Unit 4

Question 1

Elements of carbohydrates

Answer 1

. Carbon
. Hydrogen
. Oxygen

Question 2

Carbohydrates: glucose (cellulose, starch, glycogen)

Answer 2

. Glucose: Makes glycogen, cellulose and starch
. Glycocen and starch: used as energy stores
. Carbohydrates are made of simple sugars (eg. starch, glycogen and cellulose)
. Cellulose: build up cell walls
. Starch: storage molecules in plants
. Glycogen: storage molecules in animals

Question 3

Elements of proteins

Answer 3

. Carbon
. Hydrogen
. Oxygen
. Nitrogen

Question 4

Proteins

Answer 4

Made up of long chains of amino acids

Question 5

Two examples of proteins: collagen and elastin

Answer 5

. Collagen: for connective tissues and cartilage around the body
. Elastin: makes tissues and organs elastic

Question 6

Fats

Answer 6

Made of glycerol and fatty acids (three)

Question 7

Elements of fats

Answer 7

. Carbon
. Hydrogen
. Oxygen

Question 8

DNA

Answer 8

Two strands of nucleotides coiled together to form a double helix -> each strand contains chemicals called bases
. Bonde between bases: hold strands together

Question 9

Base pairings of DNA

Answer 9

. A with T
. C with G

Question 10

Test for starch

Answer 10

1. Fill test tube halfway with extract being testes
2. Add 2 or 3 drops of iodine solution

Question 11

If molecule present: Starch

Answer 11

From: Yellow/light brown
To: Blue/black

Question 12

Test for reducing sugars

Answer 12

1. Fill beaker halfway with boiling water
2. Add 5 drops of benedict’s solution to test tube containing extract being tested, and place it onto the beaker

Question 13

If molecule present: reducing sugars

Answer 13

From: blue TO green -> little amount present
From: blue TO red -> big amount present

Question 14

Test for protein

Answer 14

1. Fill test tube halfway with extract being tested
2. Add 5 or 6 drops of biuret solution

Question 15

If molecule present: protein

Answer 15

From: blue
To: purple/violet/lilac

Question 16

Test for fats and oils

Answer 16

1. Put extract being tested into test tube and add enough ethanol to cover it -> fats don’t dissolve in water, but do dissolve in ethanol
2. Pot topper on test tube + shake it
3. Add distiled water halway up test tube
4. Shake test tube once more

Question 17

If molecule present: Fats and oils

Answer 17

From: clear
To: Cloudy white/milky

Question 18

Test for Vitamin C

Answer 18

1. Put known volume of DCPIP solution in test tube
2. Add extract being tested one drop at a time

Question 19

If molecule present: Vitamin C

Answer 19

From: Blue
To: Clear