Biological Molecules Part 1

Question 1

What is a monomer

Answer 1

Smaller units from which larger molecules are made

Question 2

What is a polymer

Answer 2

Molecule made from a large number of monomers joined together

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 molecule of water

Question 4

What is a hydrolysis reaction

Answer 4

Breaks a chemical bond between two molecules, involves the addition of water

Question 5

What bond forms between the condensation of two monosaccharides

Answer 5

Glycosidic bond

Question 6

Glucose + Glucose

Answer 6

Maltose

Question 7

Glucose + Fructose

Answer 7

Sucrose

Question 8

Glucose + Galactose

Answer 8

Lactose

Question 9

What is amylose

Answer 9

1,4 glycosidic bonds

Question 10

What is amylopectin

Answer 10

1,6d and 1,4 glycosidic bonds
Branched and more terminal ends

Question 11

Describe the structure and function of starch/ glycogen

Answer 11

Insoluble- doesn’t effect water potential
Helical/ coiled - compact
Large molecules- cannot leave cell
Branched- faster enzyme action
Polymer of alpha glucose, joined by glycosidic bond- provides glucose for respiration

Question 12

What is the difference between glycogen and starch

Answer 12

Glycogen has more 1,6 bonds- humans have higher metabolic and respiration rate

Question 13

Describe the structure of cellulose

Answer 13

Polymer of beta glucose
Long and straight chains
Become linked together by many hydrogen bonds to form fibrils
Cellulose chains run parallel to each other
Each other beta glucose is inverted and chains off beta glucose are stacked on top of each other
Collective strength

Question 14

Explain the difference between starch and cellulose

Answer 14

Alpha, beta
Position of hydrogen and hydroxyl groups on carbon atom 1 inverted

Cellulose is made up of B-glucose (monomers) and glycogen is made up of a-glucose (monomers);
Cellulose molecule has straight chain and glycogen is branched;
Cellulose molecule has straight chain and glycogen is coiled: glycogen has 1,4- and 1,6- glycosidic bonds and cellulose has only 1,4- glycosidic bonds;
Ignore ref. to H bonds / microfibrils

Question 15

Suggest how glycogen acts as a source of of energy

Answer 15

Hydrolysed to glucose
Glucose used in repsiration

Question 16

What is the chemical test for starch

Answer 16

Iodine
Turns blue-black

Question 17

What is the test for reducing sugars

Answer 17

Add food sample, add Benedict’s, heat in water bath
Turns red

Question 18

What is the test for non-reducing sugars

Answer 18

Heat with Add HCl and neutralise
Benedict’s
Heat
Red

Question 19

Why should you use a colorimeter

Answer 19

Standardises Method
Provides a quantitive result
To minimise human error

Question 20

Suggest a method to measure the quantity of reducing sugar

Answer 20

Filter and dry the precipitate
Find mass/ weight

Question 21

What is soluble starch

Answer 21

Partially hydrolysed starch into shorter chains of alpha glucose
Helps to reduce the size of the starch polymer

Question 22

What allows cellulose to form straight , strong fibres in biological tissues

Answer 22

Alternating glycosidic bonds that form on opposite sides of the chain
Due to the position of -oh and -h groups in beta glucose

Question 23

What are the two types of lipids

Answer 23

Triglycerides
Phospholipids

Question 24

How are triglycerides formed

Answer 24

Condensation
Between one glycerol molecules and three fatty acids
Ester bond
Loos of 3 water molecules

Question 25

Difference between saturated and unsaturated

Answer 25

Saturated- no double bonds between carbon atoms Usually solid at room temperature

Question 26

What is the difference between phospholipids and triglycerides

Answer 26

In phospholipids, one of the fatty acids in substituted by a phosphate-containing group

Question 27

What chemical test is use do test for lipids

Answer 27

Emulsion Add ethanol and shake and water Milky-white emulsion formed

Question 28

What are the properties of triglycerides

Answer 28

Source of energy Waterproofing Insulation Protection

Question 29

What are phospholipids for

Answer 29

Cell membranes

Question 30

What is the group represented by COOH

Answer 30

Carboxyl

Question 31

The scientist expressed their results as percentage of lipid in plasma membrane by mass. Plain how they would find these results

Answer 31

Divide mass of each lipid by total mass of all lipids (in that type of cell) Multiply answer by 100

Question 32

What is needed to break down fat stores

Answer 32

Water

Question 33

Why are saturated fats solid at room temeprature

Answer 33

Straight unlinked hydrocarbon chain Molecules stack/ less able to flow around each other

Question 34

Why are triglycerides metabolised

Answer 34

Synthesis of new plasma membranes Converted to other fatty acids (energy storage ) Respired - to genate energy Converted to transport fat-soluble substances (vitamins)

Question 35

Describe the strucuture of a protein

Answer 35

Primary- linear sequence of amino acids - peptide bonds Secondary - alpha helix, beta pleated- hydrogen bonds between amine and carboxyl Tertiary - disulfide bridge, ionic, hydrogen between r-groups Quaternary - two or more polypeptide chains held together by hydrogen bonds

Question 36

What is the tests for proteins

Answer 36

Purple/ mauve Blue if negative

Question 37

Give the structure of collagen

Answer 37

3 indetical polypeptide chains Triple helix Glycine- smaller Collective strength of hydrogen bonds

Question 38

Explain how a substrate is broken down by the enzyme

Answer 38

-induced model causes active site (of enzyme) to change shape -binding to form an enzyme-substrate complex -lowing of activation energy -conformational/ shape change -breaking of bonds in substrate -products no longer fit the active site and so are released

Question 39

How does temperature effect enzyme activity

Answer 39

Low- low- too little kinetic energy, few collision High- high- successful Higher- denatured- breaking bond sin tertiary, change in active site, no longer fits

Question 40

How does substrate concentration affect enzyme activity

Answer 40

Low- low High- higher At high- plateaus all active site share occupied Enzyme conc in now limiting factor

Question 41

What is a competitive inhibitor

Answer 41

Molecule simila rot substrate Bind to as Compete with enzyme activity site Redu availability Increasing substrate concentration reduce effect

Question 42

What is a non-competitive inhibitor

Answer 42

Attached dot allosteric site - other than active site Alter shape Substrate no longer fits and present e-s complexes formed