chonky exam questions Flashcards
(12 cards)
LDR non cyclic photophosphorylation
MOD 5
- Photon strikes PSII, excites 2 electrons which leaves chlorophyll A and passes down electron carriers (associated with Fe)
- The electrons release energy that pumps H+ into the thylakoid space
- PSII has a —— that in light performs PHOTOLYSIS of water forming 2H+, 2e- and 1/2O2 . The 2e- reduce the oxidised chlorophyll is PSII that had originally lost electrons
- Light hits PSI and excites 2 electrons which leave the chlorophyll and pass down the electron carriers. They are accepted by NADP. The electrons from PSII replace those lost from PSI
- H+ flow down the proton gradient (chemiosmosis) through ATP synthase and this potential energy creates ATP
- The protons along with the 2e- from PSI join with NADP to form reduced NADP
LDR cyclic photophosphorylation
MOD 5
- Light hits PSI and excites 2 electrons which leave the chlorophyll and pass down electron carriers
- They then move back through the carriers and create ATP
NO PHOTOLYSIS AND NO REDUCED NADP
LIR calvin cycle
MOD 5
- occurs in stroma
- CO2 fixed by RuBP (rubisco adds CO2 to RuBP)
- makes unstable 6C molecule
- this breaks into 2 3C GP molecules (used to make fatty acids and amino acids)
- converted to TP (using ATP (energy) NADPH (provides H to make TP) from light dependant reaction)
- 5/6 TP converted to RuP
- phosphate from ATP given to make RuBP
- 1/6 TP used to make glucose fructose sucrose starch cellulose glycerol and amino acids
induced fit model
MOD 2
active site is not fully complementary to the shape of the substrate
active site has charged amino acids opposite to those of the substrate
substrate randomly collides with active site
enzyme changes shape
active site becomes complementary to the substrate
forms an enzyme-substrate complex
active site fits more closely around substrate
charges holds substrate in place
change in enzyme active site puts strain on substrate
destabilises bonds in substrate lowering activation energy
produces enzyme product complex
products formed are a different shape to substrate
no longer complementary to the active site and leave it
cardio cycle
MOD 3
DIASTOLE- heart muscles relax
SL valves close
low pressure in heart
atria pressure higher (contains blood from vena cava)
AV valves open (higher pressure in atria than ventricle)
ATRIAL SYSTOLE- atria muscles contract
higher pressure in atria then ventricle
AV open SL closed
blood forced into ventricles
VENTRICULAR SYSTOLE- atria muscles relax
ventricle muscles contract
higher pressure in ventricles than atria
AV close
higher pressure in ventricles than arteries
SL open
Initiation and coordination of the heart action
MOD 3
SAN initiates a wave of excitation over the atrial wall
atrial muscles contract
AVN transfers electrical impulse to the bundle of His
this conducts impulse to the purkyne fibres
these carry electrical impulse to muscles of ventricles which then contract from the apex upwards
CO2 + haemoglobin
MOD 3
CO2 diffues into erythrocyte
CO2 + H2O converted by carbonic anahydrase
Enzyme converted to carbonic acid
Carbonic acid dissociated into H+ and HCO3- ions
HCO3- diffuses into plasma
H+ binds with oxyhaemoglobin
Form haemoglobinic acid (to release more O2)
Low pO2 at lungs causes reverse of process
Cl- moves in to replace HCO3- (electrical neutrality)
Inhalation
MOD 3
Diaphragm and external intercostal muscles contract
Volume of thorax increase
Pressure of thorax decreases below atmospheric levels
Air moves into lungs
Describe how assimilates are loaded in and out of pholem
MOD 3
- active transport of H+ ions out of companion cells
- creates concentration gradient
- facilitated diffusion of H+ ions back into companion cells
- sucrose moves in with H+ ions by co transport using a co transport protein
- sucrose then diffuses through plasmodesmata from companion cells into sieve tube elements
- due to low water potential in phloem water from xylem moves in creating a high hydrostatic pressure which moves to an area of low hydrostatic pressure
- assimilates move into companion cell via diffusion
- water leaves phloem by osmosis from high water potential to low water potential
Transpiration stream
MOD 3
- water enters xylem by osmosis from higher water potential in soil to lower water potential in root cells
- this is caused by active transport of ions into root cells and xylem
- causes high hydrostatic pressure at the bottom of xylem
- transpiration of water from leaf mesophyll cells / diffusion of water vapour through stomata from high water vapour potential to low
- water under tension
cohesion H bonds between water molecules
adhesion H bonds between water molecules and xylem wall - casues water to mive up (mass flow) from high hydrostatic pressure to low hydrostatic pressure
Bony fish mouth open
MOD 3
floor of buccal cavity lowered
volume of buccal cavity increases
pressure of buccal cavity drops
water moves into buccal cavity causing operculum to shut
oppercular cavity expands lowering pressure
floor of buccal cavity moves up increasing pressure
water moves from buccal cavity over the gills
Bony fish mouth closed
MOD 3
