Biological molecules

Question 1

What is a condensation reaction?

Answer 1

Two monomers link together,
A water molecule is released,
A new covalent bond is formed,
A larger molecule is formed

Question 2

What is a hydrolysis reaction?

Answer 2

One or more polymers split,
A water molecule is used,
A covalent bond is broken,
Smaller molecules are formed

Question 3

What do carbohydrates consist of?

Answer 3

Carbon, Hydrogen, Oxygen

Question 4

What do lipids consist of?

Answer 4

Carbon, Hydrogen, Oxygen

Question 5

What do proteins consist of?

Answer 5

Carbon, Hydrogen, Oxygen, Nitrogen, Sulphur

Question 6

What does nucleic acid consist of?

Answer 6

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorous

Question 7

What is a covalent bond and what are its characteristics?

Answer 7

The bond formed between two non-metals,
Forces an atom to share electrons with others around it,
Strong bonds which require a lot of energy to break

Question 8

Define metabolism and the types of chemical reactions it does

Answer 8

Metabolism-The sum total of all chemical reaction within an organism

Anabolic-Builds large molecules from smaller ones

Catabolic-Breaks large molecules into smaller ones

Question 9

What are the four functions of carbohydrates?

Answer 9

Energy source- glucose in respiration

Energy store- starch in plants, glycogen in animals

Structure- cellulose

Forms larger molecules- nucleic acids or glycolipids

Question 10

What three elements do all carbohydrates contain?

Answer 10

Carbon, hydrogen and oxygen

Question 11

What are the three main carbohydrate groups and what are their structures like?

Answer 11

Monosaccharides-Simple sugars that form things like glucose

Disaccharides- Double sugars formed from two monosaccharides like maltose

Polysaccharides- Large molecules formed from many monosaccharides like cellulose

Question 12

What are three characteristics of monosaccharides?

Answer 12

Have between three and 6 carbon atoms

Soluble in water

Sweet tasting

Question 13

What is the formula for a monosaccharide?

Answer 13

Cn(H2nO)n

n is a placeholder for the number of atoms and 2 means there must be twice as many hydrogens as oxygens

Question 14

What are three types of monosaccharides?

Answer 14

Triose sugars-3 carbons C3H6O3 like glyceraldehyde

Pentose sugars-5 carbons C5H10O5 like ribose and deoxyribose (important to know)

Hexose sugars-6 carbons(most common C6H12O6 like glucose(important to know)

Question 15

How do you get deoxyribose?

Answer 15

Remove the oxygen from the hydroxide that comes off carbon1 in a ribose sugar

Question 16

What are three characteristics of glucose and its formula?

Answer 16

The major energy source for most cells

Highly soluble

Main form in which carbohydrates are transported around the body

Formula-C6H12O6

Question 17

Define an isomer and state the two structural isomers glucose can form

Answer 17

Isomer-Compounds with the same molecular formula but different structural formula

Alpha and Beta glucose

Question 18

Give an example of an alpha glucose molecule and its characteristics

Answer 18

Fructose:
Very soluble
Main sugar in fruits and nectar
Sweeter than glucose
Has a hydroxide on top of carbon1

Question 19

Give an example of a beta glucose molecule and its characteristics

Answer 19

Galactose:
Not as soluble as glucose
Used in production of glycolipids and glycoproteins
Has a hydrogen on top of carbon1

Question 20

What are the formulas for the three main disaccharides?

Answer 20

Maltose= glucose + glucose

Sucrose= glucose + fructose

Lactose= glucose + galactose

Question 21

How are disaccharides formed?

Answer 21

Two monosaccharides undergo a condensation reaction by using their hydroxides to form two glycosidic bonds with an oxygen in the middle

Question 22

What are polysaccharides?

Answer 22

Polymers containing many monosaccharides linked by glycosidic bonds

Question 23

What are the three major polysaccharides?
Must know the structure for these

Answer 23

Starch-energy store in plants

Glycogen-energy store in animals

Cellulose-structural role in plants

Question 24

What is the structure for starch?

Answer 24

Made of amylose:
Alpha glucose
1-4 glycosidic bonds
Coiled structure

Made of amylopectin:
Alpha glucose
1-4 glycosidic bonds
Coiled structure
Contains side branches that have 1-6 glycosidic bonds

Question 25

What is the structure for glycogen?

Answer 25

Made of: Alpha glucose 1-4 glycosidic bonds Coiled structure Contains many branches with 1-6 glycosidic bonds

Question 26

Starch and glycogen shared features

Answer 26

Both energy storage molecules Insoluble so does not affect water potential of cell Glucose can be broken off the ends via hydrolysis for respiration and glycogen is more compact so this becomes easier

Question 27

What are the characteristics of cellulose?

Answer 27

Structural polysaccharide Found in plant cell walls Long chains of beta glucose molecules Joined by beta 1-4 glycosidic bonds Every second glucose is rotated 180 degrees Forms straight chains Hydrogen bonds form between chains

Question 28

What is the structure of microfibrils?

Answer 28

Around 50-100 beta glucose molecules cross-link via their hydrogen bonds to form bundles called microfibrils

Question 29

What is the structure of macrofibrils?

Answer 29

Bundles of microfibrils cross-link via hydrogen bonds to form Macrofibrils which then make up cellulose fibres

Question 30

What is the structure and function of cell walls?

Answer 30

Provide strength to the cells and plant Prevents cells bursting and keeps them turgid The arrangement of macrofibrils allows the passage of water(apoplast) by having a straight passage Arrangement allows cells to grow or change shape. E.g guard cells Cell walls can be reinforced with other substances so that they are waterproof. E.g lignin

Question 31

Similarities and differences between starch and glycogen

Answer 31

Similarities: Made of alpha glucose Form 1-4 glycosidic bonds Form a coiled structure Differences: Starch is made of amylose and amylopectin whereas glycogen is just glucose Glycogen is an energy store for animals whereas starch is an energy store for plants