3.1 Biological Molecules

Question 1

What is a monomer?

Answer 1

A molecule that combines to make a polymer

Question 2

What is a polymer?

Answer 2

A large molecule made of repeating subunits/monomers

Question 3

What is a hydrolysis reaction?

Answer 3

Breaking down a larger molecule into smaller molecules by adding water

Question 4

What is a condensation reaction?

Answer 4

Two molecules combine to make a larger molecule by losing a water molecule

Question 5

What is polymerisation?

Answer 5

The building up of polymers

Question 6

What elements does a carbohydrate contain?

Answer 6

Contains Carbon, Hydrogen and Oxygen

Question 7

Give two examples of a monosaccharide

Answer 7

Glucose
Fructose

Question 8

Give three examples of a disaccharide

Answer 8

Maltose
Sucrose
Lactose

Question 9

Give three examples of a polysaccharide

Answer 9

Starch
Glycogen
Cellulose

Question 10

What is a monosaccharide?

Answer 10

A single sugar

Question 11

How is a ring structure formed from glucose?

Answer 11

When glucose forms a ring, carbon 1 joins to the oxygen on carbon 5

Question 12

How is a ring structure formed from pentose or hexose?

Answer 12

Pentose and hexose are long enough to close up on themselves to form a more stable ring structure

Question 13

What is isomerism?

Answer 13

Compounds with the same chemical formula but different structures

Question 14

Why are isomers important?

Answer 14

Different structures determine different properties

Question 15

Name the two isomers of glucose

Answer 15

Alpha glucose
Beta glucose

Question 16

How are disaccharides formed?

Answer 16

Formed from a condensation reaction between two monosaccharides, joined together by glycosidic bonds

Question 17

What is produced from two alpha glucose molecules?

Answer 17

Maltose + Water

Question 18

What is produced from alpha glucose and galactose?

Answer 18

Lactose + Water

Question 19

What is produced from alpha glucose and fructose?

Answer 19

Sucrose + Water

Question 20

How are polysaccharides formed?

Answer 20

Repeated condensation reactions between many monosaccharides, forms lots of glycosidic bonds

Question 21

What is starch made up of?

Answer 21

Straight chained alpha amylose and branched amylopectin

Question 22

What is the structure of amylopectin?

Answer 22

Alpha glucose molecules with 1,4 glycosidic bonds and 1,6 glycosidic bonds every 24-30 units

Question 23

Why is it advantageous that amylopectin is highly branched?

Answer 23

Allows compounds to easily be hydrolysed to release glucose monomers

Question 24

Why do glycosidic bonds make starch an ideal energy store compound?

Answer 24

Produce twisted chains that give them a compact shape so they can be stored in a small space
Insoluble in water

Question 25

What is glycogen?

Answer 25

A carbohydrate stored in animal cells

Question 26

How does glycogen differ from starch?

Answer 26

Linked glucose shorter and has a more highly branched structure than starch

Question 27

Why is a branched structure important?

Answer 27

Branching allows for a fast breakdown of molecules during respiration

Question 28

How is glycogen adapted?

Answer 28

Has more ends, which enzymes can start hydrolysis from

Question 29

What is cellulose made up of?

Answer 29

Beta glucose molecules

Question 30

What is the structure of cellulose?

Answer 30

Each alternate glucose molecule flips 180° to allow bonding of hydroxyl groups

Question 31

How does cellulose get its stability?

Answer 31

Chains run parallel forming microfibrils, which are strengthened with cross-linkages (hydrogen bonds)

Question 32

What is the function of cellulose?

Answer 32

Gives strength and support to cell wall

Question 33

How are substances transported through cellulose?

Answer 33

Space between fibrils allow water and mineral ions to pass through Sometimes gaps are blocked by suberin making it waterproof

Question 34

Where are microfibrils found?

Answer 34

Embedded into the framework of other substances such as hemicellulose and pectins

Question 35

What is the function of lipids?

Answer 35

Hormones Energy Store (respire to release ATP) Protection Membranes Insulation

Question 36

How are lipids a form of protection?

Answer 36

Insoluble so prevent osmotic changes

Question 37

What elements do lipids contain?

Answer 37

Carbon, Hydrogen and Oxygen

Question 38

What are triglycerides made up of?

Answer 38

A glycerol molecule and three fatt7 acids

Question 39

How are triglycerides formed?

Answer 39

Three condensation reactions to produce a triglyceride and three water molecules

Question 40

What are the two types of fatty acids?

Answer 40

Saturated and Unsaturated

Question 41

What is a saturated fatty acid?

Answer 41

Has no double bonds between carbons

Question 42

What is an unsaturated fatty acid?

Answer 42

Has at least one double bond between carbons, which causes the chain to kink

Question 43

What are the properties of triglycerides?

Answer 43

Energy Store Contains twice as much (chemical) energy as carbohydrates Insoluble

Question 44

What are phospholipids made up of?

Answer 44

A glycerol molecule and two fatty acids, covalently bonded together

Question 45

What are the properties of phospholipids?

Answer 45

Cell Membranes (Phospholipid Bilayer) Controls what enters/leaves cell

Question 46

How is a bilayer formed?

Answer 46

Phospholipid heads are hydrophilic and face towards water, fatty acid tails are hydrophobic and face away from water For a double layer with heads on outside

Question 47

Why is it difficult for substances to pass through phospholipid bilayer?

Answer 47

The centre is hydrophobic, so substances can't easily pass through