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.