Lecture 1: Biological molecules

Question 1

What is a monomer?

Answer 1

A basic unit of polymers, which combine to other monomers to form repeating chain molecules (a polymer)

Question 2

What are examples of a monomer?

Answer 2

Monosaccharides, amino acids and nucleotides

Question 3

What is a polymer?

Answer 3

Long molecule consisting of many smaller and identical repeating monomers

Question 4

What happens during a condensation reaction?

Answer 4

2 monomers combine with a chemical bond between

Question 5

What happens during hydrolysis?

Answer 5

Breakdown of polymers into monomers (using a water molecule)

Question 6

What are macromolecule are polymers

Answer 6

A giant complex molecules

Question 7

What are the four important biological molecules?

Answer 7

Carbohydrates, Proteins, Nucleic acids and Lipids

Question 8

Carbohydrates

Answer 8

Starch and sugar/Energy and structural support

Question 9

Proteins

Answer 9

Amino acids/catalysing reactions

Question 10

Nucleic acids

Answer 10

Nucleotides/store genetic info

Question 11

Lipids

Answer 11

Provide energy

Question 12

Carbohydrates - sugar

Answer 12

• C, H and O
• Monomers which carbohydrate are formed - Monosaccharides (glucose, fructose, galactose)
• Disaccharides (maltose, sucrose, lactose). Formed by condensation from two monosaccharides.
• Condensation reaction (glycosidic bond)
• Polysaccharides (glycogen, starch and cellulose)

Question 13

Glucose + Glucose =

Answer 13

Maltose

Question 14

Glucose + Galactose =

Answer 14

Lactose

Question 15

Glucose + Fructose =

Answer 15

Sucrose

Question 16

How is sucrose made?

Answer 16

Glucose + Fructose

Question 17

How is maltose made?

Answer 17

Glucose + Glucose

Question 18

How is lactose made?

Answer 18

Glucose + Galactose

Question 19

Condensation reactions

Answer 19

• A reaction that releases a molecule of water when it links molecules together.
• A chemical bond is formed.
• Disaccharides (maltose, sucrose, lactose). Formed by condensation of monosaccharides (glycosidic bond)

Question 20

Testing for sugars (non-reducing sugars)

Answer 20

1)
Heat sample with Benedict’s reagent.
sample=blue=no recuing sugar present

Question 21

Testing for sugars (reducing)

Answer 21

1)
Heat sample with Benedict’s reagent.
sample=orange/brick red=reducing sugar present

Question 22

Testing for sugars step 2

Answer 22

Heat a new sample with dilute hydrochloric acid then neutralise sample by adding sodium hydrogen carbonate. Heat sample with Benedict’s reagent.
-> sample stays blue=no non reducing (or reducing) sugar present
-> sample form orange/brick red= non reducing sugar present

Question 23

Carbohydrates - starch

Answer 23

• Polysaccharides (starch)
• Condensation reactions – glycosidic bonds
• Storage in plants (iodine test)
• Insoluble
• 2 types of Starch amylose and amylopectin

Question 24

Amylose

Answer 24

Unbranched

Question 25

Amylopectin

Answer 25

Somewhat branched

Question 26

What are the two types of Starch?

Answer 26

Amylose and Amylopectin

Question 27

What is the test for starch?

Answer 27

iodine is dissolved in potassium iodide solution No starch= browny orange colour Starch= dark blue/black colour

Question 28

Carbohydrates - cellulose

Answer 28

- Polysaccharides (cellulose) - Condensation of beta- glucose molecules - Straight cellulose chains linked with H bonds to form strong fibrils called microfibrils (cell walls) - Insoluble

Question 29

Carbohydrates- glycogen

Answer 29

- Animals store excess glucose as glycogen - Polysaccharide - Condensation reaction to form glycosidic bonds - Alpha-glucose - Side branches (quick release) - Compact (storage)

Question 30

What is a protein?

Answer 30

- proteins made up of amino acids (1=monomer) 2 amino acids is dipeptide more than two amino acids polypeptide proteins one or more polypeptide

Question 31

one amino acid is known as

Answer 31

monomer

Question 32

two amino acids is known as

Answer 32

dipeptide

Question 33

more than two amino acids is known as

Answer 33

polypeptide

Question 34

protein is

Answer 34

one or more polypeptides

Question 35

Dipeptide formation

Answer 35

- Condensation - Two Amino acids linked together - Peptide bond

Question 36

Polypeptide (amino acid polymers) formation

Answer 36

- Condensation - Many Amino acids linked together - Peptide bond

Question 37

What is the test for protein?

Answer 37

sodium hydroxide and copper(II) sulphate solution Negative result= solution stays blue = no protein Positive result= purple colour= indicates protein

Question 38

Lipids

Answer 38

- Not polymers - Made from a variety of different components - All contain hydrocarbons - Triglycerides (pic) and phospholipids - Ester bond between the glycerol and fatty acid

Question 39

Triglycerides

Answer 39

Tails = hydrophobic Insoluble in water

Question 40

2 types of fatty acids

Answer 40

(difference is their hydrocarbon tail) R groups. Saturated = single bonds (saturated with H) Unsaturated = double bonds (chain has a kink)

Question 41

Fatty acids

Answer 41

-Fatty acids general formula CnH2nO2 -This illustrates how the number of hydrogen atoms is always double the number of carbon atoms, and that here are always 2 oxygen atoms.

Question 42

Phospholipids

Answer 42

Two fatty acids and a phosphate group Cell membranes Phospholipids head hydrophilic (likes water) tails hydrophobic (dislikes water)