AS- Topic 1: Molecules

Question 1

What makes Water a polar molecule, and what does polar molecule mean?

Answer 1

The hydrogen has a slight positive charge, the oxygen has a slight negative charge this is due to the electrons in the covalent bond not being shared evenly

Question 2

What is a pH buffer?

Answer 2

A chemical or substance that resist pH changes and ensure that the environment maintains a particular pH

Question 3

Give and example of a natural pH buffer

Answer 3

Hydrogen carbonate - HCO3

Question 4

What is a Monosaccharide?

Answer 4

Basic carbohydrate monomers, and are single sugars

Mono - one

Question 5

What are the names of the 3 important Monosaccharide groups and what differentiates them?

Answer 5

They are grouped based on the number of carbons they have, Not on the shape of the bonds
Trioses- 3 carbons
Pentoses- 5 carbons
Hexoses- 6 carbons

Question 6

What is the general formula for Monosaccharides?

Answer 6

(CH2O)n

Question 7

What is the difference between Alpha Glucose and Beta Glucose?

Answer 7

On the first carbon of Beta Glucose the hydroxyl and hydrogen switch

Question 8

What group do the monomers Glucose and Fructose belong to?

Answer 8

Hexose, due to them both having 6 carbons

Look at carbons not bonds in the structure

Question 9

What is a Disaccharide?

Answer 9

Double sugars, formed through condensation of two Monosaccharides monomers
Di - two

Question 10

What Monosaccharides make Sucrose?

Answer 10

A alpha glucose molecule and a fructose molecule

Question 11

What Monosaccharides make Maltose?

Answer 11

2 alpha glucose molecules

Question 12

What is a Polysaccharide?

Answer 12

Complex molecules consisting of many Monosaccharide monomers

Poly - many

Question 13

What is the reaction called when Monosaccharide monomers react to form Disaccharide’s/ Polysaccharides, and what are the products formed?

Answer 13

Condensation, and the Disaccharide along with a molecule of water

Question 14

What is the reaction called when Disaccharides/Polysaccharides are broken down into Monosaccharide monomers?

Answer 14

Hydrolysis, it uses water to break the bonds

Question 15

What is the function of Starch?

Answer 15

An energy store in plants

Question 16

What 2 Polysaccharides make up Starch?

Answer 16

Amylose and Amylopectin

Question 17

How are branching and non branching molecules different?

Answer 17

Branching molecules release energy faster than non branching molecules because they have more ends

Question 18

What is Amylose made of?

Answer 18

Alpha glucose

Question 19

Is Amylose a branching molecule and what bonds hold the individual glucose units together?

Answer 19

Not branching, and 1-4 glycosidic bonds

Question 20

What shape does Amylose take and what’s the advantage of that?

Answer 20

A helix which allows it to be compact

Question 21

What is Amylopectin made of?

Answer 21

Alpha glucose

Question 22

What kinds of bonds hold Amylopectin together?

Answer 22

It has 1-4 glycosidic bonds between the individual glucose molecules, also has 1-6 glucosidic to form branches

Question 23

Is Amylopectin a branching molecule?

Answer 23

Yes

Question 24

Why is Amylopectin better than Amylose for energy release?

Answer 24

It is able to release energy easier than Amylose

Question 25

What is Glycogen?

Answer 25

It is the way in which animals and fungi store their carbohydrates

Question 26

Is Glycogen a branching molecule?

Answer 26

Yes

Question 27

How is Glycogen different from Amylopectin and explain the difference

Answer 27

It has more branching due to more frequent 1-6 glycosidic bonds, this is because animals need to move and respond to stimuli faster than plants

Question 28

What is the function of cellulose?

Answer 28

To give plant cells structure, it is a structural pollysaccharide

Question 29

What is Cellulose made of?

Answer 29

Beta glucose

Question 30

What bonds hold the molecules together?

Answer 30

1-4 glycosidic bonds

Question 31

What has to happen to the glucose molecules to allow them to form bonds?

Answer 31

Alternate beta glucose molecules have to be flipped upside down to allow 2 hydroxyl groups to become adjacent to each other

Question 32

What bonds form between parallel chains of beta glucose molecules?

Answer 32

Hydrogen bonds

Question 33

What gives Cellulose very high tensile strength?

Answer 33

The long chains of beta glucose (microfibrils) laid over each other forms a lattice

Question 34

What are the two types of Lipids?

Answer 34

Triglycerides and Phospholipids

Question 35

What is the function of Triglycerides?

