3. Biological Molecules

Question 1

What are the elements that all biological molecules are made of.

Answer 1

Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorus
Sulphur

Question 2

Ca²+ ion function

Answer 2

Nerve impluse transmission

Question 3

K+ ion function

Answer 3

Nerve impulse transmission

Question 4

Na+ ion function

Answer 4

Nerve impulse transmission

Question 5

H+ ion concentration

Answer 5

Determination of pH in solutions

Question 6

NH4+ ion function

Answer 6

Source of nitrogen for plants

Question 7

NO3- ion function

Answer 7

Source of nitrogen for plants

Question 8

HCO3- ion function

Answer 8

Transport of respiratory gases

Question 9

Cl- ion function

Answer 9

Transport of respiratory gases

Question 10

PO4³‐ ion function

Answer 10

Nucleic acid and ATP formation

Question 11

OH- ion function

Answer 11

Determination of pH in solutions

Question 12

Properties of water

Answer 12

Good solvent, high specific heat capacity, high heat of vaporisation, cohesion and adhesion and lower density as a solid

Question 13

Test for reducing sugar

Answer 13

Mix with Benedict’s reagent and heat
-ve = blue
+ve= green -> orange -> brick red

Question 14

Test for non-reducing sugar

Answer 14

Conduct Benedict’s test. Take -ve result boil with dilute HCl. Conduct Benedict’s test again

Question 15

Test for starch

Answer 15

Add iodine/KI solution with sample
-ve = yellow/brown
+ve = blue black

Question 16

Describe the process of using a colourimeter to determine sugar concentration

Answer 16

1. Insert red filter in colourimeter
2. Use cuvette of distilled water to zero
   colourimeter
   3.Construct callibration curve using known conc. of the sugar (filter precip. obtain reading (transmission or absorbtion) and plot graph of transmission or absorbtion against comcentration)
3. Conduct the Benedict’s test and filter the precip.
4. Obtain reading and calculate sugar conc. from calibration curve

Question 17

What advantage does a biosensor have over the Benedict’s test

Answer 17

Ability to detect specific sugars

Question 18

What bonds are found between glycerol molecules and fatty acid chains

Answer 18

Ester bonds

Question 19

What do phospholipids and cholesterol have in common

Answer 19

Both amphipathic. Both found in membranes

Question 20

What is the purpose of cholesterol in a membrane

Answer 20

Increase fluidity by binding to fatty acid chains and increasing the packing of the membrane.
Decrease fluidity at high temperatures by attracting phospholipids.
Membrane buffer

Question 21

What is the basic structure of an amino acid

Answer 21

H2N–CRH–COOH

Amine R Carboxyl

Question 22

What bonds occur between amino acids

Answer 22

Peptide bonds

Question 23

What bonds are found in amylose

Answer 23

Alpha glycosidic 1-4 bonds

Question 24

What bonds are found in amylopectin

Answer 24

Alpha glycosidic 1-4 and 1-6 bonds

Question 25

What bonds are found in glycogen

Answer 25

Alpha glycosidic 1-4 and 1-6 bonds

Question 26

What are the bonds in cellulose

Answer 26

Beta glycosidic 1-4 bonds

Question 27

What is the bond between galactose and alpha glucose in lactose

Answer 27

Beta glycosidic bonds