Biological Molecules

Question 1

What is an inorganic ion?

Answer 1

An ion that does not contain carbon

Question 2

What is an organic ion?

Answer 2

An ion that contains carbon

Question 3

What is the role/function of hydrogen (H+) ions?

Answer 3

Important in determining the pH of solutions and therefore functioning of enzymes

Question 4

What is the role/function of iron (Fe2+) ions?

Answer 4

Found in haemoglobin - play role in transport of oxygen

Question 5

What is the role/function of phosphate (PO4 3-) ions?

Answer 5

Structural role in DNA molecules and a role in storing energy in ATP molecules

Question 6

What is the role/function of sodium (Na2+) ions?

Answer 6

Important in transport of glucose and amino acids across plasma membranes

Question 7

Define polymerisation

Answer 7

The formation of polymers from monomers joining together

Question 8

What is a condensation reaction?

Answer 8

Reaction in which the joining of two organic compounds results in the production and release of water

Question 9

What is a hydrolysis reaction?

Answer 9

Process of breaking bonds through the addition of water

Question 10

General formula for monosaccharides

Answer 10

Cn(H2O)n
1:2:1

Question 11

What is the name of sugars with 3,4,5,6 carbons?

Answer 11

3 - Triose
4 - Tetrose
5 - Pentose
6 - Hexose

Question 12

Example of a triose

Answer 12

Glyceraldehyde

Question 13

Example of a pentose

Answer 13

Ribose/deoxyribose

Question 14

Example of a hexose

Answer 14

Glucose, fructose, galactose

Question 15

What is the name of a bond between two monosaccharides, and what is the product?

Answer 15

Glycosidic bond
Disaccharide

Question 16

What monosaccharides is maltose made from?

Answer 16

alpha glucose + alpha glucose

Question 17

What monosaccharides is lactose made from?

Answer 17

alpha glucose + galactose

Question 18

What monosaccharides is sucrose made from?

Answer 18

alpha glucose + fructose

Question 19

What is an isomer?

Answer 19

Molecule with the same chemical formula but a different arrangement of atoms

Question 20

What is a monomer?

Answer 20

single, small, soluble, repeating units that can be bonded together to form a much longer chain, or polymer

Question 21

What is a polymer?

Answer 21

large, insoluble molecule (chains and / or branched) made up from many monomers

Question 22

What does OIL RIG stand for?

Answer 22

Oxidation is loss (of electrons)
Reduction is gain (of electrons)

Question 23

How do you check for the presence of reducing sugars?

Answer 23

Benedict’s test

Question 24

What is the positive result of a reducing sugars test?

Answer 24

Benedict’s solution changes colour from blue to red - could be orange/yellow/green if there is a low conc. of sugar

Question 25

Ionic equation of the reaction in Benedict’s solution

Answer 25

Cu2+ + e- —> Cu+ Blue Brick red

Question 26

What are polysaccharides

Answer 26

Polymers formed from many monosaccharides joined by glycosidic bonds

Question 27

Structure of starch + reasons

Answer 27

Made of alpha glucose Coiled - compact so lots stored in small space Branched - more ends for faster hydrolysis Large and insoluble - doesn’t diffuse out of cells or affect water potential

Question 28

Structure of glycogen

Answer 28

Formed from alpha glucose Very branched Coiled

Question 29

Test for starch

Answer 29

Iodine test - changes from yellow/orange to blue-black

Question 30

Structure of cellulose

Answer 30

Formed from beta glucose Straight, unbranched Every other glucose molecule flipped 180• - H+ bonds form between OH groups forming cross linkages. Microfibrils Macrofibrils Cellulose fibres - strength

Question 31

Function of cellulose in cell walls

Answer 31

Provides strength Prevents bursting when water enters by osmosis Maintains turgidity and rigidity Maximises surface area for light absorption for photosynthesis

Question 32

What elements do all lipids contain?

Answer 32

Carbon Hydrogen Oxygen

Question 33

What are lipids soluble in?

Answer 33

Other organic solvents (eg. alcohols) NOT WATER

Question 34

Two main groups of lipids

Answer 34

Triglycerides - component of our diet Phospholipids - component of cell membranes

Question 35

Difference between saturated and unsaturated fatty acids

Answer 35

Saturated - only C-C - linear Unsaturated - one or more C=C - bends

Question 36

Properties of saturated fatty acids

Answer 36

Only C-C Fatty acids can pack closely together Strong intermolecular attraction between fatty acid chains High melting point Solid at room temp

Question 37

Properties of unsaturated fatty acids

Answer 37

One or more C=C Not closely packed fatty acids Weaker attraction (intermolecular) Lower melting points Liquid at room temp

Question 38

Triglyceride structure

Answer 38

3 fatty acids and one glycerol

Question 39

Triglycerides are large and insoluble, therefore …..

Answer 39

hydrophobic

Question 40

Phospholipids structure

Answer 40

Phosphate and 2 fatty acids

Question 41

What is a phospholipid bilayer (plasma membranes)?

Answer 41

Head of phospholipid is hydrophilic and tail is hydrophobic so outside and inside of cell lined with heads and inside of cell membrane lined with tails.

Question 42

Examples of proteins

Answer 42

Enzymes In cell membrane Structural eg. collagen Hormones Antibodies Transport eg. haemoglobin

Question 43

What elements do all proteins contain?

Answer 43

Carbon, hydrogen, oxygen, nitrogen

Question 44

Protein monomer units and polymer

Answer 44

Amino acids Polypeptide chain

Question 45

How many amino acids are there?

Answer 45

20

Question 46

What is the sequence of amino acids in the polypeptide chain called?

Answer 46

Primary structure

Question 47

Biuret test

Answer 47

Add a few drops of biuret reagent to the sample Blue to purple = protein present

Question 48

What is the order of protein structure

Answer 48

Primary —> Secondary —> Tertiary —> Quaternary

Question 49

What is the primary structure of proteins?

Answer 49

Order/sequence of amino acids in the polypeptide chain

Question 50

What is the secondary structure of proteins?

Answer 50

Hydrogen bonds form between C=O and N-H Pulls polypeptide chain into either: α-helix coil - more common β-pleated sheets

Question 51

What is the tertiary structure of proteins?

Answer 51

Further twisting and folding of polypeptide chain to give very specific shape/structure

Question 52

What bonds are present between R-groups in tertiary structure of proteins?

Answer 52

- Disulfide bridges - Ionic bonds - Hydrogen bonds - Hydrophobic interactions

Question 53

What is the quaternary structure of proteins?

Answer 53

Proteins made up of multiple polypeptide chains joined together Can also be prosthetic (non-protein) groups

Question 54

What are the two types of proteins?

Answer 54

Globular and fibrous

Question 55

What are globular proteins?

Answer 55

Form spherical shape with compact structure. Carry out metabolic functions E.g enzymes and haemoglobin

Question 56

What are fibrous proteins?

Answer 56

Form long chains in parallel to one another. Linked by cross bridges Fibre like and have structural functions e.g collagen

Question 57

How many amino acids are there?

Answer 57

20