U4. Biological molecules

Question 1

What are the four macromolecules in our body?

Answer 1

• carbohydrates
• protein
• lipids
• DNA

Question 2

What are macromolecules made of? (term)

Answer 2

monomers

Question 3

Carbohydrates: chemical elements

Answer 3

carbon, hydrogen, oxygen

Question 4

Carbohydrates: state three examples (polysaccharides), their function, where they are found

Answer 4

1. starch
   - storage of energy
   - plant
2. cellulose
   - cell wall
   - plant
3. glycogen
   - storage of energy
   - animal

Question 5

What is the structure of carbohydrates?

Answer 5

long chains of glucose (by condensation)

Question 6

What is formed when 2 glucose molecules join together?

Answer 6

Maltose

Question 7

What is formed when 2 glucose molecules join together? Name 3

Answer 7

Lactose, sucrose, maltose

disaccharides

Question 8

What is the simple form of carbohydrates?

Answer 8

glucose

Question 9

Lipids: chemical elements

Answer 9

carbon, hydrogen, oxygen

Question 10

Lipids: simple form (chemicals)

Answer 10

Glycerol and fatty acids

Question 11

Lipids: functions (3)

Answer 11

• component of cell membrane
• fats under skin provide heat insulation (warmth)
• storage of energy

Question 12

Lipids: what are they divided into?

Answer 12

Lipids are divided into fats (solids at room temperature) and oils (liquids at room temperature)

Question 13

What is 1 basic unit of triglycerides made up of?

Answer 13

1 glycerol molecule chemically bonded to 3 fatty acid chains

Question 14

Protein: chemical elements

Answer 14

Carbon, hydrogen, oxygen, nitrogen

Question 15

Protein: simplest form

Answer 15

amino acids ( in a long chain)

Question 16

Why do protein molecules have different functions?

Answer 16

• different sequence of amino acids give different shapes to them
• the shapes determines the functions

Question 17

Protein: name the four types of proteins, functions, example in body

Answer 17

1. structural
   - give support to body
   - protein in muscles
2. enzymes
   - speed up reactions
   - enzymes for respiration
3. hormones
   - chemical messengers in the body
   - growth hormones
4. antibody
   - made by wbc that destroy pathogens
   - IgG

Question 18

DNA: what are they made of?

Answer 18

Nucleotides

Question 19

DNA: name the 3 parts of a nucleotide

Answer 19

• 5-carbon sugar molecule
• organic base
• phosphate group

Question 20

DNA: how does base pairing work?

Answer 20

It is complementary:

A with T, C with G

Question 21

DNA: chemical elements

Answer 21

Carbon, hydrogen, oxygen, nitrogen

base: A,T,C,G

Question 22

Food test: how to test for starch?

Answer 22

• add a few drops of iodine solution

- orange/brown -> black/purple

Question 23

Food test: how to test for reducing sugars(glucose)?

Answer 23

• add 10 drops of benedict’s solution into the test tube with food sample
• hot water bath (5 mins)
• blue-green/yellow-orange/red-brick red

Question 24

Food test: how to test for proteins?

Answer 24

• add 10 drops of biuret solution to the test tube
• gently swirl it
• blue -> purple, lilac

Question 25

Food test: how to test for fats

Answer 25

• add 10 drops of ethanol
• shake mixture
• colourless -> white, cloudy

Question 26

Food test: how to test for vitamin C?

Answer 26

• add DCPIP solution
• swirl it
• purple/blue -> colourless