Ch 3

Q: What are the four main functions of the plasma membrane?

A: Physical isolation, regulation of exchange, sensitivity to environment, structural support.

Q: What is the plasma membrane made of?

A: A phospholipid bilayer with embedded proteins and carbohydrates.

Q: What do hydrophilic heads and hydrophobic tails of phospholipids do?

A: Heads face watery environments; tails form a barrier to water-soluble substances.

Q: What is the function of cholesterol in the plasma membrane?

A: Reduces fluidity and permeability.

Q: What are the types of membrane proteins by function?

A: Anchoring, recognition, enzymes, receptors, carriers, channels.

Q: What is the glycocalyx and what does it do?

A: A sugar coating outside the membrane; it aids in protection, binding, movement, and immune recognition.

Q: What are the two types of organelles?

A: Membranous and nonmembranous.

Q: What are the components of the cytoskeleton?

A: Microfilaments, intermediate filaments, microtubules.

Q: What do microfilaments do?

A: Provide support and aid in muscle contraction.

Q: What do intermediate filaments do?

A: Maintain shape and stabilize organelles.

Q: What do microtubules do?

A: Provide strength, move organelles, and form the spindle apparatus.

Q: What are microvilli and what is their function?

A: Projections that increase surface area for absorption.

Q: What do centrioles do?

A: Help form spindle apparatus during cell division.

Q: What is the function of cilia?

A: Move fluids across the cell surface.

Q: What is the function of ribosomes?

A: Synthesize proteins.

Q: What is the role of the smooth ER?

A: Synthesizes lipids and stores glycogen.

Q: What is the role of the rough ER?

A: Synthesizes and processes proteins.

Q: What does the Golgi apparatus do?

A: Modifies, packages, and ships proteins and lipids.

Q: What do lysosomes do?

A: Break down waste, damaged organelles, and pathogens.

Q: What do peroxisomes do?

A: Break down fatty acids and neutralize hydrogen peroxide.

Q: What is the role of mitochondria?

A: Produce ATP through aerobic respiration.

Q: What is membrane flow?

A: The continuous movement and recycling of membrane parts.

Q: What are the functions of the nucleus?

A: Control metabolism, store/process genetic info, regulate protein synthesis.

Q: What are nucleoli?

A: Nuclear structures that make rRNA and ribosomal subunits.

Q: What is chromatin vs. chromosomes?

A: Chromatin is loose DNA; chromosomes are tightly coiled for cell division.

Q: What is diffusion?

A: Movement from high to low concentration.

Q: What is osmosis?

A: Diffusion of water toward higher solute concentration.

Q: What is tonicity?

A: The effect of solute concentration on cell shape (isotonic, hypotonic, hypertonic).

Q: What is carrier-mediated transport?

A: Transport through membrane proteins—specific, saturable, and regulated.

Q: What is facilitated diffusion?

A: Passive transport using carrier proteins.

Q: What is primary active transport?

A: Uses ATP to move substances against concentration gradients (e.g., Na⁺/K⁺ pump).

Q: What is secondary active transport?

A: Uses gradient created by primary transport to move other substances.

Q: What is vesicular transport?

A: Uses vesicles and ATP to move materials in/out of the cell.

Q: What are the types of endocytosis?

A: Receptor-mediated, pinocytosis, phagocytosis.

Q: What is exocytosis?

A: Vesicles release materials outside the cell.

Q: What is transcytosis?

A: Substance is transported across the entire cell.

Q: What is the resting membrane potential?

A: The electrical charge difference across the membrane (−10 mV to −100 mV).

Q: What are the stages of the cell cycle?

A: Interphase (G1, S, G2), M phase (mitosis + cytokinesis).

Q: What is mitosis?

A: Division of the nucleus into two identical nuclei.

Q: What is cytokinesis?

A: Division of the cytoplasm into two daughter cells.

Q: What is apoptosis?

A: Genetically programmed cell death.

Q: What are stem cells?

A: Unspecialized cells that divide to produce new specialized cells.

Q: What is cellular differentiation?

A: The process where cells become specialized by turning off specific genes.

Q: What is cytoplasm?

A: All materials between the plasma membrane and the nuclear membrane, including cytosol and organelles.

Q: What is cytosol?

A: The intracellular fluid containing dissolved nutrients, ions, proteins, and waste products.

Q: What is the function of proteasomes?

A: They contain enzymes that break down and recycle damaged or unneeded proteins.

Q: What are inclusions?

A: Masses of insoluble materials in cells, such as stored nutrients or pigment granules.

Q: What is the centrosome?

A: A region near the nucleus that organizes microtubules and contains centrioles.

Q: What is the function of motile cilia?

A: To move substances like mucus across cell surfaces in the respiratory and reproductive tracts.

Q: What is the nuclear envelope?

A: A double membrane surrounding the nucleus that is connected to the ER and contains nuclear pores.

Q: What are aquaporins?

A: Water channel proteins in the plasma membrane that facilitate rapid osmosis.

Q: What is the sodium–potassium pump?

A: A membrane protein that uses ATP to pump 3 Na⁺ out and 2 K⁺ into the cell.

Q: What is membrane potential used for?

A: It helps conduct electrical impulses and powers transport processes across the membrane.

Q: What does the nucleus do?

A: It controls the cell and stores DNA.

Q: What do ribosomes do?

A: They make proteins.

Q: What does the rough ER do?

A: It helps make and package proteins (has ribosomes on it).

Q: What does the smooth ER do?

A: It makes lipids and helps detoxify drugs.

Q: What does the Golgi apparatus do?

A: It modifies, sorts, and ships proteins.

Q: What do lysosomes do?

A: They break down waste, old parts, and bacteria.

Q: What do peroxisomes do?

A: They break down fatty acids and toxins.

Q: What do mitochondria do?

A: They produce energy (ATP) from food.

Q: What does the cytoskeleton do?

A: It gives the cell shape and helps it move things inside.

Q: What do centrioles do?

A: They help organize the spindle for cell division.