LS7A AOL 1

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge, found in the orbitals

Electronegativity

the ability of a molecule to attract electrons

Polarity

A lack of electrical symmetry in a molecule. Charge differences on opposite ends of a structure.

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

Polar Covalent Bond

A covalent bond in which electrons are not shared equally

What are the four main elements of life?

carbon, oxygen, hydrogen, nitrogen

Which elements are highly electronegative?

Oxygen (O) and Nitrogen (N)

Which elements will create nonpolar covalent bonds if bonded together

Carbon (C) and Hydrogen (H)

Potential energy and intermolecular distance graph

A graph that illustrates bond strength based on distance between bonds

How much potential energy does the strongest bond have on the Potential energy and intermolecular distance graph?

The lowest amount

What does it mean to be positive on the potential energy and intermolecular distance graph?

The molecules are repulsed (repulsion)

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Ionic Bond

Formed when one or more electrons are transferred from one atom to another

hydrogen bond

weak attraction between a hydrogen atom and another electronegative atom

van der Waals Interactions

A temporary negative charge from the accumulation of electrons that gives a molecule the ability to interact with other molecules

Which bond/interaction is the strongest? (in biology)

Covalent Bond

Which bond/interaction is the weakest?

Van Der Waals

intermolecular bonds

bonds between molecules

hydrophilic

water loving (polar)

hydrophobic

water fearing (nonpolar)

What does a molecule need in order to hydrigen bond with itself?

it must have a polar bond with a partially negative electronegative molecule (usually O or N) and a partially positive hydrogen

What does a molecule need in order to bond with water (H2O)

it must have a polar bond with a partially negative electronegative molecule (usually O or N) (it does not need a partially positive hydrogen because the water already has one)

prokaryotic cell

cell that does not have a nucleus or other membrane-bound organelles. Has a cell wall. Typically smaller than eukaryotic cells.

Eukaryotic cells

cells that contain a nucleus and other membrane-bound organelles. Usually much larger than prokaryotic cells.

What are the differences between plant and animal cells?

Plant cells have chloroplasts, a cell wall (and a central vacuole)

Organelle

specialized structure that performs important cellular functions within a eukaryotic cell

cytoplasm

the portion of the cell outside the nucleus

cytosol

Fluid portion of cytoplasm

mitochondria

organelle that is the site of ATP (energy) production

chloroplast

Site of photosynthesis

nucleus

A part of the cell containing DNA and RNA and responsible for growth and reproduction

Endoplasmic Reticulum (ER)

A system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids.

Smooth ER

makes lipids

Rough ER

That portion of the endoplasmic reticulum studded with ribosomes, creates proteins

ribosome

site of protein synthesis

Triglycerides

an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid.

fatty acid

hydrocarbon chain often bonded to glycerol in a lipid

phospholipid

a lipid that contains a phosphate head and fatty acid tail; is a structural component in cell membranes

Cholesterol

A lipid that forms an essential component of animal cell membranes

Fluid mosaic

the membrane is a fluid structure with a "mosaic" of various proteins embedded in or attached to a double layer (bilayer) of phospholipids

What is the effect of cholesterol on membrane fluidity?

Cholesterol is a buffer, in low temperatures, it increases fluidity by preventing the phospholipids from pacing, and in high temperatures it decreases fluidity by forming van der waals interactions with the fatty acid tails of the phospholipids which make up the cell.

What is the effect of longer fatty acid tails on membrane fluidity?

Increases stability, since there is more surface area for van der waals interactions

unsaturated fatty acid

A fatty acid with double bonds, has a kinked shape

saturated fatty acid

a fatty acid with no double bonds, straight shape

what is the effect of unsaturated fatty acids on membrane fluidity?

the unsaturated fatty acids increase fluidity because their shape prevents compaction of the phospholipids

phospholipid bilayer

A double layer of phospholipids that makes up plasma and organelle membranes.

amphipathic

having both a hydrophilic region and a hydrophobic region

phospholipid heads are:

hydrophilic

Phospholipid tails are:

hydrophobic

transmembrane protein

An integral membrane protein that spans the phospholipid bilayer.

integral proteins

proteins embedded in the phospholipid bilayer.

peripheral proteins

The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.

channel proteins and carrier proteins

Two types of transport proteins facilitate the movement of molecules or ions across membranes:

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

Diffusion

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

osmosis

Diffusion of water

hypertonic

Having a higher concentration of solute than another solution.

hypotonic

Having a lower concentration of solute than another solution

isotonic

when the concentration of two solutions is the same

tonicity

the ability of a surrounding solution to cause a cell to gain or lose water

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

secondary active transport

Form of active transport which does not use ATP as an energy source; rather, transport is coupled to ion diffusion down a concentration gradient established by primary active transport.

primary active transport

Active transport that directly relies directly on the hydrolysis of ATP.

electrochemical gradient

The combination of chemical and electric forces that creates a powerful gradient

Co-Transporter

gradient generated by one molecule drives active transport of another (one goes with the gradient, the other goes against)

pump

active transport mechanism that works against electrochemical gradients

Which molecule is most likely to diffuse across a membrane?

a nonpolar molecule

which molecule is least likely to diffuse across a membrane (with no assistance)?

an ion (Charged Molecule)

Rank the following molecules by their likelihood of diffusing through the cell: a large uncharged polar molecule, a small uncharged polar molecule, an ion, and a nonpolar molecule

1. nonpolar 2. small, uncharged, polar molecule 3. a large uncharged, polar molecule 4. an ion

metabolism

All of the chemical reactions that occur within an organism or cell

anabolism

Metabolic pathways that construct molecules, requiring energy.

Catabolism

Metabolic pathways that break down molecules, releasing energy.

breaking bonds ________ energy

requires

kinetic energy

energy of motion

Examples of kinetic energy

light, thermal energy/heat, electricity

potential energy

stored energy that results from the position or shape of an object

Gibbs free energy

the energy of a system that is available to do work

ΔG

Gibbs Free energy

Enthalpy

total energy of a system (including unusable energy)

ΔH

Enthalpy

Entropy

a measure of the disorder of a system

ΔS

Entropy

Gibbs free energy equation

ΔG = ΔH - TΔS

Gibbs free energy, nonstandard conditions

ΔG=ΔG°+RTln(Q)

What does Q mean in the nonstandard gibbs free energy equation?

Products/reactants

exergonic

releases energy, has a negative ΔG

endergonic

requires energy, has a positive ΔG

spontaneous reaction

A reaction that occurs without the input of energy (exergonic)

non-spontaneous reaction

a reaction that needs an input of energy to occur (endergonic)

reaction coupling

an endergonic reaction occurs because it is paired with an exergonic reaction

pH

measurement of the concentration of H+ ions in a solution. (More H+ means more acidic which means lower pH)

enzyme

A type of protein that speeds up a chemical reaction in a living thing

substrate

reactant of an enzyme-catalyzed reaction

active site

The part of an enzyme where the substrate bonds to and the chemical reaction occurs.

reaction rate

the rate at which reactants change into products over time

activation energy

the minimum amount of energy required to start a chemical reaction

What do enzymes do?

They stabilize the transition state to lower the activation energy