Biological Molcules

Question 1

What are the 3 polysaccharides (big ones)

Answer 1

Maltose, sucrose, lactose

Question 2

What are the monosaccharides (small ones)

Answer 2

Glucose, fructose, galactose

Question 3

What are the monomers of lactose

Answer 3

Glucose + galactose

Question 4

What are the monomers of sucrose

Answer 4

Glucose + fructose

Question 5

What are the monomers of maltose

Answer 5

Glucose + glucose

Question 6

How do you test for protein

Answer 6

1) label the test tubes you are going to test for proteins
2) add 2cm3 of test solution to a test table, then add 2cm3 of water and shake
3) add ten drops of biuret solution
4) if proteins are present the solution will turn violet/ purple

Question 7

What is the protein test

Answer 7

Biuret test

Question 8

What bond holds amino acids together

Answer 8

Peptide bond

Question 9

What is a nucleotide made up of

Answer 9

Pentose sugar, base, phosphate

Question 10

What are the 3 key features of an amino acid

Answer 10

Amine group, r group, carboxyl group

Question 11

Rf calculation

Answer 11

Distance moved by spot/ distance moved by solvent front

Question 12

What is primary structure

Answer 12

A sequence of amino acids (polypeptide chain)

Question 13

What is secondary structure

Answer 13

Hydrogen and disulphide bonds form between the chain causing it to coil c from beta pleated sheets or alpha helix coil

Question 14

What is the tertiary structure

Answer 14

More coils + folds form further hydrogen, disulphide, ionic bonds

Question 15

How do you test for lipids

Answer 15

The emulsion test
-place 2cm^3 of the sample into a test tube
-add 5cm^3 of ethanol
-shake
Add 5cm^3 of water
-shake
-cloudy white means lipids are present

Question 16

In a phosphoric ehat part is hydrophobic and what part is hydrophilic

Answer 16

Hydrophobic-fatty acid tail
Hydrophilic- phosphate head

Question 17

What is a phospholipid made up of

Answer 17

One phosphate group, two fatty acids, and one glycerol

Question 18

What are the two types of lipid

Answer 18

Triglycerides and phospholipids

Question 19

What bonds hold triglycerides and phospholipids together

Answer 19

Ester bonds

Question 20

What monomer is cellulose made out of

Answer 20

B glucose

Question 21

What monomer is glycogen made out of

Answer 21

A glucose

Question 22

What do plants store glucose as

Answer 22

Starch

Question 23

What do animals store glucose as

Answer 23

Glycogen

Question 24

How do you test for reducing/ non reducing sugars

Answer 24

1) Mix 2cm^3 of food sample with 2cm^3 of Benedicts
2) Mix up solution and heat, if colour change is visible reusing sugars are present and non reducing ones are not
3) add another 2cm^3 of food sample to 2cm^3 of dilute hydrochloric acid
4) slowly heat up as the hydrochloric acid hydrolyses the glycosidic bonds present
5) slowly add sodium carbonate while testing with pH paper to see if the solution is alkaline
6)add 2cm^3 off denedicts and heat up solution again
7)if non reducing sugars were present the solution will now go brown form the reducing monosaccharides released

Question 25

How to test for iodine

Answer 25

Add iodine dissolved in potassium iodide to a solution. If starch is present it will go from browny orange to gluey black

Question 26

What is alpha glucose made up of

Answer 26

Amylopectin and amylase