Microbio preppy

What does the 1st law of thermodynamics state?

Energy cannot be created or destroyed; it only changes form.

What does the 2nd law of thermodynamics refer to in this chapter?

Entropy — the tendency toward disorder or disorganization.

Why do cells need energy first for maintenance?

Because entropy constantly pushes systems toward disorder, so cells must spend energy to stay organized.

What can cells use leftover energy for after maintenance?

Growth and reproduction.

What are the forms of energy listed in the new PowerPoint?

Chemical, radiant, and heat energy.

Can cells make their own energy?

No. They must gather, absorb, or ingest outside energy and convert it to cellular energy.

What is the usable form of energy in the cell?

ATP (adenosine triphosphate).

What reaction forms ATP?

Phosphorylation: ADP + P + energy → ATP.

What is an endergonic reaction?

A reaction that requires energy to be put in to make a bond.

What is an exergonic reaction?

A reaction that releases energy when a bond is broken.

What is potential energy?

Stored energy.

What is kinetic energy?

Energy of movement.

What are the intermediate energy carriers named in the files?

NADH and FADH2.

What do NADH and FADH2 carry?

High-energy electrons.

What is reduction?

Gain of electrons.

What is oxidation?

Loss of electrons.

What is cellular respiration?

The conversion of organic molecules like sugars, fats, and proteins into cellular energy, ATP.

What are the 3 initiating carbohydrate pathways in prokaryotes?

Glycolysis, hexose monophosphate pathway (shunt / pentose phosphate), and Entner-Douderoff pathway.

What molecule starts glycolysis?

Glucose, a 6-carbon sugar.

How many ATP are used to start glycolysis?

2 ATP.

What major structural event happens in glycolysis?

The 6-carbon molecule is split into two 3-carbon molecules.

What is the gross yield of glycolysis?

4 ATP, 2 NADH, and 2 pyruvate.

What is the net yield of glycolysis?

2 ATP, 2 NADH, and 2 pyruvate.

Where does glycolysis occur?

In the cytoplasm.

What type of phosphorylation is glycolysis?

Substrate-level phosphorylation.

Can glycolysis occur without oxygen?

Yes. Glycolysis can occur with or without oxygen.

Which pathway here is the only one that yields ATP aerobically or anaerobically?

Glycolysis.

If oxygen is present, where do glycolysis products go next?

Pyruvate goes to pyruvate prep; NADH goes to the electron transport system.

What are the two fermentation types named in the files?

Lactic acid fermentation and alcoholic fermentation.

What are the products of alcoholic fermentation?

Ethanol and CO2.

What is the product of lactic acid fermentation?

Lactic acid.

What are the other names for the hexose monophosphate pathway?

The shunt and pentose phosphate pathway.

How many ATP are needed to start the shunt?

1 ATP.

What is lost early in the shunt?

One carbon as CO2.

What is the net yield of the shunt?

1 ATP, 2 NADH, 1 pyruvate.

What 2-carbon product of the shunt is not useful for energy production?

Acetaldehyde.

Why is the shunt’s ATP yield lower than glycolysis?

Because it produces only one pyruvate instead of two, so there is less downstream energy production.

What total ATP yield does the shunt give?

22 ATP.

Which organisms use the Entner-Douderoff pathway according to the files?

Certain gram-negative bacteria / Pseudomonads.

What special energy carrier appears in Entner-Douderoff that was not listed for glycolysis?

NADPH.

What total ATP yield does the Entner-Douderoff pathway give?

37 ATP.

Where does pyruvate prep occur?

In the matrix of the mitochondria.

What are the products of pyruvate prep per pyruvate?

1 acetyl CoA, 1 NADH, and 1 CO2.

What are the products of pyruvate prep per glucose?

2 acetyl CoA, 2 NADH, and 2 CO2.

What is CoA?

Coenzyme A, the carrier of the 2-carbon acetyl group.

Where does the Krebs cycle occur?

In the matrix of the mitochondria.

What combines to start the Krebs cycle?

A 2-carbon acetyl group and a 4-carbon molecule (oxaloacetate).

