UNIT 1 OBJECTIVES Chemistry of Life Vocabulary

Polarity

A molecule with uneven distribution of charges, like water having a positive and negative end.

Hydrogen bonding

Weak attraction between a hydrogen atom and another electronegative atom, important in water and DNA.

Cohesion

Attraction between molecules of the same substance, like water sticking to itself.

Adhesion

Attraction between different substances, like water sticking to glass.

Surface tension

The tightness across the surface of water caused by cohesive forces of hydrogen bonding.

Properties of water

Water is polar, has high specific heat, is a universal solvent, and shows cohesion, adhesion, and surface tension.

Matter

Anything that has mass and takes up space.

Grow, reproduce, and maintain organization

Key characteristics of living organisms enabled by biological molecules.

Atoms

Basic units of matter consisting of protons, neutrons, and electrons.

Molecules

Groups of two or more atoms bonded together.

Carbon

Element that forms the backbone of biological molecules due to its four bonding sites.

Biological molecules

Molecules essential for life, including carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates

Macromolecules used for energy and structure; made of sugar monomers.

Proteins

Macromolecules made of amino acids that perform a variety of functions in the body.

Lipids

Nonpolar macromolecules used for energy storage and cell membranes.

Nucleic acids

Macromolecules like DNA and RNA that store and transmit genetic information.

Storage compounds

Macromolecules like starch or fat used to store energy or materials in organisms.

Cell formation

Process of assembling molecules into cells, the basic units of life.

Nitrogen

Element essential for amino acids and nucleotides.

Phosphorus

Element needed to form nucleic acids and phospholipids.

Hydrolysis

Chemical reaction that breaks polymers into monomers using water.

Dehydration synthesis

Reaction where monomers bond together by removing water, forming polymers.

Cleave and form

Breaking (cleaving) or making (forming) bonds between monomers.

Covalent bonds

Strong chemical bonds formed by sharing electrons between atoms.

Monomers

Small building block molecules that make up polymers.

Types of bonds

Covalent, ionic, and hydrogen bonds involved in biological molecules.

Polymer

Large molecule made by joining many monomers together.

Structure and function

The shape of a biological molecule determines what it does.

Nucleotide monomers

Building blocks of nucleic acids made of a sugar, phosphate, and nitrogen base.

Five carbon sugar (deoxyribose and ribose)

Sugar found in nucleotides; ribose in RNA, deoxyribose in DNA.

Phosphate group

Part of a nucleotide that links sugars together in the backbone.

Nitrogen bases (adenine, thymine, cytosine, guanine, uracil)

Bases in DNA and RNA that pair to store genetic code.

DNA and RNA structure and function

DNA is a double-stranded molecule storing genetic code; RNA is single-stranded and helps in protein synthesis.

Polypeptide

Chain of amino acids linked by peptide bonds.

Primary structure

Order of amino acids in a protein.

Structure of protein

Includes four levels: primary, secondary, tertiary, and quaternary.

Amino acids

Monomers of proteins, each with a unique R group.

Directionality

Order in which monomers are arranged, like 5' to 3' in nucleic acids.

Amino (NH2) terminus

Start of a protein with a free amine group.

Carboxyl (COOH) terminus

End of a protein with a free carboxyl group.

R group (hydrophobic, hydrophilic, or ionic)

Variable side chain of an amino acid that affects protein folding.

Interactions of R groups for structure and function

R group interactions (e.g., hydrogen bonds, ionic bonds) shape proteins.

Complex carbohydrates

Polysaccharides like starch or cellulose made of sugar monomers.

Sugar monomers

Simple sugars like glucose that build carbohydrates.

Structure determines function

Shape of a molecule affects how it works.

Nonpolar

Molecules that do not have charged regions and do not dissolve in water.

Saturation

Refers to single or double bonds in fatty acids; affects fluidity.

Phospholipids

Lipids with a phosphate head and fatty acid tails, major part of cell membranes.

Polar regions

Parts of molecules with uneven charge distribution.

Polar molecules

Molecules like water with opposite charges on each end.

Nonpolar regions

Parts of molecules without charge, repel water.

Hydrophobic

"Water-fearing"; nonpolar substances that don't mix with water.

Linear sequence of nucleotides

Order of nucleotides in DNA or RNA.

3' hydroxyl of the sugar

End of a DNA strand where new nucleotides are added.

5' phosphates of the sugar

Start of a DNA strand with a phosphate group.

DNA and RNA synthesis

Building DNA or RNA strands using enzymes.

Add to 3' end of growing strand

New nucleotides attach to the 3' end during replication/transcription.

Antiparallel double helix

DNA strands run in opposite directions and twist to form a helix.

5' to 3' orientation

Direction DNA or RNA is built, from 5' phosphate to 3' hydroxyl.

Number of hydrogen bonds between bases

A-T has 2 bonds, G-C has 3 bonds in DNA.

Linear chains of amino acids

Primary structure of proteins formed by peptide bonds.

Peptide chain

Chain of amino acids connected by peptide bonds.

Protein primary structure

Sequence of amino acids in a polypeptide.

Secondary structure

Local folding into alpha-helices or beta-sheets.

Alpha-helices

Coiled shape in protein secondary structure.

Beta-sheets

Folded, pleated sheet shape in protein secondary structure.

Tertiary structure

3D shape of a protein due to R group interactions.

Three dimensional shape

Final folded shape of a protein.

Minimizes free energy

Proteins fold into the most stable, low-energy structure.

Quaternary structure

Structure formed by multiple polypeptides coming together.

Interactions between multiple polypeptide units

How different protein chains combine to function.

Linear chains of sugar molecules

Monomers joined to form carbohydrates.

Linear or branched polymers

Structure of complex carbs; can be straight or branched.

Sugar, phosphate, and nitrogenous base

Three parts of a nucleotide.

Nucleotides

Building blocks of DNA and RNA.

Sugar-phosphate backbone

Repeating sugar and phosphate in DNA/RNA strands.

Structural differences between DNA and RNA

DNA is double-stranded with thymine; RNA is single-stranded with uracil.

Deoxyribose

Sugar in DNA, lacks one oxygen atom.

Ribose

Sugar in RNA, has one more oxygen than deoxyribose.

Uracil

Base in RNA that pairs with adenine.

Thymine

Base in DNA that pairs with adenine.

Double stranded

DNA has two complementary strands.

Single stranded

RNA has one strand.

Antiparallel

One DNA strand runs 5' to 3' and the other 3' to 5'.