Dr Bell

Question 1

What’s a polymer and what’s a monomer ?

Answer 1

Polymer - a long complex chain of similar monomers

Question 2

Glucose +glucose =
Glucose +fructose =?
Glucose +galactose=

Answer 2

Maltose
Sucrose
Lactose

Question 3

How to test for a reducing sugar

Answer 3

Benedict’s and heat , brick red precipitate is a positive result.

Question 4

What is the main storage material in plants ?

Answer 4

Starch

Question 5

Describe starch

Answer 5

Plants store excess glucose as starch , contains amylose (long unbranched , coiled , compact ), amylopectin(long batches alpha glucose , side branches that can be easily broken down )
Insoluble in water sod oesnt affect water potential.

Question 6

What is the main storage material in animals ? Describe it

Answer 6

Glycogen , polysaccharide of alpha glucose many side branches , very compact.

Question 7

How is cellulose suites for its purpose ?

Answer 7

Long , unbranched beta glucose, straight cellulose chains held by hydrogen bonds , microfribrils that give good support for cell walls.

Question 8

What’s the test for starch ?

Answer 8

Add iodine in dissolved potassium iodide solution. Positive result - blue black coloration

Question 9

What are lipid made form ?

Answer 9

Proteins carbs and hydrocarbons

Question 10

Describe a triglyceride

Answer 10

One molecule of glycerol , three fatty acids(hydrophobic tails men’s they are insoluble ) , three ester bonds

Question 11

What’s the basic structure of a fatty acid ?

Answer 11

O—C—R

OH

Question 12

What’s the difference between saturated and unsaturated ?

Answer 12

Unsaturated fatty acids have double bonds between each carbon and can cause the hydrocarbon chain to kink.

Question 13

How are triglycerides formed ?

Answer 13

Condensation reaction between glycerol and. A fatty acid to form ester bonds.

Question 14

Describe a phospholipid

Answer 14

Found in cell membranes , two fatty acids , one phosphate head , two ester bonds.

Question 15

What are the properties of triglycerides and phospholipids ?

Answer 15

Triglyceride-energy storage molecules , long HC chains have lots of chemical energy , insoluble in water don’t affect water potential due to fatty acid tails facing inwards.
Phospholipids- make up Bauer of cell meme range , hydrophilic heads , centre is hydrophobic so water soluble substances can’t pass through.

Question 16

How to test for a lipid

Answer 16

Emulsion test, shake substance with ethanol and pour solution into water , any lipid will= milky emulsion

Question 17

What are proteins made from?

Answer 17

Monomers =amino acids , dipepride =two amino acids , polypeptide =several amino acids , proteins are made from one or more polypeptides.

Question 18

What’s the general structure of an amino acid ?

Answer 18

Carboxyl group (-COOH)
Amino group(-NH2)
R group (always contain carbon apart from glycine which has H)

Question 19

How are dipeptides and polypeptides formed ?

Answer 19

Condensation reactions

Question 20

Describe primary structure

Answer 20

Sequence of amino acids in the polypeptides chain.

Question 21

Describe secondary structure

Answer 21

Hydrogen bonds form between amino acids into alpha helix or beta pleated sheets

Question 22

Describe tertiary structure

Answer 22

Cooked even more hydrogen bonds and ionic bonds , disulfide bridges between cysteine (sulfers )

Question 23

Describe quarternary structure

Answer 23

Several polypeptide chains assembled together.

Question 24

What’s the test for proteins ?

Answer 24

Add sodium hydroxide , then add copper sulfate solution . Purple =positive result

Question 25

What do enzymes do ?

Answer 25

Catalyst metabolic reactions by lowering activation energy.

Question 26

How does temperature affect enzyme activity ?

Answer 26

Low temp =low ROR Optimum temp =highest ROR high temp =enzyme denatures

Question 27

How does pH affect enzyme activity ?

Answer 27

Optimum =best ROR Too low/too High H+ and OH- ions disrupt the ionic bonds and hydrogen bonds that hold tertiary structure in place-denaturation

Question 28

How does substrate conc affect enzyme activity ?

Answer 28

Higher conc=higher ROR , eventually plateus when all active sites are full

Question 29

How does enzyme conc affect enzyme activity ?

Answer 29

More enzyme =higher ROR , but if substrate amount is limited the increase in enzymes has no affect .

Question 30

Describe competitive inhibitors

Answer 30

Similar shape to substrate , compete for active site

Question 31

Describe non competitive inhibitors

Answer 31

Bind away from the active site causing active site to change shape so substrates can no longer bind.

Question 32

How to estimate initial rate of reaction

Answer 32

Draw tangent from 0, calculate gradient , work out the units

Question 33

What’s the structure of a nucleotide ?

Answer 33

Phosphate , pentose sugar, nitrogenous base

Question 34

Describe polynucleotide structure

Answer 34

Joined via condensation reactions ,?forming phosphodiester bonds , sugar phosphate back bone .

Question 35

Describe the structure of DNA

Answer 35

Double helix , two strands , really long and cooled tightly.

Question 36

How many hydrogen bonds between AT and GC

Answer 36

AT 2 | GC 3

Question 37

What’s different about RNA ?

Answer 37

Ribose sugar, uracil instead of thymine , single strand , shorter .

Question 38

Describe the process of DNA replication.

Answer 38

DNA helicase breaks hydrogen bonds between bases on DNA strands , unwinds . Each original strand acts as a template for new strand , complementary bad pairing means nucleotide join on to exposed bases Condensation reactions join the nucleotides of the new strand together catalysts by DNA polymerase , forming hydrogen bonds Each new dna has half the original strand

Question 39

Messlson and stalls experiment

Answer 39

N15 put into N14 to make hybrids Hybrids put into N14 to make 50% hybrids Those hybrids put into N14 to make 25% hybrids. Semi conservative replication .

Question 40

Describe the structure of ATP

Answer 40

Adenine , ribose , three phosphate heads (phosphate group )

Question 41

How is energy released from ATP?

Answer 41

Hydrolase hydrolysis , from ATP to ADP +P, the in organic phosphate head and be used in phosphorylation to make compounds more reactive

Question 42

Describe waters importance

Answer 42

Polar , metabolite , good solvent polarity of water pulls ions apart ,high latent heat of vapouutisation , can resist changes in temp ,very cohesive , high surface tension .

Question 43

Describe the differences between prokaryotes and eukaryotes .

Answer 43

Eukaryotes are animal and plant cells -they have membrane bound organelles and nucleus , large 80S ribosomes Prokaryotes (bacteria ) free genetic material , cell wall is made of morein, small 70S ribosome , fully developed flagella.