Edit · lab week 2

Nucleus.

Contains the cell's DNA and controls cellular activities.

Nuclear envelope

Encloses the nucleus.

Nucleolus

Produces ribosomes.

Nuclear pore

Allows materials to move into and out of the nucleus.

Plasma membrane Forms the external boundary of the cell.

Cytosol The fluid portion inside the cell.

Smooth ER

Site of lipid synthesis.

Rough ER

Internal cellular membrane network covered with ribosomes; involved in protein processing and transport.

Ribosome

Site of protein synthesis.

Golgi apparatus Packages, modifies, and transports proteins.

Lysosome

Contains a sac of digestive enzymes.

Mitochondrion

Main site of ATP synthesis.

Centriole

Forms basal bodies and helps direct mitotic spindle formation.

Cytoskeleton

Acts as a scaffolding for cellular attachment and movement.

Inclusions

Examples include glycogen granules and ingested foreign materials.

Microfilaments

Thin cytoskeletal fibers that help with cell shape and movement.

Microtubules

Large cytoskeletal fibers involved in cell shape, movement, and chromosome movement.

Intermediate filaments

Cytoskeletal fibers that provide strength and support.

Peroxisome

Contains enzymes that break down harmful substances and fatty acids.

Sperm cell

Has a flagellum for movement.

Smooth muscle cell

Has an elongated shape tapered at each end.

Cardiac muscle cells

Cells that are joined closely together.

Red blood cells

Circular cells that are anucleate, meaning they have no nucleus.

Squamous epithelium

Cells that are thin and flat with irregular borders.

Longest cell

Mature neuron.

Mitosis Cell

division that produces two genetically identical daughter cells.

Function of mitosis

Growth and repair; replaces damaged or old cells.

Interphase

The stage when the cell carries out normal metabolic activities and prepares for division.

G1 phase

Cell grows and carries out normal metabolic activities.

S phase

DNA is replicated.

G2 phase

Final preparation for mitosis.

Prophase

Chromosomes condense, the nucleolus disappears, the nuclear envelope breaks down, and the mitotic spindle begins to form.

Metaphase

Chromosomes line up in the center of the cell and attach to spindle fibers.

Anaphase

Chromosomes separate and move toward opposite poles; chromosomes appear V-shaped.

Telophase

Nuclear envelopes reform around each set of chromosomes.

Cytokinesis

Division of the cytoplasm to form separate daughter cells.

Chromatin

Uncondensed DNA in the nucleus.

Chromosome

Condensed form of chromatin.

Centromere

The region where sister chromatids are attached.

Binucleate

Containing two nuclei.

Mitotic spindle

Structure that attaches to chromosomes and helps separate them during mitosis.

Kinetic energy of molecules

Energy of motion.

Molecular movement

Reflects the kinetic energy of molecules.

Random molecular movement

Movement that is random and erratic.

Temperature and molecular speed

Molecular speed increases as temperature increases.

Molecule size and movement

Smaller molecules generally move faster than larger molecules.

Passive transport

Movement that does not require cellular energy.

Active transport

Movement that requires energy, usually ATP.

Simple diffusion

Movement of molecules from an area of higher concentration to lower concentration.

Facilitated diffusion

Passive movement through membrane proteins or channels from high to low concentration.

Osmosis

Diffusion of water across a selectively permeable membrane.

Concentration gradient

A difference in concentration between two areas.

Equilibrium

State in which there is no net movement because concentrations are balanced.

Selectively permeable membrane

Allows some substances to pass through while restricting others.

Membrane permeability

Depends partly on pore size and the properties of the substances.

Hydrophilic

Water-loving; generally cannot easily pass through the lipid bilayer without assistance.

Hydrophobic

Water-fearing; can more easily pass through the lipid portion of the membrane.

Channel protein

Provides a passageway through the membrane for specific substances.

Carrier protein

Binds to and helps move specific substances across the membrane.

Isotonic solution

Has the same solute concentration as the cell; there is no net water movement.

Hypotonic solution

Has a lower solute concentration than the cell; water moves into the cell.

Hypertonic solution

Has a higher solute concentration than the cell; water moves out of the cell.

Cell in a hypotonic solution

Swells because water enters the cell.

Cell in a hypertonic solution

Shrinks or crenates because water leaves the cell.

Cell in an isotonic solution

Remains about the same size because there is no net movement of water.

Crenated red blood cell

A shrunken red blood cell caused by water leaving in a hypertonic solution.

Diffusion

Net movement of particles down their concentration gradient.

Simple diffusion vs. osmosis

Both are passive, but simple diffusion moves solutes while osmosis moves water.

Simple diffusion vs. facilitated diffusion

Both are passive and move substances down a concentration gradient; facilitated diffusion requires a membrane protein.

Pinocytosis

A type of endocytosis in which the cell takes in extracellular fluid.

Receptor-mediated endocytosis

A selective form of endocytosis in which receptors bind specific substances before bringing them into the cell.

Endocytosis

Movement of substances into a cell using vesicles.

Exocytosis

Movement of substances out of a cell using vesicles.

Osmosis in a U-tube experiment

Water moves across a selectively permeable membrane toward the side with the higher solute concentration.

10% NaCl inside a sac and 4% NaCl outside

NaCl diffuses out of the sac down its concentration gradient if the membrane is permeable to NaCl.

10% glucose inside a sac and 40% glucose outside

Glucose moves into the sac if the membrane is permeable to glucose.

Albumin and a membrane impermeable to albumin

Albumin does not cross the membrane.

Water movement across a membrane

Water moves toward the side with the higher concentration of nonpenetrating solute.

Why plasma cells have abundant rough ER

Plasma cells produce and secrete large amounts of protein antibodies.

Why lysosomes are important in decomposition

They contain digestive enzymes that break down cellular materials.

Blocking DNA synthesis

Stops DNA replication during S phase and prevents normal cell division.

Water intoxication

Too much water can make blood plasma hypotonic, causing water to enter cells and potentially making them swell.

LDL receptor function

Receptors help remove LDL from the blood by allowing cells to take it in.

Defective LDL receptors.

LDL remains in the bloodstream and can contribute to deposits in arterial walls.