Week 1 - chemicals building life

Question 1

water

Answer 1

• COHESION: of water via hydrogen bonds create SURFACE TENSION
• electronegativity creates a polar molecule w/ hydrogen bonding

Question 2

isomers

Answer 2

structural: diff C skeleton
stereoisomers: same C skeleton
- differ in how groups attached
- enantiomers: D- sugars & L- AA

Question 3

carbon

Answer 3

• can form up to 4 covalent bonds
• hydrocarbons: molecules of carbon & hydrogen
• nonpolar
• function groups: hydroxyl, carbonyl, carbooxyl, amino, sulfhydryl, phosphate, methyl

Question 4

lipids

Answer 4

• insoluble → hydrophobic
• terpenes
• steroids
• prostaglandins
• in water, phospholipids form a BILAYER

Question 5

lipids- triglycerides

Answer 5

• 1 glycerol + 3 fatty acids
• saturated: no double bond between C atoms → high melting point in ANIMALS
• unsaturated: 1 or more double bonds →low melting point in PLANTS

Question 6

lipids - steroids

Answer 6

carbon skeleton is bent to form four fused rings

CHOLESTEROL: base steroid produces other steroids

Question 7

proteins - functions

Answer 7

• enzyme catalysis
• defence
• transport
• support
• motion
• regulation
• storage

Question 8

proteins - amino acid structure

Answer 8

• central carbon atom
• amino grtoup (NH2)
• carboxyl group (COOH)
• single hydrogen
• variable R group

Question 9

proteins - peptides

Answer 9

• amino acids joined by dehydration - peptide bond
• long chains of AA spontaneously fold up
• FOLDING: congregation of hydrophobic AA in interior of protein & hydrophilic AA on ext

AA composition:

• hydrophobicity = solubility
• cysteine cont = stability

STRUCTURE DEFINES FUNCTION

Question 10

proteins - levels of structure

Answer 10

1. seq. of amino acids
2. interaction of groups in peptide backbone: alpha helix & beta sheet
3. folded, stabilised by forces →final level of structure: single PP chain
4. arrangement of subunits → 2+ polypeptide

Question 11

RNA

Answer 11

• ribose not deoxyribose
• uracil not thymine
• single polynucleotide strand
• specifies seq. of amino acids proteins

Question 12

nucleic acid - nucleotide

Answer 12

Monomer: nucleotide → sugar + phosphate+ nitrogenous base

• PURINES: adenine, guanine
• PYRIMIDINES: thymine, cytosine, uracil
• nucleotides connected by PHOSPHODIESTER BONDS

Question 13

DNA

Answer 13

encodes info

• AA seq. in protein
• base seq in DNA

double helix

• 2 polynucleotide strands
• hydrogenbonds

Question 14

carbohydrates - function

Answer 14

• provide structure
• short & long term storage of energy
• part of nucleic acid backbone
• combine w/ proteins (glycoprotein)
• combine w/ lipids (glycolipids)
• involved in intracellular interactions between animal cells

Question 15

carbohydrates - structure

Answer 15

MONOSACCHARIDE - simplest
DISACCHARIDE: transport or storage
POLYSACCHARIDE (dehydration) : storage: starch ; glycogen || struc supp: cellulose, chitin
- D-Glucose: most common → product of photosynthesis
- glycogen: in humans + broken down to release glucose when needed

Question 16

amino

Answer 16

NH2

found in proteins, nucleic acids

Question 17

sulfhydryl

Answer 17

SH

found in proteins

Question 18

phosphate

Answer 18

PO4

found in nucleic acids

Question 19

methyl

Answer 19

CH3

found in proteins

Question 20

hyroxyl

Answer 20

-OH

found in: carbohydrates, proteins, nucleic acids, lipids

Question 21

carbonyl

Answer 21

CO

found in: carbohydrates, nucleic acids

Question 22

carboxyl

Answer 22

COOH

found in proteins, lipids