Topic 1A- Biological Molecules

Question 1

What are polymers?

Answer 1

Large, complex molecules composed of long chains of monomers joined together

Question 2

3 examples of monomers

Answer 2

Monosaccharides, nucleotides, amino acids

Question 3

3 examples of monosaccharides

Answer 3

Glucose, fructose, galactose

Question 4

What is a condensation reaction?

Answer 4

When two molecules join together by a glycosidic bond and a water molecule is released

Question 5

What’s a disaccharide?

Answer 5

Two monosaccharides joined together

Question 6

What’s sucrose

Answer 6

A disaccharide formed from a condensation reaction between a glucose and fructose molecule

Question 7

What’s lactose made up of?

Answer 7

A glucose molecule and a galactose molecule

Question 8

Hydrolysis reaction

Answer 8

Breaks the chemical bond between monomers using a water molecule

Question 9

Benedict’s test

Answer 9

•Add Benedict’s reagent
•Heat in water bath
•Positive- precipitate is formed and will turn from blue to an orangey-red

Question 10

Test for non-reducing sugars

Answer 10

•Add dilute hydrochloric acid and heat in water bath
•Neutralise with sodium hydrogen carbonate
•Do the Benedict’s test
•Positive- turns from blue to an orangey-red

Question 11

What is a polysaccharide?

Answer 11

Formed when two or more monosaccharides are joined together by a condensation reaction

Question 12

Starch information

Answer 12

Plants store excess glucose as starch, when plants need more glucose for energy, it breaks down starch to release glucose.

Question 13

What is starch a mixture of?

Answer 13

Two polysaccharides of alpha-glucose: amylose and amylopectin

Question 14

Structure of amylose

Answer 14

Long unbranched chain of alpha glucose, coiled structure to make it compact therefore good for storage

Question 15

Structure of amylopectin

Answer 15

Long, branched chain of alpha glucose, side branches allow the enzymes that break down the molecule to get at the glycosidic bonds quickly

Question 16

Why is it good starch is insoluble in water?

Answer 16

Doesn’t affect water potential so water can’t enter the cell through osmosis which makes starch good for storage

Question 17

Iodine test

Answer 17

Add iodine dissolved in potassium iodide solution. If positive- it changes from browny-Orange to blue-black

Question 18

How do animals store excess glucose?

Answer 18

As glycogen- another polysaccharide of alpha glucose

Question 19

Glycogen structure

Answer 19

Loads of side branches coming off it so the stored glucose can be released quickly

Question 20

Cellulose structure

Answer 20

Long unbranched chains of beta glucose, linked together by hydrogen bonds

Question 21

Microfibrils definition

Answer 21

Strong fibres formed by hydrogen bonds in cellulose chains

Question 22

Triglycerides?

Answer 22

Type of lipid

Question 23

What are triglycerides made up of?

Answer 23

One molecule of glycerol and three fatty acids attached to it

Question 24

Fatty acid tails

Answer 24

Long tails made up of hydrocarbons, hydrophobic so they repel water. These tails make lipids insoluble in water.

Question 25

Why is there a carbon atom in a fatty acid?

Answer 25

To link the fatty acid to the glycerol

Question 26

How are triglycerides formed?

Answer 26

Condensation reaction- the fatty acid joins the glycerol to create an ester bond and a water molecule is released

Question 27

Saturated acids

Answer 27

Don’t have any double bonds between their carbon atoms

Question 28

Unsaturated fatty acids

Answer 28

Have at least one double bond between carbon atoms, causes the chain to kink

Question 29

Phospholipids definition

Answer 29

Found in the cell membrane, has two fatty acids attached to glycerol and a phosphate group, the phosphate group (head) is hydrophilic so attracts water and the tails are hydrophobic

Question 30

What are triglycerides mainly used for?

Answer 30

Energy storage, lipids contain about twice as much energy per gram as carbohydrates

Question 31

What do phospholipids make up?

Answer 31

The bilayer of cell membranes

Question 32

Emulsion test (lipids)

Answer 32

Shake the test substance with ethanol for about a minute so it dissolves then pour into water, any lipid will show up as a milky emulsion

Question 33

Cell membrane (function)

Answer 33

Lets things in and out of the cell

Question 34

Nucleus

Answer 34

Controls cell’s activities and stores DNA. Pores (hint with word pores) allow substances (RNA) to move between nucleus and cytoplasm

Question 35

Nucleolus

Answer 35

Makes ribosomes

Question 36

Mitochondrion

Answer 36

Where aerobic respiration occurs, and ATP is produced

Question 37

Chloroplast

Answer 37

Where photosynthesis happens

Question 38

Golgi body

Answer 38

Sorting office, directs molecules where they need to go. Forms lysosomes containing lysozyme to digest worn out organelles

Question 39

SER

Answer 39

Synthesises and transports lipids and carbohydrates

Question 40

RER

Answer 40

Synthesises and transports proteins, has ribosomes

Question 41

Ribosomes

Answer 41

Contains protein and RNA. Can be free in cytoplasm or attached to RER

Question 42

Cytoskeleton

Answer 42

Holds everything where it needs to be

Question 43

Thylakoids (PLANT CELL)

Answer 43

Contain chlorophyll

Question 44

Chloroplasts (PLANT CELL)

Answer 44

Absorbs sunlight for photosynthesis

Question 45

Differential centrifugation

Answer 45

•add ice cold buffer (maintains PH and reduces enzyme activity)
•blend
•put in centrifuge machine
•pour out supernatant
•you’ve now got nuclei, spin again for mitochondrion and again for ribosomes and membranes