AP Biology Review Guide

Matter

Anything that has mass and takes up space

Matter is made up of?

Elements

Matter

Anything that has mass and takes up space

Matter is made up of?

Elements

Elements differ by...?

number of protons, neutrons, and electrons

Atomic mass equals

protons + neutrons

Elements are made of...?

atoms

S,Px, Py, Pz orbitals hold how many electrons?

2 electrons

How many val e- makes an element stable

8 val e-

How are covalent bonds formed?

Bonds created by sharing electrons with other atoms.

How are ionic bonds formed?

by the transfer of electrons

Oxidation

loss of electrons

Reduced

gains electrons

Is energy stored or released when e- are elevated to higher levels?

energy is stored

Is energy stored or released when e- are dropped to lower levels?

energy is released

The movement of e- between energy levels is used in...?

Cellular reactions (Photosynthesis and respiration)

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

What 4 elements make up 96% of living matter?

oxygen, carbon, hydrogen, nitrogen

Essential element

A chemical element required for an organism to survive, grow, and reproduce.

Trace element

an element that is essential for life but required in extremely minute amounts

Helium-3 has how many protons?

2 protons

Helium-3 has how many electrons?

2 electrons

Helium-3 has how many neutrons?

1 neutron

Neutron

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

Proton

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

Electron

A subatomic particle that has a negative charge

Atomic number

The number of protons in the nucleus of an atom. Specific to each element

Atomic mass

Number of protons and neutrons

Isotope

An atom with the same number of protons and a different number of neutrons from other atoms of the same element.

Electron shells

An energy level representing the distance of an electron from the nucleus of an atom.

Energy

The ability to do work or cause change

Radioactive isotope

An isotope whose nucleus decays spontaneously, giving off particles and energy.

What is directly involved in chemical reactions between atoms

Electrons

Which shell is the highest energy level- 1st or 3rd

3rd energy level

Which shell is the lowest energy level- 1st or 3rd

1st energy level

What is potential energy?

The energy that matter posses because of its location/structure

Which has more potential energy- water or glucose

Glucose due to more bonds being present

Valence electrons

Electrons on the outermost energy level of an atom

How many val e- does Na have

1 val e-

Molecule

two or more atoms held together by covalent bonds

Is water a molecule or a compound?

both

Is carbon dioxide a molecule or a compound?

compound

Is methane a molecule or a compound?

compound

Is oxygen a molecule or a compound?

molecule

Why does oxygen bond to 2 hydrogen atoms

They satisfy the val e- of an oxygen atom

What type of bond is seen in O2

Double, non-polar, covalent bond

What is electronegativity?

a measure of the tendency of an atom to attract a bonding pair of electrons

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. The shared electron is pulled closer to the more electronegative atom, making it more negative and the other atom more positive

Anion

A negatively charged ion

Cation

A positively charged ion

Van der Waals interactions

Weak attractions between molecules or parts of molecules that result from transient local partial charges.

What is the strongest bond?

ionic bond

What is the weakest bond?

van der Waals interactions

Which is stronger- covalent or hydrogen bonds

covalent bonds

Why is molecular shape important?

it determines how biological molecules recognize and respond to one another with specificity

dynamic equilibrium

a state of balance between continuing processes

What bonds are present in water

Polar covalent bonds

Are covalent bonds usually non-polar or polar

Non-polar

What happens to water molecules when they are heated

They separate from each other

What is high specific heat

The ability to absorb and give off heat without changing temperature

What is high heat of vaporization

The ability to absorb heat upon evaporation - it is used as a cooling mechanism (sweating)

Define cohesion

Attraction between molecules of the same substance

Define adhesion

An attraction between molecules of different substances

What is it called when water dissolves something

Dissolution

What does water do to prevent ions from re-associating

water surrounds the ions

Hydrophobic

Water fearing

Hydrophilic

water loving

What is the polarity of the interior and exterior of a protein

Interior- Non-polar
Exterior- Polar

Define calorie

the amount of energy/heat needed to raise the temperature of 1 gram of water 1 degree Celsius

Does water have a high or low specific heat?

high specific heat

Why does water have a high specific heat?

hydrogen bonds

Evaporization

Liquid to gas

What is heat of vaporization?

the heat a liquid must absorb for 1 g to be converted to gas

Why does ice float on water?

Ice is less dense than water

why is 4 degrees celsius a critical temperature with water?

Water behaves like other liquids, expands when warmed, contracts when cooled

Solvent

A liquid substance capable of dissolving other substances

Solution

A homogeneous mixture of two or more substances

Solute

A substance that is dissolved in a solution.

aqueous solution

a solution in which water is the solvent

Define molarity

the number of moles of solute per liter of solution

What 2 ions form when water dissociates?

hydronium (H+) and hydroxide (OH-)

What is a hydronium ion?

H3O+ or H+

What is the concentration of H+ and OH- in pure water at 25 degrees celsius

10^-7 M

What is pH

a measure of the hydrogen ion concentration of a solution

What is an acid

An acid is a source of hydrogen ions, H⁺

What is a base

a substance that reduces the hydrogen ion concentration of a solution by releasing OH- ions

How many times more acidic is a pH of 3 compared to a pH of 5

10^2=100

How many times more basic is a pH of 12 compared to a pH of 8

10^4=10,000

What is a buffer

a substance that minimizes changes in pH

How do buffers moderate pH change?

By accepting hydrogen ions from the solution when they are in excess and donating them to the solution when they have been depleted.

What type of bond is the water molecule?

polar covalent bond

What part of a water molecule is negative?

oxygen atom

Bonds between carbon and hydrogen are...

nonpolar due to carbon having less electronegativity

Bonds between nitrogen and hydrogen are...

polar due to nitrogen having more electronegativity

Ionic bonds are formed when...

electrons are completely transferred from one atom to another

What is dehydration synthesis?

The process that allows cells to remove a hydrogen from one molecule and a hydroxyl group from another (forming water) and bond the remaining subunits together

What is hydrolysis?

Hydrolysis is the separation of two macromolecules by adding water.

examples of dehydration synthesis

2 amino acids -> protein and H2O
3 monosaccharides-> polysaccharide and 2 H2O
3 fatty acids and glycerol -> lipid and 3 H2O

examples of hydrolysis

adding water to break...
- polysaccharide into a monosaccharide
- proteins into amino acids
- triglycerides into fatty acid chains

Types of carbohydrates

monosaccharides, disaccharides, polysaccharides

Examples of monosaccharides

glucose, fructose, galactose