Flashcards in Lecture 3 - Macromolecules Deck (27)
hydrogen and other elements covalently bonded to carbon
What are the four organic macromolecules?
carbohydrates, lipids, proteins, nucleic acids
bonding behaviour of carbon
Carbon's outer shell has 4 electrons but holds 8, each atom can form covalent bonds with up to four other atoms.
atoms or clusters of atoms that are bonded covalently to the carbon backplane, giving organic compounds their different properties
Monomers are single "units" which join together to form polymers, examples of which include simple sugars and amino acids.
join together to form macromolecules
Also called condensation reactions, they form longer polymers by joining other monomers/polymers together, cellular machinery removes hydroxyl group (-OH) from one molecule and H from the other to bond the molecules together, discarded H and OH may form water afterwords.
A type of cleavage reaction, breaks apart polymers into monomers/shorter polymers, splitting water to form H and hydroxyl group (-OH) to cap exposed ends.
what are carbohydrates?
- Sugars and their polymers
- C:H:O ratio of 1:2:1
- Possess polar covalent bonds, form H bonds, generally interact favourably with water
functions of carbohydrates
- short term energy storage
monosaccharides (ex. glucose, fructose)
disaccharides (ex. sucrose, lactose)
- long term energy storage
starch in plants, glycogen in animals can be hydrolysed into sugar monomers
- structural roles
chitin, cellulose both not easily hydrolysed
- cell communication
glycoproteins and glycolipids on cell surface
properties of lipids
- not polymers
- almost exclusively comprised of C and H
non-polar bonds means no hydrogen bonding
functions of lipids
- energy storage (usually long term)
fatty acids, glycerol; saturated or unsaturated
- structural (membrane components)
- cell communication
What are proteins?
Amino acid polymers, covalently linked by condensation reactions, different proteins are made by using a different combination of the 20 amino acids.
functions of proteins
- structural (collagen, elastin, keratin)
- transport (haemoglobin)
- chemical messengers (hormones, neurotransmitters)
- receptors (respond to messengers)
- storage (of amino acids, not energy)
- defensive (antibodies)
- enzymes (highly specific biological catalysts)
primary protein structure
A linear sequence of amino acids, genetically determined, that will ultimately affect secondary structure.
protein secondary structure
Formed by regular hydrogen bonding along polypeptide backbone between non-adjacent amine groups
tertiary protein structure
Formed by covalent, hydrogen or ionic bonds, also affected by hydrophobic interactions; gives protein 3D shape.
quaternary protein structure
Forms when two or more polypeptides (proteins) join together, not all proteins possess quaternary structure.
Because the 3D protein structure it critical to its function, changes in conformation may comprise the function. Factors affecting protein conformation include temperature, pH, and salt concentration. Often denaturation is irreversible.
functions of nucleic acids
- hereditary information
- code for proteins