AP Biology Unit 2

Phospholipid

a lipid that contains phosphorus and that is a structural component in cell membranes

Ribosome

Made of rRNA, synthesizes proteins

Plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

Smooth ER

Functions in detoxification and lipid synthesis

Hydrophobic

Water fearing

Rough ER

Associated with ribosomes, compartmentalizes the cell

Hydrophilic

water loving

Golgi complex

Corrects the folding and chemical modification of newly synthesized proteins, packaging for protein trafficking

Fluid mosaic model

model that describes that cell membranes consist of a structural framework of phospholipid molecules that is embedded with steroids and proteins

Lysosome

Membrane-enclosed sac that contain hydrolytic enzymes

Vacuole

Storage and release of macromolecules and cellular waste products.

Correct arrangement of phospholipids in bilayer

hydrophobic tails pointing toward inside the membrane, hydrophilic heads pointing out to the extracellular or intracellular space

Bilayer

a layer that is two molecules thick

Mitochondria

Provides compartments for different metabolic reactions.

Phosphate group

A functional group consisting of a phosphorus atom covalently bonded to four oxygen atoms

Chloroplast

Specialized organelles that are found in photosynthetic algae and plants.

Fatty acid

hydrocarbon chain often bonded to glycerol in a lipid

Matrix

Inside mitochondria, the Krebs cycle (aka citric

acid cycle) occurs here

Phospholipid structure

Phosphate group, glycerol, 2 fatty acids

Inner mitochondrial membrane

Electron transport and ATP synthesis occurs

Thylakoid

Inside the chloroplast, organized in stacks called grana. Responsible for the light-dependent reactions of photosynthesis

Stroma

The fluid within the inner chloroplast membrane and outside of the thylakoid, involved in the light-dependent reactions of photosynthesis (Calvin cycle)

Surface area-to-volume ratio

Ratio of a cell's outside area to its internal volume.

hydrophilic region of phospholipid

phosphate "head" pointed away from the interior of the cell membrane

hydrophobic region of phospholipid

fatty acid "tails" pointed towards the interior of the cell membrane

embedded protein

proteins embedded into the phospholipid bilayer

selective permeability

A property of a plasma membrane that allows some substances to cross more easily than others.

substances that can freely pass through the plasma membrane

small nonpolar molecules, such as N2, O2, and CO2

substances that pass through embedded channels and transport proteins

hydrophilic substances such as large polar molecules and ions

cell wall

provides structural boundary for plants, fungi, and prokaryotes, composed of complex carbohydrates

passive transport

the net movement of molecules from high concentration to low concentration without the use of energy

active transport

requires the direct input of energy to move molecules from low concentration to high concentration

exocytosis

process of moving substances out of the cell, internal vesicles fuse with the plasma membrane and secrete large macromolecules out of the cell, requires energy input

endocytosis

the cell takes in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane, requires energy input

facilitated diffusion

movement of specific molecules across cell membranes through protein channels

aquaporins

water channel proteins

membrane potential

The voltage across a cell's plasma membrane, generated by a difference in ion concentrations on either side

osmosis

Diffusion of water through a selectively permeable membrane

water potential

the physical property that predicts the direction in which water will flow

hypotonic

Having a lower concentration of solute than another solution

hypertonic

Having a higher concentration of solute than another solution.

isotonic

the concentration of two solutions is the same

solute potential

This measurement has a maximum value of 0; it decreases as the concentration of a solute increases.

pressure potential

This measurement has a minimum value of 0 (when the solution is open to the environment); it increases as pressure increases.

water potential equation

Ψ = Ψp+Ψs

solute potential equation

Ψs = -iCRT

symbol for pressure potential

Ψp

symbol for solute potential

Ψs

symbol for water potential

Ψ

endosymbiosis

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.

prokaryote

type of cell that generally lack internal membrane-bound organelles, but have internal regions with specialized structures and functions

eukaryote

type of cell that maintain internal membranes, partitioning the cell into specialized regions