5.7-repspspsiration Flashcards
what are some biological processes atp drives?
active transport endocytosis+exocytosis protein synthesis dna replication cell division movement eg flagella, cilia, undulipodia activation of chemicals
what are anabolic reactions?
building up
catabolic?
breaking down
what is the structure of atp?
adenine attached to ribose (adenosine) attached to three phosphates
what is adenosine?
adenine and ribose attached
what happens to atp in solution in cells?
relatively stable, can be easily moved around
why is atp convenient?
a small quantity of energy is released at each stage of hydrolysis-cells can obtain energy they need for process in small amounts that won’t cause damage or be wasteful
why is atp not wasteful?
release of heat helps keep living organisms warm
what are the 4 stages of respiration of glucose?
glycolysis
link reaction
krebs cycle
oxidative phosphorylation
what is glycolysis?
the first stage of respiration; a 10 stage metabolic pathway that converts glucose to pyruvate
what are the 3 main stages of glycolysis?
phosphorylation of glucose into hexose biphosphate
splitting each hexose biphosphate into 2 triose phosphates
oxidation of triose phosphate to pyruvate
what does nad stand for?
nicotinamide adenine dinucleotide
what is nad?
non-protein molecule that helps dehydrogenase enzymes carry out oxidation reactions- COENZYME
what does NAD do in glycolysis, the link reaction and the krebs cycle?
oxidises substrate molecules
what is NAD synthesised from?
nicotinamide
ribose
adenine
2 phosphoryl groups
what is nicotinamide also called?
vitamin B3
what can the nicotinamide ring on NAD do?
accept 2 Hs, becoming reduced NAD.
what does reduced NAD do?
carries the protons and electrons to the cristae of mitochondria + delivers them to be used in oxidative phosphorylation
what needs to happen to glucose before it can be split?
it’s stable so its molecules need to be activated
what are the stages of phosphorylation of glucose?
1) 1 molecule of atp is hydrolysed + the released phosphoryl group is added to glucose to make hexose monophosphate
2) another atp is hydrolysed and the phosphoryl group is added to make hexose biphosphate.
where do the phosphoryl groups attach to the glucose when it’s getting phosphorylated?
carbons 1 and 6
what happens when hexose biphosphate splits?
the energy from the hydrolysed atp molecules activates the hexose sugar and prevents it from being transported out the cell, each molecule is split into 2 3C molecules, triose phosphate.
what kind of process is the oxidation of triose phosphate to pyruvate?
anaerobic
what are the stages of the oxidation of triose phosphate to pyruvate?
1) dehydrogenase enzymes, helped by nad, remove hydrogens from triose phosphate.
2) 2 NADs accept Hs and become reduced
how many molecules of NAD are reduced for every molecule of glucose undergoing glycolysis?
2
how many molecules of atp are made for every 2 triose phosphates undergoing excitation?
4
what are the end products of glycolysis?
2 molecules of atp (4 were made but 2 were used to kick start the process)
2 molecules of reduced nad
2 molecules of pyruvate
which stages of respiration only take place under aerobic conditions?
link reaction
krebs cycle
oxidative phosphorylation
what happens to the pyruvate formed in glycolysis under aerobic conditions?
actively transported to mitochondria for link reaction
what happens to the pyruvate formed in glycolysis under anaerobic conditions?
converted in the cytoplasm to lactate or ethanol
what happens in the process of turning pyruvate to lactate or ethanol?
reduced NAD molecules are reoxidised so glycolysis can continue to run, generating 2 ATPs for every glucose molecule metabolised.
what happens in the ethanol fermentation pathway?
pyruvate–> ethanal +CO2 (pyruvate decarboxylase)
ethanal +rNAD –> ethanol +NAD (ethanol dehydrogenase)
what happens in the lactate fermentation pathway?
pyruvate + rNAD–> lactate + NAD (lactate dehydrogenase)
what happens to the lactate made in anaerobic conditions?
carried to the liver
when more o2 is available what happens to the lactate in the liver?
- converted to pyruvate which enters the link reaction
- recycled to glucose and glycogen
what would happen if lactate wasn’t removed from the muscle tissues?
pH would be lowered, inhibiting action of enzymes involved in glycolysis and muscle contraction
for each molecule of glucose, what’s the ATP yield of anaerobic compared to aerobic respiration ?
1/15
what are haemocytometers?
thick slide with bevelled edges and grooves in an H shape.
what is a respiratory substrate ?
an organic substance that can be oxidised by respiration, releasing energy to make ATP.
how are monosaccharides used in respiration?
can be changed by isomerase enzymes to glucose
what are triglycerides hydrolysed into?
glycerol and 3 fatty acids
how is glycerol used in respiration?
converted to triose phosphate and respired
how are fatty acids used in respiration?
converted to acetyl groups and enter krebs cycle
how do fatty acids become acetyl groups?
1) ATP–> AMP, allowing each fatty acid to combine with coA.
2) fatty acid-coA complex transported into mitochondrial matrix.
3) fatty acid-coA complex broken down into acetyl groups each attached to coA-beta oxidation. the beta oxidation generates rNAD and rFAD.
how does a keto acid enter respiration?
can become:
pyruvate
acetyl coA
an acid in the krebs cycle like oxaloacetate
what’s the order of energy values of carbohydrates, lipids, and proteins?
lipid
protein
carbohydrate
what are cristae?
inner highly folded mitochondrial membrane
what does the mitochondrial matrix contain?
mitochondrial ribosomes+dna
enzymes for link reaction + krebs cycle
what is the cofactor of an electron carrier protein?
haem group-contains iron ion
who uses the ethanol fermentation pathway?
fungi
plants
who uses the lactate fermentation pathway?
mammals
what is RQ?
Co2 produced/o2 consumed
what is the rq of glucose?
1
what is the rq of fatty acids?
0.7
what is the rq of amino acids?
0.8-0.9
what are 5 reasons the theoretical yield of atp is smaller than the actual yield? (long)
1) some ATP used to (actively) transport pyruvate
(into the mitochondrion) ;
2) some ATP used to (actively) transport
H(+) from (reduced) NAD formed in glycolysis / into the mitochondrion ;
3) some energy released in ETC is not used to transport H+/is released as heat ;
4) H+ leaking back through inner membrane;
5) not all the, reduced NAD / red NAD / NADH ,
is used to feed into the ETC-rNAD used for other things.
why is the lactate fermentation pathway reversible?
no atoms lost / other product formed ;
lactate dehydrogenase available to reverse the reaction.
why is the ethanol fermentation pathway reversible?
carbon dioxide is lost
(de)carboxylase enzyme cannot
reverse the reaction.
