BIOL 162 | Complete Practice Quiz Lectures 11–19

Comprehensive practice flashcards covering cell structure and organelles, cellular respiration and photosynthesis, the cytoskeleton, the extracellular matrix and junctions, membrane dynamics, membrane transport, bulk transport, thermodynamics, and enzyme kinetics.

What are the three main principles of cell theory?

All organisms are made of cells, cells are the basic unit of life, and cells come from preexisting cells.

What is a eukaryotic cell?

A cell with a nucleus and membrane-bound organelles.

What is a prokaryotic cell?

A cell without a nucleus or other membrane-bound organelles.

What is compartmentalization?

Separating cellular processes into different organelles.

What is the nucleolus?

The site where ribosomal components are manufactured.

What is the endomembrane system?

A network of membranes and organelles that manufacture, modify, and transport materials.

What is the function of the smooth ER?

Lipid synthesis, detoxification, and calcium storage.

What is the typical pathway of a secreted protein?

Rough ER → transport vesicle → Golgi apparatus → secretory vesicle → plasma membrane.

What is the main function of mitochondria?

Produce ATP through cellular respiration.

What are cristae?

Folds of the inner mitochondrial membrane that increase surface area.

What is the mitochondrial matrix?

The innermost fluid-filled compartment of the mitochondrion.

Where does glycolysis occur?

Cytosol.

Where does the citric acid cycle occur?

Mitochondrial matrix.

Where is the electron transport chain located?

Inner mitochondrial membrane.

What mitochondrial molecule can trigger apoptosis?

Cytochrome c.

What is the endosymbiotic theory?

Mitochondria and chloroplasts originated from bacteria engulfed by ancestral cells.

What evidence supports endosymbiosis?

Circular DNA, bacterial-like ribosomes, double membranes, and division resembling bacterial fission.

What are the three types of cytoskeletal filaments?

Actin filaments, microtubules, and intermediate filaments.

What is myosin?

A motor protein that interacts with actin to produce movement.

How do actin and myosin produce contraction?

Myosin uses ATP to move along actin filaments.

What are microtubules?

Hollow tubes involved in transport, movement, and cell division.

What protein makes up microtubules?

Alpha- and beta-tubulin dimers.

What is kinesin?

An ATP-powered motor protein that generally moves toward the microtubule plus end.

What is dynein?

An ATP-powered motor protein that generally moves toward the microtubule minus end.

What are intermediate filaments?

Strong, rope-like fibers that provide mechanical strength.

What is the 9+2 arrangement?

Nine outer microtubule doublets surrounding two central microtubules.

What are the three major functions of cell junctions?

Sealing, adhesion, and communication.

What is the function of tight junctions?

Prevent substances from leaking between cells.

What is a desmosome?

An adhesive junction that connects neighboring cells and provides mechanical strength.

What are gap junctions?

Communicating channels between animal cells.

What are plasmodesmata?

Channels connecting the cytoplasm of neighboring plant cells.

What is the extracellular matrix (ECM)?

A network of proteins and other molecules outside animal cells that provides support.

What is the main structural component of plant cell walls?

Cellulose.

What is the fluid mosaic model?

A model describing the membrane as a fluid lipid bilayer containing proteins.

What are the four major structural components of the plasma membrane?

Phospholipid bilayer, transmembrane proteins, interior protein network, and cell surface markers.

What substances easily cross the lipid bilayer?

Small, nonpolar molecules such as oxygen and carbon dioxide.

What substances have difficulty crossing the lipid bilayer?

Ions and large or strongly polar molecules.

How do saturated fatty acids affect membrane fluidity?

Decrease fluidity because their straight tails pack tightly.

How do unsaturated fatty acids affect membrane fluidity?

Increase fluidity because double bonds create bends in the tails.

How does fatty acid tail length affect fluidity?

Shorter tails generally increase fluidity.

What is the function of cholesterol in membranes?

Helps regulate membrane fluidity and stability.

What is diffusion?

Net movement of molecules from high to low concentration.

What is facilitated diffusion?

Passive movement through membrane transport proteins.

What is the difference between channels and carriers?

Channels provide passageways; carriers change shape to move substances.

In which direction does water move during osmosis?

Toward the side with higher effective solute concentration.

What happens to an animal cell in a hypotonic solution?

Water enters, causing the cell to swell and possibly burst.

What happens to an animal cell in a hypertonic solution?

Water leaves, causing the cell to shrink.

What is primary active transport?

Transport powered directly by ATP hydrolysis.

What is secondary active transport?

Transport powered indirectly by energy stored in an ion gradient.

How many ions does the sodium-potassium pump move per ATP?

$3\text{ Na}^+$ out and $2\text{ K}^+$ in.

What are the three types of endocytosis?

Pinocytosis, phagocytosis, and receptor-mediated endocytosis.

What is pinocytosis?

Nonspecific uptake of extracellular fluid.

What is phagocytosis?

Engulfment of large particles, such as bacteria.

What is receptor-mediated endocytosis?

Selective uptake of substances that bind to specific membrane receptors.

What is clathrin?

A protein that helps form coated vesicles during endocytosis.

What is familial hypercholesterolemia?

An inherited disorder that can impair LDL removal from the blood.

How is familial hypercholesterolemia related to endocytosis?

Defective LDL receptor function can prevent normal uptake of LDL cholesterol.

How does exocytosis affect the plasma membrane?

Adds vesicle membrane to the plasma membrane.

How does endocytosis affect the plasma membrane?

Removes portions of membrane to form internal vesicles.

What is a redox reaction?

A reaction involving the transfer of electrons.

What does OIL RIG stand for?

Oxidation Is Loss, Reduction Is Gain.

What is the first law of thermodynamics?

Energy cannot be created or destroyed, only transferred or transformed.

What is the second law of thermodynamics?

The total entropy of an isolated system tends to increase.

What is the Gibbs free energy equation?

$$\Delta G = \Delta H - T\Delta S$$

What is the $\Delta G$ of an endergonic reaction?

Positive ($\Delta G > 0$).

What is the $\Delta G$ of an exergonic reaction?

Negative ($\Delta G < 0$).

What does a negative $\Delta G$ indicate?

A reaction is thermodynamically favorable in the forward direction.

What is ATP hydrolysis?

ATP reacts with water to form ADP and inorganic phosphate, releasing free energy.

What is energy coupling?

Using energy released by an exergonic reaction to drive an endergonic process.

How do enzymes speed up reactions?

By lowering activation energy.

Do enzymes change the $\Delta G$ of a reaction?

No, they change reaction rate, not the overall free energy change.

What is the induced fit model?

A model in which enzyme shape changes upon substrate binding.

What is denaturation?

Loss of a protein's normal three-dimensional structure and function.

What is competitive inhibition?

An inhibitor competes with the substrate for the active site.

What is noncompetitive inhibition?

An inhibitor reduces enzyme activity by binding at a different site rather than competing directly for the active site.

What is an allosteric site?

A regulatory binding site separate from the active site.

What is an example of a cofactor?

Zinc ion ($\text{Zn}^{2+}$).

What is an example of a coenzyme?

$\text{NAD}^+$ or $\text{NADH}$.

What is HMG-CoA reductase?

An enzyme involved in cholesterol synthesis.

What type of drugs inhibit HMG-CoA reductase?

Statins.

What is feedback inhibition?

When a product of a pathway inhibits an earlier enzyme to reduce further production.