IH Biology Experience 1: Molecules of Life

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hydrogen bonding

weak attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge

why are water’s shared electrons found near the nucleus?

water’s oxygen nucleus attracts electrons more strongly than the single protons of water’s hydrogen nuclei

2 special properties of water that occur from hydrogen bonding

• water expanding when freezing

• water’s ability to dissolve many substances

cohesion

the attraction between molecules of the same substance; water is extremely cohesive

adhesion

the attraction of molecules of different substances, stronger than cohesive forces

capillary action

draws water up against the force of gravity, notably in plants

solution

type of solution in which all components are evenly distirbuted

solute

a substance being dissolved

solvent

the substance in which the solute dissolves

suspensions

mixtures of water and nondissolved material

pH scale

scales with values from 0-14; used to measure the concentration of H+ ions in a solution by a factor of 10

acid

any compound that releases H+ ions into a solution

base

a compound that produces hydroxide ions in a solution

buffers

weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH; control pH levels

monomers

small chemical units that make up a polymer

polymers

molecules composed of many monomers, making up macromolecules

carbohydrates

• C, H, O → 1 : 2 : 1 ratio

• for storing and releasing immediate energy and cell structure

• sugar, starch, cellulose

monosaccharides

simple sugars such as glucose, galactose, and fructose

dehydration reaction

a reaction in which a water molecule is released

glycogen

polysaccharide animals store excess sugar as; for energy and movement

starch

polysaccharide plants store excess sugar as

lipids

• C, H

• oils, fats, and waxes

• stores long-term energy and helps with cell structure (membrane)

• can function as hormones, i.e. estrogen

fatty acids

monomers that form lipids

unsaturated fatty acid

when there’s at least one carbon-carbon double bond present in a fatty acid; liquid at room temperature; from plants

saturated fatty acid

no carbon-carbon double bond; solid at room temperature; from animals

nucleotides

monomers that consist of: 5-carbon sugar, a phosphate group, and a nitrogenous base

• i.e. ATP → captures and transfers chemical energy

• joined by covalent bonds in dehydration to form nucleic acids

nucleic acids

polymers assembled from nucleotides; H, O, N, C, P

• includes RNA and DNA, containing genetic information

protein

biomolecules made of monomer amino acids

• control reaction rates and regulate processes

• form cellular structures

• transport in and out substances

• act as signal receptors

• made of an AMINO, CARBOXYL, and UNIQUE R-Group

amino acids

compounds with an amino group (NH2) and carboxyl group (COOH

peptide bonds

covalent bonds that link amino acids together