biomolecule revision

Question 1

Covalent bonds

Answer 1

formed by sharing of electrons

Question 2

single covalent bonds

Answer 2

share 2 electrons between atoms

Question 3

double covalent bonds

Answer 3

share 4 electrons & stronger than single covalent bonds

Question 4

polar covalent bonds

Answer 4

unequal sharing of electrons producing a postive charge at one end of the molecule, and a negative charge at the other end = net dipole

Question 5

non polar covalent bonds

Answer 5

equal sharing of electrons & no net dipole

Question 6

whats stronger covalent or non covalent bonds

Answer 6

covalent bonds

Question 7

types of non covalent bonds

Answer 7

1. thermal energy
2. can der waals
3. hydrogen bonds
4. iconic bonds

Question 8

ionic bonds

Answer 8

occur between two opposite charged ions & involve the complete transfer (either gained or loss) of electrons

Question 9

how are ionic bonds weakened

Answer 9

by water, water can cluster around charged ions to weaken the interaction

Question 10

what compounds formed by non covalent bond is soluble in water

Answer 10

ionic bonds e.g. NaCl = table salt

Question 11

hydrogen bonds

Answer 11

occur due to attraction of positively charged H atoms to negatively charged atoms

Question 12

how are hydrogen bonds weakened

Answer 12

water, as water competes for H bond interactions

Question 13

hydrophobic forces

Answer 13

occur due to the attraction between non polar molecules & exclusion of water

water molecules cannot form hydrogen bonds with non polar molecules & tend to form pentagon or hexagon cages around the non polar molecules instead

Question 14

molecular complementarity

Answer 14

Multiple non-covalent interactions can form between complementary molecules causing them to bind.

It can be thought of as a lock and key fit between molecules whose shape and charge are complementary to each other.

E.g. molecular complementarity and non-covalent bonds are what holds two DNA strands together into a double helix.

Question 15

Van der Wall forces

Answer 15

attraction of neutral molecules in gases e.g. hydrogen bonding = weak bond formal transient dipoles

Question 16

amino acid structure

Answer 16

determines the properties of the protein

Question 17

amino group

Answer 17

designates the N terminus of a protein. has a positive charge when ionised.

Question 18

carboxyl group

Answer 18

this designates the C terminus of a protein. has a negative charge when ionised

Question 19

which isomer is most common in proteins found in humans

Answer 19

L isomers NOT D isomers

Question 20

where do peptide bonds occur

Answer 20

between carboxyl group of one amino acid & amine group of another amino acid

Question 21

what does a peptide bond result in molecular wise

Answer 21

results in ned loss of one H molecule (from N terminus) & one OH molecule (from C terminus) in a process called a dehydration or condensation reaction (net loss of one water molecule)

Question 22

primary structure

Answer 22

linear sequence of amino acids formed by peptide bonds into a polypeptide chain

Question 23

secondary structure

Answer 23

organisation of the polypeptide chain in a alpha helix or b sheets or turns. structures are stabilised by hydrogen bonds between backbone of the amino acids

Question 24

tertiary structure

Answer 24

arrangement of secondary structures

Question 25

quaternary structures

Answer 25

number of polypeptide chains that is stabilised by non-covalent bonds in a multimeric protein

Question 26

two types of nucleic acids

Answer 26

deoxyribonucleic acid

ribonucleic acid

Question 27

nucleotides consist of

Answer 27

sugar molecule, attached to a phosphate group &. a nitrogen containing base

Question 28

phosphodiester bonds

Answer 28

joins nucleotides into a chain to form nucleic acids

• between the hydroxyl group of phosphate with the sugar molecule (C3) & the hydroxyl group of the same phosphate with another sugar molecule (C5)

Question 29

nucleic acid

Answer 29

multiple nucleotides

Question 30

difference between saturated & unsaturated

Answer 30

saturated - no double bonds, higher boiling point, solid at room temp

the longer the chain the less double bonds, the higher the melting point

Question 31

transfat

Answer 31

c not z

hydrogens same side of double bond

Question 32

formation of triglycerides reaction name

Answer 32

condensation

Question 33

are phospholipids amphipathic & importance

Answer 33

yes, cell membrane

Question 34

bonds of

1. nucleic acids
2. proteins
3. carbs
4. glycerol & fatty acids

Answer 34

1. phosphodiester bonds
2. peptide bonds
3. glycosidic bonds
4. ester bonds