C1.2 Cell Respiration Flashcards
What is ATP?
A nucleotide that has three phosphate groups a nitrogen base (adenine) and a ribose sugar.
Exergonic reaction
Reactions that release energy
(ATP–>ADP)
Endergonic reaction
Reactions that require energy
What cellular processes require ATP?
- Active transport
- Synthesis of macromolecules by anabolism
- Movement of a cell by its cilia or flagella
- movement of cellular components in cells
What does ADP stand for?
Adenosine Diphosphate
Is ADP–> ATP and endergonic or exergonic reaction
Endergonic (requires energy)
Is ATP hydrolysed to ADP endergonic or exergonic?
Exergonic (gives out energy)
Cell respiration
The process where carbon compounds are oxidised to release energy and this energy is used to produce ATP
What are the two main carbon compounds used during respiration?
Glucose and Fatty Acids
Respiration uses ___ and produces ___
Oxygen, Carbon dioxide
What is the interdependence between respiration and gas exchange?
Gas exchange is needed to provide cells with oxygen and get rid of excess (harmful) CO2. The consumption of O2 and production of CO2 creates the conc gradients needed to drive gass exchange.
Aerobic Respiration….
Requires Oxygen
Anaerobic Respiration….
Occurs in the absence of O2
Word equation: Aerobic (in plants and animals)
glucose + oxygen –> carbon dioxide + water
Word equation: Anaerobic (animals and some bacteria)
glucose –> pyruvate + 2ATP –> Lactate
Word equation: Anaerobic (yeast, other fungi)
glucose –> ethanol + carbon dioxide + 2ATP
Four stages of aerobic respiration
- Glycolysis
- Link Reaction
- Krebs Cycle
- Electron Transport system
Where does glycolysis occur?
Cytoplasm
Where does the link reaction occur?
The matrix of mitochondria
Where does the krebs cycle occur?
The matrix of mitochondria
Where does the electron transport system occur?
On the increased surface area of the folded cristae (in mitochondria)
What type of respiration are mitochondria required for?
Aerobic
What factors effect rate of cell respiration?
- Glucose available
- Oxygen available
- Enzyme efficiency
Respirometer
A device used to measure the rate of respiration of a living organism
How do respirometers measure rate of respiration?
By measuring the rate of oxygen consumption.
Oxidation
Loss of electrons
Reduction
Gain of electrons
What does NAD stand for?
Nicotinamide adenine dinucleotide
NAD
A coenzyme used by respiration enzymes to carry out oxidation and reduction
What happens when H is added to NAD?
It is reduced to NADH
What do reduced species have the ability to do?
Reduce other species
What happens when H is removed from NADH?
NADH is oxidised to NAD
What do NADH molecules carry?
Energy rich electrons
Steps of Glycolysis
- Phosphorylation
- Lysis
- Oxidation
- ATP formation
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Phosphorylated
A phosphate group is added
What does glycolysis produce?
2 ATP, 2 Pyruvate, 2 NADH (+ H+ ion)
Phosphorylation
1st step of glycolysis. A hexose sugar (6C) is phosphorylated by 2 ATP to become hexose bisphosphate - a less stable molecule.
Lysis
2nd Step of glycolysis. The hexose bisphosphate is split into two triose phosphates (3C)
Oxidation
3rd step of glycolysis. Hydrogen is removed from the triose phosphates via oxidation (NAD is reduced to NADH + H+)
ATP Formation
4th step of glycolysis. 4 ATP molecules are produced (2 from each 3C) as the triose phosphates are converted into pyruvate
What is produced overall in Glycosis
2 Pyruvate, 2 NADH + H+, 2ATP
Decarboxylation
Losing a carbon (usually as CO2)
What is the most important part of the krebs cycle
many hydrogens are produced by oxidation reactions
Reduced NAD
NADH
What is the role of NADH
To carry a pair of electrons to the start of the electron transport train
Electron transport chain
A group of proteins embedded in the inner membrane of the mitochondria that accept and pass on electrons
What happens when NADH ‘delivers’ its pair of electrons
It is oxidised back to NAD
Where is the electron transport system located?
The cristae of mitochondria
Chemiomiosis
ATP being produced as Hydrogen returns back down the concentration gradient
How many molecules of ATP are produced by the electron transport system?
34 molecules
What molecule is the final electron acceptor?
Oxygen
What happens in anaerobic respiration when there is no Oxygen to accept the electrons?
NADH cannot be oxidised to NAD so the link reaction and krebs cycle will stop, only glycolysis will continue making ATP yield small
In humans the reduction of pyruvate leads to the formation of….
Lactate
In glycosis____ is oxidised and ___ is reduced
Glucose, NAD
