bio sem review (again)

polar

having a pair of equal and opposite charges

H2O= covalent bond

O has more electronegativity

(CH 3)

Water

hydrogen bonding makes H2O more structured and is reason for why ice floats (H bonds are far apart= less weight)

Cohesion: hydrogen bonds hold water together

ex: plants use cohesion to transport water against gravity up the roots

Adhesion: the clinging of one substance to another

had HIGH surface tension

it absorbs/releases large amount of heat with only a little temp change

high specific heat

evaporative cooling: liquid evaporates and surface of liquid left behind cools

solvent

(CH 3)

Carbon

4 valence electrons

Mathane: CH4

Ethane: C2H6

ethene: C2H4

(CH4)

Isomers

Same atoms but different arrangement.

1) structural isomers: differ in the covalent arrangements of their atoms (may differ in location of double bond)

2) cis-trans isomers: carbons have covalent bonds to the same atom but differ in spatial arrangements due to inflexibility of bonds.

3) Enantiomers: mirror images of each other; differ due to presence of an asymmetrical carbon (important in drugs)

(CH4)

chemical groups

functional groups: chemical groups involved directly in the chemical reaction

(CH4)

carbs

monomer: monosaccharides

polyer: polysaccharides

glycosidic linkage (covalent bond) --\> purpose is determined on where linkage is

purpose:

1) storage

-starch: plants (amylose-simplest form)

- rings are in alpha configuration

-glycogen: animals

2) structure

-cellulose: in cell walls of plants (tough)

-rings are in beta configuration

-Chitin: carb used my anthropods to build exoskeleton Glucose

- alpha (H is on the top and OH on the bottom)

- beta (OH is on the top and H on the bottom)

(CH5)

lipids

fat: glycerol + fatty acid chains

trans fats: unsaturated fats are synthetically converted to saturated fats by adding H+

phospholipids: 2 fatty acid chains, glycerol, phosphate head

steroids: 4 fused rings

-cholesterol: animals

(CH5)

protein

catalysts: proteins that speed up chemical reactions without being absorbed in them

polypeptides: polymer

amino acids: monomer

- amino group (NH2), carboxyl group (COOH), H, R

peptide bonds

function: determined by R group and sequence of polypetide

structures:

1) primary

-linear chain of amino acids

-amino end, carboxyl end

-sequence determines function

-covalent bonds/peptide bonds

2) Secondary

-Regions stabilized by hydrogen bonds between atoms of the polypeptide backbone

-a helix

-coil held together by hydrogen bonds on the 4th amino acid

-b pleated sheet

-2 or more strands of polypeptides held together by hydrogen bonds

3) Tertiary

-Three-dimensional shape stabilized by interaction between side chains

-hydrophobic interactions: hydrophobic (nonpolar) side chains attach together towards the middle of the protein

-Van der walls interactions: hold ^ together

-Disulfide bridges: covalent bonds b/w 2 cysteine monomer (-SH R group)

4) Quaternary

-Association of multiple polypeptides, forming a functional protein

-2 + Tertiary structures

-not all proteins go into this structure

denaturation: unfolding of protein

(CH5)

chaperonins

protein molecules that assist the proper folding of other proteins

(CH5)

sickle cell disease

Genetic disorder in which red blood cells have abnormal hemoglobin molecules and take on an abnormal shape.

(CH5)

nucleic acids

gene: unit of inheritance

monomer: nucleotides

- Nitrogen base, five-carbon sugar, phosphate group

polymer: nucleic acids

DNA and RNA

- mRNA: transports DNA to ribosomes

BASES

Pyrimidines: small

-cytosine, thymine, uracil

Purines: large

-adenine, guanine

5' --\> 3'

(CH5)

bonds

nonpolar: electronegativity is less than 0.5, electrons are shared equally

polar: electronegativity is b/w 0.5-1.7, electrons are shared equally but one holds more tightly

ionic: electronegativity is above 2.0, one atom steals electron= opposite charge

(CH5)