Chemistry of life

Elements

Elements

Any substance that cannot be broken down into simpler substances by chemical means

Trace elements

Only required by organisms in a really small quantities

Atom

the basic unit of a chemical element that retains its chemical properties

Nucleus

Center of an atom

Protons

positively charged subatomic particles

Neutrons

Uncharged particles

Electron

A subatomic particle that has a negative charge

Isotope

Same Number of protons but different in the number of neutrons

Compound

Two or more different elements combined in a fixed ratio

chemical bonds

the forces that hold atoms or ions together in a compound

Ions

Charged atoms

Covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

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

Hydrogen

Partial positive charge

Oxygen

Partial negative charge

Polar

Molecule with partial charges. Mixes with water.

hydrogen bond

Weak chemical bonds that form when a hydrogen atom is covalently bonded to one electronegative atom that is also attracted to another electronegative atom; individually weak, but strong in large numbers

cohesive forces

Strong tendency for water molecules to stick together

Adhesive

Likes to stick to other substances

capillary action

The ability of a water to flow against gravity up a narrow tube

heat capacity

the amount of heat needed to increase the temperature of an object exactly 1°C; The ability of a substance to store heat

organic compounds

compounds that contain carbon

Carbohydrates

Contains carbon hydrogen and oxygen

Monosaccharide

A single sugar molecule such as glucose or fructose, the simplest type of sugar

glycosidic bond

Bond between two monosaccharides

dehydration synthesis

Condensation reaction where molecules are connected by loss of a water molecule.

Hydrolysis

Water is used to break down a polymer

Polysaccharide

Many repeated units of monosaccharides

Polymer

A long molecule consisting of many similar or identical monomers linked together.

carbon, hydrogen, oxygen, nitrogen

96% of mass of organisms

Ionic bond

Attraction between two oppositely charged ions

Expansion on freezing

Because ice is less dense than water, water expands on freezing

Acidic

Contains many hydrogen ions; having a pH below 7; acidity

Basic

Release a lot of hydroxide ions; alkaline

pH scale

A range of values used to express the concentration of hydrogen ions in a solution; logarithmic

neutral

on pH scale, 7 is neutral

Disaccharide

A double sugar, consisting of two monosaccharides joined by dehydration synthesis.

Glucose

A simple sugar that is an important source of energy. C6H12O6

Fructose

A monosaccharide found predominantly in fruit and honey

Starch

A storage polysaccharide in plants consisting entirely of glucose.

Cellulose

polysaccharide consisting of glucose monomers that reinforces plant-cell walls

Glycogen

starch; glucose is stored in the form of glycogen in liver and muscle cells

Plastids

where plants stockpile a-glucose in form of starch

Amino acids

Building blocks of protein

Amino group

NH2

Carboxyl group

-COOH

R group

The distinguishing group of atoms of a particular amino acid; also known as a side chain.

side chain

The distinguishing group of atoms of a particular amino acid; also known as a R group

functional groups

A group of atoms responsible for the characteristic reactions of a particular compound

Dipeptide

Two amino acids bonded together at the carboxyl group

peptide bond

The covalent bond between two amino acid units, formed by a dehydration reaction.

polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

protein

polypeptide chain twisted and folded on itself

lipids

Nonpolar molecules that include fats, oils, and cholesterol, functions as structural component of cell membranes, sources of insulation, and energy storage

fat

triglyceride, each of the carboxyl groups of the three fatty acid's reacts with one of the three hydroxyl groups of the glycerol molecule, formed by dehydration synthesis

oils

lipids that are liquid at room temperature

phospholipids

Contain two fatty acid tails and one negatively charged phosphate head

steroids

lipids characterized by a carbon skeleton consisting of four fused rings

neutral fats

Consists of three fatty acids and one molecule of glycerol

glycerol

A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils.

ester linkage

Linkage formed between the glycerol molecule and the fatty acid

saturated

One covalent bond between each pair of carbon atoms

unsaturated

Adjacent carbons are joined by double bonds

polyunsaturated

Many double bonds within the fatty acid

hydrophobic

Water hating

hydrophilic

Water loving

amphipathic

Both hydrophobic and hydrophilic regions (ex. Fatty acid tails are hydrophobic because they are nonpolar but phosphate head is hydrophilic because it carries a negative charge and is attracted the positive end of a molecule

nucleic acids

Polymers that are made up of monomers called nucleotides building blocks of DNA and RNA

nucleotides

Basic units of DNA molecule, composed of a sugar, a phosphate, and one of 4 DNA bases

deoxyribonucleic acid

nucleic acid that contains the sugar deoxyribose DNA

ribonucleic acid

responsible for transmiting genetic info from the DNA; RNA

Oparin and Haldane

Hypothesized that life arose from the chemicals in the atmosphere; primordial soup hypothesis

Stanley Miller

Conducted an experiment attempting to prove chemical evolution

Harold Urey

tested the Oparin-Haldane model

heterotrophs (consumers)

organisms that get their energy by eating other living or once living resources

autotrophs (producers)

organisms that get their energy from nonliving resources