paper 1 Flashcards
describe how energy for photosynthesis reaction is gained by plants
light is absorbed by the green pigment in leaves called chlorphyll
describe how movement of potassium oons into guard cells causes the stomata to open
- potassium ions increase the concentration of the solution
- water moves in by osmosis
- the cell swells uneavenly
- because the inner walls are less flexible than the outer walls
causes of anomolous results in pondweed experiment
- temparature changed
- there were different mass/length of pondweed
- there was air/oxygen in the syringe/measuring cylinder/apparatus
- pondweed had not acclimatised yet
why is percentage change used?
so that results can be compared
sources of error in potato osmosis experiment
- the concentration of the solutions
- the chips might not have been dried properly
- the accuracy of the balance
how does water move from roots to the leaves
- from the transpiration stream
- through the xylem (in the xylem)
why is having less stomata on the upper surface of the leaf an advantage? (2 marks)
- there is less water lost
- so it does not wilt
why is the surface of the potatos dried in osmosis experiment?
so that excess water does not contribute to the mass of the cubes
aseptic techniques for culturing microorganisms
- sterilise equipment
- use sterilised agar
- secure lid of petri dish with adhesive tape
- only lift lid of petri dish a little when setting up
ways the body prevnts entry of pathogens
- acid in stomach kills pathogens in food
- skin is a physical barrier and produces antimicrobial secretions
- hairs in nose trap pathogens
- trachea/bronchi has mucus which is sticky and traps pathogens
- bronchi have cilia which waft mucus to throat to be swallowed
how does less chlorphyll lead to stunted growth
- less photosynthesis as theres less chlorophyll
- this means less glucose made
- so less energy released for growth
- because glucose is needed for respiration
- and less amino acids/proteins/cellulose for growth
- as glucose is needed for making these
why is haveing less stomata an advantage to the plant?
- less water evaporates
- so the plant does not wilt
steps for drug testing
- preclinical trials of new drug on cells/tissue/live animals to test for toxicity, dosage and efficacy
- clinical trials to test on healthy volunteers at very low dosages
- to monitot safety and side effects
- then on volunteers with illness for trials to find the optimum dosage and test for for efficacy
- double blind trials and using a placebo which does not contain the new drug
- should be given randomly to patients so no one knows who has it
- then peer review of data to help prevent false claims
how is glucose moved from small intesitne to a muscle cell
- glucose absorbed by diffusion into bloodstream
- then blood delivers glucose to muscles in capillaries
how can cancer in stomach cause cancer in the liver
if the cancer is malignant then cancer cells can spread to other organs via the blood forming a secondary tumor
magnesium deficiency symptoms
yellowing of leaves / chlorosis
nitrate deficiency symptoms
stunted growth
how is the circulatory system adapted to supply oxygen to tissues and remove waste products from tissues
- dual/double circulatory system which means that it has a higher blood pressure and a greater flow of blood to the tissues
- heart is made of specialised cardiac muscle cells w long protein filaments that contracts for pumping blood
- heart pumps blood to lungs in pulmonary artery so oxygen can diffuse into blood from air in alveoli
- blood returns to heart via pulmonary vein where muscles pump blood to the body via aorta
- oxygen carried by specialised cells / RBCs which contain haemoglobin to bind oxygen and have no nucleus so there is more space available to carry oxygen
- arteries carry oxygenated blood to tissues where capillaries deliver oxygen to cells for respiration and energy release
- thin walls allow for easy diffusion to cells
- large surface area of capillaries to maximise exchange
- waste products removed eg CO2 diffuse from cells into the blood plasma
- blood goes back to the heart in veins which have valves to prevent backflow
- cardiac output can vary according to demand / is affected by adrenaline
uses of glucose in plants
- release energy for respiration
- active transport
- convert to amino acids/proteins
- convert to cellulose
- to make fats/oils for storage
- to store as starch
changes in body when you start to excercise
heart rate increases
- more blood flows to the lungs and alveoli
- means more oxygen enters blood and more carbon dioxide removed
- more glucose is supplied to muscles
- more lactic acid is removed
breathing rate increases
- means more oxygen is supplied to the lungs
- so more oxygen enters the blood from alveoli
- and more carbon dioxide is removed from the blood
more oxygen in the blood means
- more oxygen in muscles for more respiration so more energy released for muscle contraction
anaerobic respiration happens when there is a lack of oxygen
- this leads to build up of lactic acid
- causing an oxygen debt and muscle fatige
why can excersise not be sustained when anaerobic respiration happens
not enough energy supplied so the muscles become fatigued and stop contracting
speciality of nerve cell
- long
- has branches
- has insulation
describe the lock and key theory in terms of enzymes and substrate
enzyme binds to the substrate because they are complementary (shapes)
(so) substrate is broken down (into products)
(so) products are released or enzyme is not changed
