Unit 7 Study Guide Bio

glycolysis

• 1st stage of cellular respiration that occurs in the cytoplasm

• breaks down glucose into 2 pyruvate molecules

• generates small amounts of ATP and NADH that are essential for further energy production

energy investment phase

2 ATP molecules are invested to activate glucose and prepare it for breakdown (1st stage of glycolysis)

energy harvesting phase

4 ATP molecules are produced resulting in a net gain of 2 ATP molecules per glucose molecule (2nd stage of glycolysis)

glucose

the starting molecule for glycolysis

fructose-1,6 bisphosphate

a key intermediate formed during the energy investment phase of glycolysis

glyceraldehyde-3-phosphate (GAP)

a 3 carbon molecules produced from fructose-1,6- bisphosphate during glycolysis

pyruvate

the final product of glycolysis

hexokinase

catalyzes the phosphorylation of glucose to glucose-6- phosphate

phosphofructokinase

• catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate (key regulatory step in glycolysis)

• has 2 ATP binding sites

• is inactive when ATP levels are high which slows down glycolysis

• is active when ATP levels are low allowing glycolysis to proceed

fermentation

a metabolic process that occurs in the absence of oxygen that allows glycolysis to continue by regenerating NAD+ from NADH

lactic acid fermentation

pyruvate is reduced to lactate, regenerating NAD+ which occurs in muscle cells during strenuous exercise

ethanol fermentation

pyruvate is decarboxylated to acetaldehyde which is then reduced to ethanol, regenerating NAD+ which occurs in yeast and some bacteria

pyruvate oxidation

the process where pyruvate is oxidized to acetyl-CoA which enters the citric acid cycle which requires oxygen and occurs in the mitochondrial matrix

mitochondrial matrix

the space within the inner membrane of the mitochondria

acetyl-CoA

a 2 carbon molecule that’s the starting molecule for the citric acid cycle

pyruvate dehydrogenase

the enzyme that catalyzes the conversion of pyruvate to acetyl-CoA

citric acid cycle (Krebs cycle)

a series of reactions that occur in the mitochondrial matrix that completes the oxidation of glucose, generating ATP, NADH, FADH2, and CO2

inner membrane

folded into cristae which increase the surface area for electron transport

intermembrane space

the space between the inner and outer membranes of the mitochondria

cristae

infoldings of the inner membrane that increase the surface area for electron transport

NADH

a reduced electron carrier that carries electrons to the electron transport chain

CO2

a waste product of cellular respiration

GTP

a high-energy molecule that can be used to generate ATP

FADH2

a reduced electron carrier that carries electrons to the electron transport chain

electron transport chain

a series of protein complexes embedded in the inner mitochondrial membrane that uses the energy from NADH and FADH2 to pump protons across the inner membrane, creating a protein gradient which is then used by ATP synthase to generate ATP

proton pumps (I - IV)

the protein complexes in the electron transport chain that use the energy from electron transfer to pump protons across the inner mitochondrial membrane

protein gradient

the difference in proton concentration across the inner mitochondrial membrane

ATP synthase

an enzyme that uses the energy from the proton gradient to synthesize ATP

NADH/FADH2 oxidation

NADH and FADH2 are oxidized releasing electrons that are passed along the electron transport chain

H2O formation

oxygen is the final electron acceptor in the electron transport chain and it’s reduced to water

O2 consumption

cellular respiration requires oxygen as the final electron acceptor

glycolysis

located in the cytoplasm

pyruvate oxidation

located in the mitochondrial matrix

citric acid cycle

located in the mitochondrial matrix

electron transport chain

located in the inner mitochondrial membrane

ATP

the primary energy currency of cells

NAD+ and NADH

electron carriers that play a crucial role in cellular respiration

FADH2

another electron carrier involved in cellular respiration

mitochondria

the powerhouse of the cell where most ATP is produced

proton gradient

a key driving force for ATP synthesis in the electron transport chain

oxygen

the final acceptor in the electron transport chain

aerobic conditions

in the presence of oxygen, pyruvate is transported into the mitochondria where it’s oxidized to acetyl-CoA; process generates NADH and releases carbon dioxide

anaerobic conditions

in the absence of oxygen, pyruvate is converted to lactate through fermentation; process regenerates NAD+ from NADH allowing glycolysis to continue

chemiosmosis

the proton gradient created by the electron transport chain drives the movement of proteons back across the membrane though ATP synthase