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Question 1

why is water a polar molecule?

Answer 1

• uneven distribution of charge within molecule
• hydrogen atoms are more positive than oxygen atom

Question 2

what are properties of water that help living organisms?

Answer 2

• high heat capacity
• minimises temperature fluctuations in living things
• acts as a buffer
• high latent heat of vaporisation provides cooling effect
• water is incompressible so provides good support
• ice less dense than water creating an insulating layer
  -cohesion

Question 3

list properties of water

Answer 3

• strong cohesion
• high latent heat of vaporisation
• high heat specific capacity
• solvent
• incompressible

Question 4

what is a monomer?

Answer 4

small units of larger molecules

Question 5

Example of monomers

Answer 5

• nucleotides
• monosaccharides (glucose)
• amino acids

Question 6

what are polymers

Answer 6

• molecules made from monomers joined together

Question 7

what is condensation reaction?

Answer 7

• joins monomers by chemical bonds
• involves elimination of water molecule

Question 8

what is a hydrolysis reaction?

Answer 8

• water added to break chemical bond between 2 molecules

Question 9

what are the components of carbohydrates?

Answer 9

carbon
hydrogen
oxygen

Question 10

what are carbohydrates

Answer 10

long chains of sugar called saccharides

Question 11

How are disaccharides formed?

Answer 11

monomers joined together by glycosidic bonds
formed in condensation reactions

Question 12

what is glucose?

Answer 12

a monosaccharide contain six carbon atoms in each molecule

Question 13

glucose is the main substrate for

Answer 13

respiration

Question 14

what are two isomers of glucose

Answer 14

alpha glucose
beta glucose

Question 15

2 glucose molecules make

Answer 15

maltose

Question 16

glucose and fructose makes

Answer 16

sucrose

Question 17

glucose and galactose makes

Answer 17

lactose

Question 18

what are polysaccharides

Answer 18

• many glucose units joining together

Question 19

example of polysaccharides

Answer 19

glycogen
starch
cellulose

Question 20

what is a glycosidic bond

Answer 20

A condensation reaction between two monosaccharides forms a glycosidic bond.

Question 21

why is glycogen a good energy source

Answer 21

• large number of side branches
• meant that glucose and energy can be released quickly
• large and compact maximising energy storage

Question 22

How is glycogen formed

Answer 22

alpha glucose molecules joined by 1,4 and 1,6 glycosidic bonds

Question 23

How is starch formed

Answer 23

• mixture of amylose and amylopectin

Question 24

what makes amylose a good energy source?

Answer 24

• unbranched chain and joined by 1,4 glycosidic bonds
• making it coiled and compact
• so can store a lot of energy

Question 25

how is amylopectin formed?

Answer 25

- glucose molecules joined by 1.4 and 1,6 glycosidic bonds

Question 26

what is cellulose?

Answer 26

- component of cell walls - composed of long unbranched chains of beta glucose - joined by glycosidic bond

Question 26

what makes amylopectin a good energy source?

Answer 26

- has many side branches - rapidly digested by enzymes - so energy released quickly

Question 27

what are microfibrils?

Answer 27

- strong threads made up of long cellulose chains - joined by hydrogen bonds - provides structural support in plant cells

Question 28

what are lipids?

Answer 28

- molecules only soluble in organic solvents e.g alcohols

Question 29

what are the two types of lipids

Answer 29

- saturated -unsaturated

Question 30

saturated lipids

Answer 30

- found in animal fats - does not contain carbon-carbon double bonds

Question 31

unsaturated lipids

Answer 31

- found in plants - contains carbon- carbon double bonds

Question 32

why are unsaturated lipids liquid at room temp?

Answer 32

- double bonds weakens intermolecular bonds - causing lower melting point

Question 33

why are saturated fats solid at room temperature

Answer 33

- does not contain any double bonds - so has higher melting point

Question 34

what is the composition of triglycerides?

Answer 34

- one molecule of glycerol - three fatty acids

Question 35

How are triglycerides formed?

Answer 35

- ester bonds formed in condensation reaction (esterification)

Question 36

what are triglycerides used for?

Answer 36

- energy reserves in plant and animal cells

Question 37

what is the composition of phospholipids?

Answer 37

- one molecule of glycerol - one of the three fatty acids substituted by phosphate group

Question 38

what are micelles?

Answer 38

- molecules formed when phospholipids interact with water

Question 39

position of phospholipids

Answer 39

heads on outside tails inside

Question 40

what is the composition of proteins?

Answer 40

- amino acids, that contain an amino group NH2, carboxylic acid and variable R group

Question 41

How are proteins formed?

Answer 41

- joined by peptide bonds formed in condensation reactions.

Question 42

what is a dipeptide?

Answer 42

- contains two amino acids

Question 43

what is polypeptide

Answer 43

- contains three or more amino acids

Question 44

what is the primary structure of proteins?

Answer 44

- the order and number of amino acids in a protein

Question 45

what is the secondary structure of proteins

Answer 45

- shape that the chain of amino acids take -- can be pleated beta sheet or alpha helix - shape is determined by hydrogen bonding

Question 46

what is the tertiary structure of proteins?

Answer 46

- proteins in 3D shape - can be globular or fibrous - globular - compact - fibrous - long make fibres

Question 47

what is collagen

Answer 47

- fibrous protein - strong due to presence of hydrogen and covalent bonds - structure of bones , cartilage and connective tissue -main component of tendons

Question 48

collagen molecules

Answer 48

wrap around each other to make fibrils witch form string collagen fibres

Question 49

what is haemoglobin

Answer 49

- globular protein - water soluble - contains 2 alpha and 2 beta polypeptide chains - contains haem group - carries oxygen to blood as oxygen can bind to haem group and release energy when needed

Question 50

what are inorganic ions

Answer 50

- occurs in solution of the cytoplasm and body fluid.

Question 51

list names of essential ions

Answer 51

- hydrogen, iron , sodium, phosphate

Question 52

hydrogen ions

Answer 52

- determines pH of substances e.g blood - higher concentration of hydrogen ions, the lower the pH

Question 53

iron ions

Answer 53

component of haemoglobin

Question 54

sodium ions

Answer 54

co transport of glucose and amino acids

Question 55

phosphate ions

Answer 55

component of DNA and ATP