AP Bio Unit 3 CELLS

Prokaryote

Cells that do NOT contain a nucleus or other membrane bound organelles; bacteria

Eukaryote

Cells that contain a nucleus and other membrane bound organelles (ER, GA, lysosome, vacuole, mitochondria, etc)

Fluid mosaic model

Model that describes the plasma membrane as a mosaic (mixture) of protein molecules bobbing in a fluid (moves) bilayer of phospholipids

Vesicle

Membrane surrounded container used to ship or store materials for the cell

Endomembrane system

System of organelles that are continuous or connected through the transfer of vesicles; example: ER --> GA --> plasma membrane

Nucleus

Contains most of the DNA in a eukaryotic cell

Asexual reproduction

The generation of offspring from a single parent, without the fusion of reproductive cells

Plasma membrane

The membrane at the boundary of every cell that acts as a selective barrier, regulating the cell's chemical composition; a phospholipid bilayer with embedded proteins

Selectively permeable

Allows only some substances to cross

Free ribosomes

Uses mRNA to build proteins that remain in cytosol (such as cytoskeleton or motor proteins); NOT attached to ER

Bound ribosomes

Attached to endoplasmic reticulum; builds proteins that need to enter the endomembrane system (such as excreted from the cell, integrated into the plasma membrane, found inside an organelle)

Smooth ER

Organelle that synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, stores calcium ions; no ribosomes

Rough ER

Has attached ribosomes that make proteins found in membrane & secreted proteins, distributes transport vesicles, and is a membrane factory for the cell

Golgi apparatus (GA)/ Golgi complex

Modifies certain products of the ER;

Manufactures certain macromolecules;

Sorts and packages materials into transport vesicles, adds molecular "ID tags" for proper delivery

Lysosome

Vesicle containing hydrolytic enzymes that can digest macromolecules

Vacuole

Organelle that store molecules, mainly water

Mitochondria

Organelle that uses sugar & oxygen to generate ATP (process called cellular respiration)

Contains circular DNA, ribosomes, double phospholipid membrane, cristae (folds)

Chloroplast

Organelle that uses light energy to generate oxygen & sugars (process called photosynthesis)

Contains circular DNA, ribosomes, double phospholipid membrane, thylakoids, stroma

Endosymbiosis theory

The theory that mitochondria and chloroplast originated as prokaryotic cells engulfed by host cells

Evidence includes that they both contain:

Phospholipid membrane

Free-floating circular DNA

Ribosomes

Similar size (1-10 mm)

Similar reproduction

Diffusion

The tendency for molecules to spread out evenly into the available space

A substance will move from where it is MORE concentrated to where it is LESS concentrated

Osmosis

Diffusion of water

Lysis

To break; the disintegration of a cell by rupture of the cell wall or membrane; example: when an animal cell is placed in a hypotonic solution

Salinity

Measure of all the salts dissolved in water

Hypertonic solution

Solute concentration is greater than that of the other solution; cell placed in a hypertonic solution will shrink

Hypotonic solution

Solute concentration is less than that of the other solution; cell placed in a hypotonic solution will expand

Isotonic solution

Solute concentration is the same as inside the cell; no net water movement across the plasma membrane

Osmoregulation

The control of solute concentrations and water balance; example: paramecium in freshwater (hypo) have contractile vacuoles to pump incoming water back out

Facilitated diffusion

Movement of specific molecules across cell membranes through protein channels; passive transport process (no energy required); example includes aquaporins

Water potential

Tendency of water to diffuse from one area to another;

= Water's potential energy;

Always moves from regions of higher water potential to regions of lower water potential

Exocytosis

transport vesicles migrate to the membrane, fuse with it, and release their contents

EXO= EXIT

Endocytosis

Cell takes in molecules and particulate matter by forming new vesicles from the plasma membrane

ENDO= ENTER

ATP

Adenosine triphosphate; Main energy source that cells use for most of their work

An organic molecule called adenosine attached to a string of three phosphate groups

Active transport

Moves substances against their concentration gradients

Requires energy, usually in the form of ATP

Solute

A substance that is dissolved in a solution.

Osmolarity

Total concentration of all solute particles in a solution

Homeostasis

Process by which organisms maintain a relatively stable internal environment

Proton pump

An active transport protein in a cell membrane that uses ATP to transport hydrogen ions against their concentration gradient, generating a membrane potential in the process.

Passive transport

Requires NO energy, Movement of molecules from high to low concentration, Examples include diffusion, osmosis, & facilitated diffusion

Plasmolyzed

Plant cell in hypertonic solution; Cell membrane Pulls away from cell wall

Turgid

Plant cell in hypotonic solution

Thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Stroma

In plants, the fluid in a chloroplast