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61 Cards in this Set

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what happens in glycolysis? (in general)
glucose and a six carbon sugar is changed into two molecules of pyruvate (a three carbon molecule).
where does glycolysis occur?
cytoplasm
what are the main stages of glycolysis?
phosphorylation, lysis, oxidation, ATP formation
What is phosphorylation?
adding a phosphate group
What is used to phosphorylate the hexose?
2 ATP molecules
What is the result of phosphorylation?
a hexose biphosphate and 2 ADP molecules
What is the purpose of phosphorylation?
The energy of the hexose is raised and this makes the subsequent reactions possible.
What is lysis?
Splittling of the hexose biphosphate into two molecules of triose phosphate.
What is oxidation?
Oxidation occurs when an element loses 1/more elections in a reaction with other elements
What happens during the oxidation in glycolysis?
2 hydrogen atoms are removed from each triose phosphate molecule and attaches to NAD+ and forms NADH
What happens after oxidation?
The energy released by this oxidation links on another phosphate group, producing a 3-carbon compound + 2 phosphate groups.
How is pyruvate formed?
By removing the 2 phosphate groups and by passing them to ADP which results in ATP formation
What energy causes ATP formation from ADP?
An endergonic reaction (a reaction that absorbs energy from environment)
What are the products of glycolysis?
1 glucose converted into 2 pyruvates (six carbon into 2 three carbon molecules), NET GAIN of 2 ATP molecules, 2 NAD+ converted into 2 NADH+ H+
If there is no oxygen what happens to the pyruvate?
Fermentation occurs.
What is fermentation?
The anaerobic breakdown of glucose that results in a gain of 2 ATP molecules and end products such as alcohol and lactate.
Why does the process of fermentation occur after glycolysis?
To gain back the NAD+ used up in glycolysis and because there is no oxygen, won't be able to accept electrons in the ETC.
Where does the link reaction occur?
Mitochondria
How does the pyruvate enter the mitochondria?
From the outer membrane through diffusion
Why is it able to enter through the outer membrane?
It is "leaky" and so it's permeable to small ions and molecules
How does pyruvate enter the matrix?
By the carrier proteins in the inner mitochondrial membrane
What happens during the link reaction? (in general)
Pyruvate-->Acetyl CoA
How does the pyruvate convert to an acetyl CoA?
Through oxidative decarboxylation
Describe the process of oxidative decarboxylation
The enzyme pyruvate dehydrogenase removes one hydrogen and one CO2 molecule from pyruvate and attach it to CoA, resulting in the acetyl CoA.
What happens o the acetyl group in the first reaction of the Kreb's cycle?
It is transferred to a 4-carbon compound (oxalaoacetate) to form a 6-carbon compound (citrate).
Name the first reaction in kreb's cycle and what does it do?
Decarboxylation; CO2 removed and excreted as waste.
What does oxidation in kreb's cycle do?
Removes the hydrogen in 4 of the reactions. in 3 of the oxidations, hydrogen accepted by NAD+ and the other by FAD
What happens to the energy released by these oxidation reactions?
Mostly stored by the carriers when they accept hydrogen. This energy is later released by the ETC to make ATP.
How is ATP produced from the kreb's cycle?
Directly from the substrate-level phosphorylation.
What are the products of the Kreb's cycle for 1 pyruvate molecule?
1 ATP, 2 CO2, 3 NADH, 1 FADH
What are the products of the Kreb's cycle for 1 glucose molecule?
2 ATP, 4 CO2, 6 NADH, 2 FADH2
What is the main purpose of the kreb's cycle?
To transfer high energy electrons from carbon molecules to electron carriers (NADH, FADH2)
Where do these electron carriers (NADH, FADH2) go after the Kreb's cycle?
Electron Transport Chain
What is the electron transport chain?
A series of electron carriers located in the inner membrane of the mitochondria.
What supplies two electrons to the first carrier in the chain?
NADH
Where did these electrons come from?
From oxidation reactions in earlier stages of cell respiration.
How do the electrons pass along the ETC?
by giving up energy each time the pass from one carrier to the next.
How is ATP made from this process?
By using the energy to phosphorylate ADP molecules to form ATP at 3 points along the chain.
Why is chemiosis also called oxidative phosphorylation?
The energy available from a molecule of glucose is released during a series of OXIDATION reactions, and is transferred to a molecule of ATP in the form of a PHOSPHATE bond.
What is ATP synthase?
Transports the protons back across the membrane down the concentration gradient.
What pumps protons across the inner mitochondrial membrane?
energy released as electrons pass the ETC
What drives ATP production during H+ movement across the membrane?
The rotation of parts of ATP synthase as H+ moves across the membrane.
What is concentration gradient?
A store of potential energy
Why is the concentration gradient important?
To control the energy available from the oxidation reactions in glycolysis and the Krebs Cycle.
What's oxygen's role at the end of the ETC?
Since NAD+ is in limited supply in the matrix, the electrons that were being passed down are accepted by oxygen, and a water molecule is formed.
Why is oxygen so important?
Without oxygen, there is no ultimate electron acceptor, and the NADH can never be converted back to NAD+.
What will happen if there is no NAD+?
Without NAD+ the Krebs cycle cannot proceed, and the cell must proceed through fermentation.
How many ATP molecules formed after chemiosis?
32 or 34
What happens to the NADH and FADH molecules?
Gives up their electrons and return NAD+ and FAD+
How many molecules of water were produced?
6
How does the outer mitochondrial membrane contribute to cellular respiration?
It separates the contents of the mitochondria from the rest of the cell, creating a compartment with ideal conditions for aerobic respiration?
How does the matrix contribute to cellular respiration?
The matrix is the fluid inside the mitochondria contains enzymes for the Krebs cycle and the link reaction.
How does the space between inner and outer membranes contribute to cellular respiration?
this space is very small, thus a high proton concentration can easily be formed in chemiosis when protons are being pumped into this space by the ETC.
How does the cristae contribute to cellular respiration?
the tubular shapes of the inner membrane increases the surface area available for oxidative phosphorylation.
How does the inner mitochondrial membrane contribute to cellular respiration?
the inner membrane contains ETC and ATP synthase which carry out chemiosis
What's reduction?
when an element GAINS 1/more electrons when reacting with other elements.
What are redox reactions?
any reaction in which the reactants have their oxidation state changed.
What's an oxidation state?
the charge on an element if all of its bonded elements (and their shared electrons) are removed.
Anabolic pathways?
uses energy to convert simple-->complex molecules
Catabolic pathways?
uses energy to break bonds so complex-->simple molecules
What are "pathways"?
a series of chemical reactions that occur in order, the product of one being used as the reactant for another.