Biological Molecules Acc

Question 1

What the key molecules in organisms

Answer 1

Protein
Lipids
Carbohydrates
Nucleic acid
Water

Question 2

Define monomers

Answer 2

Smaller units from which larger molecules are made

Question 3

What are polymers

Answer 3

Molecules made from a large number of monomers joined together in a chain

Question 4

What are examples of monomers

Answer 4

Monosaccharides
Amino acids
Nucleotides

Question 5

What does a condensation reaction do

Answer 5

Joins two molecules together with the formation of a chemical bonds and involved the elimination of a water molecule

Question 6

What does a hydrolysis reaction do

Answer 6

Breaks the chemical bond between two molecules and involves the use of water

Question 7

That are monosaccharides

Answer 7

Monomers from which larger carbohydrates are made

Question 8

What are common monosaccharides

Answer 8

Glucose, galactose, fructose

Question 9

What bond is formed between 2 monosaccharides

Answer 9

Glycosidic bond

Question 10

That is maltose made from

Answer 10

Glucose and glucose

Question 11

What is sucrose made from

Answer 11

Fructose and glucose

Question 12

What is lactose made from

Answer 12

Galactose and glucose

Question 13

Draw Alpha glucose

Answer 13

Look it up

Question 14

Draw beta glucose

Answer 14

Look it up

Question 15

How are polysaccharides formed

Answer 15

From the condensation of many glucose units

Question 16

What are glycogen and starch made of

Answer 16

Alpha glucose

Question 17

What is cellulose made from

Answer 17

Beta glucose

Question 18

How do you test for reducing sugars

Answer 18

Benedict’s test
Heat in a water bath
will go from blue to green to orange or red depending on the sugar conc

Question 19

What is the structure of glycogen

Answer 19

Highly branched and not coiled

Question 20

What is the function of glycogen

Answer 20

The storage polysaccharide for animals and fungi

Question 21

What is the structure of starch

Answer 21

Made of Alpha- glucose
Amylose is unbranched and coiled so it’s compact
Amylopectin is branched allowing quick release of glucose
Insoluble in water so doesn’t effect water potential

Question 22

What is the function of starch

Answer 22

Energy storage in plants

Question 23

What is the structure of cellulose

Answer 23

Made of beta glucose joined by glycosidic bonds in a condensation reaction
Every other beta glucose molecule is flipped to allow bonding
Forms a straight unbranched chain
Hydrogen bonds between chains forming microfibrils
Which form fibres

Question 24

What is the function of cellulose

Answer 24

Structural support in plant cell walls

Question 25

What tests for starch

Answer 25

Iodine goes from orange to blue/black

Question 26

How do you test for non reducing sugars

Answer 26

First do Benedict’s test heat in a water bath if no colour change Hydrolyse it using dilute hydrochloric acid Heat in a water bath Neutralise using sodium hydrogen carbonate See if it’s neutral Do Benedict’s test again Heat in a water bath

Question 27

What are the two groups of lipids

Answer 27

Phospholipid and triglycerides

Question 28

How are triglycerides formed

Answer 28

By the condensation of one glycerol molecule and three molecules of fatty acid

Question 29

What bond is formed between glycerol and fatty acids

Answer 29

Ester bond

Question 30

What is significant about the R group of a fatty acid

Answer 30

It can be saturated or unsaturated

Question 31

What is the structure of a phospholipid

Answer 31

One or the fatty acids are substituted for a phosphate containing group

Question 32

What does the emulsion test invlove

Answer 32

Test for lipids Add ethanol to sample Shake Add water A cloudy emulsion forms if lipids are present

Question 33

What are triglycerides properties relating to its structure

Answer 33

Has a hydrophobic tail making it a good energy storage molecule as it is insoluble and so does not have an osmotic effect Triglycerides are apart of the myelin sheath which surround nerve fibres

Question 34

What are phospholipids properties reacting to its structure

Answer 34

Has a hydrophillic head Hydrophobic tail In water phospholipids automatically form a bi layer with the heads facing outwards towards the water and the tail facing inwards away from the water forming a hydrophobic centre which acts as a barrier to Water soluble substances And small non polar molecules Water however is small enough to pass through slowly Function Forms main structure of cell membranes Controls what enters and leaves the cell

Question 35

Draw structure of amino acid

Answer 35

should include C COOH N H2N

Question 36

How is a dipeptides formed

Answer 36

By the condensation reaction of 2 amino acids

Question 37

How is a polypeptides formed

Answer 37

By the condensation reaction of many amino acids