Module 2 Biological Molecules

Question 1

Glycosidic bond

Answer 1

A bond formed between two monosaccharides by a condensation reaction

Question 2

define macromolecule

Answer 2

a molecule containing a large number of atoms

Question 3

how are polymers formed from monomers

Answer 3

condensation reaction

Question 4

how is water formed from condensation reactions

Answer 4

the grouping of a hydroxyl (OH) from one monomer and hydrogen (H) from another

Question 5

how are polymers broken down into monomers

Answer 5

hydrolysis reaction

Question 6

the general formula of a monosaccharide

Answer 6

(CH2O)n

Question 7

properties of glucose make it well adapted to its function

Answer 7

• small so easily transported in and out of cells through carrier proteins
• soluble so easily transported around an organism
• less reactive than other monosaccharides so breakdown must be catalysed and therefore controlled by enzymes

Question 8

list monosaccharides

Answer 8

fructose, galactose, glucose

Question 9

what is ATP

Answer 9

(adenine triphosphate) an adenine base bonded to ribose and three phosphate groups.

Question 10

what are the two polysaccarides of starch

Answer 10

amylose and amylopectin

Question 11

amylose

Answer 11

spiral shape(makes it more compact),
long chain of alpha glucose molecules , joined together by 1-4 glyosidic bonds,
only has two accessible ends where amylase can bind so it is broken down slowly.

Question 12

amylopectin

Answer 12

spiral shape,
branched,
joined with 1-4 glycosidic bonds however has the occasional 1-6 glycosidic bond this causes branches,
more accessible ends foe amylase to bond to.

Question 13

glycogen (in animals)

Answer 13

joined by 1-4 and 1-6 glycosidic bonds (similar to amylopectin),
branching is more often than in amylopectin therefore there are even more accessible ends(can be rapidly hydrolysed to alpha glucose)

Question 14

cellulose

Answer 14

polysaccharide of beta glucose molecules joined together by 1,4 glycosidic bonds

Question 15

why are the cellulose chains straight

Answer 15

to be able to form the 1,4 glycosidic bonds each beta glucose molecule must be inverted from the previous molecule because to OHs need to face each other

Question 16

how do cellulose chains form layers

Answer 16

the chains line up parallel to each other and hydrogen bonds form between hydroxyl groups that are in close proximity to each other on adjacent chains.

Question 17

how are fibers of cellulose formed

Answer 17

• cellulose chains come together to form micro fibrils
• micro fibrils are then bundled together to form macro fibrils
• the macro fibrils wrap around the plant cells in multiple layers at different angles

Question 18

what is the role of triglycerides

Answer 18

they are a source of energy found in foods (fats, oils)

Question 19

what is an ester bond

Answer 19

the covalent bond formed by a condensation reaction between the -OH group of a carboxyl acid and the -OH group of an alcohol

Question 20

why are fats solid and oils liquid

Answer 20

due to the presence of double bonds between carbon atoms in the fatty acid tail. in unsaturated fatty acids the fatty acids are bent so they are less compact and the space between the molecules increase causing the intermolecular forces to weaken and the molecule becomes a liquid at room temperature.

Question 21

define saturated hydrocarbon chain

Answer 21

no double bonds (lipids are solid at room temperature)

Question 22

why do triglycerides release lots of energy

Answer 22

there is a large number of carbon hydrogen bonds that are broken down

Question 23

what is the biuret test used for

Answer 23

testing proteins (by detecting peptide bonds)

Question 24

procedure of biuret test

Answer 24

place sample in a clean test tube
add biuret A (sodium hydroxide)
add biuret B (copper (II) sulphate)
if protein is present colour changes from blue to purple

Question 25

what is the emulsion test used for

Answer 25

to test for lipids

Question 26

procedure of emulsion test

Answer 26

-add ethanol to dissolve any lipid
-add water and mix
-if lipids are present a cloudy white substance will form (fat precipitates out)

Question 27

what are hydrogen bonds formed between

Answer 27

hydrogen and lone pair of electrons (from oxygen, nitrogen)

Question 28

properties of water

Answer 28

-solvent of polar substances
-surface tension
-ice insulates water beneath
-high SHC
-high SLH of vaporisation
-polar

Question 29

what monosaccharides make lactose

Answer 29

beta galactose and alpha glucose

Question 30

what causes interactions in the tertiary structure of a protein

Answer 30

ionic
disulphide bridges
hydrogen bonds
hydrophilic hydrophobic interactions

Question 31

what bonds hold together the secondary structure of a proteins

Answer 31

hydrogen bonds