The Chemistry Of Life

Four major categories of of organic molecules

carbohydrates, lipids, proteins, nucleic acids

broad concept

chemical elements form organic molecules that interact to perform the basic functions of life

6 most common elements

C, H, O, N, P, S

isotopes

Atoms of the same element that have different numbers of neutrons but same protons

ex carbon 12 vs carbon 14

What are the uses of radioactive isotopes?

age of rocks/fossils, treating cancer/killing bacteria, tracers to follow substances

ionic bond

transfer of electrons

covalent bond

shared electrons

single: 2 electrons

double: 4 electrons

triple: six electrons

polarity (polar molecule)

electrons are shared unequally between atoms in a molecule causing regions of positive and negative charge

ex: oxygen has a stronger attraction to electrons making it slightly negative

hydrogen bond

attraction between the hydrogen of one water molecule and the oxygen of another water molecule

cohesion

Attraction between molecules of the same substance which causes molecules of water on the surface to be drawn inward

adhesion

An attraction between molecules of different substances

meniscus forms in a graduated cylinder because adhesion > cohesion

capillary action

adhesion between water and glass causes water to rise in a small tube

one of the forces that helps water rise in trees

solute

substance that is dissolved

solvent

substance that does the dissolving

hydrophobic

water fearing substances that will not dissolve in water

fats and oils

hydrophilic

water loving substances that will dissolve in water

acid

a compound that donates H+ ions to a solution

base

a compound that removes H+ ions from a solution

why are carbon atoms so common in living things

bonding ability depends on # electrons in its outermost energy level

carbon has only 4 electrons outer shell so it can form up to 4 bonds

hydroxyl group

carbonyl group

C=O

carboxyl group

COOH

amino group

A functional group that consists of a nitrogen atom bonded to two hydrogen atoms

carbohydrates

Elements: C, H, O

Functions: energy quick and stored

monomers: glucose, fructose

polymers: starch, cellulose, glycogen

To test simple sugars use benedicts (red)

for starch use Iodine (black)

Monosaccharides are

glucose

broken down by cells to get energy

disaccharide

sucrose

main carb in plant sap

table sugar

lipids

Elements: C, H, O

Functions: for long term energy storage

insulation,

makes up cell membrane

monomers: glycerol, fatty acids

polymers: triglyceride, steroids

other: cholesterol

hydrophobic dissolve in oils not water

fat

three carbon backbone called glycerol attached to 3 fatty acids which contain long hydrocarbon chains

saturated fatty acid vs unsaturated

steroids

lipid molecule in which the carbon skeleton forms four fused rings

hydrophobic

chemical signal

proteins

elements: C,H,O,N

functions: for chemical messengers

repairing cells

building muscle

long lasting energy

helps immune system

movement

hormone signals

helps transport oxygen with hemigloben

chemical receptors

monomers: amino acid

polymers: polypeptide

(amino acids linked by peptide bonds)

USE BIURET (purple)

nucleic acids

elements: C, H, O, N, P

uses: hereditary information,genetic code

monomers: nucleotide

polymers: Dna and rna

what is dna

threalike double-helical macromolecule

deoxyribonucleic acid

subunits called nucelotides

hydrolysis

adding water breaks down the polymer

dehydration synthesis or condensation reaction

hydroxyl group of one monomer reacts with a hydrogen from another monomer to release h20

peptide bond

a molecule of water is removed from two glycine amino acids to form a peptide bond

organic molecules

molecules in a cell including a skeleton of carbon atoms

inorganic molecules

molecules that do not contain carbon skeletons like water

hydrocarbons

organic molecules composed of only carbon and hydrogen

functional groups

different arrangements of atoms bonded to a carbon skeleton which give specific properties to molecules

monomers

small, similar molecular units

polymers

long chains of monomers

monosaccharides

simple sugars that contain just one sugar molecule

Disaccharide

sugars constructed from 2 monosaccharides

fatty acids

long chain hydrocarbons that end in a single carboxyl acid (COOH group)

-poorly soluble

tryglicerides

lipids composed of three fatty acids that are covalently bonded to a 3 carbon glycerol molecule ex: solid fats and liquid oils

phospholipids

main structural component of cell membrane

glycolipids

the outer membrane of most cells and sit in membranes

enyzme

made of protein

speeds up reaction rate but must overcome activation energyf

without reactions are too slow for body needs

active site

part of the enzyme where the substrate binds and the chemical reactions takes place

denaturation

proteins lose shape as thermal energy breaks down hydrogen bonds holding secondary and tertiary structure together

ph changes/salt concentrations

becomes nonfuctional

pH of blood and bodily fluids

7.4

maintained by bicarbonate buffering system

Steps in an Enzyme-Catalyzed Reaction

1. substrate binds to active site of enzyme forming enzyme-substrate complex

2. substrate-products

3. product is released

4. enzyme can be used again