2.2 Biological Molecules

Question 1

What are the 3 types of lipids?

Answer 1

• Phospholipids
• Triglycerides
• Cholesterol

Question 2

What makes a fatty acid saturated?

Answer 2

If it has no double carbon bonds

Question 3

What are triglycerides composed of?

Answer 3

3 fatty acid binding to one glycerol molecules. Each fatty acid binds to one of the 3 free OH- groups on the glycerol.

Question 4

What type of reaction binds the fatty acids to the glycerol in triglycerides?

Answer 4

Condensation Reaction

Question 5

What are triglycerides used for?

Answer 5

• buoyancy
• energy storage
• protection
• insulation
• energy sources

Question 6

What are phospholipids composed of?

Answer 6

2 fatty acids and a phosphate group binding to a glycerol molecule.

Question 7

What bonds form in the condensation of lipids?

Answer 7

Ester bonds.

Question 8

Which areas of the phospholipid bilayer are hydrophobic and which are hydrophillic?

Answer 8

The inwards facing fatty acids are hydrophobic and the outwards facing phosphate groups are hydrophilic.

Question 9

What is cholesterol composed of?

Answer 9

4 carbon based rings.

Question 10

What is the job of cholesterol in the phospholipid bilayer?

Answer 10

To regulate the membrane’s fluidity.

Question 11

What type of bond is an ester bond?

Answer 11

A covalent bond

Question 12

What 3 elements are in carbohydrates?

Answer 12

Carbon
Oxygen
Hydrogen

Question 13

What are the 3 types of carbohydrates?

Answer 13

Monosaccharides
Disaccharides
Polysaccharides

Question 14

Give 3 examples of monosaccharides.

Answer 14

Glucose (a or b)
Fructose
Galactose

Question 15

What bond is formed in the condensation reaction between two monosaccharides.

Answer 15

A glycosidic bond (where the two hydroxyl (OH-) groups line up)

Question 16

Give 3 examples of disaccharides.

Answer 16

Lactose
Sucrose
Maltose

Question 17

Give 4 examples of polysaccharides.

Answer 17

Amylose
Amylopectin
Glycogen
Cellulose

Question 18

Which two polysaccharides make up starch.

Answer 18

Amylose and Amylopectin

Question 19

Which polysaccharides are made by alpha glucose?

Answer 19

Amylose
Amylopectin
Glycogen

Question 20

What polysaccharide is made from beta glucose?

Answer 20

Cellulose

Question 21

What polysaccharides only have 1-4 glycosidic bonds?

Answer 21

Amylose and Cellulose

Question 22

What polysaccharides have 1-4 and 1-6 glycosidic bonds?

Answer 22

Glycogen and Amylopectin

Question 23

Describe the structure and function of amylose.

Answer 23

Amylose is coiled but unbranched. Therefore it is very compact and can store a lot of energy.

Question 24

Describe the structure and function of amylopectin.

Answer 24

Amylopectin is coiled and branched. It has many side branches and can release energy quickly.

Question 25

Describe the structure and function of glycogen.

Answer 25

Glycogen has a lot of side branches so it can release energy quickly. It is compact and insoluble so it can be stored without changing the water potential of the cell.

Question 26

Describe the structure and function of cellulose.

Answer 26

Cellulose has long and unbranched microfibrils which provide structural support in plant cell walls.

Question 27

What is the monomer that makes up proteins?

Answer 27

Amino Acids

Question 28

What is the structure of the proteins dependant on?

Answer 28

The order of the amino acids.

Question 29

How many different amino acids are there?

Answer 29

20

Question 30

What is a prosthetic group?

Answer 30

Anything part of a protein that isn't made of amino acids.

Question 31

What are the two types of proteins?

Answer 31

Globular proteins and Fibrous proteins

Question 32

Describe the structure of globular proteins.

Answer 32

Tightly folded polypeptides that cause a spherical shape. They are hydrophilic on the outside and hydrophobic on the inside, this makes them soluble in water.

Question 33

Give 3 examples of globular proteins.

Answer 33

- enzymes - haemoglobin - hormones

Question 34

Describe the structure of fibrous proteins

Answer 34

Parallel polypeptide chains held together by cross links that create long fibres. They are insoluble in water.

Question 35

Give 3 examples of fibrous proteins.

Answer 35

- collagen - keratin - elastin

Question 36

What bonds are formed between amino acids in a condensation reaction?

Answer 36

Peptide bonds

Question 37

What is a chain of amino acids called?

Answer 37

A polypeptide

Question 38

Describe the primary structure of proteins.

Answer 38

The order and amount of amino acids which make a simple chain.

Question 39

Describe the secondary structure of proteins.

Answer 39

Hydrogen bonds that cause the protein to either coil into an alpha helix or fold into a beta pleated sheet.

Question 40

Describe the tertiary structure of proteins.

Answer 40

Either hydrogen bonds, ionic bonds, disulphide bonds or hydrophilic/phobic interactions give the proteins a 3D shape. It is either globular or fibrous.

Question 41

Describe the quaternary structure of proteins.

Answer 41

The protein has two or more interlinked polypeptide chains.

Question 42

Describe how the emulsion test, tests for lipids.

Answer 42

Combining the lipid with ethanol dissolves the lipid. Adding water will then turn the solution cloudy in the presence of lipids.

Question 43

What colour does a substance turn if proteins are present during a buirets test.

Answer 43

Lilac

Question 44

What sugars are reducing sugars?

Answer 44

All monosaccharides and some disaccharides.

Question 45

Describe the benedicts test for reducing sugars.

Answer 45

The substance is added to copper sulphate and then heated. Benedicts solution is added and if there are reducing sugars, a red precipitate will form.