Section 1: Chapter 1: Biological molecules

Question 1

What is covalent bonding?

Answer 1

Atoms sharing electrons in their outer shells to make a more stable compound.

Question 2

What is ionic bonding?

Answer 2

Ions with opposite charges attract each other.

Question 3

What is hydrogen bonding?

Answer 3

Polar molecules attract each other. Individually weak but collectively strong.

Question 4

What is a polar molecule?

Answer 4

Molecule with an uneven distribution of charge.

Question 5

What is a hydrolysis reaction?

Answer 5

Breaking down of polymers by adding water.

Question 6

Are monosaccharides soluble or insoluble?

Answer 6

Soluble.

Question 7

What is the test for a reducing sugar?

Answer 7

• Add benedicts.
• Heat.
• Orange-brown = reducing sugar present.

Question 8

What molecules join to make maltose?

Answer 8

Glucose + glucose.

Question 9

What molecules join to make sucrose?

Answer 9

Glucose + fructose.

Question 10

What molecules join to make lactose?

Answer 10

Glucose + galactose.

Question 11

What bond is formed between monosaccharides?

Answer 11

Glycosidic bond.

Question 12

What reaction takes place when monosaccharides join?

Answer 12

Condensation reaction.

Question 13

What is the test for non-reducing sugars?

Answer 13

• Add benedicts.
• Heat.
• Add hydrochloric acid.
• Add sodium hydrocarbonate.
• Add benedicts.
• Heat.
• Orange-brown = non-reducing sugar.

Question 14

Why is hydrochloric acid and sodium hydrocarbonate needed to test for a non-reducing sugar?

Answer 14

• Hydrochloric acid - to hydrolyse disaccharides → monosaccharides.
• Sodium hydrocarbonate - neutralise the HCL.

Question 15

Are polysaccharides soluble or insoluble?

Answer 15

Insoluble because very large.

Question 16

What is the test for starch?

Answer 16

• Add iodine.
• Shake.
• Blue-black = starch.

Question 17

Where is starch found?

Answer 17

In plants - mainly seeds.

Question 18

What is starch’s function?

Answer 18

energy storage.

Question 19

Is starch branched or unbranched?

Answer 19

could be either.

Question 20

How is starch suitable for it’s function of energy storage? (5 points)

Answer 20

• Insoluble - doesn’t affect ψ.
• Large - doesn’t diffuse out of cells.
• Compact - lots of storage in small space.
• Hydrolysed into a-glucose so can be easily transported and used in respiration.
• Branched form has many ends - all acted on by enzymes at once.

Question 21

Is starch made up of alpha or beta glucose?

Answer 21

Alpha.

Question 22

Where is glycogen found?

Answer 22

Animals and bacteria - in muscles and liver.

Question 23

What is glycogen’s function?

Answer 23

Carbohydrate storage.

Question 24

Is glycogen branched or unbranched?

Answer 24

Highly branched.

Question 25

How is glycogen suitable for it's function of storage?

Answer 25

- Insoluble - doesn't bring in water or diffuse out of cells. - Compact - lots can be stored in a small space. - Highly branched - more ends for enzymes to act on.

Question 26

Is glycogen made up of alpha or beta glucose?

Answer 26

Alpha.

Question 27

Where is cellulose found?

Answer 27

Plant cell walls.

Question 28

What is cellulose's function?

Answer 28

Structural support.

Question 29

Is cellulose branched or unbranched?

Answer 29

Unbranched.

Question 30

How is cellulose suitable for its function?

Answer 30

- Has an inward pressure - cell wall won't burst when water enters. - Long, straight, unbranched chains. - Hydrogen bonds - collectively strong.

Question 31

Is cellulose made up of alpha or beta glucose?

Answer 31

Beta glucose

Question 32

What bonds form between the adjacent chains of a cellulose molecule?

Answer 32

Hydrogen bonds.

Question 33

What are 3 general characteristics of lipids?

Answer 33

- Contain C,H,O. - Insoluble in water. - Soluble in organic solvents.

Question 34

What are the 2 main groups of lipids?

Answer 34

- Triglycerides. | - Phospholipids.

Question 35

What are 5 roles of lipids?

