Biology Notes

What makes up 96% of matter?

Hydrogen, carbon, nitrogen, oxygen

What determines function?

Shape dictates how a molecule behaves

What is mass number?

Protons plus neutrons in nucleus

What is atomic number?

Protons

How is atomic mass measured?

In special units called the dalton (Da)

What are isotopes?

Forms of an element with different # neutrons

What changes in an isotope?

The neutron, which means mass number changes

What does a radioactive isotope indicate?

It is unstable

What is the atomic weight?

The average of all naturally occurring isotopes in an element

What to know about orbitals?

Can hold up to two electrons, are the “houses” on the electron shell “road”. They will each have 1 electron before having pairs.

What is the outermost shell called?

Valance shell, # of unpaired electrons is called the valence

How many electrons are in a filled valence shell?

8

What is a covalent bond?

Two atoms sharing electrons

What is electronegativity?

Electrons are not shared equally when atoms of different elements are bonded together in a compound.

What is a polar versus non polar covalent bond?

Polar is when electrons are shared unequally versus non polar is when they are shared equally

What situation means high electronegativity?

More protons and less shells

What are ionic bonds

Formed when electrons fully transfer from one to the other.

What are positive versus negative ions called?

Positive cations versus negative anions

What are ways to represent molecules?

Molecular formula, structural formula, ball-and-stick model, space-filling model

Where did the Earth form?

In aqueous environments

What is water good at?

Being a solvent, meaning an agent for dissolving substances into a solution

What is water’s most dense form?

Liquid, the molecules have kinetic energy to break and reform in liquid but in ice have rigid state which is why ice floats

What is specific heat?

Amount of energy required to raise temperature of 1 gram by 1 degree C.

What is a good equation for specific heat?

As polarity rises, hydrogen bonds rise, and more energy is needed.

How do chemical reactions work?

The reactant (initial) on the left and product (resulting) on the right work to have an equal number of atoms in each element

What is chemical equilibrium?

There is a constant concentration that is trying to become equal

What are ions?

Substances that have an electric charge because of gaining or losing electrons

What is molecular weight?

The sum of the atomic weights of all atoms in a molecule

What is Molarity?

The number of moles in solute present per liter of solution

What molecules release versus accept protons?

Basic accepts, acids release

Where were chemical reactions started that spurred chemical evolution?

They started in the atmosphere and in deep-sea hydrothermal vents

What is endothermic verses exothermic

Liquid to gas is endothermic and gas to liquid is exothermic

What is energy?

The capacity to do work or supply heat

What does the transfer of energy look like?

Heat

1st law of thermodynamics

Energy can only be transferred or transformed not destroyed

2nd law of therodynamics

Entropy rises when both system and environment are accounted for

Miller’s Spark Discharge Experiment

Simulated early Earth by adding electrodes to methane, ammonia, hydrogen, etc. and with water

What are amino acids?

Building blocks that have a common core structure

How are amino acids structured?

A central carbon atom will bond covalently to H, NH2 (amino acid), COOH (carboxyl), and an “R” group side chain

What is the function of “R” groups?

They make each of the 20 amino acids unique — shaping its orientation, directionality, and flexibility

Adding water does what to a polymer?

It breaks it up, in a process called hydrolysis, opposite is dehydration reaction

What is a peptide bond?

C-N covalent that gives molecule its backbone

What are proteins?

The complete functional form of a molecule, with 4 levels of structure

What is a protein primary structure?

The unique sequence of amino acids in a protein

What is the protein secondary structure?

Either an a-helix or B-pleated sheet, only using hydrogen bonds

What is the protein tertiary structure?

Residues are brought together through hydrogen bonding, hydrophobic interactions, van Der Waals interactions, covalent or ionic bonding

What is an inactive protein look like?

It loses shape, and can be unfolded/denatured

What facilitates folding?

Molecular chaperones

What are prions?

Infectious proteins that have different structure but same shape

What are some protein functions?

Catalysis to chemical reactions through enzymes, defense (antibodies), movement of cells/other substances, signaling, structure, transportation of molecules

What are biomolecules?

Carbs, lipids, proteins, nucleic acids

What is a monomer

Building blocks

Carbohydrates

Monomer is a monosaccharide and this is a major energy source stored in things like glycerol or starch

Lipids

Have many types that are usually made with glycerol and fatty acids. They are hydrophobic, make up membrane structure, and have long-term energy storage. They are also important for insulation and may act as hormones.

Protein

Monomer is amino acids bonded together, makes muscle tissue, hair, collagen, protein channels in cell membranes, cell receptors, most enzymes, antibodies, hormones

What are enzymes?

Things that break or build substances

Nucleic acids

Monomer is a nucleotide, they are DNA or RNA, all genetic information is nucleic acids

What is the difference between DNA and RNA?

DNA has double helix and is for long term genetic storage use while RNA is for transferring information and is single strand

How to remember the structure for each biomolecule (carbs, lipids, proteins, nucleic acids)

CHO, CHO, CHON, CHONP