photosynthesis and respiration

Question 1

LDR

Answer 1

-in photoionisation, light excites the electrons in chlorophyll II and move to the carrier proteins in the thylakoid membrane
-the electrons are replaced by the electrons produced in photolysis, which also produces oxygen and H+
-electrons move along carrier proteins in a series of redox reactions losing energy as they go
-the lost energy is used to pump H+ into the thylakoid space creating a chemiosmotic gradient
-H+ moves down the gradient through ATP synthase during photophosphorylation, producing ATP from ADP + Pi
-the electrons are donated to chlorophyll II and more are excited by light, travelling along another ETC until they reduce NADP to NADPH with a H+ from photolysis

Question 2

glycolysis

Answer 2

-glucose is phosphorylated with 2 ATP to form phosphorylated glucose and a by product of 2 ADP
-lysis occurs to phosphorylated glucose forming 2 triose phosphates which have 3 carbons each
-each triose phosphate is oxidised with NAD and ADP forming 2 x 3 carbon pyruvate, 2 ATP molecules and NADH
-occurs in the cytoplasm

Question 2

LIR

Answer 2

-CO2 is fixed, combining with RuBP using the enzyme rubisco
-this produces two glycerine-3-phosphate (GP)
-GP is reduced to triose phosphate (TP), using energy from ATP and reduced NADP
-TP can be regenerated to RuBP using energy from ATP
-1C from TP is converted to organic molecules such as glucose, amino acids and glycerol

Question 3

link reaction

Answer 3

-pyruvate is oxidised
-CO2 is released
-NAD is reduced
-acetyl coenzymeA is formed
-occurs in mitochondria matrix

Question 4

kreb’s cycle

Answer 4

-acetyl coenzymeA reacts with a 4 carbon acceptor to create a 6 carbon intermediate
-6 carbon intermediate is oxidised into a 5 carbon intermediate by releasing CO2, NAD is reduced into NADH
-5 carbon intermediate is oxidised into a 4 carbon intermediate releasing CO2
-a series of redox reactions occurs forming 2 x NADH, FADH and ATP (by phosphorylation), 5 carbon intermediate is oxidised into 4 carbon intermediate

Question 5

oxidative phosphorylation

Answer 5

-FADH and NADH are oxidised and lose an e- and H+
-the e- are passed from carrier protein to carrier protein in the mitochondria inner membrane in a series of redox reactions
-this releases energy
-the energy is used to pump H+ through the membrane into the inner membrane space building a chemiosmotic gradient
-H+ moves back through the membrane, through ATP synthase
-ADP + Pi -> ATP (phosphorylation)
-oxygen is the terminal electron acceptor
-this forms water

Question 6

anaerobic respiration in mammals

Answer 6

-pyruvate is reduced to lactate
-NADH is oxidised during this process
-this prevents NAD running out and allows ATP to continue being made in glycolysis

Question 7

anaerobic respiration in yeast

Answer 7

-pyruvate is reduced to ethanal
-it is then reduced to ethanol
-NADH is oxidised during this process
-CO2 is produced
-this prevents NAD running out and allows ATP to continue being made in glycolysis

Question 8

inhaling cyanide

Answer 8

-it inhibits the final dehydrogenase enzyme from working so ETC stops working
-this stops the Krebs cycle from working
-this stops the link reaction from working
-this stops glycolysis from working
-this kills you