respiration Flashcards
whats the need for energy in living organisms
=for active transport / against concentration gradient
=movement requires energy :
- cellular movement e.g. transport protein; spindles
- move tissues, organs e.g mechanical contraction of muscles
=anabolic reactions : using small molecules to form large molecules
how is ATP suited for the role as the universal energy currency
= hydrolysis of ATP is quick and easy (for energy demand)
= hydrolysis can produce a prefect quantity of energy for the cell (enough to fuel metabolic reactions while minimising excess energy wasted)
= relatively stable at cellular pH levels
how is ATP synthesised
ATP synthesis is condensation as ATP hydrolyses to form ADP and Pi
ATP = when a phosphate group is added to ADP
describe glycolysis
splitting of glucose
glucose –> FP –> FBP –> 2 TP —————–> 2 pyruvate
ATP. ATP. 2ATP 2ATP 2Red NAD
takes place in cytoplasm
describe link reaction
links glycolysis to the Krebs cycle pyruvate enters mitochrondrial matrix PCN -> ACN pyruvate + CoA + NAD --> A CoA + CO2 + Red NAD CO2 from pyruvate is decarboxylation H from pyruvate is dehydrogenation
describe Krebs cycle
-A CoA + oxaloacetate = citrate
-citrate goes to 6C
-6C to 5C forms Red NAD and CO2
-5C to 4C forms Red NAD and CO2
-4C to 4C forms ATP
-4C to 4C forms Red FAD
4C to 4C
-back to oxaloacetate forming Red NAD
goes through twice
describe oxidative phosphorylation
takes place at the inner mitochondrial membrane
Red NAD and Red FAD donate their hydrogen atoms and get oxidised
Hydrogen atoms are split into H+ and e-
the e- move through the electron transport chain which creates energy for active transport
the H+ is actively pumped out against their concentration gradient from matrix to inter-membrane space.
The high concentration of H+ outside the matrix causes them to diffuse back through facilitated diffusion
They pass by ATP synthase
the movement of H+ down a concentration gradient creates energy for ATP synthesis
(chemiosmosis)
The ETC are a series of membrane proteins called electron carriers which allows electrons to pass from carrier to carrier.
The Oxygen recieves the electrons as the ETP ends and form H2O
O2 + 4e- + 4H+ –> 2H2O
roles of NAD
hydrogen carrier in respiration
roles of FAD
hydrogen carrier in respiration
the relationship between structure and function of mitochrondria
- densely packed cristae = large SA
- smooth outer membrane = permeable to small molecules, movement of reactants/products for respiration e.g. CO2, ADP, Pi, ATP
- inner membrane = less permeable, ETC
- intermembrane space has low pH = lots of H+ to create concentration gradient back into matrix for ATP
- matrix = site of link and Krebs. contains enyzmes for these reactions and small ribosomes and DNA
They have a large surface area due to the presence of cristae (inner folds) which enables the membrane to hold many electron transport chain proteins and ATP synthase enzymes. More active cell types can have larger mitochondria with longer and more tightly packed cristae to enable the synthesis of more ATP because they have a larger surface area
describe lactic acid fermentation
glucose to pyruvate makes ATP
removes 2H to make Red NAD
pyruvate reduces to lactate by enzyme lactate dehydrogenase and it accepts the 2H to oxidise Red NAD.
Lactate can be metabolised
describe ethanol fermentation
glucose to pyruvate makes ATP
Removes 2H to make Red NAD
pyruvate decarboxylates (produces CO2) to ethanal
ethanal is hydrogenated to ethanol
Red NAD is oxidised to NAD which can be reduced again.
ethanol is waste and can’t be further metabolised
anaerobic respiration
No oxygen means there is nothing to accept the electrons at the the of ETC so the ETC stops functioning. No ATP made from step 4. When Red NAD/FAD aren’t oxidised, there aren’t any available in the Krebs cycle. Krebs cycle stops.
how can rice live in water
usually leaves submerged can mean no photosynthesis and aerobic respiration
they grow fast above so top parts of plant are above water and can have gas exchange through stomate of leaves.
they have aerenchyma in stems/roots to allow gases to diffuse to bottom parts of plant; some aerobic respiration
however, it mainly relies on anaerobic ethanol respiration.
ethanol is toxic and builds in tissues but the cells in rice roots can tolerate it more because they produce more ethanol dehydrogenase.
Respiratory values for each and RQ VALUES
Lipid: 39.4 / 0.7
Carb: 15.8 / 1.0
Protein: 17.0 / 0.9
RQ = CO2/O2
