molecules of life N

Question 1

amino acid

Answer 1

a monomer which makes up protein
has a central carbon atom bonded to a carboxylic acid group, an amino group a hydrogen atom and an R group

Question 2

condensation reaction

Answer 2

a chemical procss when two monomers combine to form a polymer eliminating a simple substance - usually water

Question 3

covalent bond

Answer 3

bond between two non metals that share a pair of electrons

Question 4

hydrolysis

Answer 4

breaking down of large molecules into smaller ones by the addition of water molecules

Question 5

monomer

Answer 5

a single unit which is used to form larger more complex molecules

Question 6

nucleotide

Answer 6

a compound consisting of an organic base and ribose sugar linked to a phosphate group

they form monomers of nucleic acids such as dna

Question 7

organic molecule

Answer 7

molecules containing carbon which can be found in living things
- carbohydrates
- proteins
- lipids
- nucleic acids

Question 8

what elements are common to all forms of life

Answer 8

carbon, oxygen and hydrogen

Question 9

3 examples of polymers

Answer 9

polysaccarides
protein
dna/rna

Question 10

3 hexos monosaccarides

Answer 10

glucose
fructose
galactos

all have molecular formula : C6H12O6

Question 11

type of bond formed when monosaccarides react

Answer 11

1-4or 1-6 glycosidic bonds

Question 12

3 disaccarides and how they form

Answer 12

• glucose + glucose = maltose
• glucose + galactose = lactose
• lucose + fructose = sucrose

all have molecular formula C12H22011

Question 13

molecular formula of sucros / maltose/ lactose

Answer 13

C12H22O11

Question 14

3 things

starch

Answer 14

• storage molecule of alpha glucose in plant cells
• insouluble - so osmotic effect in cells
• large - does not diffuse out of cells

Question 15

2 properties of starch and their uses

Answer 15

• large - so it doesnt diffuse out of plant cells
• insoluble - so no osmotic effect in cells

Question 16

amylose

Answer 16

• 1-4 glycosidic bonds
• long unbranched chain of alpha glucose
• coiled shape with intermolecular h bonds making it compact

found in starch

Question 17

amylopectin

Answer 17

• 1-4 and 1-6 glycosidic bonds
• branched - increases surface area for enzyme action for hydrolysis into glucose - glucose can be released fast

found in starch

Question 18

5 things

glycogen

Answer 18

• main storage molecule of glucose in animals - also found in plants
• 1-4 and 1-6 glycosidic bonds
• insoluble - no osmatic effect
• coiled shape with intermolecular hydrogen bonds - compact
• branched - many terminal ends increase surface area for hydrolysis

Question 19

why is cellulose needed in cell walls

Answer 19

prevents bursting under turgor pressure and holds up stem

Question 20

4 things

cellulose

Answer 20

• polymer of beta glucose which reinforces cell walls
• 1-4 glycosidic bonds
• cellulose chains linked by H bonds forming microfibrils
• H bonds between cellulose chains make microfibrils strong and flexible

Question 21

uses of starch

Answer 21

storage molecule for excess glucose in plants as it is too large to exit cell and insoluble so wont effect water potential

starch is hydrolised to release glucose for respiration

Question 22

uses of cellulose

Answer 22

major structoral component in plant cells allowing cells to become turgid and providing support

Question 23

uses of glycogen

Answer 23

used to store excess glucose in muscle and liver cells which can be used as an energy source when hydrolised to release glucose for respiration (i.e during exercise)

Question 24

test for starch

Answer 24

iodine

Question 25

iodine test

Answer 25

• tests for starch
• addiodine dissolved in potassium iodide to sample
• if starch present change from browny orange - bluey black

Question 26

why is being insoluble good for storage

Answer 26

-doesnt affect water potential so water doesnt enter cells via osmosis causing them to swell

Question 27

Glycerol

Answer 27

a molecule which combines 3 fatty acids to form triglycerides

its a 3 carbon chain with 3 hydrocyl groups

Question 28

hydrophillic

Answer 28

section of a molecule attracted to water

Question 29

hydrophobic

Answer 29

section of molecule repulsed by water