4: biological molecules

Question 1

what are biological molecules?

Answer 1

organic molecules

Question 2

what is the purpose of biological molecules?

Answer 2

to provide energy and raw materials for the growth and repair of tissues

Question 3

what are the 4 main groups of biological molecules?

Answer 3

1. carbohydrates
2. lipids
3. proteins
4. nucleic acids

Question 4

what is a monomer?

Answer 4

a single repeating molecule that can be joined with other identical ones to form a polymer through the process of polymerisation

Question 5

what are the 2 types of polymers?

Answer 5

• natural polymers
• industrial polymers

Question 6

list down examples of natural polymers

Answer 6

• cellulose
• rubber

Question 7

list down examples of industrial polymers

Answer 7

• PVC
• polyester
• polythene
• nylon

Question 8

what are the polymers for carbohydrates?

Answer 8

polysaccharides

Question 9

what are the polymers for proteins?

Answer 9

polypeptides

Question 10

what are the polymers for nucleic acids?

Answer 10

polynucleotides

Question 11

what are the polymers for lipids?

Answer 11

lipids are non-polymers

Question 12

list down 3 monosaccharides of carbohydrates

Answer 12

galactose, fructose, glucose

Question 13

what are monosaccharides?

Answer 13

• an easily soluble sugar unit containing carbon, hydrogen, and oxygen
• they are all reducing sugars

Question 14

what is the difference between monosaccharides and monomers?

Answer 14

monosaccharides are the monomers that make up carbohydrates whilst monomers are the building blocks of larger organic molecules

Question 15

what are the 2 main biological roles of monosaccharides?

Answer 15

• primary energy source (releases ATP from C–H bonds)
• building blocks (repeated glucose molecules build-up)

Question 16

how does the formation of a disaccharide like maltose happen?

Answer 16

two glucose molecules meet, and when the reaction takes place, the hydrogen bonds with the hydroxide and so water is expelled

Question 17

what is a condensation reaction?

Answer 17

joins two molecules together with the formation of a chemical bond and involves the elimination of molecule of water

Question 18

what is a hydrolysis reaction?

Answer 18

a larger molecule forms two or more smaller molecules and consumes a molecule of water

Question 19

what are the disaccharides that are reducing sugars?

Answer 19

lactose and maltose

Question 20

what reactants form sucrose?

Answer 20

glucose + fructose (plant sap)

Question 21

what reactants form maltose?

Answer 21

glucose + glucose

Question 22

what reactants form lactose?

Answer 22

glucose + galactose (milk sugar)

Question 23

what are polysaccharides?

Answer 23

• polymers with subunits of monosaccharides formed by repeated condensation
• they ARE NOT sugars

Question 24

what is starch?

Answer 24

• compact, inert and insoluble store of glucose

Question 25

what can starch be used for?

Answer 25

- fuel store in plants - to make cellulose for germinating seeds

Question 26

what is the animal equivalent of starch?

Answer 26

glycogen

Question 27

what is cellulose?

Answer 27

- a polymer of glucose - the most abundant organic molecule

Question 28

what are lipids?

Answer 28

hydrophobic organic molecules that are insoluble in water

Question 29

what are fatty acids?

Answer 29

a series of acids found in fats

Question 30

what is a triglyceride?

Answer 30

when a molecule of glycerol joins with 3 fatty acid molecules

Question 31

why are triglycerides not polymers?

Answer 31

because fatty acids are not made out of repeating subunits

Question 32

what are the two types of fatty acids?

Answer 32

saturated and unsaturated fatty acids

Question 33

explain saturated fatty acids

Answer 33

- fatty acids with the max. number of hydrogen atoms - does not have double bonds

Question 34

explain unsaturated fatty acids

Answer 34

- fatty acids w/out the max. number of hydrogen atoms - has double bonds

Question 35

what are the biological functions of lipids? [5]

Answer 35

- important for making cell membranes - shock absorbers - insulation - energy store - buoyancy

Question 36

what are fats used for?

Answer 36

for the production and storage of energy

Question 37

what are amino acids?

Answer 37

- building blocks of protein - contains carbon, hydrogen, oxygen & nitrogen

Question 38

what is an R group of an a.a?

Answer 38

it gives the unique characteristics and 3D shape

Question 39

what are proteins?

Answer 39

polymers made up of a.a

Question 40

what is a polypeptide?

Answer 40

many a.a linked together by peptide bonds

Question 41

how is a polypeptide formed?

Answer 41

by condensation

Question 42

where are a.a linked?

Answer 42

at the ribosomes

Question 43

primary structure of protein

Answer 43

- backbone of a peptide chain - particular a.a and its sequence

Question 44

secondary structure of protein

Answer 44

when sections of the primary structure start interacting with other sections of the same chain

Question 45

list the properties of a.a [2]

Answer 45

- soluble; easily transportable to do chemical reactions in the cytoplasm - sequence determines the shape and function of the protein

Question 46

what is a globular protein?

Answer 46

4 polypeptide chains packed closely together

Question 47

why do sickle cells happen?

Answer 47

- the a.a glutamic acid is replaced with valine, which is non-polar and therefore less soluble, resulting in a sickle shaped cell

Question 48

what is a fibrous protein?

Answer 48

polypeptide chains lying parallel to each other

Question 49

what are the differences between fibrous and globular protein? [3]

Answer 49

- g: spherical shape, f: long thin fibres - g: folded peptide chains, f: parallel peptide chains - g: metabolic, transport & protective function; f: structural & contractile function

Question 50

what is denaturation?

Answer 50

process where proteins loses its specific 3D shape, disallowing it to perform its normal biological function

Question 51

what can denaturation be caused by?

Answer 51

- heat - pH - heavy metals ^all these break the bonds

Question 52

what is DNA?

Answer 52

the material that makes up our genes and chromosomes

Question 53

what is DNA made of?

Answer 53

nucleotides

Question 54

what are nucleic acids?

Answer 54

many nucleotides linked in a long chain

Question 55

what are the 3 components of a nucleotide?

Answer 55

1. sugar group 2. phosphate group 3. nitrogenous base group

Question 56

what are the nitrogenous base group components and the pairings?

Answer 56

A, C, T, & G - G & C - A & T

Question 57

what does the sequence of the nitrogenous base pairings do?

Answer 57

determines the proteins that are made in a cell

Question 58

what is the difference between RNA and DNA?

Answer 58

RNA is usually single-stranded while DNA forms a double-helix structure

Question 59

list the importance of nucleic acids [2]

Answer 59

- carries the genetic code which holds the genetic info - sequence of bases determines the sequence of a.a