3.5.2 Respiration Flashcards
Role of mitochondria?
synthesis of ATP in oxidative phosphorylation.
structure of outer membrane in mito
smooth and permeable to small molecules
structure of inner membrane in mito
folded (cristae), less permeable to maintain proton gradient, site of electron transport chains and ATP synthase.
How does Structure relate to function of Mitochondria?
Large s.a. due to cristae: enables membrane to hold many ETC and ATP synthase enzymes.
Active cells can have more cristae or more mitochondria
What is ATP used for? transportation examples.
Active transport, through potassium sodium pumps.
exocytosis of waste hydrolysed bacterium, or acetylcholine in cholinergic synapses, or chylomicrons into lacteal ducts)
ATP uses. Anabolic reactions examples
Syntheses of DNA through nucleotides. (helicase uses ATP to break hydrogen bonds)
Synthesis of proteins through amino acids (add amino acids to tRNA)
also maintaining body temperature in mammals and birds
ATP uses movements examples
cellular movements of chromosomes via the spindle fibres
muscle contraction
What are the four stages in Aerobic respiration?
- Glycolysis (cytoplasm)
-LInk reaction (mito matrix)
-Krebs cycle (mito matrix)
-Oxidative Phosphorylation (cristae)
Describe glycolysis.
(hints: phosphorylation, split, oxidation, production)
1.Two ATP molecules are hydrolysed to phosphorylate glucose to glucose phosphate. This lowers activation energy for enzyme controlled reactions.
2. Glucose phosphate molecule is split into two molecules of triose phosphate.
3. Triose phosphate is oxidised (-1H+) and forms NADH from NAD. (one per triose phosphate)
4. Enzyme controlled reactions form pyruvate from triose phosphate and release 2 ATP (per triose phosphate)
Yield of one glucose molecule from glycolysis?
- 2 atp
- 2 pyruvate
- 2 NADH
Describe Link Reaction.
hints, oxidised. enzyme.
1.Pyruvate (3C) is actively transported to matrix of mitochondria.
2. Pyruvate is oxidised to acetate(2C) forming one molecule of NADH from NAD and releasing carbon dioxide.
3.Acetate combines with co-enzyme A to form acetylcoenzyme A. (2C)
Describe Krebs cycle
hints, NAD + FAD + 2C + 4C = 6C = 4C - 2CO2 + NADH + FADH
The 2C Acetylcoenzyme A combines with a 4C molecule to form a 6C molecule.
6C Molecule loses two molecules of carbon dioxide and becomes a 4C molecule, but produces one NADH from NAD, one FADH from FAD and one ATP molecule.
Products of link reaction and Krebs cycle per glucose molecule.
4NADH (one from link pyruvate to acetate, one from krebs 6C to 4C) *2
2 FADH ( 6C to 4C)
2 ATP (6C to 4C)
Why is the Krebs cycle significant?
Breaks down macromolecules ( pyruvate) into carbon dioxide and 4C molecule that would otherwise accumulate.
Produces NADH which carries hydrogen to ETCs.
Source of intermediate molecules used in other important substances like fatty acids, amino acids and chlorophyll.
Describe the Oxidative Phosphorylation.
NADH and FADH donate the electrons of the hydrogen atoms
the electrons move down an electron transport chain through a series pf oxidation-reduction reactions.
This releases energy which causes active transport of protons through inner membrane into inter membrane space.
protons accumulate in inter membrane space before diffusing back down the concentration gradient into mitochondria matrix through atp synthase channels embedded into the inner membrane.
at the end of the chain, electrons bind with protons and oxygen. (!H = electron + proton + neutron)
What would happen without oxygen as the final electron acceptor?
Electrons would back up the ETC and therefore respiration would halt.
In Anaerobic respiration, what produces lactate and NAD?
Animals
In Anaerobic respiration , what produces ethanol, CO2 and NAD?
microorganisms (yeast) and plants
Describe anaerobic respiration in yeast.
Pyruvate from glycolysis loses a molecule of carbon dioxide and accepts a molecule of hydrogen, forming NAD from NADH and ethanol. The NAD is then reduced in glycolysis of glucose to form 2 molecules of ATP.
Describe Anaerobic respiration in animals.
Pyruvate from glycolysis accepts 2 molecules of hydrogen, forming NAD from NADH and lactate. The NAD is then reduced in glycolysis of glucose to form 2 molecules of ATP.
