Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
61 Cards in this Set
- Front
- Back
|
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.
|
