Topic 9: The molecules of life part 2

Question 1

Synthesis/decomposition

Answer 1

Where reactants produce a combination as a product

Where reaction breaks stuff down

Question 2

Macromolecule formation

Answer 2

Built from smaller subunits (monomers) linked by covalent bonds formed via chemical reactions

Often dehydration reaction where a bond if formed and water is released

2 sugars - glyosidic bond
AAs - peptide bond

Question 3

Hydrolysis

Answer 3

Breaks down polymers and requires water

Question 4

Basic unit of carbohydrates

Answer 4

(CH20)n

n=3 triose
n=5 pentose
n=6 hexose

Question 5

Polysaccharides

Answer 5

Hundreds of monomers

branched - glycogen (breaks down faster)

Unbranched - starch

Also form rigid cell structures like walls in plats or chitin in insects

Question 6

Lipids

Answer 6

Hydrophobic and insoluble in water

Metabolism, steroid hormones and phospholipids which make cell membranes

Glycerol + fatty acids
A triglyceride is gllycerol and 3 FAs

Question 7

cis and trans fats

Answer 7

Unsaturated fats have two forms depending on the shape of the H in the C+C bond. Together, cis = bent

Opposite = trans = straight

Question 8

Phospholipids

Answer 8

Diglycerol + phosphate
phosphate is polar

Diglycerol has one cis unsaturated FA and one saturated FA that is straight

Makes membranes which form when phospholipids are added to water (micelles)

Question 9

Steroids

Answer 9

Cholesterol is a precursor for the synthesis of vitamins and hormones

Question 10

DNA/RNA composition

Answer 10

DNA
Purines: Adenine & Guanine
Pyrimidines: Cytosine & THYMINE

RNA
Purines: Adenine & Guanine
Pyrimidines: Cytosine & URASIL

Question 11

DNA and RNA subunits

Answer 11

Phosphate + Sugar = backbone

+ one base ATGC

Question 12

Purines pair with

Answer 12

pyrimidines 
A-T
T-A
G-C
C-G

Question 13

Monomer of proteins

Answer 13

Amino group
Carboxyl group
Alpha carbon joined to R

Where r is a side chain

(20 side chains)

Question 14

Amino acid side chain goups

Answer 14

non polar
polar
Acidic (-ve charge)
Basic (=ve charge)

Question 15

A polypeptide is

Answer 15

a polymer of amino acids joined by a peptide bond (covalent bond between the NH2 group and the COOH group

forms a chain

Question 16

Protein levels of shape

Answer 16

primary structure - sequence of the chain of AAS

secondary folding into beta pleated sheets or alpha helices via H bonds

Tertiary is the 3d shape it folds into

Hydrogen bonds will form between H and O atoms, and will give rise to beta sheets and alpha helices. Opposite charges will form ionic bonds and similar charges will repel each other. Cysteine can form stable di-sulfide bonds that link parts of the same polypeptide in tertiary structure, or two polypeptides in the quaternary structure. Non-polar amino acids will be located close to each other in the interior of the protein

Quaternary shape is when two or more proteins form a unit eg hemoglobin