BIOL211 Unit 2 Exam Review

Ch 6-10 All of the study guide... she = me ate = burgers = flopped

What is the function of the nucleus?

It stores DNA and coordinates cell activities like growth, metabolism, and reproduction.

What is the nucleolus responsible for?

Synthesizing ribosomal RNA (rRNA) and assembling ribosome subunits.

What does the rough ER do?

Synthesizes proteins that are secreted, inserted into membranes, or shipped to organelles.

What are ribosomes?

Complexes of rRNA and proteins that synthesize proteins; can be free or attached to the rough ER.

Function of the Golgi apparatus?

Modifies, sorts, and packages proteins and lipids for transport or secretion.

What do lysosomes do?

Contain digestive enzymes that break down macromolecules, old organelles, and foreign substances.

What is the endomembrane system?

Network of membranes (ER, Golgi, lysosomes, vesicles, nuclear envelope) involved in protein and lipid transport.

What is the cytoskeleton?

A network of fibers (microfilaments, intermediate filaments, microtubules) that provide structure, movement, and transport.

What is vesicle transport?

Movement of substances within membrane-bound vesicles between organelles or to the plasma membrane.

Function and structure of mitochondria?

Site of cellular respiration; has double membrane (inner membrane folded into cristae) and its own DNA.

Function and structure of chloroplasts?

Site of photosynthesis; has double membrane and thylakoid membranes stacked into grana.

Function of peroxisomes?

Break down fatty acids and detoxify harmful compounds using hydrogen peroxide.

Role of the smooth ER?

Synthesizes lipids, metabolizes carbohydrates, detoxifies drugs, and stores calcium.

Function of gap junctions?

Channels that allow communication and molecule transfer between adjacent animal cells.

What are desmosomes?

Anchoring junctions that hold cells together with strong protein filaments.

What are plasmodesmata?

Channels between plant cells allowing transport and communication through cell walls.

What are tight junctions?

Seal neighboring animal cells to prevent leakage of extracellular fluid.

What is the function of flagella?

Long, whip-like structures that propel cells (e.g., sperm).

What is the function of cilia?

Short, hair-like structures that move fluid or the cell itself.

Function of microvilli?

Increase surface area for absorption (especially in intestinal cells).

What is the fluid mosaic model?

Membranes are fluid structures with proteins embedded in a phospholipid bilayer.

Role of saturated vs. unsaturated fatty acids?

Unsaturated tails increase fluidity; saturated tails decrease fluidity.

Role of cholesterol in membranes?

Stabilizes membrane fluidity—reduces fluidity at high temp and prevents solidification at low temp.

What passes easily through a membrane?

Small, nonpolar molecules (O₂, CO₂, lipid-soluble).

What cannot pass easily through a membrane?

Ions, large polar molecules, and charged compounds.

Difference between transmembrane and peripheral proteins?

Transmembrane span the bilayer; peripheral attach to one surface.

Function of contractile vacuoles?

Pump excess water out of freshwater protists to maintain osmotic balance.

What are aquaporins?

Channel proteins that facilitate rapid water movement across membranes.

Define passive transport.

Movement of substances down their concentration gradient without energy.

Define diffusion.

Movement of molecules from high to low concentration.

Define facilitated diffusion.

Passive movement through transport proteins.

Define osmosis.

Diffusion of water across a selectively permeable membrane.

What is tonicity?

The ability of a solution to cause a cell to gain or lose water.

Define active transport.

Movement of substances against their gradient using energy (ATP).

What is co-transport?

Coupling the movement of one molecule down its gradient to move another against its gradient.

What is endocytosis?

Process of taking materials into the cell by engulfing them in vesicles.

What is phagocytosis?

"Cell eating" — engulfing large particles.

What is pinocytosis?

"Cell drinking" — engulfing extracellular fluid.

What is receptor-mediated endocytosis?

Uptake of specific molecules via receptor proteins.

What is exocytosis?

Secretion of materials from vesicles fusing with the plasma membrane.

What do ion gradients power?

ATP synthesis, co-transport, nerve signals.

How do medications/mRNA vaccines cross membranes?

Often via lipid nanoparticles or transport proteins to bypass hydrophobic barriers.

Difference between potential and kinetic energy?

Potential is stored energy; kinetic is energy of motion.

Difference between exergonic and endergonic reactions?

Exergonic releases energy; endergonic requires energy input.

Anabolism vs. catabolism?

Anabolism builds molecules (requires energy); catabolism breaks them down (releases energy).

What is ATP's role?

Main energy currency that powers cellular work.

What happens in ATP hydrolysis?

ATP → ADP + Pi, releasing energy.

What do enzymes do?

Speed up reactions by lowering activation energy.

Key enzyme properties?

Reusable, specific, work under optimal pH/temp.

What is substrate specificity?

Each enzyme acts on a specific substrate.

What is an active site?

Region where the substrate binds and reaction occurs.

What is denaturation?

Loss of enzyme structure and function due to extreme pH/temp.

Cofactor vs. coenzyme?

Cofactor = inorganic (metal ion); coenzyme = organic (vitamin-derived).

Allosteric activation vs. inhibition?

Activators stabilize the active form; inhibitors stabilize the inactive form.

Competitive vs. noncompetitive inhibitors?

Competitive bind active site; noncompetitive bind elsewhere to change shape.

What is the role of redox reactions?

Transfer electrons and energy during metabolism.

Role of electron carriers?

NAD⁺ and FAD shuttle electrons to the electron transport chain.

Equation for glucose metabolism?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP.

Where does glycolysis occur and does it need oxygen?

In cytoplasm; no oxygen required.

Glycolysis inputs and outputs?

Inputs: Glucose, 2 ATP; Outputs: 2 pyruvate, 2 ATP (net), 2 NADH.

Pyruvate oxidation inputs/outputs?

Input: Pyruvate; Output: Acetyl-CoA, CO₂, NADH.

Citric acid cycle inputs/outputs?

Inputs: Acetyl-CoA; Outputs: 3 NADH, 1 FADH₂, 1 ATP, 2 CO₂ per cycle.

Where is the electron transport chain?

Inner mitochondrial membrane.

How is the proton gradient created?

Electron flow pumps H⁺ into intermembrane space.

What is the proton gradient used for?

Drives ATP synthesis via ATP synthase.

What is the role of oxygen?

Final electron acceptor; forms water.

What is fermentation?

Anaerobic process regenerating NAD⁺ from NADH.

Lactic acid vs. alcohol fermentation?

Lactic: produces lactate (animals); Alcohol: produces ethanol and CO₂ (yeast).

What wavelengths do chlorophyll and carotenoids absorb?

Chlorophyll absorbs blue/red; carotenoids absorb blue/green.

What happens in the light reactions?

Light energy → ATP + NADPH + O₂ (via water splitting).

Photosystem II vs. I?

PSII (P680) generates ATP; PSI (P700) produces NADPH.

Role of the ETC in photosynthesis?

Pumps H⁺ to create gradient for ATP synthase.

Role of NADPH?

Carries electrons for carbon fixation in the Calvin cycle.

What happens in the Calvin cycle?

Uses ATP and NADPH to convert CO₂ → G3P (sugar).

Inputs and outputs of the Calvin cycle?

Inputs: CO₂, ATP, NADPH; Outputs: G3P (sugar), ADP, NADP⁺.

What enzyme fixes carbon in the Calvin cycle?

RUBISCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase).