12. Respiration Flashcards
Name the full name of ATP and name the groups in it.
Adenosine triphosphate. Adenine, ribose and three phosphate
Write the hydrolysis equation for ATP
ATP + H2O ——> ADP + Pi
Define glycolysis
First part of cellular respiration in which (6-carbon) glucose is broken down anaerobically in the cytoplasm to two molecules of (3 carbon) pyruvate.
Why does the cell store energy as ATP
- ATP cannot pass out of the cell
- ATP is easily hydrolysised
- Stores and relases energy in small amounts
Name the molecules needed in glycolysis
- glucose
- 2 ATP
- 2 NAD (oxidised, hydrogen removed)
Name the molecules produced in glycolysis
- 2 Pyruvate
- 4 ATP
- 2 NADH (reduced, hydrogen added)
Name the stages of glycolysis
- Phosphorylation of glucose.
- Splitting of phosphorylated glucose
- Oxidation of triose phosphate
- The production of ATP
What happens in the phosphorylation of glucose
Glucose is phosphorylated by adding 2 phosphate molecules which come from the hydrolysis of two ATP molecules. This activates the glucose and lowers the activation energy for the enzyme controlled reactions that follow
What happens in the splitting of phosphorylated glucose
The molecule is split up into two 3 carbon sugars, triose phosphate
What happens in the oxidation of triose phosphate
One hydrogen is removed from each TP molecule and is transferred to a hydrogen- carrier molecule known as NAD to form reduced NAD.
What happens in the production of ATP (hydrolysis)
Both triose phosphate are converted into 3 carbon molecules: pyruvate. In this process 2 ATP molecules are produced for 2 ADP for each pyruvate molecule.
What must occur before the krebs cycle
- the two pyruvate molecules produced in glycolysis must be oxidised
- this is done in the link reaction
What occurs in the link reaction
- pyruvate molecules are oxidised to acetate,
- it loses a CO2 molecule and a hydrogen molecule which forms NADH
- it combines with a molecule called Coenzyme A to form acetylcoenzyme A.
Where do link reactions and krebs cycle take place
Inside the mitochondria (matrix)
What is the link reaction equation
pyruvate + NAD+ CoA——> acetylcoenzyme A + NADH + CO2
Name the order of the carbon molecules in the krebs cycle
4 ——> 6 ——> 5 ——> 4 ——>beginning
How many separate steps are there in the krebs cycle
4
Reactions in the krebs cycle
- 4 carbon molecule binds with acetylchoenzyme (ACoA has been fixed) to produce CoA and 6 carbon molecule. (4C + ACoA —> CoA + 6C)
- The 6 carbon molecule loses a CO2 (decarboxylation) and a hydrogen to form a 5 carbon molecule (oxidised) and NADH (reduced) . (6c+ NAD —> 5c +CO2 +NADH).
- The 5 carbon molecule loses a CO2 (decarboxylation) and hydrogen to form a 4 carbon molecule and 2 NADH and FAD. (5c+ 2NAD + FAD —> 4c +CO2 +2NADH +FADH+ ATP). A single ATP molecule is also produced by substrate level phosphitylation.
- 4C molecule can bind with ACoA to start the cycle again
For one glucose molecule how many cycles of krebs are there
Glucose = 2 pyruvate so 2 ACo A so goes round twice.
Where does glycolysis take place
Cytoplasm of all living cells
Glycolysis is the initial stage of which type of respiration
Both aerobic and anaerobic
How is glycolysis indirect evidence for evolution
Glycolysis is a universal feature of every living organism
Does glycolysis require any organelles or membranes to take place
- no
- the enzymes for the glycolytic pathway are found in the cytoplasm
Does glycolysis require oxygen
- no
- therefore it can take place even when oxygen is not present