Chapter 5: Macromolecules {Campbell Biology}

Polymer

A long molecule consisting of many similar or identical building blocks linked by covalent bonds

Monomer

A simple compound whose molecules can join together to form polymers

Monosaccharide

A simple sugar that is the basic subunit of a carbohydrate

Disaccharide

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

polysaccharide

Carbohydrates that are made up of more than two monosaccharides

glycosidic linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

starch

A storage polysaccharide in plants consisting entirely of α glucose.

glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

cellulose

A storage polysaccharide in plants consisting of β glucose

chitin

A polysaccharide that makes up the exoskeleton in arthropods and the cell wall in fungi

maltose

Two glucose monomers form this disaccharide

sucrose

Glucose + fructose form this disaccharide

lactose

milk sugar

fructose

fruit sugar

glucose

C₆H₁₂O₆ ; primary energy source in cell metabolism

fatty acid

A hydrocarbon chain bonded to a carboxyl (COOH) functional group.

triglyceride

lipids that consist of three fatty acid (hydrocarbons) chains and one glycerol

saturated fat

Example: Lard and butter

Solid at room temp because single bonds allow molecules to pack close together

unsaturated fat

Example: Olive oil

Liquid at room temp because presence of cis double bonds prevent molecules from being close together

ester linkage

Bond in fats, between glycerol and the three fatty acids.

trans fat

Unsaturated fats with trans double bonds that cause atherosclerosis

4 functions of fats

1. Storage

2. Insulation

3. Protection

4. Structure Formation

phospholipid

A lipid with a phosphate group in its hydrophilic head, and two nonpolar fatty acid tails; main constituent of cell membranes

steroid

Lipids characterized by a carbon skeleton containing four fused rings.

cholesterol

Crucial molecule in animals; is a component of membranes; example of a steroid

catalyst

A substance that affects the reaction rate without being used up in the reaction.

amino acid

A compound that contains both an amino group, a carboxylic acid group, alpha carbon and hydrogen; monomers from which proteins are built.

peptide bond

Bond between an amine group and a carboxyl group of two amino acids, forming bond between C-N

primary structure

the linear sequence of amino acids in a polypeptide

secondary structure

Alpha-helix (twisting formation) or Beta-pleated sheet (where the it lies alongside itself). Reinforced by hydrogen bonds between the carbonyl oxygen and the hydrogen on the amino group.

tertiary structure

Overall shape of a polypeptide resulting from interactions between R-groups

- Hydrophobic interactions lead some to hide in center

- Disulfide bridges form between two cysteine groups

quaternary structure

When two or more globular polypeptide chains bind together. Same forces in tertiary structure at work in quaternary structure.

alpha helix

A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure.

beta pleated sheet

One form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where two regions of the chain lie parallel to each other and are held together by hydrogen bonds.

denaturation

When a protein's chemical bonds and interactions are altered due to...

1. change in pH

2. change in temperature

3. change in salt concentration

and becomes misshapen, preventing it from fulfilling its duties

chaperonin

Proteins that assist in the proper folding of proteins

DNA

Deoxyribose, ATCG, double stranded, stores hereditary information

RNA

Ribose, AUCG, single stranded, gene expression and protein synthesis

nucleotide

consists of a phosphate, a 5-carbon sugar (ribose or deoxyribose), and a nitrogenous base. Adenine (purine), Guanine (purine), Uracil (pyrimidine), Thymine (pyrimidine), and Cytosine (pyrimidine).

polynucleotide

DNA nucleotides combined together

purine

Adenine and Guanine, has 2 rings

pyrimidine

Thymine, Cytosine, and Uracil, one ring

ribose

deoxyribose

double helix

antiparallel

the 5' end of one strand will align with the 3' end of the other strand

Enzymatic protein

Protein that accelerates chemical reactions.

Ex. digestive enzymes catalyze hydrolysis to digest food

Storage protein

Protein that stores amino acids

Ex. Casein is a milk protein that is a source of a.a. for baby mammals

Hormonal protein

Protein that coordinates organism's activities

Ex. Insulin regulates blood sugar concentration

Motor protein

Protein that is responsible for movement

Ex. Actin and myosin contract muscles

Defensive protein

Protein that protects against disease

Ex. antibodies destroy viruses and bacteria

Transport protein

Protein that transports substances

Ex. Hemoglobin transports oxyen in blood

Receptor protein

Protein that tells the cell to respond to chemical stimuli

Ex. Receptors in nerve cells detect signalling molecules

Structural protein

Protein that supports structures

Ex. Keratin makes up hair, horns, feathers, etc

Hydroxyl

Carbonyl

Carboxyl

Amino

Sulfhydryl

Phosphate

Methyl

Dehydration reactions

Create polymers from monomers by removing water

Hydrolysis

Water is added to split large molecules

Carbohydrate

Simple sugars and polymers; CH₂O