HW part for Unit three APBIO

NADH and FADH2 donate electrons to the electron transport chain. Where did these electrons come from?

Breakdown of Glucose to CO2 during Glyclysis and Kerbs cycle

After donating their electrons, NADH becomes NAD+, and FADH2 becomes FAD. Exaplin how the cell reuses NAD+ and FAD

In the kerbs cycle and glycolysis, they pick up electrons reforming/recycling/reusesing NADH and FADH2

Each protein in the electron transport chain is slightly more electronegative than the last.  Given this, what happens to the potential energy of the electron as it moves down the chain?  How does the cell take advantage of this change in potential energy?

The PE decreases, meaning energy is released. With the new engery hte cell is like yayy lets couple htis engery with the movement of H+ going against their concentration gradient

An H⁺ gradient is central to the activity of the electron transport chain.  How is this H⁺ gradient formed and how is it used to make ATP?

As electrons are passed from protein to protein, energy is released.  This release of energy is coupled with the movement of H⁺ AGAINST their concentration gradient.  The H⁺ move back DOWN their concentration gradient by passing through ATP synthase.  ATP synthase couples the movement of H⁺ DOWN their concentration gradient with the production of ATP.

H⁺ passing through ATP synthase

is this exergonic or edergonic

exergonic

ATP is produced from ADP + P_i

endergonic or exergonic

endergonic

Explain why the electron transport chain cannot function in the absence of oxygen

Oxygen is the final electron acceptor.  If it is not present, the electrons “back up like a clogged toilet and the oxygen is the flush” in the electron transport chain, preventing NADH and FADH₂ from passing on their electrons

Explain how the process of fermentation allows glycolysis to continue in the absence of oxygen

In converting pyruvate to lactic acid or ethanol, NADH is used and NAD⁺ is regenerated.  This allows glycolysis to continue, resulting in 2 ATP per molecule of glucose.

Defintion of Aerobic

with/needs oxygen

Defintion of Anaerobic

can live with the absense of oxygen

What are the reactant of lactic acid fermentation

Pyruvate

What are the products of Lactic acid fermentation

Lactic acid

What are the reactants of Alcoholic fermentation

pyruvate

What are the products of Alchoholic fermentation

Ethanol + CO2

What type of cells organisms are carried out by Lactic acid fermentation

Animals

What type of cells organism carry out Alchoholic fermentation

Yeast and some bacteria

In a Eukaryotic animals cell where is the following located

Glycolysis

Pyruvate oxidation

Krebs Cycle

Electron transport chain

Fermentation

Glycolysis- cytoplasm

Pyruvate oxidation- mitochondrial matrix

Krebs Cycle- mitochondrial matrix

Electron transport chain- inner mitochondrial membrane

Fermentation- cytoplasm

In a Eukaryotic Plant cell where is the following located

Glycolysis

Pyruvate oxidation

Krebs Cycle

Electron transport chain

Fermentation

Glycolysis - cytoplasm

Pyruvate oxidation- mitochondrial matrix

Krebs Cycle- mitochondrial matrix

Electron transport chain- inner mitochondrial membrane

Fermentation- n/a

In a Aerobic Prokaryotic cell where is the following located

Glycolysis-

Pyruvate oxidation-

Krebs Cycle-

Electron transport chain-

Fermentation-

Glycolysis- Cytoplasm

Pyruvate oxidation- Cytoplasm

Krebs Cycle- Cytoplasm

Electron transport chain- Cell membrane

Fermentation- cytoplasm

In a Anaerobic Prokaryotic cell where is the following located

Glycolysis-

Pyruvate oxidation-

Krebs Cycle-

Electron transport chain-

Fermentation-

Glycolysis- cytoplasm

Pyruvate oxidation- n/a

Krebs Cycle- n/a

Electron transport chain- n'/a

Fermentation- cytoplasm

Define Autotroph

Autotrophs are able to produce their own food.  An example is plants.

Define Heterotroph

Heterotrophs must eat other things for food.  An example is an animal.

6 carbon atoms enter glycolysis as glucose.  At the end of glycolysis, what has happened to these 6 atoms of carbon?

They are in two 3-carbon molecules of pyruvate

How many ATP molecules are USED during glycolysis?  How many are PRODUCED?  What is the net gain of ATP by the cell, per molecule of glucose?

2 ATP are used, and 4 are produced.  The net gain is 2 ATP per glucose.

 How many NADH are produced during glycolysis?  What is the role of NADH?   

2 NADH; it’s an electron acceptor.  It brings electrons to the electron transport chain, which is a later step in the process of cellular respiration.

 Where in the cell does pyruvate go after glycolysis?

If oxygen is present, it will enter the mitochondria and be used in the Kreb’s cycle.  If oxygen is absent, it will stay in the cytoplasm and fermentation will occur

During pyruvate oxidation, a 3-carbon pyruvate molecule is converted to a 2-carbon molecule called acetyl-coenzyme A.  What happened to the “missing” carbon atom?

it becoems CO2

How many times does pyruvate oxidation and the Kreb’s cycle happen for each molecule of glucose?  Explain

2.  Glycolysis produces 2 molecules of pyruvate.  Each pyruvate undergoes pyruvate oxidation and the Kreb’s cycle.

How many ATP are produced each time the Kreb’s cycle occurs.  How many ATP are produced during the Kreb’s cycle for each molecule of glucose?

1 ATP is produced per turn of the cycle.  

2 ATP are produced per molecule of glucose, since the cycle happens twice for each glucose molecule

 In what part of the cell does the Kreb’s cycle occur?  Be as specific as you can.

Mitochondrial Matrix

Re-forming ATP from ADP + P_i is an endergonic process.  Where does the energy come from?

• Mitochondria: breakdown of food

• Photosynthesis: light

What causes induced fit and what effect does it have on the substrate?

Induced fit is when enzymes change their shape when the substrate binds

They do this because the intermolecular forces between the substrate and the enzyme active site affect the intermolecular forces holding the enzyme together, leading to a change in the shape of the enzyme

This change in the enzyme shape affects the bonds in the substrate changing their shape and facilitating the chemical reaction

Summarize the relationship between substrate concentration and reaction rate.  Explain WHY this relationship exists, including an explanation for why a maximum rate seems to be reached.

• Increasing the substrate concentration → increased rate of reaction to a certain point.  Then it levels off.

• More substrate means more “starting molecules” for enzymes to collide with.  This makes it more likely that enzymes will collide with substrate, increasing the rate.  Eventually the enzyme becomes saturated, meaning it’s working at its maximum rate.  Adding more substrate at this point has no effect.

Cofactor vs Coenzyme

Both help enzymes function by binding to the enzyme and changing its shape into a proper conformation for the reaction so the substrate will fit properly into its active site

A cofactor is inorganic

Coenzyme is organic