Lecture 7: Harvesting Chemical Energy Flashcards
Mitochondria
ATP factory
ATP
ATP powers cellular work - it is our energy curreny
ATP (The hydrolosis)
The hydrolosis of ATP to ADP and inorganic phosphate releases energy
Many cellular
Many cellular processes require energy in the form of ATP
They are not spontaneous
ATP cycle
transfer of energy between complex & simple molecules in the body, with ATP as the mediator
Fuel is needed to
generate ATP
3 major components of fuel
Carbohydrate: broken down to simple sugars
Proteins: broken down to amino acids
Fats: broken down to simple facts
which are then absorbed
Cellular respiration
The fate of glucose (diagram)
Cellular respiration
the controlled release of energy from organic compounds to produce ATP
Conversion of ATP is up to 4 steps
Glycosis
pyruvate oxidation
citric acid cycle (or krebs cycle)
oxidative phosphorylation
where does cellular respiration occur (diagram)
Glycolysis - step 1
invests and produces ATP - but not much
Occurs in the cutosol and Oxygen is not required
Glycosis steps
2 ATP are invested
4 ATP are produced
2 ATP and 2NADH are produced (net)
NADH
is an e- carrier later in the e- transport chain
The lysis of glucose to produce
2 pyruvate molecules
Pyruvate oxidation to form acetyl CoA - step 2
This step links glycosis to the citric acid cyle
functions of step 2
no ATP, but produces 1 NADH per pyruvate (or 2 per glucose) plus CO2.
step 2 - the 2
The 2 carbon acetyl CoA mlecule is able to enter the citric acid cycle
step 2 - occurs
occurs in the mitochondrial matrix and oxygen IS required
Step 3 - citric acid cycle (occurs)
occurs in the miochondiral matrix
Step 3 - citric acid cycle (results in)
2 ATP
6 NADH
requires oxygen - aerobic process
Step 3 - citric acid cycle (results in)
2 FADH2
4CO2
(per glucose molecule)
Step 3 - citric acid cycle (FADH2 & NADH)
FADH2 & NADH are e- donors in the e- transport chain
Citric acid cycles intermediates
Citric acid cycles intermediates are used in other metabolic pathways
Citric acid cycles (a series)
a series of reactions: product of one reaction is the substrate for the next
Citric acid cycles (the citric acid)
the citric acid cycle completes the extraction of energy from glucose
Substrate phosphorylation (ATP generated)
ATP generated by direct transfer (from a substrate) of a phosphate group to ADP
Substrate phosphorylation (glycolysis)
glycolysis and citric acid cycle make ATP via substrate phosphorylation
oxidative phosphorylation
ATP is generated from the oxidation of NADH and FADH2 and the subsequent transfer of e- and pumping protons
Step 4: the e- transport chain
occurs at proteins within the inner membrane
Require oxygen - it is an aerobic process
Step 4 - NADH & FADH2
NADH & FADH2 are oxidized to donate e-
Step 4: e- transfer
e- transfer from protein-to-protein along the chain in a series of redox reactions
Step 4: at each transfer
at each transfer, each e- gives up a small amount of energy which enables H+ ions to be pumped into the intermembrane space
Step 4: oxygen
Oxygen pulls the e- down the chain, and is then the final e- acceptor where it is reduced to water
Step 4: NADH and FADH2 from
NADH and FADH2 from glycosis and the citric acid cycle are used
Step 4: chemiosmosis (the Hydrogen ions)
the Hydrogen ions in the intermembrane space rush down their concentration gradient (chemiosmosis) through ATP synthase.
Step 4: chemiosmosis (This causes)
This causes the “turbine” within ATP synthase to turn
Step 4: chemiosmosis (The rotation)
The rotation of the ATP synthase turbine enables the phosphorylation of ADP to generate ATP
Step 4: chemiosmosis (This results)
This results in the production of 26 or 28 ATP (per glucose)
Step 4: ETC and chemiosmosis = oxidative phosphorylation (the bulk)
the bulk of ATP production is here
Step 4: ETC and chemiosmosis = oxidative phosphorylation
This is much more efficient than substrate phosphorylation
Oxygen is required
Step 4: ETC and chemiosmosis = oxidative phosphorylation (oxygen is)
Oxygen is the final e- acceptor - cyanide blocks passage of e- to O2 = death of cell
Step 4: ETC and chemiosmosis = oxidative phosphorylation
“fall” of electrons down the chain enables
movement of H+ ions into intermembrane
space and generates a proton gradient
which “drives” the ATP synthase turbine
WATCH BioFlix cellular respiration video - EXAMINABLE
~10 million ATPs produced per second in one cell via cellular respiration
Cellular respiration
is versatile
Cellular respiration (we can drive)
we can drive energy from more than just glucose
Cellular respiration (fats, proteins)
fats, proteins and more complex carbohydrates generate ATP also
Cellular respiration (Monomer)
Monomer enter glycosis and the citric acud cycle at different points
Phosphofructokinase
is the “gate keeper” for glycolysis; it catalyses step 3 - where glycolysis becomes irreversible
Phosphofructokinase (inhibited)
inhibited by citrate and ATP
ie. product of cellular respiration
Phosphofructokinase (stimulated)
by AMP
AMP accumalates when ATP is being used rapidly
Homeostasis
Insulin (produced)
Produced by beta cells of islets of langerhands in pancreas
Insulin (promoted)
function: promoted glucose uptake into cells (for ATP production/storage in liver)
Glucagon (produced)
produced by alpha cells of islets of langerhans in pancreas
Glucagon (function)
function: stimulates the breakdown of glycogen to increase blood sugar levels
islets
endocrine, prod hormones
What happens if you lose the function of insulin
No glucose in cells
No ATP from glucose
No glycogen stored for harder times
diabetes mellitus: (the ability)
the ability to produce or respond to the hormone insulin is impaired
diabetes mellitus: (results)
results in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood
Type 1/insulin-dependent diabetes: (body does not)
Body does not produce insulin, as beta cells of pancreas are destroyed, often this is autoimmune, or genetic or through environmental factors
Type 1/insulin-dependent diabetes: (affects, requires)
Affects 5 – 10 % of diabetics, and onset usually occurs in children or adolescents.
Requires insulin replacement
Type 2 or non-insulin-dependent diabetes: (body, most)
Body produces insulin, but receptors are non functional (insulin resistance)
Most (>90%) diabetics are Type II, usually adults over the age of 40
Type 2 or non-insulin-dependent diabetes: (can)
Can be linked to other pathologies and obesity
contradictory symptoms
Diabetes mellitus is caused by a lack of functional insulin.
contradictory symptoms (as a result)
As a result, levels of glucose in the blood build up, well beyond normal
homeostatic limits.
contradictory symptoms (increased)
Increased blood glucose alters the volume and osmolarity of blood, with subsequent pathological consequences.
contradictory symptoms (these 2 symptoms)
these 2 symptoms seem to be in opposition to each other: if the patient is constantly hungry and eating, why would they then lose weight?
contradictory symptoms (2 symptoms are)
significant weight loss
significant increased hunger