What 6-carbon molecule is formed at the start of Krebs?

Citric acid.

What is the yield per turn of the Krebs cycle?

3 NADH, 1 FADH2, and 1 ATP.

What is the yield per glucose for the Krebs cycle?

6 NADH, 2 FADH2, and 2 ATP.

Why does Krebs occur twice per glucose?

Because one glucose produces two acetyl CoA molecules.

What is the job of the electron transport system?

To convert NADH and FADH2 into ATP.

Where is the electron transport system located?

On the cristae of the mitochondria.

What is another name for the electron transport system?

Oxidative phosphorylation.

Why is it called oxidative phosphorylation?

Oxidative because electrons are removed; phosphorylation because ATP is made.

What is the ATP exchange rate for NADH?

1 NADH = 3 ATP.

What is the ATP exchange rate for FADH2?

1 FADH2 = 2 ATP.

Why is oxygen necessary for ETS?

Because the electrons removed from NADH and FADH2 are ultimately accepted by oxygen.

What term is associated with ETS because it involves transport across a membrane?

Chemiosmosis.

What are the main stored fats called?

Triglycerides.

What are triglycerides broken into?

Glycerol and 3 fatty acids.

Where does glycerol enter glycolysis?

At the point where the 6-carbon molecule is split into two 3-carbon molecules.

Which part of a triglyceride can yield energy anaerobically?

Glycerol.

What is the total ATP yield for glycerol in the new PowerPoint?

20 ATP.

What group is found at the end of a fatty acid?

A carboxyl group (-COOH).

What are saturated fats?

Fats with only single bonds between carbons; found in animals.

What are unsaturated fats?

Fats with one or more double bonds between carbons; found in plants.

Under what conditions are fats broken down through beta-oxidation?

Only under aerobic conditions.

What happens in beta-oxidation?

A pair of carbons is cleaved off as an acetyl group, while NADH and FADH2 are produced.

How much ATP is required to initiate beta-oxidation?

1 ATP.

What are the main products of each beta-oxidation cycle?

1 NADH, 1 FADH2, and 1 acetyl CoA.

What net ATP yield is given in the beta-oxidation example table?

50 ATP.

What are proteins first broken into?

Amino acids.

What must be removed from amino acids before they can be used for energy?

The amine group.

Where do protein breakdown intermediates enter respiration?

Into the Krebs cycle in the middle rather than at the beginning.

Why are proteins used last for energy?

Because the removed amine group is toxic and the remaining molecules yield less energy.

What does deamination produce?

Free ammonia.

Does deamination use water?

Yes.

In deamination, what replaces the amine group?

=O, and the oxygen comes from water.

What energy carrier is produced during deamination?

FADH2.

Is deamination reversible?

No.

Does transamination produce free ammonia?

No.

Does transamination use water?

No.

In transamination, what replaces the amine group?

=O, and the oxygen comes from the other molecule.

Does transamination produce energy?

No.

Is transamination reversible?

Yes.

What is decarboxylation?

Removal of one or more carboxyl groups, yielding CO2.

What are the two major parts of photosynthesis in the notes?

Light-dependent pathways and light-independent pathways.

What do the light-dependent pathways produce?

ATP and NADPH.

What does the light-independent pathway produce?

Sugar.

What pigment is the most important in photosynthesis?

Chlorophyll a.

Why is chlorophyll a the most important pigment?

Because it is the only pigment that can pass captured light energy into the biochemical pathways of photosynthesis.

Where are photosynthetic pigments found in eukaryotic organisms according to the new PowerPoint?

In chloroplasts.

What is the visible light mnemonic given in the chapter?

ROY G BIV.

What is an accessory pigment?

A pigment that absorbs light where chlorophyll a does not.

Can accessory pigments pass energy directly into photosynthesis?

No. They must give the energy to chlorophyll a first.

What is a photon?

A packet of light energy.

What happens when a photon strikes an electron in a pigment?

The electron absorbs the energy and jumps to a higher energy state.

What is a photosystem?

A collection of pigments and enzymes involved in the light-dependent pathway.

Where is the photosystem associated?

With the thylakoid membrane.