Respiration- Topic 5 Flashcards
(48 cards)
What is respiration?
The process by which an organism extracts the energy stored in organic molecules and uses it to generate adenosine triphosphate
What is the equation for aerobic respiration?
C6H12O6 + 6O2—
What happens during aerobic respiration?
The respiratory substrate glucose is split in the presence of oxygen to release carbon dioxide and water. Lots of ATP is produced.
What is the equation for anaerobic respiration: ethanol?
C6H12O6—>2C2H5OH + 2CO2 (+2ATP)
What is the equation for anaerobic respiration: lactate?
C6H12O6—> 2C3H6O3 + (2ATP)
What happens during anaerobic respiration?
Glucose is converted in the absence of oxygen to either lactate or ethanol.The ATP yield is low
Functions of a Mitochondria: they contain a highly folded inner membrane that holds respiratory enzymes
Which gives a large surface area for respiration
Functions of a Mitochondria: they have a double membrane that separates it from the cytoplasm
Which provides an isolated environment with optimum conditions for respiration
Functions of a Mitochondria: they have their own DNA and ribosomes
Which means they can manufacture their own enzymes
Why convert glucose into ATP?
- ATP releases its energy instantly in a single reaction.
- The hydrolysis of ATP releases a small amount of energy which is ideal for fuelling reactions in the body.
- Glucose adds osmotic potential which means water moves into the cell which will swell and burst.
Explain the two types of phosphorylation that occur during Respiration
- Substrate level: glycolysis and Krebs cycle. A single reaction involving the direct transfer of a phosphate group from a donor molecule to ADP.
- Oxidative: electron transport chain. A series of oxidation reactions that produce sufficient energy to form ATP
What are the 3 major coenzymes involved?
NAD- Nicotinamide adenine dinucleotide
CoA- coenzyme A
FAD- flavine adenine dinucleotide
Role of NAD
Can accept a hydrogen molecule forming reduced NAD (NADH)
NAD+ + 2H—
Role of coenzyme A
Aids the transition between glycolysis and the Krebs cycle by converting pyruvic acid to acetyl coenzyme A
Role of FAD
Can accept hydrogen to form reduced FAD
Why is it crucial that the bonds between coenzyme and product break after a reaction?
So that coenzyme concentration will not drop which would limit respiratory rate
Where does glycolysis take place?
Cytoplasm
Where does the link reaction take place?
Matrix
Where does the Krebs cycle take place?
Matrix
Where does the electron transport chain take place?
Cristae
The process of Glycolysis
- ATP is used to phosphorylate 2 Pi onto 6-carbon glucose.
- Cleavage of phosphorylated glucose= 2X triose phosphate
- Each triose phosphate molecule is converted into GP. This step is oxidation where 2 hydrogen atoms from each triose phosphate is removed and accepted by NAD. This produces ATP.
- GP is now converted into pyruvic acid. This step releases sufficient energy to form a molecule of ATP for each reaction.
The process of the link reaction
- The Pyruvic acid molecules diffuse into the matrix.
- Each 3 carbon pyruvic acid molecule is converted into a 2 carbon compound called acetyl CoA (done by CoA) through oxidation (removal of 2 hydrogen’s which are accepted by NAD)
- CO2 is removed from pyruvic acid to reduce the number of carbon atoms to 2. CoA is recycled
- This two carbon compound enters the Krebs cycle
The process of the Krebs cycle
- The 2 carbon compound joins the 4 carbon compound to make 6C Citric acid.
- Decarboxylation and oxidation = reduced NAD and 5C
- Decarboxylation and oxidation = reduces NAD and 4C. A molecule of ATP is generated.
- Oxidation= reduced FAD and 4C
- Oxidation= reduced NAD and 4C
- At the beginning again.
Which processes are happening twice for every glucose molecule?
Link reaction and Krebs cycle
