biological molecules

Question 1

what is a monomer?

Answer 1

a smaller unit from which larger units are made.

Question 2

what is a polymer?

Answer 2

a molecule made from large numbers of monomers.

Question 3

what is a condensation reaction?

Answer 3

joins two molecules together with the formation of a chemical bond and involves the elimination of a water molecule.

Question 4

what is hydrolysis?

Answer 4

a reaction involves the breaking of a chemical bond between two molecules and involves the use of water.

Question 5

name the 3 named monosaccharides

Answer 5

glucose, fructose, galactose.

Question 6

name the 3 disaccharides

Answer 6

maltose, sucrose, lactose

Question 7

what makes maltose?

Answer 7

glucose + glucose

Question 8

what makes sucrose?

Answer 8

glucose + fructose

Question 9

what makes lactose?

Answer 9

glucose + galactose

Question 10

what bond forms between 2 monosaccharides? and what reaction takes place?

Answer 10

glycosidic bond through condensation reaction.

Question 11

which disaccharide is non-reducing?

Answer 11

sucrose

Question 12

what is the test for reducing sugars?

Answer 12

benedicts test

Question 13

how do you do the benedicts test?

Answer 13

1. HEAT with benedicts solution
2. brick-red colour is positive result
3. blue is negative result

Question 14

why is the benedicts test qualitative?

Answer 14

colour perception is subjective.

Question 15

how can you make the benedicts test quantitative?

Answer 15

use a colourimeter

Question 16

describe how you’ll test for a non-reducing sugar

Answer 16

1. do benedicts test to confirm negative result.
2. hydrolyze sample by heating with acid then cool and neutralize with alkali.
3. heat with benedicts solution.
4. brick-red colour confirms positive result.

Question 17

what are the isomers of glucose?

Answer 17

alpha and beta

Question 18

what’s the difference between alpha and beta glucose

Answer 18

the OH and H on the right side are flipped in beta glucose.

Question 19

what is a polysaccharide?

Answer 19

a polymer made of glucose

Question 20

what are the 3 polysaccharides?

Answer 20

starch, glycogen, cellulose

Question 21

which isomer of glucose is starch made of?

Answer 21

alpha

Question 22

where is starch found?

Answer 22

plants

Question 23

what’s the function of starch?

Answer 23

acts as a storage carbohydrate.

Question 24

what 2 structures can starch take?

Answer 24

branched and helical

Question 25

how is starch adapted to being a compact storage molecule?

Answer 25

- large so cant pass the cell surface membrane -insoluble so osmotically inactive -helical so compact store -branched so glucose easily released for respiration

Question 26

describe the test for starch

Answer 26

-add drops of iodine to sample -positive is blue/black -negative is yellow

Question 27

where is glycogen found?

Answer 27

animals

Question 28

Where in the human body is glycogen stored?

Answer 28

Liver and muscle

Question 29

What isomer of glucose is glycogen made of?

Answer 29

Alpha

Question 30

What structure is glycogen?

Answer 30

Heavily branched

Question 31

What is the function of glycogen

Answer 31

A storage molecules

Question 32

How is glycogen suited to its function?

Answer 32

-it’s insoluble so osmotically inactive -many free ends so can be hydrolysed more rapidly

Question 33

Where is cellulose found?

Answer 33

Plants

Question 34

What isomer of glucose forms cellulose?

Answer 34

Beta

Question 35

What is the structure of cellulose

Answer 35

Long straight chains

Question 36

How is cellulose in straight lines?

Answer 36

Every other beta glucose is inverted

Question 37

What is the function of cellulose

Answer 37

To provide strength and rigidity

Question 38

What’s a microfibril

Answer 38

Crosslinked chains of cellulose bonded together with hydrogen bonds, which provides strength

Question 39

What is the monomer in proteins?

Answer 39

Amino acids

Question 40

How many amino acids are there

Answer 40

20

Question 41

What groups do all amino acids have

Answer 41

Amine group (NH2) Carboxylic acid group (COOH)

Question 42

What bond joins amino acids?

Answer 42

Peptide bonds

Question 43

If the R group in a protein is polar what does that mean?

Answer 43

It’s soluble in water

Question 44

How can you hydrolyse a protein?

Answer 44

-heat with an acid -use enzyme at optimum temperature

Question 45

Describe the primary structure of a protein

Answer 45

Sequence of amino acids in a polypeptide chain, joined with peptide bonds

Question 46

Describe the secondary structure of a protein

Answer 46

polypeptide chains coil or pleats due to hydrogen bonding.

Question 47

What are the 2 second structures of proteins?

Answer 47

-alpha helix -beta pleated sheet

Question 48

Describe the tertiary structure of a protein?

Answer 48

The secondary structure further folds and coils as hydrogen, ionic and disulphide bonds form

Question 49

Describe the quaternary structure of a protein

Answer 49

More than one polypeptide chain coils or

Question 50

What protein level are enzymes?

Answer 50

Tertiary

Question 51

How do you test for protein?

Answer 51

1. Add biuret reagent 2. Lilac colour indicates positive result 3. Blue means negative

Question 52

What is denaturing in protein?

Answer 52

Breaking of bonds (hydrogen, ionic) in the tertiary structure that results in the protein changing shape

Question 53

What can cause denaturation in proteins?

Answer 53

- high temperatures - extreme changes in pH -heavy metals