AP Bio UNIT 2

super cool

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

amphipathic

A molecule that has both a hydrophilic region and a hydrophobic region.

Apoptosis

programmed cell death

Channel Protein

A membrane protein, specifically a transport protein, that has a hydrophilic channel that certain molecules or atomic ions use as a tunnel.

centrioles

Cell organelle that aids in cell division in animal cells only

Carrier Protein

A membrane protein, specifically a transport protein, that holds onto molecules and changes their shapes in a way that shuttles them across the membrane.

cell communication

the process of cells detecting and responding to signals in the extracellular environment

cyclic AMP (cAMP)

Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons.

concentration gradient

difference in the concentration of a substance from one location to another

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

Diffusion

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

electron microscope

microscope that forms an image by focusing beams of electrons onto a specimen

Endoplasmic Reticulum (ER)

A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.

Glycolipids

Membrane carbohydrates that are covalently bonded to lipids.

Glycoproteins

Membrane carbohydrates that are covalently bonded to proteins.

G-protein-linked receptor

A signal receptor protein in the plasma membrane that responds to the binding signal molecule by activating a G protein.

G protein

a protein coupled to a metabotropic receptor; conveys messages to other molecules when a ligand binds with and activates the receptor

hormone

Chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another

ion pumps (active transport)

integral membrane proteins that use metabolic energy to transport ions against a gradient or electrical potential. USES ATP!!!

ligand

A molecule that binds specifically to a receptor site of another molecule.

light microscope

microscope that uses a beam of light passing through one or more lenses to magnify an object

Magnification

the increase of an object's apparent size by using lenses or mirrors

membrane

thin layer of tissue covering a structure or cavity

necrosis

tissue death

nuclear envelope

Double membrane perforated with pores that control the flow of materials in and out of the nucleus.

nuclear pores

structures in the nuclear envelope that allow passage of certain materials between the cell nucleus and the cytoplasm

phosphorylation cascade

A series of chemical reactions during cell signaling mediated by enzymes (kinases), in which each kinase in turn phosphorylates and activates another, ultimately leading to phosphorylation of many proteins.

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

Plasmolysis

A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment.

protein kinase

An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.

quorum sensing

The ability of bacteria to sense the presence of other bacteria via secreted chemical signals.

Receptor

protein that detects a signal molecule and performs an action in response

Resolution of a microscope

measures direct clarity or ability to distinguish small but close objects

second messenger

a molecule that is generated when a specific substance attaches to a receptor on the outside of a cell membrane, which produces a change in cellular function

signal cascade

An entire series of reactions which occurs as a result of a single trigger reaction or compound.

signal transduction

the transmission of molecular signals from a cell's exterior to its interior

signal transduction pathway

A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response.