Electron transport chain, ATP efficiency, anaerobic cellular respiration

where does electron transport chain occur ?

In the inner mitochondrial membrane

How many proteins complexes are there and what are the names ?

-There are four protein complexes.
-Complex 1 is NADH dehydrogenase
-Complex 2 is succinate dehydrogenase
-Complex 3 is cytochrome complex
-Complex 4 is cytochrome oxidase

-Complex 2 is a single peripheral membrane protein while the other three complexes are multiple proteins

What are the two electron shuttles and where are they located ?

-Ubiquinone located between complex 1 and complex 2 as well as complex 2 and complex 3.
-cytochrome c is located between complex 3 and complex 4

Complex 4

-loses two electrons to oxygen
-pumps 1 H+
-oxygen combines with 2 protons and 2 electrons to make H2O

Complex 3

-Loses 2 electrons to cytochrome oxidase
-transfers electrons via cytochrome C
-pumps 1 H+

Complex 1

-loses 2 electrons to complex 3
-transfers electrons via ubiquinone
-receives 2 electrons from NADH
- pumps 1 H+

Complex 2

-receives 2 electrons from FADH2
-transfers electrons from Ubiquinone to complex 3
-Doesn't pump protons

Pumping of protons

-All complexes except complex 2 pump protons
-protons are pumped into intermembrane space due to energy released when electrons move
-Builds up H+ gradient in the intermembrane space

What happens to the energy of electrons as they move across the electron transport chain ?

-electrons release energy (exergonic reaction) as they are pulled through the electron transport chain -allows active transport of H+

ATP synthesis

-Also called oxidative phosphorylation
-protons move passively into matrix through ATP synthase
-ATP synthases turns at the protons pass. phosphorylates ADP to create ATP
- 3 protons pumped for each NADH = 3 ATP each NADH
-2 protons pumped for watch FADH2 = 2 ATP each FADH

What is electrochemical gradient ?

The difference of concentration (chemical) gradient and membrane potential (electrical gradient)

What is chemiosmosis ?

movement of ions across a selectively permeable membrane, down their electrochemical gradient

What is proton-motive force ?

energy stored in the form of an electrochemical gradient of protons across a membrane (causes protons to move)

What is the theoretical yield of cellular respiration ?

38 ATPs

What percentage of Glucose energy is converted to ATP ?

41 % is converted to ATP. 59% is loss as thermal energy

What is creatine phosphate ?

A quick and short term source of energy in cells. Creatine phosphate is used when excess ATP is available in their cells which can phosphorylate creatine. When phosphorylated creatine becomes a high energy molecule called creatine phosphate

What is metabolic rate ?

The amount of energy that is expended per unit time in an organism

What is basal metabolic rate (BMR) ?

The metabolic rate of an organism at rest

What if there is an excess ATP ?

Excess ATP in the cytosol binds to enzyme phosphofructokinase and acts as a negative regulator. This results in decrease of concentration of fructose 1-6 biphosphate and stops glycosis.

What if there is a shortage of ATP ?

The rates of glycolysis and ATP production increase proportionately as cellular activities convert ATP to ADP.

What is lactic acid fermentation ?

-occurs in humans and mammals
-pyruvate turns into lactate and oxidizes NADH to NAD+
-allows continuation of glycosis

What is alcohol fermentation ?

-occurs in yeast, fungi, bacteria, and plants
-pyruvate becomes acetaldehyde via decarboxylate and oxidizes NADH to NAD+
-acetaldehyde turns into ethanol

What do anaerobic organisms have as final electron acceptor ?

Sulfate, nitrate or iron

How is cellular respiration regulated ?

- high levels of ATP and citric acid cycle intermediate citrate inhibit phophofructokinase levels
-low levels of ATP ADP and AMP increase production of ATP

Alternatives to glucose for carbohydrates, fats, and proteins

- disaccharide carbohydrates ( sucrose,lactose, and maltose )are hydrolyzed into monosaccharides (glucose, furctose, and galactose) which enter glycosis

-triglyceride is major source of energy for ATP synthesis. Triglycerides are hydrolyzed into glycerol and individual fatty acids. Glycerol is converted into G3P before entering glycolsis. Fatty acids are split into 2 carbon fragmnets which enter the citric acid cycle as acetyl groups attached to coA via beta-oxidation.

-proteins are hydrolyzed to amino acids. The amino group (-NH2) is removed and the remainder of the molecule either enters cellular respiration through pyruvate, acetyl units carried by coenzyme A, or intermediates of the citric acid cycle, depending on R group and carbon backbone that is left

What is beta oxidation ?

A process in which fatty acids are broken down into acetyl-CoA through catabolism.

formula of alcohol fermentation

pyruvate + NADH +H -> NAD + CO2 + ethanol

What is the formula of lactate fermentation ?

pyruvate + NADH + H -> NAD + lactate

Why is the actual yield different from theoretical yield ?

-inexact NADH and FADH2 to ATP ratio
-NADH from glycolysis uses glycerol phosphate which generates 2 instead of 3 ATP