Biological Molecules

Question 1

What is a monomer?

Answer 1

Monomers are small units which larger molecules are made up of

Question 2

Examples of monomers

Answer 2

Monosaccharides, amino acids and nucleotides

Question 3

What is a polymer?

Answer 3

A polymer is a molecule made out of a large chain of monomers joined together

Question 4

What is a condensation reaction

Answer 4

A condensation reaction joins two molecules together with the formation ofa hydrogen bond and eliminates water molecules

Question 5

What is a hydrolysis reaction?

Answer 5

A hydrolysis reaction is a break of the chemical bond between two molecules and uses water molecules

Question 6

What are carbohydrates made out of?

Answer 6

They are made out of monosaccharides

Question 7

What are the most common type of monosaccharide

Answer 7

Glucose, fructose and galactose

Question 8

What bond is formed from a condensation reaction in carbohydrates?

Answer 8

A glycosidic bond is formed

Question 9

Types of dissaccharides

Answer 9

Sucrose= glucose + fructose
Maltose= glucose + glucose
Lactose= glucose + galactose

Question 10

Isotopes of glucose

Answer 10

Alpha glucose, beta glucose

Question 11

Structure of alpha glucose

Answer 11

In alpha glucose the hydroxyl group is known the same side. This means the alpha glucose is more reactive to enzymes meaning it is easier to break down.

Question 12

Structure of beta glucose

Answer 12

Beta glucose has the hydroxyl groups on opposite size of the molecule which makes the molecule more stable

Question 13

Polysaccharides of a-glucose

Answer 13

Glycogen and starch

Question 14

Polysaccharide of B-glucose

Answer 14

Cellulose

Question 15

What types of sugar is glucose made out of?

Answer 15

Hexose sugar which has 6 carbon atoms

Question 16

Starch

Answer 16

Monosaccharide: a-glucose
Structure: mixture of amylose and amylopectin. Amylose- long unbranched forms coiled shape. Amylopectin- long branched chain due to 1-6 glycosidic bonds.
Properties: amylose= coiled shape makes it compact to store I’m small spaces. Amylopectin= branched chain increases surface area for enzymes to hydrolyse glycosidic bonds- glucose released faster.
Uses: plant uses starch to store excess glucose. Starch can also be hydrolysed.

Question 17

Glycogen

Answer 17

Monosaccharide: a-glucose
Structure: long branched chain with lots of side branches. 1-6 glycosidic bonds
Properties: lots of branches increases the surface area so allows enzymes to hydrolyse glycosidic bonds allowing glucose to be released fast. compact molecule- good for storage.
Uses: animals store excess glucose as glycogen in muscles and the liver. Glycogen can be hydrolysed and turned in glucose to be released when glucose is needed for respiration.

Question 18

Cellulose

Answer 18

Monosaccharide: B-glucose
Structure: long unbranded chain. Glycosidic bonds are 1-4. Linked with hydrogen bonds between glucose molecules in each chain to for thicker erodes called microfibrils
Properties: hydrogen bonds and microfibrils makes it very strong however still flexible.
Uses: major structural component in cell walls of plants, provides support and allows cells to become turgid

Question 19

What biochemical test is used to look for reducing/ non-reducing sugars

Answer 19

The Benedict’s test

Question 20

What are the two groups of lipids?

Answer 20

triglyerides and phospholipid

Question 21

How is a triglyceride formed

Answer 21

It is formed from 1 glycerol molecule and 3 fatty acids

Question 22

How is a phospholipid formed

Answer 22

1glycerol molecule, 2 fatty acids and a phosphate group

Question 23

What is a triglyceride

Answer 23

Triglycerides can either be saturated with no double bonds between the carbon or it can be unsaturated where there is a double bond between a carbon group. Ester bonds are formed by condensation reaction between the 3 OH groups on the glycerol and 3 fatty acids

Question 24

What are phospholipids

Answer 24

Phospholipids have ester bonds between the 2 of the OH on the glycerol and 2 fatty acids and a phosphate group binded to the other OH on the glycerol

Question 25

What are triglycerides good for

Answer 25

They are a good energy store as there is a lot of energy released into the cells after being carried in the blood.

Question 26

What practical is used to test for a lipid

Answer 26

The emulsion test- take the sample and mix 5cm³ of ethanol. Add 5cm³ of water. If a milking white emulsion forms in it there are lipids present

Question 27

What are proteins made up of

Answer 27

Amino acids

Question 28

How to amino acids make proteins

Answer 28

They are joined together by peptide bonds to form a polypeptide protein

Question 29

What is the structure of an amino acid

Answer 29

They have an alpha carbon, hydrogen, a carboxyl group (COOH), an amino group (H²N) and an R group

Question 30

What is an R group

Answer 30

An r group has a specific side chain which is attached to the alpha carbon. This allows amino acids to be grouped according to chemical properties.

Question 31

What is a primary structure

Answer 31

A primary structure is the sequence of the amino acids

Question 32

What is a secondary structure

Answer 32

The folding of the polypeptide chain either alpha helix or beta pleted sheets

Question 33

What is a tertiary structure

Answer 33

The 3D shape of the polypeptide due to hydrogen, covalent bonds and disulfite bridges

Question 34

How do 2 amino acids form a peptide bond

Answer 34

Whe one of the amino acids carboxyl groups reacts with the other amino acids amino group they go through a condensation reaction, eliminating water molecules and bonding them together. Creates a dipeptide

Question 35

How to test for proteins

Answer 35

Buiret test, will turn purple if present

Question 36

Define an enzyme

Answer 36

They are biological catalysts which lower activation energy by finding a different pathway

Question 37

What is the enzyme model called

Answer 37

The induced fit model

Question 38

How does the induced fit model work

Answer 38

. The matching substrate will find the correct enzyme active site . Binds to the active site to create an enzyme-substrate complex . This results in a conformative change so the substrate fits perfectly into the active site of the enzyme. . Substrate then broken down to form products and pushed out due to energy built up inside the enzyme

Question 39

What factors effect rate of reaction

Answer 39

Concentration, temperature, pH

Question 40

How does increased concentration of enzymes or substrate impact enzymes

Answer 40

Increasing enzymes or substrate will initially increase the amount of enzyme substrate complexes as it means there are more active sites to be filled or more substrate to fill enzymes. Overtime it will plateau as there will be another limiting factor such as not enough substrate to fill extra active sites or not enough active sites to fit all of the substrate

Question 41

How does pH impact enzymes

Answer 41

Above or below the optimum level of pH, the H+ ions and OH- ions will disrupt the bonds holding the enzymes 3D structure causing them to denature

Question 42

How does temperature impact enzymes

Answer 42

As the temperature increases so will rate of reaction however then it reacts over 45 degrees the active sites will denature and change shape due to being to hot so rate of enzymes will dramatically decrease

Question 43

What is a competitive inhibitor

Answer 43

They have a similar shape to the substrate molecule. They block the active site so that the substrate cannot bind so there is no enzyme-substrate complexes.

Question 44

What is a non-competitive inhibitor

Answer 44

They do not bind to the active site however they bind to the allosteric site. This binds and changes the shape of the active site so the substrate cannot bind so no enzyme substrate complexes.