Cells alive 2- mitochondria Flashcards
describe the structure of mitochondria
- oragnelles bound by a double membrane
- outer membrane
- inner membrane forms invaginations called cristae
- space between membranes is intermembrane space
- inside of mitochondrion is mitochondrial matrix
what are the functions of mitochondria
- generates most of the energy a cell requires
- Most nutrients delivered to cell are broken down in cytoplasm to simple constituents which are transported to the mitochondria
- Constituents are further oxidised producing CO2 and H2O which releases energy as ATP
- Mitochondria often located close to sites of high ATP utilisation
adenosine triphosphate (ATP) energy release is by hydrolysis of what bonds?
phosphoanhydride bonds
Which stages of aerobic respiration occur in the cell cystoplasm?
Glycolysis
Which stages of aerobic respiration occur in the mitochondria?
Link reaction
TCA/Krebs cycle
Oxidative phosphorylation
Describe the metabolism of fatty acids
B oxidation
can be in peroxisome also
2 C removed from hydrocarbon tail at a time
- used to produce acetyl-coA
how is glucose converted to pyruvate?
glycolysis
How and where is pyruvate converted into acetyl coA?
- Link reaction -in mitochondria
- Decarboxylated
*remove a C = CO2
Leaves acetate
*2 C molecule
Actetate combines with coenzyme A = acetyl- CoA
How are amino acids used in aerobic respiration?
- Deamination
*removal of amino group - Leaves a carbon skeleton
- can enter at different points depending on the amino acid it was
What does acetyl coA feed into?
TCA/Krebs/Citric acid cycle
what are the end products of acetyl- CoA oxidation ( Krebs) and how many
3 x NADH
1 x FADH2
what is produced as waste from acetyl-CoA oxidation (Krebs) and how many
2 x CO2
What are NADH and FADH2 needed for?
Carrying electrons to be used in the electron transport chain
What is oxygen’s role in aerobic respiration?
Final electron acceptor in oxidative phosphorylation, it is reduced to H2O
Describe the movement of electrons in the ETC
Move from areas of low affinity to high
3 protein complexes in the mitochondria inner membrane
Each has higher affinity for electron than the previous
Energy released from the movement of electrons in the ETC causes what?
H+ to be pumped from matrix to intermembranal space
Creates an electrochemical gradient across the inner membrane
How does ATP synthase generate ATP in oxidative phosphorylation?
Uses energy from H+ diffusing back into matrix
chemiosmosis - H flow down electrochemical gradient
H+ rotates transmembranous rotor domain stalk attached to ATP synthase
Enzymatic head held still by arm attached to membrane
Mechanical energy generated as stalk grinds against head
Mechanical converted to chemical
ADP + PI -> ATP
Theoretically how many ATP are made in aerobic respiration?
how many are actually produced?
36 -38
glycolysis 2
krebs 2
oxidative phosphorylation - 34
30-32
Some are used for active transport within the mitochondria
How many ATP made per:
NADH
FADH2
NADH - 3
FADH2 - 2
Describe transport in and out of the mitochondria’s outermembrane
- Has porins that are permeable to molecules less that 5kDa
- gases oxygen and carbon dioxide freely diffuse across the membranes down their concentration gradients- no energy or transporters needed
Describe transport in and out of the mitochondria’s innermembrane
- electrochemical gradient
- pyruvate and inorganic phosphate transport driven by H+ gradient, they are co-transported in the same direction- SYMPORTER
- ATP and ADP are co-transported in opposite directions using charge gradient- ANTIPORTER
Where are most mitochondrial proteins encoded and produced?
How do they get to the mitochondria?
Encoded - nucleus
Produced - cytosolic ribosomes
Transported by hsp70 chaperones across cytosol to nucleus
Importance of chaperones?
Keeps mitochondrial protein unfolded
N terminal signal peptides target them to mitochondria
When does transport of mitochondrial proteins occur?
After translation
