AP Bio: Unit 1 Biochem

Why are water molecules polar?

uneven distribution of electrons between hydrogen and oxygen

What are the properties of water?

cohesion, adhesion, temperature regulation, expansion upon freezing, evaporative cooling, universal solvent

Cohesive behavior

the linking of like molecules; water molecules stick together causing water to have a high surface tension

Adhesion

water molecules stick to other molecules

Transpiration

water travels against gravity from roots to leaves in plants due to adhesion and cohesion

Moderation of temperature

water has a high specific heat; it must absorb or give off a lot of energy before its temperature will increase or decrease

Expansion upon freezing

ice floats at the top of large bodies of water, preventing them from freezing solid enabling a moderation of water temperature

Universal solvent

things easily dissolve in water

Hydrophilic substances

are water soluble and dissolve easily in water

Hydrophobic substances

do not easily dissolve in water

pH scale

runs from 0-14 measuring relative acidity and alkalinity ("basicity") of aqueous solutions

Acids

have excess H+ ions and a pH below 7.0

Bases

have excess OH- and a pH above 7.0

Pure water

neutral with a pH of 7.0

Buffers

substances that minimize the changes in pH within the body; a partnership between a weak acid and a weak base that forms as the acid dissolves in water

Carbon

can form many molecules by bonding to 4 other atoms

Tetravalent

having 4 valence electrons, can bond to 4 atoms

Hydrocarbons

compounds made only of H atoms that are covalently bonded to C

Isomers

compounds with the same number of atoms but different structures, and therefore different properties

Polymers

long molecules made of many similar or identical building blocks linked by covalent bonds

Monomers

small building blocks to polymers

Carbohydrates

main source of energy, most abundant molecules for life, monosacchrides

Disaccharides (Oligosaccharides)

short chain of 2 or more sugar monomers

Polysaccharides

complex carbohydrates; straight or branched chain of 100s or 1000s of sugar

Starch

plant storage of sugars, polysaccharide

Cellulose

firebrick material in plant cell walls, polysaccharide

Glycogen

energy storage in animal muscles and liver

Lipids

most consist of one glycerol and 3 fatty acids (triglyceride), hydrocarbon chain with a carboxyl group at one end can be saturated or unsaturated

Saturated fatty acid

animal fats, linked to heart disease

Unsaturated fatty acid

has 1 or more double bonds formed when a hydrogen is removed (plant fats)

steroids
'

4 fused rings (3 6-C rings and 1 5-C ring)

Proteins

complex macromolecules that carry out bodily functions such as growth and repair, signaling between cells, defense against invaders, catalyze

What is the structure of protein?

made of amino acids (20 different ones), held together by peptide bonds making polypeptide chains

Primary

linear; Covalent bonds

Secondary

coils (alpha helix) or folds (beta pleated sheet); H bonds

Tertiary

hydrogen bonding, ionic bonding and other interactions among the R groups\= overall shape; disulfide

Quaternary

more than one polypeptide chain are attached (collagen or hemoglobin); H & Disulfide

Denaturation

unraveling of protein/loss of 3D shape due to change in pH, temperature, salt conc; not able to function as a protein within the cell

Nucleic acid

made of nucleotides (the monomers)

Nucleotides

5-C sugar (ribose or deoxyribose), nitrogen containing base (A, T, G, C, U), and a phosphate group

DNA

double stranded helix that carries heritable information

RNA

single stranded, functions to translate the code from DNA to make proteins

Specific heat

the amount of heat that must be absorbed or lost for 1 g of that substance to change by 1C

Phospholipid

make up cell membranes

Steroids

lipids characterized by a carbon skeleton consisting of 4 fused rings

Cholesterol

steroid, common component of animal cell membranes and is also the precursor from which other steroids are synthesized

Peptide bond

the chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

Four Steps for life to emerge on earth

1. an abiotic synthesis of amino acids and nucleic acids must occur
2. monomers must be able to join together to form more complex polymers using energy obtained from the surrounding environment.
3. the rna/ dna form and gain the ability to reproduce and stabilize by using chemical bonds and complimentary bonding.
4. the evolution of protobiont (first life form) membrane of phospholipids and proteins to keep the cell intact.

Protobiont

first life form

Miller-Urey Experiment

took inorganic gases and used an electrical spark to form organic molecules

the first molecule to evolve first

RNA

Molecule that is not as molecularly stable as DNA

RNA

essential for storing, retrieving, or conveying by inheritance molecular information on constructing the components of living cells; DNA or RNA

nucleic acids

building blocks for proteins, needed to construct the work horse molecules of the cells

amino acids

the majority of the cell, in biomass, is

proteins