Answer 35

- Cell membrane. - Energy source. - Waterproofing - insoluble in water. - Insulation - slow producer of heat. - Protection - fat stores around organs.

Question 36

Draw a fatty acid.

Answer 36

http://heartratezone.com/monounsaturated-fatty-acids-examples/

Question 37

What is the difference between a saturated and non-saturated fatty acid?

Answer 37

Unsaturated has at least one carbon-carbon double bond.

Question 38

Draw a triglyceride.

Answer 38

https://www.researchgate.net/figure/Fig-1-Transesterification-of-triglyceride-with-alcohol-Triglycerides-from-oils-and_fig1_23656725

Question 39

What is the structure of a triglyceride related to it's function?

Answer 39

- Low mass:energy ratio - good storage for a small vol. - Large and non-polar - insoluble in water so don't affect ψ. - Release water when oxidised - good source of water for organism.

Question 40

Draw a phospholipid.

Answer 40

https://ibiologia.com/phospholipid-bilayer/

Question 41

What's the difference between a triglyceride and a phospholipid?

Answer 41

Phospholipids swap a fatty acid for a phosphate molecule.

Question 42

What are the two parts of a phospholipid?

Answer 42

1) Hydrophilic head - attracted to water not fat. 2) Hydrophobic tail - repels water but attracted to fat. These two opposites make phospholipids polar.

Question 43

What is the structure of phospholipids related to it's properties?

Answer 43

- Polar - form a bilayer within cell-surface membranes. | - Can form glycolipids for cell recognition.

Question 44

What is the test for lipids?

Answer 44

Emulsion test. - Add ethanol. - Shake. - Add water. - Shake. - milky-white emulsion = lipid.

Question 45

Draw an amino acid.

Answer 45

https://sites.google.com/site/ellesmerealevelchemistry/module-6-organic-chemistry-analysis/6-2-nitrogen-compounds-polymers-and-synthesis/6-2-2-a-reactions-of-amino-acids

Question 46

What are the 4 chemical groups in an amino acid?

Answer 46

- Amine group. - Carboxyl group. - Hydrogen atom. - R group.

Question 47

What is the bond between amino acid molecules?

Answer 47

Peptide bond.

Question 48

What is the primary structure of proteins?

Answer 48

A sequence of amino acids - polypeptide chain.

Question 49

What is the secondary structure of proteins?

Answer 49

- Sequence folds into either α-helix or β pleated sheets. | - Held in place by hydrogen bonds.

Question 50

What is the tertiary structure of proteins?

Answer 50

- More folding. - 3-D. - Held in place by H, ionic and disulphide bonds.

Question 51

What is the quaternary structure of proteins?

Answer 51

Multiple polypeptide chains. | Eg/ haemoglobin.

Question 52

What is the test for proteins?

Answer 52

- Add buret. | - Purple = peptide bond = protein.

Question 53

Do enzymes lower or higher activation energy?

Answer 53

Lower - less energy required to activate the reaction.

Question 54

What is the induced fit model?

Answer 54

Enzyme can alter it's shape slightly when a substrate is present.

Question 55

What 4 things effect enzyme action?

Answer 55

1) Temperature. 2) pH. 3) Enzyme concentration. 4) Substrate concentration.

Question 56

How does temperature effect enzyme action?

Answer 56

- ↑ temp = ↑ kinetic energy. - ↑ collisions. - More E-S complexes. - Until denatured.

Question 57

How does pH effect enzyme action?

Answer 57

- change in pH can alter the charges of amino acids. | - Could also break bonds, changing the active sites shape.

Question 58

How does enzyme concentration effect the rate of reaction?

Answer 58

↑ enzymes = ↑ E-S complexes.

Question 59

how does substrate concentration effect the rate of reaction?

Answer 59

↑ substrate = ↑ E-S complexes.

Question 60

What are the two types of enzyme inhibitors?

Answer 60

Competitive and non-competitive.

Question 61

How do competitive inhibitors work?

Answer 61

- Similar shape to substrate, so occupy enzymes active site. | - Not permanent - substrate can reoccupy active site if inhibitor leaves.

Question 62

How do non-competitive inhibitors work?

Answer 62

Bind to allosteric site, altering the active site so the enzyme can no longer function.