biological molecules

Question 1

Describe condensation and hydrolysis

Answer 1

Condensation- when water is removed and 2 molecules are joined together
Hydrolysis- when water is added which causes 2 molecules to split apart

Question 2

why is water polar

Answer 2

as there is an uneven distribution of charge, the oxygen atom has a double pair of electrons which makes it slightly negative on that end and as the shared negative h electrons are pulled towards o it leaves one end slightly more positive

Question 3

what is hydrogen bonding

Answer 3

when the slightly negatively charged oxygen end attracts the positive hydrogen molecules of other water molecules
- electrostatic attraction

Question 4

why are hydrogen bonds weaker than covalent bonds

Answer 4

as covalent bonds are when 2 atoms share a pair of electrons so are strong whereas Hydrogen bonds are just electrostatic attraction between a slightly charged hydrogen atom and another atom with an opposite charge

Question 5

why are water particles able to move constantly

Answer 5

they constantly make/break h bonds with other molecules surrounding them allowing them to move

Question 6

what 5 properties of water make it useful for living organisms

Answer 6

• high specific heat capacity
• high latent heat of evaporation
• cohesive
  good solvent
• less dense when its solid

Question 7

how is waters structure related to its properties

Answer 7

• hydrogen gives water a high SHC as hydrogen bonds can absorb a lot of energy so it takes a lot of energy to heat up
  which means water won’t experience rapid temp changes
• Hydrogen bonds also give water high SLH as to break hydrogen bonds require a lot of energy as a lot of energy is used up when water evaporates which makes it ideal for animals as water is good for cooling things e.g when we sweat

Question 8

what does water’s polarity do?

Answer 8

• makes it cohesive
  cohesions is the attraction of molecules of the same type. water is cohesive as it’s polar helps water flow ( good transport)
• makes a good solvent as most substances are ionic made from one + atom/m and one - atom . Water is polar so it means the slightly + end will be attracted to - ions while - end will be attracted to + ions so water molecules totally surround the substances so it will dissolve

Question 9

what monosaccharides make up the following
- sucrose
- lactose
- maltose
- cellulose

Answer 9

B-glucose + B fructose -> sucrose
b- glucose + a glucose -) lactose
a glucose + a glucose -> maltose
b glucose + b glucose - > cellulose

Question 10

what is a glycosidic bond

Answer 10

a covalent bond formed between between 2 monosaccharides in a condensation reaction

Question 11

Amylose Amylopectin glycogen

function
Bonds
chain
found as

Answer 11

Amylose- energy store, glycosidic bonds 1-4 - h bonds hold spiral and OH make molecules less soluble, coiled with no branches

Amylopectin- energy stores, 1-4 glycosidic bonds + 1-6 bonds , coiled with branches , found as granules

Glycogen- energy stores, 1-4 bonds and 1-6 bonds , coiled + heavily branched, granules

Question 12

cellulose structure

Answer 12

structure: 1-4 bonds , has to be inverted - results in long chains , but forms hydrogen bonds between rotated b glucose molecules in chains

Question 13

cellulose chains and why is cellulose strong? pt 1

Answer 13

straight, run parallel so they line up , results in oh groups being in close proximity which causes hydrogen bonds to form between other OH groups in an adjacent chains - results in cross linking which make cellulose strong

Question 14

why is cellulose strong pt2

Answer 14

chains come together to form microfibres , many microfibres come together to form macrofibres which wrap around plant cells which give plants strength