are adapted for efficient exchange of gases by diffusion
many alveoli provide a larger surface area to volume ratio
capillaries are thin or one cell thick which provides short diffusion path for oxygen/ carbon dioxide
breathing mechanism moves air in and out to bring in fresh oxygen to remove carbon dioxide to maintain a concentration gradient
large capillary network around the alveoli to remove oxygenated blood quickly to bring carbon dioxide to lungs quickly to maintain a concentration gradient
what is active transport
the movement of substances move across a biological membrane across a concentration gradient from a region of lower concentration to a region of higher concentration against the concentration gradient
explain the lock and key theory of enzyme action
enzymes bind to the substrate because they are complimentary so substrate is broken down into products so products are released and enzyme is not changed
