Lecture 3 - Macromolecules

Question 0

What are the four organic macromolecules?

Answer 0

carbohydrates, lipids, proteins, nucleic acids

Question 1

organic molecules

Answer 1

hydrogen and other elements covalently bonded to carbon

Question 2

bonding behaviour of carbon

Answer 2

Carbon’s outer shell has 4 electrons but holds 8, each atom can form covalent bonds with up to four other atoms.

Question 3

functional groups

Answer 3

atoms or clusters of atoms that are bonded covalently to the carbon backplane, giving organic compounds their different properties

Question 4

methyl group

Answer 4

-CH3

Question 5

hydroxyl group

Answer 5

-OH

Question 6

amino group

Answer 6

-NH3(+)

Question 7

carboxyl group

Answer 7

-COOH

Question 8

phosphate group

Answer 8

-PO3(-)

Question 9

sulfhydryl group

Answer 9

-SH

Question 10

monomers

Answer 10

Monomers are single “units” which join together to form polymers, examples of which include simple sugars and amino acids.

Question 11

polymers

Answer 11

join together to form macromolecules

Question 12

dehydration reaction

Answer 12

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.

Question 13

hydrolysis reactions

Answer 13

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.

Question 14

what are carbohydrates?

Answer 14

• Sugars and their polymers
• C:H:O ratio of 1:2:1
• Possess polar covalent bonds, form H bonds, generally interact favourably with water

Question 15

functions of carbohydrates

Answer 15

• 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

Question 16

properties of lipids

Answer 16

• not polymers
• almost exclusively comprised of C and H
  non-polar bonds means no hydrogen bonding
• hydrophobic

Question 17

functions of lipids

Answer 17

- energy storage (usually long term)
fatty acids, glycerol; saturated or unsaturated
- structural (membrane components)
phospholipids, cholesterol
- cell communication
steroid hormones

Question 18

What are proteins?

Answer 18

Amino acid polymers, covalently linked by condensation reactions, different proteins are made by using a different combination of the 20 amino acids.

Question 19

functions of proteins

Answer 19

• structural (collagen, elastin, keratin)
• movement
• transport (haemoglobin)
• chemical messengers (hormones, neurotransmitters)
• receptors (respond to messengers)
• storage (of amino acids, not energy)
• defensive (antibodies)
• enzymes (highly specific biological catalysts)

Question 20

primary protein structure

Answer 20

A linear sequence of amino acids, genetically determined, that will ultimately affect secondary structure.

Question 21

protein secondary structure

Answer 21

Formed by regular hydrogen bonding along polypeptide backbone between non-adjacent amine groups

Question 22

tertiary protein structure

Answer 22

Formed by covalent, hydrogen or ionic bonds, also affected by hydrophobic interactions; gives protein 3D shape.

Question 23

quaternary protein structure

Answer 23

Forms when two or more polypeptides (proteins) join together, not all proteins possess quaternary structure.

Question 24

protein denaturation

Answer 24

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.

Question 25

functions of nucleic acids

Answer 25

• hereditary information

- code for proteins

Question 26

What are nucleotides and deoxynucleotides composed of?

Answer 26

pentose sugar, nitrogen base, phosphate