paper 1 biology

damage to pituitary gland

involved in regulating of hormones (can affect sleep schedule [melatonin] or menstrual cycle [oestrogen and progesterone])
can also affect the hormone production of other organs

damage to the hypothalamus

damage to thermoregulatory centre which affects sensitivity to cold

Damage to nervous system

role of hair erection during fight or flight

for the animal to appear larger/more aggressive

role of liver cell in fight or flight

release of glycogen from liver once adenyl cyclase binds to it

of [spine] and [spinal cord] , what do you use in the exam?

spinal cord

How many synapses do reflexes involve?

Reflexes typically involve one to two synapses, allowing for rapid response to stimuli.

biological drawings criteria

type of microscope used

6 marks

Aerobic respiration (A)

 (No oxygen so) no aerobic respiration occurs

 No , link reaction / Kreb’s cycle / ETC / oxidative phosphorylation

 No oxygen to act as the final , electron / hydrogen acceptor

Anaerobic respiration (An)

 (Plant has to) switch to anaerobic respiration / only anaerobic respiration can occur

 Only glycolysis occurs

 Alcoholic fermentation occurs

 NAD regenerated (for glycolysis)

 Pyruvate to ethanal to ethanol using enzyme e.g. pyruvate decarboxylase

 (Only) 2 ATP

Scientific consequences for the plant (C)

 ethanol is toxic

 (alcoholic fermentation) is irreversible

 Less ATP produced / only 2 ATP from glycolysis

 Less / no , active transport

 (root hair cells) cannot take up mineral ions (by active transport)

 so (plant) cannot make , proteins / amino acids / DNA / chlorophyll etc

 cannot generate water potential gradient (into roots) / water potential (in root hair cells) is too high

 water cannot be absorbed (so cells cannot remain turgid)

 less / no , photosynthesis

label U, W, and Z

U — matrix (fluid)

W — inner membrane

Z — inter membrane space

related to selection of seedlings (S)

S1 no method for , selecting / AW , (20) seedlings

S2 could lead to biased results

S3 idea of random selection

B1 degree of bending (of seedlings) not considered

B2 could lead to biased results

B3 measure angle of bend

related to replicates (R)

R1 experiment / trial , was not repeated

R2 cannot , calculate mean / identify anomalies / carry out statistical analysis 

R3 repeat (experiment at least) twice

related to size of dish (D)

D1 size of petri dish not , controlled / specified

D2 different sized dishes could affect , spacing of seeds / access to light

D3 specify , size / volume / diameter , of petri dish