Past Paper Corrections Flashcards
Enzymes at hot temperatures
The enzymes are denatured which changes the shape of their active site so the substrate can no longer fit.
Which two blood vessels connect to the kidney?
Renal artery & renal vein
Ureter definition
The tube that carries urine from the kidney to the bladder.
How do saprotrophs cause decomposition?
They digest organic matter by secreting extracellular enzymes onto it.
How are gills adapted for gas exchange?
Large surface area, lots of capillaries & blood supply, permeable & thin.
Investigation to show chlorophyll is needed for photosynthesis
Use variegated leaf & compare starch areas with areas with chlorophyll.
Focusing of distant objects
Ciliary muscles relax which causes the suspensory ligaments to tighten. The lens become thinner & light refracted less.
Genetic control of most phenotypic features
They are polygenic which means many genes are controlling one phenotype, with each having a small effect.
How do low carb & fat diets cause weight loss?
Carbohydrates & lipids are high energy molecules. Energy intake is less than energy use so stored fat is respired
Why does exercise reduce BMI?
Muscle contraction uses energy from respiration
How does increasing temperature increase crop yield? (Enzyme Question)
Increasing the temperature increases the rate of photosynthesis. It creates optimum temperature for enzymes so more starch is produced.
Mineral magnesium
Needed for chlorophyll, else causes yellowing between the leaf veins.
Mineral phosphate
Needed for DNA.
Mineral nitrate
Needed for amino acids, else stunted growth & yellowing of leaves.
Why is glucose concentration higher in hepatic portal vein than hepatic vein after meal?
Glucose is removed from the blood as insulin causes it to be converted to glycogen which lowers blood glucose in the hepatic vein.
Why is glucose concentration higher in hepatic vein than hepatic portal vein 5h after meal?
There is less food in the gut. No insulin is released, glycogen is converted to glucose which is released from liver.
Why do water lilies only have stomata on the upper surface?
Because the lower surface is in water. Stomata allow gas exchange & water loss by transpiration.
Role of lymphocytes
Produce antibodies which are specific to antigens & attach to antigens to destroy pathogens
What happens to bacteria after phagocyte ingestion?
They are destroyed as they are digested by enzymes.
Observation seen when seed has germinated
The testa splits and radicle & plumule is seen
Why do plants store carbohydrates as starch?
Starch is insoluble so it does not diffuse out of cells
Transgenic definition
Transfer of a gene from a different species
How does style help pollen tube grow?
Supplies glucose for respiration & amino acids to make protein
How does oesophagus move down food?
Peristalsis which are waves of muscular contractions
Why is the fermenter cleaned using steam?
To kill pathogens in order to prevent contamination.
Function of oestrogen during menstrual cycle
Thickens the uterus lining for implantation
How does placenta structure enable efficient exchange of substances?
Villi provide a large surface area for diffusion, and capillaries bring nutrients & maintain diffusion gradient.
Dominant allele definition
Only one copy of an allele is needed to affect the phenotype