Answer 35

It is an energy store, provide thermal insulation and a protective cushioning for delicate organs such as kidneys

Question 36

What are Triglycerides?

Answer 36

Fats and oils

Question 37

What is the general formula for Triglycerides?

Answer 37

CH3(CH2)nCOOH

Question 38

What are the parts of a Triglyceride?

Answer 38

Glycerol and Fatty Acids

Question 39

What is the difference between a Saturated and a Unsaturated Fatty Acid?

Answer 39

A Saturated Fatty Acid contains the max number of hydrogen atoms, whereas Unsaturated Fatty Acid has a C=C bond meaning it has less hydrogens

Question 40

Why is Fat solid at room temperature whereas Oils are liquid.?

Answer 40

Fat is made up of all Saturated Fatty Acids, this means there is no space in its structure. Oils are made up of Unsaturated Fatty Acids so due to the C=C bond there is a “kink” in their structure so there is space making it a liquid

Question 41

Does Triglyceride have a charge and explain why

Answer 41

It doesn’t as it is a neutral molecule and doesn’t react with water

Question 42

What is the bond called which occurs in a condensation reaction to form Triglycerides?

Answer 42

Ester bond

Question 43

What is the function of Phospholipids?

Answer 43

Major part of all cell membranes

Question 44

What difference is there between Triglycerides and Phospholipids structure wise?

Answer 44

Triglycerides have 3 tails, whereas Phospholipids only have 2 and their last tail is replaced with a phosphate group

Question 45

What will happen if Phospholipids are put into water?

Answer 45

It will form a bilayer with the hydrocarbon tails facing each other and the phosphate heads facing into the water

Question 46

What are Proteins?

Answer 46

Large macromolecules that are polymers of Amino Acids

Question 47

What causes difference to occur in Amino Acids?

Answer 47

The “R” group

Question 48

What is the bond called that occurs between two Animoji Acids and what is the product called?

Answer 48

A peptide bond and the product is a dipeptide

Question 49

Are Phospholipids hydrophilic or hydrophobic?

Answer 49

Both, the “head” is hydrophilic due to the phosphate group gibing the molecule a charge. The “tails” are hydrophobic as they have no charge so cannot react with water

Question 50

What are the 4 levels of protein structure?

Answer 50

Primary, Secondary, Tertiary, Quaternary

Question 51

What is the Primary structure is proteins?

Answer 51

The order of Animo Acids in the chain

Question 52

What is the Secondary structure is proteins?

Answer 52

This has 2 major structural patterns, Alpha helix and Beta sheet. Both of these structures are held together with hydrogen bonds

Question 53

What is the Tertiary structure is proteins?

Answer 53

This is characterised by globular and more spherical shape, are held together by bonds such as Hydrogen bonds, Disulphide bonds, Ionic bonds, Hydrophobic interactions

Question 54

What is the Quaternary structure is proteins?

Answer 54

Made up of more than 1 polypeptide chain, examples would be collagen and haemoglobin

Question 55

What is a Fibrous protein?

Answer 55

These proteins tend to form long strands and have a structural role, examples are collagen or keratin

Question 56

What is a Globular protein?

Answer 56

These proteins are more spherical in shape and usually have a metabolic role in cells, examples include enzymes and haemoglobin

Question 57

What is a Conjugated protein?

Answer 57

It is a protein with non protein parts added to its final functional structure, an example would be haemoglobin

Question 58

What are the 3 components of a nucleotide?

Answer 58

Pentose sugar, phosphate group, nitrogenous base

Question 59

What reaction happens to join the components of a nucleotide together?

Answer 59

Condensation reaction

Question 60

What is the bond between the phosphate of one nucleotide and the ribose sugar of another called?

Answer 60

Phosphodiester bond

Question 61

What are the 3 forms of RNA?

Answer 61

mRNA-carry coded info from the nucleus to ribosomes tRNA- responsible for placing amino acids in the correct place in a polypeptide chain rRNA-is a component of the ribosome

Question 62

What’s the structural difference between DNA and RNA

Answer 62

Single stranded- RNA, double stranded- DNA | A,G,C present in DNA and RNA, RNA has U, DNA has T

Question 63

What is the model used to describe the replication of DNA?

Answer 63

Semi conservative model

Question 65

What enzyme crates a new complimentary chain to the parent strand in DNA replication?

Answer 65

DNA polymerase

Question 66

What enzyme breaks the hydrogen bonds in replication of DNA?

Answer 66

DNA Helicase