UCI Bio 93 Midterm 2

What is a metabolic pathway?

A pathway that a molecule goes through, resulting in a specific product.

What is metabolism?

The totality of an organisms chemical reactions

Gibbs free energy

Portion of a system that can perform work when temp and pressure are uniform throughout the system.

What is a way to show change in free energy?

What does a negative Delta G mean?

A process that is spontaneous

What does spontaneous mean?

Means that a process will occur.

What happens to the energy in a exergonic reaction?

It is released

What happens to the energy in an endergonic reaction?

It is consumed in the reaction.

True or False

A cell must have endergonic and exergonic reactions

True

Is ATP Hydrolysis an exergonic or endergonic reaction?

Exergonic

Mechanical and Transport work are what kind of reactions?

Endergonic

Why does ATP hydrolysis release so much energy?

All 3 phosphate groups ate neg. charged, so there is mutual repulsion within all of them

What do enzymes do?

Lower energy barriers to drive chemical reactions

What does the suffix -ase usually mean?

An enzyme

How does an exergonic energy profile look like?

Enzymes are biological ___________

Catalysts

What is the site of cellular respiration in all eukaryotic cells?

Mitochondria

In Biology, what is another word for the addition of electrons to a substance?

Reduction

In Biology, what is another word for the loss of electrons to a substance?

Oxidation

What is cellular respiration?

Catabolic reactions used to generate ATP

Where does glycolysis happen?

In the cytosol

What is glycolysis?

The breaking down of glucose into 2 molecules of a compound of pyruvate.

What happens in the citric acid cycle?

The breakdown of glucose to carbon dioxide is completed.

What is stage 1 of cellular respiration?

Glycolysis

What is stage 2 of cellular respiration?

Pyruvate oxidation and citric acid cycle

What is stage 3 of cellular respiration?

Oxidative Phosphorylation

What is the purpose of NADH?

Transfers electrons from food to electron transport chain.

Pyruvate is converted to what compound?

Acetyl CoA

Where does the citric acid cycle occur?

In the mitochondrial matrix

What happens in substrate-level phosphorylation?

A substrate gives a phosphate to ADP, making a product and ATP

Where does oxidative phosphorylation happen?

The inner mitochondrial membrane

About how many ATP/Glucose is made during cellular respiration?

30-32

What is ATP Synthase?

An enzyme that makes ATP from ADP and inorganic phosphates.

What is chemiosmosis?

energy stored as a hydrogen ion gradient across a membrane is used to drive cellular work.

Establishing the H+ gradient is a major function of what?

The electron transport chain

What 2 processes can oxidize organic fuel and generate ATP without oxygen?

Fermentation and anaerobic respiration

What is the distinction between fermentation and anaerobic respiration?

Anaerobic respiration uses the electron transport chain

What is anaerobic respiration?

A process of harvesting chemical energy WITHOUT oxygen.

What, simply, happens in alcohol fermentation?

Pyruvate is converted into ethanol.

What happens in lactic acid fermentation?

Pyruvate is reduced by NADH to form lactate

What is lactate?

The ionized form of lactic acid

How much ATP does fermentation yield?

2

What are obligate anaerobes?

Organisms that only carry out fermentation or anaerobic respiration.

What are catabolic pathways?

Chemical reactions that break down complex molecules into energy and smaller molecules

What are anabolic pathways?

When energy is used to make smaller molecules into a larger molecules

What type of metabolic reaction releases energy?

Catabolic

What is the first law of thermodynamics?

The energy in the universe is constant. Cannot be created or destroyed

What is the second law of thermodynamics?

Every energy transformation increases the entropy (disorder) of the universe.

A spontaneous reaction is a type of reaction that leads to ___________

An increase in entropy

What is a type of reaction that decreases the entropy of the universe?

A non spontaneous reaction

What is enthalpy?

The total energy of a biological system

What is free energy?

The usable energy that is able to perform work

What is the equation to find change in free energy?

If Delta G<1 then it is a _________ reaction

Exergonic

If Delta G>1, then it is a __________ reaction

Endergonic

What are autotrophs?

Organisms that can sustain themselves without eating other organisms.

Plants are what kind of autotroph?

Photoautotrophs

What are heterotrophic organisms?

Organisms that eat other organisms

What is the mesophyll?

The tissue in the interior of the leaf

What are stomata?

Microscopic pores on the leaf

What is the dense fluid in a chloroplast?

Stroma

What are the small sacs within the Stroma?

Thylakoids

What is a stack of thylakoids called?

A grana (granum)

What is the green pigment that gives plants their color?

Chlorophyll

What are the 2 stages of photosynthesis?

Light reactions and the Calvin Cycle

What is the process called when a light reaction makes ATP, using chemiosmosis to add a phosphate to ADP?

Photophosphorylation

What happens during the light reactions in photosynthesis?

Solar energy is converted into chemical energy

What are the names of the 2 types of photosystems in light reactions?

Photosystem I and Photosystem II

What is a photosystem composed of?

A reaction-center complex and light harvesting complexes.

Chloroplast and Mitochondria both use what process to generate ATP?

Chemiosmosis

What is the name of the sugar that is produced by the Calvin Cycle?

G3P

What are the 3 stages of the Calvin Cycle?

1. Carbon Fixation
2. Reduction
3.Regeneration of the CO2 acceptor

What happens during carbon fixation?

A CO2 molecule is attached to an RuBP sugar and then splits in half to make 2 molecules of 3-Phosphoglycerate

What is the name of the enzyme that catalyzes carbon fixation?

Rubisco

Where are chlorophyll molecules found?

Thylakoid membrane

What is fluorescence?

Emission of a photon of light.

What is transformation in DNA genetics?

A change in the genotype and phenotype

What is the name of a virus that infects bacteria?

Bacteriophages

What is a shorter name for Bacteriophages?

Phages

What is the name of the 4 nucleotides of DNA?

Adenine, Thymine, Cytosine, and Guanine

What is Chargaff's rule?

The percentages of A and T, and G and C are roughly equal.

What is the name of the process that Rosalind Franklin used to make a picture of DNA?

X-Ray Crystallography

What are the 3 models of DNA Replication?

Conservative, Semi- Conservative, and Dispersive

What happens at the origin of replication?

The 2 DNA Strands are separated, making a replication bubble.

What kind of structure does DNA make?

A double helix

In base pairing, what 2 structures have to be paired together?

1 purine and 1 pyrimidine

DNA replication follows what model?

Semi-Conservative

Where does the replication of chromosomes start?

Origins of replication

What are helicases?

Enzymes that untwist the double helix

What are the 3 steps of glycolysis?

Energy Investment, Energy Payoff, and net output phase

How many net ATP does glycolysis make?

2

Why is pyruvate important?

It assists in making Acetyl coA

Is Glycolysis anaerobic or anaerobic?

Both

What is the ratio when 1 pyruvate is broken down.

1:1:1

What is 1 pyruvate broken down into?

1 CO2
1 NADH
1 Acetyl CoA

In Glycolysis, in what step does substrate-level phosphorylation occur?

The energy payoff phase

What is the ratio when 1 Acetyl CoA is broken down?

2:3:1:1

What is 1 Acetyl CoA broken down into?

2 CO2
3 NADH
1 FADH
1 ATP

How many pyruvate does 1 Glucose make?

2

What are NADH and FADH?

Electron Carriers