Block 2: Lecture 7 Cell respiration Flashcards
ATP cycle
ATP cycle: the transfer of energy between complex and simple molecules in the body, with ATP as the mediator
Catabolic reactions vs anabolic reactions
Catabolic reactions- transfer energy from complex molecules to ATP( break down the larger molecules)
Anabolic reactions-transfer energy from ATP to complex molecules.(building of larger molecules from smaller)
two pathways of glucose within the cell
cellular respiration–> cellular work
storage( glucose cross-linked together, called glycogen)
how is glucose stored
in the form of glycogen
What helps glucose get into the cell from the blood stream
insulin
Homeostasis
in general terms: the tendency towards a relatively stable equilibrium between interdependent elements
in context: the ways body regulates glucose levels to keep them in a safe range.
4 main steps of conversion of glucose to ATP
- Glycolysis(breakdown of sugar)- no oxygen required
- Puryvate oxidation(links 1 & 3 steps together) OXYGEN REQUIRED
- Citric acid cycle(Krebs cycle) OXYGEN REQUIRED
- Electron transport chain
where does glycolysis occur in the mitochondria?
cytosol( outside the mitochondria)
where do pyruvate oxidation and citric acid cycle occur in the mitochondria?
in the matrix
where does oxidative phosphorylation happen in the mitochondria?
across inner membrane
4 important proteins in the membrane( ATP synthase turbine, 1 peripheral, 3 integral)
in reality 100-1000nds of proteins like that
mitochondria structure
Outer membrane–> intermembrane space–> inner membrane–> matrix inside
What are the products of Glycolysis
FROM 1 GLUCOSE MOLECULE:
(Gross 4 ATP made
2 ATP used)
Net ATP= 4-2=2 ATP
2 ATP produced
2 NADH(electron carrier) produced
2 pyruvate molecules produced
( through lysis of glucose molecule, i.e 6 carbon molecule splits into 2 3-carbon molecules)
Products of pyruvate oxidation
Per 1 pyruvate molecule( 2 pyruvate molecules from 1 glucose molecule):
1 NADH per pyruvate ( 2 NADH per glucose)
1 CO2 per pyruvate ( 2 CO2 per glucose)
1 ACETYL CoA per pyruvate( 2 per glucose)
the function of pyruvate oxidation
acetyl CoA enables the 2-carbon molecule to enter the citric acid cycle
3-carbon pyruvate cannot enter the citric acid cycle
Products of citric acid cycle
For each acetyl CoA:
1 ATP( 2 ATP PER GLUCOSE) 3 NADH( 6 NADH PER GLUCOSE) 1 FADH2( 2 FADH2 PER GLUCOSE) 2 CO2( 4 CO2 PER GLUCOSE)
FADH2
an electron donor. Enters the electron transport chain at a different site than NADH.
FADH2
an electron donor. Enters the electron transport chain at a different site than NADH.
in the series of reactions
product of one reaction is substrate for the next
Oxidative phosphorylation
ATP is generated from the oxidation of NADH and FADN2 and the subsequent transfer of electrons and the pumping of protons.
OCCURS WITHOUT THE NEED OF A SUBSTRATE, ADP AND PHOSPHATE IONS ABLE TO BE OXIDATIVELY PHOSPHORYLATED TO FORM ATP(ATP SYNTHASE ENZYME) NO SUBSTRATE REQURED. DRIVEN BY A PROTON MOTORFORCE THROUGH THE H IONS IN THE INTERMEMBRANE SPACE
Electron transport chain
NADH and FADH2 are oxidized to donate 1 or 2 electrons
Electrons transfer from protein-to-protein along the chain
in a series of redox reactions
At each transfer, each electron gives up a small amount of energy which enables H+ ions to be pumped into the intermembrane space. H+ occumulate in the intermembrane space.
Oxygen “pulls” the electrons down the chain, and is then the final electron acceptor where it is reduced to water
Products of oxidative phosphorylation
In the electron transport chain, NADH and FADH2 from glycolysis and citric acid cycle are used
26 or 28 ATP produced( per glucose molecule)
chemiosmosis
The hydrogen ions in the intermembrane space rush down their concentration gradient (chemiosmosis) through ATP synthase.
This causes the “turbine” within ATP synthase to turn
The rotation of the ATP synthase turbine enables the phosphorylation of ADP to generate ATP
describe the action of CYANIDE
Cyanide disrupts the ability of cells to use oxygen in oxidative phosphorylation. And the cell cannot produce ATP
describe the action of CYANIDE
CYANIDE STOPS THE e- TO BE PASSED TO OXYGEN–> NO CELLULAR RESPIRATION–>CELL DIES
Maximum ATP per glucose
30 or 32 ATP
Phosphofructokinase
an enzyme that is important in regulating glycolysis(This enzyme catalyzes the first unique step in glycolysis, converting fructose-6-phosphate to fructose-1,6-bisphosphate)
- inhibited by citrate and ATP( ie products of cellular respiration) when enough ATP has been produced
- stimulated by AMP( AMP accumulates when ATP is being used rapidly–> more ATP needed)
Glucagon
- Hormone produced by alpha cells of Islets of Langerhans in the pancreas
- Function: Stimulates the breakdown of glycogen to increase blood sugar levels. (when blood glucose is low)
Insulin
-Hormone produced by beta cells of Islets of Langerhans in the pancreas
• Function: promote glucose uptake into cells (for ATP production or storage in the liver)
Diabetes Mellitus
the ability to produce or respond to the hormone insulin is impaired
results in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood.
- No glucose in cells
- No ATP from glucose
- No glycogen stored for harder times
diabetes measure fasting
≥7mmol/L fasting
Type 1 diabetes
- Body does not produce insulin, as beta cells of the pancreas are destroyed, often this is autoimmune, or genetic, or through environmental factors
- Affects 5 – 10 % of diabetics, and onset usually occurs in children or adolescents.
- Requires insulin replacement
Type 2 diabetes
- Body produces insulin, but receptors are nonfunctional (insulin resistance)
- Most (>90%) diabetics are Type II, usual adults over the age of 40
- Can be linked to other pathologies and obesity, but not sure how or why
symptoms of diabetes mellitus
lack of functional insulin
• significantly increased hunger
• significant weight loss
because glucose is not entering cells for ATP production.
Energy released by the electron transport chain is used to pump H+ ions into which location in eukaryotic cells?
INTERMEMBRANE SPACE
When DNA is wrapped around eight histone proteins it is known as
NUCLEOSOME
HOW DOES DNA INSIDE THE NUCLEUS EXIST MOST OF THE TIME
DNA is normally found as a loosely contained structure called chromatin within the nucleus, where it is wound up and associated with a variety of histone proteins.
A cell with a predominance of rough endoplasmic reticulum is most likely producing large quantities of:
proteins for secretion
Negative vs positive feedback
Positive feedback occurs to increase the change or output: the result of a reaction is amplified to make it occur more quickly. Negative feedback occurs to reduce the change or output: the result of a reaction is reduced to bring the system back to a stable state
Is insulin and glucagon release a negative or positive feedback mechanism?
negative
