DNA Structure
What are the components of a nucleotide?
1) 5 Carbon pentose sugar
2) 3' Phosphate group
3) 1' Nitrogenous base (purine --> 2 ring AG paired with pyrimidine --> 1 ring CUT)
Where does transcription and translation occur in prokaryotes vs eukaryotes?
Transcription occurs in the nucleus in eukaryotes and in the cytoplasm in prokaryotes. Translation occurs in the cytoplasm in both.
What is the difference between anabolism and catabolism?
Anabolism builds molecules and uses energy. Catabolism breaks molecules down and releases energy.
Where does glycolysis occur, and what is its net ATP gain?
Glycolysis occurs in the cytoplasm and has a net gain of 2 ATP (4 total are produced in the process).
Where in the chloroplast do the light reactions and the Calvin cycle occur?
The light reactions are on the thylakoid membrane. The calvin cycle is in the stroma.
What does the term "semi conservative" mean in DNA replication?
Semiconservative replication means that, when DNA is replicated, the new strand consists of one old (parent) strand and one new (daughter) strand.
What is a codon?
A sequence of three consecutive nucleotides that codes for a specific amino acid.
What is the sign of ΔG for an exergonic reaction, and is it spontaneous?
Bonus (+50 pts): What is G?
Negative, and yes, it is spontaneous.
Note: Spontaneous process is one that can proceed without requiring energy input.
Bonus: G is Gibbs Free Energy -- the portion of a system's energy that is available for conversion to some other form.
What are the 4 stages of cellular respiration?
Bonus (50 pts.): Breakdown major steps of stages 1 and 4.
Bonus: Which steps use substrate level phosphorylation vs. oxidative?
1) Glycolysis: Prep, Cleavage, Payoff
- Uses substrate level phosphorylation
2) Pyruvate Oxidation
3) Citric Acid Cycle
- Uses substrate level phosphorylation
4) Oxidative Phosphorylation: Electron Transport Chain, Chemiosmosis
- Uses oxidative phosphorylation
Why are chloroplasts green?
Chloroplasts contain chlorophyll, the green pigment.
Which enzyme synthesizes new DNA and proofreads during replication?
DNA polymerase
What is denaturation?
The protein unfolds and loses its structure, which causes it to lose its function.
What is the difference between kinetic energy and potential energy?
Bonus (+50 pts): What kind of energy (kinetic or potential) is heat energy?
Kinetic energy is the energy associated with motion, potential energy is the energy associated with position/location.
- Bonus: Heat energy -- Kinetic energy applied to atoms/molecules.
What is the final electron acceptor in cellular respiration?
Oxygen, which is reduced to water.
Describe the light dependent and independent reactions of photosynthesis
2) Calvin Cycle (independent): Energy is used to synthesize carbohydrates from CO2.
A DNA sample is 18% cytosine. What percentage is adenine?
32%. C = G = 18%, so G + C = 36%. That leaves 64% for A + T, and A = T, so each is 32%.
List the three eukaryotic RNA modifications and one purpose of each.
The 5' cap helps ribosome recognition and protects against exonucleases. The poly(A) tail aids export and stability. Splicing removes introns and joins exons.
Describe the first and second law of thermodynamics? (200 pts. per answer)
1st Law of Thermodynamics: Energy can be transferred and transformed but it cannot be created or destroyed.
2nd Law of Thermodynamics: Every energy transfer or transformation increases the entropy of the universe or system.
- Entropy: A measure of disorder or randomness.
What are the inputs and outputs of the citric acid cycle?
Bonus (50 pts): What is regenerated in the citric acid cycle?
Inputs: 2 acetyl-coA, 6 NAD+, 2 FADH
Output: 2 ATP, 6 NADH, 2 FADH2, 4 CO2
Bonus: Oxaloacetate
Describe the 3 chloroplast membranes and 3 chloroplast compartments
Membranes: Outer membrane, inner membrane, thylakoid membrane (stacks of thylakoids = granum)
Compartments: Intermembrane space, stroma (fluid within chloroplast), thylakoid space
Write the complement of 5' ATGCCA 3', with the ends labeled.
3' TACGGT 5' (or 5' TGGCAT 3').
Name and define the four levels of protein structure.
Primary is the amino acid sequence. Secondary is alpha helices and beta sheets. Tertiary is the final folded shape. Quaternary is two or more subunits together.
What is energy coupling?
Bonus (+100 pts): What is the most common exergonic reaction?
The accomplishing of work via using exergonic reactions to drive endergonic reaction.
Bonus: ATP hydrolysis (breaking apart of ATP)
Fermentation occurs (regenerates NAD+)
- In animals/bacteria, pyruvate is reduced to lactic acid. In plants/fungi, pyruvate is reduced to acetaldehyde and then to ethanol.
What is photorespiration?
Photorespiration occurs when, in the Calvin Cycle, Rubisco adds O2 instead of CO2 to RuBP, which wastes energy and releases CO2.