The Cell - Unit 2 AP Biology

Flashcards for reviewing the second unit of APBIO

Lysosomes

Must maintain an acidic pH in order to dispose of cellular waste.

Peroxisomes

Carry out chemical reactions called oxidation reactions and produce hydrogen peroxide.

Endomembrane System

A group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins.

Endoplasmic Reticulum

Plays an important role in the modification of proteins and the synthesis of lipids; consists of a network of membranous tubules and flattened sacs.

Rough ER

Has ribosomes that make proteins and feed the newly forming protein chains into the lumen.

Smooth ER

Synthesizes carbs, lipids, and steroid hormones; detoxifies medications and poisons; stores calcium ions.

Transitional ER

"Smooth" patches on rough ER - exit sites for vesicles budding off from the rough ER.

Golgi Apparatus

Storing, tagging, packaging, and distribution of lipids & proteins.

Lysosome

Organelle that contains digestive enzymes & acts as organelle-recycling facility; can digest foreign particles that are brought into the cell.

Peroxisomes Definition

Houses enzymes involved in oxidation reactions, which produce hydrogen peroxide as a by-product.

Mitochondria

Break down fuel molecules & capture energy in cellular respiration.

Endosymbiosis

Scientific type of symbiosis where one organism lives inside the other.

Cell membrane

Defines borders of cell and allows cell to interact with its environment in a controlled way.

Plasma membrane

Mosaic of components (phospholipids, cholesterol, & proteins) that move freely & fluidly in the plane of the membrane.

Glycoprotein

Protein with carb attached.

Glycolipid

Lipid with carb attached.

Phospholipid

Lipid made of glycerol, 2 fatty acid tails, & a phosphate-linked head group.

Phospholipid bilayer

2 layers of phospholipids with their tails pointing inward; cholesterol is found in the core of the membrane.

Integral membrane proteins

At least one hydrophobic region that anchors them to the core of the phospholipid bilayer.

Transmembrane proteins

Extend all the way across the membrane.

Peripheral membrane proteins

Found on the outside or inside surfaces of membranes; attached either to integral proteins or phospholipids; do NOT stick into the hydrophobic core of the membrane.

Phospholipids Location

Main fabric of membrane.

Cholesterol Location

Tucked between hydrophobic tails of the membrane phospholipids.

Integral proteins location

Embedded in the phospholipid bilayer; may or may not extend through both layers.

Peripheral proteins location

On the inner or outer surface of the phospholipid bilayer, but not embedded in its hydrophobic core.

Carbohydrates location

Attached to proteins or lipids on the extracellular side of the membrane (forming glycoproteins & glycolipids).

Passive transport

Transport that does not require energy.

Concentration gradient

Region of space over which the concentration of a substance changes.

Permeability

Quality of a membrane that allows substances to pass through it.

Equilibrium

State at which a substance is equally distributed throughout a space.

Active transport

Transport that requires an input of energy to occur.

ATP

Adenine triphosphate - primary energy carrier in living things.

Bulk transport

Bulk transport mechanisms involve enclosing substances in membrane which can bud from or fuse w/ the membrane.

Endocytosis

General term for the various types of active transport that move particles into a cell by enclosing them in a vesicle made of plasma membrane.

Phagocytosis

Form of endocytosis in which large particles (such as cells or cell debris) are transported INTO the cell .

Pinocytosis

Form of endocytosis in which a cell takes in small amounts of extracellular fluid.

Receptor-mediated endocytosis

Form of endocytosis in which receptor proteins on the cell surface are used to capture a target molecule.

Exocytosis

Form of bulk transport in which materials are transported from the inside to the outside of the cell in membrane-bound vesicles that fuse w/ the plasma membrane.

Aquaporin

Channel protein specialized for the transport of water.

Electrochemical gradient

Combination of the electro gradient & the concentration gradient.

Antiporter

A substance moving w/ its concentration gradient is providing the energy for another substance to move against its concentration gradient; substances move in OPPOSITE directions.

Secondary active transport

Uses an electrochemical gradient - generated by active transport - as an energy source to move molecules against their gradient.

Sodium-potassium pump

Moves Na+ out of the cell & K+ into them; uses ATP as energy source; important in animal cells.

Osmosis

Net movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Osmolarity

Total concentration of solutes in a solution.

Hyperosmotic

Higher osmolarity.

Hypo osmotic

Lower osmolarity.

Isoosmotic

Same osmolarity.

Tonicity

Ability of an extracellular solution to make water move into or out of a cell by osmosis.

Plasmolysis

Under hypertonic conditions, the cell membrane can detach from the cell wall and constrict the cytoplasm.