Genetic change
Which type of cell mutation (somatic or germ-line) is heritable, and why?
Germ-line mutations → heritable because they are passed through gametes; somatic mutations are not inherited.
What is the difference between integral and peripheral membrane proteins?
Integral = embedded in membrane (require detergent to remove)
Peripheral = loosely attached (can be removed gently)
In simple diffusion, which direction do molecules move relative to their concentration gradient?
Moves from high → low concentration
What is the terminal electron acceptor in the mitochondrial ETC?
O2
What are the main products of the Calvin cycle?
1 G3P (and 9 ADP, 6 NADP⁺ regenerated) per 3 CO2
(one cycle)
List the 6 major types of genetic change that contribute to evolution
How does cholesterol affect membrane fluidity?
Cholesterol decreases fluidity at high temps but can increase fluidity if fatty acids are saturated
What is the key difference between channels and transporters?
Channels = passive, no binding site
Transporters = can be active/passive, have binding sites
Why does the ETC stop functioning without O₂?
Without O₂ → electrons back up → NADH accumulates → ETC stops
What is the role of Rubisco in photosynthesis?
adds CO2 to ribulose-1,5-bisphophate (RuBP) to form unstable 6C intermediate, which immediately splits into 2 3C molecules (3-PGA)
How can you distinguish between a recent vs ancient gene duplication event using sequence data?
Recent duplication → sequences very similar
Ancient duplication → sequences diverged significantly due to accumulated mutations
How is membrane asymmetry established in eukaryotic cells?
Asymmetry established in ER via flippases/scramblases → maintained during vesicle transport
Identify the equation for ΔG in membrane transport. What does each term represent?
ΔG = RT ln([inside]/[outside]) + zFEm
Where are protons pumped during the ETC, and why?
Protons pumped into intermembrane space → creates gradient for proton motive force (ATP synthase)
How do the light reactions generate energy for the Calvin cycle?
Light reactions generate ATP + NADPH → used in Calvin cycle
Describe how unequal crossing-over results in gene duplication and predict one evolutionary outcome.
Unequal crossing-over misaligns homologous chromosomes → one chromosome gains extra copy → duplication → possible outcomes: pseudogene, new function, or subfunctionalization
Why can only certain proteins span the membrane as α-helices?
Transmembrane α-helices require hydrophobic amino acids to interact with lipid core
Predict whether transport will occur given both a concentration gradient and membrane potential (electrochemical gradient).
Must consider BOTH gradients:
Explain how ATP synthase converts a proton gradient into ATP.
ATP synthase uses proton flow down gradient → rotational mechanism → synthesizes ATP
Compare the roles of CO₂ and O₂ in photosynthesis vs respiration.
Photosynthesis: CO₂ in, O₂ out
Respiration: O₂ in, CO₂ out
Explain how horizontal gene transfer via plasmids contributes to antibiotic resistance.
Plasmid transfer (conjugation) allows bacteria to share genes (e.g., antibiotic resistance) → rapid spread across populations
Predict what would happen to membrane structure if phospholipids were not amphipathic.
If phospholipids weren’t amphipathic → no bilayer → no stable membranes → no compartmentalization of cells
Describe the full Na⁺/K⁺-ATPase cycle and explain how it maintains membrane potential.
Step 1: Na⁺ Binding (inside)
Step 2: ATP Hydrolysis
Step 3: Na⁺ Release (outside)
Step 4: K⁺ Binding (outside)
Step 5: Dephosphorylation
Step 6: K⁺ Release (inside)
steady state potential from pump continuously restoring gradient helps maintain membrane potential
Compare electron donors and terminal electron acceptors in chloroplasts vs mitochondria.
mitochondria:
- e donor: NADH, FADH2
- terminal e acceptor: O2
- final pdt: H20
chloroplasts:
- e donor: H20
- terminal e acceptor: NADP+
- final pdt: NADPH, O2 released as byprodt
Compare the Calvin cycle and citric acid cycle in terms of inputs and outputs.
Calvin cycle: uses CO₂, ATP, NADPH → makes 1 G3P
Citric acid cycle: oxidizes acetyl-CoA → produces 3 NADH, 1 FADH₂, 1 GTP, 2 CO2