Biological Molecules 1

Question 1

What is an organic compound?

Answer 1

Contains carbon atoms.

Question 2

What is the basic structure of all carbohydrates?

Answer 2

Made up of carbon, hydrogen and oxygen

Question 3

What are the 3 main groups of carbohydrates?

Answer 3

Monosaccharides
Disaccharides
Polysaccharides

Question 4

What are the main 2 monosaccharides?

Answer 4

Alpha glucose + beta glucose

Question 5

What is the structure of glucose?

Answer 5

6 carbons

Question 6

What is the difference between the structure of alpha glucose and beta glucose?

Answer 6

(Hydrogen at carbon 1)
Alpha = hydrogen above A=Above
Beta = hydrogen below B=Below

Question 7

What reaction happens when 2 monosaccharides join to form a disaccharide?

Answer 7

A condensation reaction
Results in a molecule of water (H2O) being removed

Question 8

What type of bond is the link between 2 monosaccharides?

Answer 8

A glycosidic bond (a type of covalent bond)

Question 9

What are the 3 main types of disaccharide?

Answer 9

Sucrose - stored in plants e.g. sugarcane (a glucose + fructose)
Lactose - milk sugar, main carb in milk (a glucose + b galactose)
Maltose - malt sugar, in germinating seeds e.g. barley (a glucose + a glucose)

Question 10

What is the structure of polysaccharides?

Answer 10

-Compact, good for storage
-Glycosidic bonds are easily broken, allowing rapid release of monosaccharides for cellular respiration
-Not soluble in water so have little effect on water potential

Question 11

What is the reaction when a glycosidic bond splits?

Answer 11

Hydrolysis reaction

Question 12

What is the reaction when a glycosidic bond splits?

Answer 12

Hydrolysis reaction
Water is added to the bond

Question 13

What compounds is starch a mixture of?

Answer 13

Amylose + amylopectin

Question 14

What is starch used as?

Answer 14

An energy store in plants
Sugars produced by photosynthesis are rapidly converted into starch which is insoluble and compact but can be broken down rapidly to release glucose when it is needed

Question 15

Amylose

Answer 15

An unbranched polymer made up of between 200 and 5000 glucose molecules. As the chain gets longer the molecules spiral making it good for storage.
1-4 glycosidic bonds (only alpha glucose)

Question 16

Amylopectin

Answer 16

A branched polymer of glucose molecules
The branching chains have many terminal glucose molecules that can be broken off when energy is needed
1-4 and 1-6 glycosidic bonds

Question 17

Glycogen

Answer 17

‘Animal starch’ as it is the only carbohydrate store found in animals
Similar to amylopectin molecules and starch however has more 1-6 glycosidic bonds giving it more branches therefore making it easier to be broken down quickly

Question 18

Cellulose

Answer 18

Makes up most of the cell wall
Made up of beta glucose
1-4 glycosidic bonds however every other glucose has to be inverted

Question 19

What chemical are fats and oils made up of and what is the bond called?

Answer 19

Fatty acids and glycerol
Forms an ester bond

Question 20

How do fatty acids vary?

Answer 20

The length of the carbon can differ
It can be saturated of unsaturated

Question 21

Forming ester bonds

Answer 21

Forms in a condensation reaction between the carboxyl group of a fatty acid and the hydroxyl group of the glycerol
It is called esterification

Question 22

When is a phospholipid formed?

Answer 22

When glycerol undergoes esterification with a phosphate group instead of a fatty acid

Question 23

How is a phospholipid bilayer or a micelle formed?

Answer 23

The polar phosphate head is hydrophilic and the lipid tail is hydrophobic

Question 24

What are proteins made up of?

Answer 24

Amino acids

Question 25

What is the basic structure of amino acids?

Answer 25

An amino group (-NH2) and a carboxyl group (-COOH) attached to a carbon atom. The R group varies between amino acids

Question 26

How do amino acids join together?

Answer 26

The amino group of one joins with the carboxyl group of another. This forms a peptide bond and relies in a dipeptide.

Question 27

What bonds can form between amino acids?

Answer 27

Peptide
Hydrogen
Disulfide
Ionic

Question 28

How do hydrogen bonds form?

Answer 28

When the opposite charges of an amino acid attract
There are lots of hydrogen bonds however they break easily meaning the protein can easily change shape if there is a change in pH or temperature

Question 29

When do disulfide bonds form?

Answer 29

When 2 cysteine molecules are close together. Disulfide bonds are very strong but occur much less often

Question 30

When do ionic bonds form?

Answer 30

Between the strongly positive and negative amino acids

Question 31

What are the 4 types of protein structure?

Answer 31

Primary
Secondary
Tertiary
Quaternary

Question 32

What are fibrous proteins and what is their structure?

Answer 32

They have little or no tertiary structure
Long parallel polypeptide chains
Insoluble and very tough
Collagen is an example of this

Question 33

What is a globular protein and its structure?

Answer 33

Have complex tertiary and sometimes quaternary structures that fold into globular shapes. They hold molecules in position in the cytoplasm. They are also important in the immune system.

Question 34

What is a conjugated protein?

Answer 34

Some proteins are conjugated with a prosthetic group. Chlorophyll and haemoglobin are conjugated.