Lecture 1: Key Molecules [G]

Question 1

What do prokaryotes include?

Answer 1

Bacteria and archea

Question 2

Name some features of prokaryotes

Answer 2

• No nucleus

Question 3

What do Eukaryotes include?

Answer 3

• Plants
• Fungi
• Animal cells

Question 4

Name some features of plant cells

Answer 4

• Cell wall
• Chloroplasts

Question 5

Name some features of fungal cells

Answer 5

• Cell wall (different material to plant cell wall)
• No chloroplasts

Question 6

What determines the Phenotype?

Answer 6

The nature of the molecules

Question 7

What does a lot of biological knowledge come from?

Answer 7

The study of mutants (i.e mutant haemoglobin)

Question 8

What does a mutant phospholipase result in?

Answer 8

Brain cells committing suicide.

Question 9

What does the absence of the hormone leptin result in?

Answer 9

The loss of a cell signalling pathway

Question 10

What are the functions of polysaccharides?

Answer 10

Energy and Structure

Question 11

What is the formula for a Monosaccharide?

Answer 11

(CH₂O)ₙ

where n = 3 or more

Question 12

What is the formula for glucose?

Answer 12

C₆H₁₂O₆

Question 13

What are the general functions of sugars?

Answer 13

Either energy storage or structural roles

Question 14

What is a sugar in animals that is used for energy storage?

Answer 14

glycogen

Question 15

What is a sugar in plants that is used for energy storage?

Answer 15

starch

Question 16

What is a sugar in plants that has a structural role?

Answer 16

Cellulose

Question 17

What type of sugar is glucose?

Answer 17

A hexose sugar

Question 18

Draw alpha glucose

Question 19

Draw beta glucose

Question 20

How does alpha glucose change to beta glucose?

Answer 20

Through a transient linear form.

Question 21

At equilibrium, what percentage of glucose in solution is alpha glucose?

Answer 21

Approx 36%

The remaining less than 0.02% is in the open-chain aldehyde form.

Question 22

At equilibrium, what percentage of glucose in solution is beta glucose?

Answer 22

Approx 64%

. The remaining less than 0.02% is in the open-chain aldehyde form.

Question 23

What equilibrium are alpha and beta glucose in in solution?

Answer 23

Dynamic equilibrium

Question 24

What is glycogen a polysaccharide of ?

Answer 24

Alpha glucose

Question 25

What is cellulose a polysaccharide of ?

Answer 25

Beta glucose

Question 26

What are the functions of glycogen?

Answer 26

- Energy storage in animals, fungi, and bacteria

Question 27

What are the functions of cellulose?

Answer 27

- Energy storage - Structure

Question 28

Are lipids soluble in water?

Answer 28

NO

Question 29

What are lipids soluble in ?

Answer 29

Organic solvents

Question 30

What are the functions of lipids?

Answer 30

Energy, structure, action (catalysis, communication)

Question 31

What is an example of an organic solvent?

Answer 31

Chloroform

Question 32

Are fatty acids high energy storage molecules?

Answer 32

Yes

Question 33

Describe the structure of fatty acids?

Answer 33

- have a carboxylic acid group at one end - hydrophobic carbon chain in the middle - have a methyl group (CH3) at the other

Question 34

What is between the carboxylic acid group at one end of a fatty acid and the methyl group at the other end of the fatty acid?

Answer 34

a long hydrophobic aliphatic (C and H) chain

Question 35

Is it true that fatty acids have twice the energy value of glucose per g?

Answer 35

Yes

Question 36

Describe a phospholipid

Answer 36

- Glycerol backbone - 2 fatty acid chains - Phosphate group - Has a structural role in biological membranes

Question 37

Are steroid hormones (like oestrogen and progesterone) a type of lipid?

Answer 37

Yes

Question 38

What do oestrogen and progesterone do?

Answer 38

They regulate the menstrual cycle

Question 39

What biological molecules are oestrogen and progesterone?

Answer 39

Lipids

Question 40

How many different amino acids are there?

Answer 40

20, all with different R groups. Therefore, each amino acid is chemically different due to the variety of side chains.

Question 41

Draw the basic structure of an amino acid

Question 42

What bonds form between amino acids?

Answer 42

Peptide bonds

Question 43

What are the ends of a protein called?

Answer 43

The N-terminus and the C terminus

Question 44

is the amino group the N terminus or the C terminus?

Answer 44

The N terminus

Question 45

Is the carboxyl group the N terminus or the C terminus?

Answer 45

The C terminus

Question 46

How are proteins read?

Answer 46

From the N terminus to C terminus

Question 47

List some functions of proteins

Answer 47

- Catalyse chemical reactions [enzymes] - Communication (peptide hormones) - Defence (antibodies) - Transport (channel proteins and carrier proteins) - Structure (keratin, collagen) - Control

Question 48

What 3 things does a nucleotide consist of?

Answer 48

- Phosphate group - Sugar (ribose or deoxyribose) - Nitrogenous Base (A, C, T, G)

Question 49

How are nucleic acids read?

Answer 49

from 5’ to 3’

Question 50

What are nucleotides polymerised to form?

Answer 50

Nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

Question 51

Why are gene sequences conserved between organisms?

Answer 51

Due to the presence of a common ancestor

Question 52

Draw the glucose intermediate

Question 53

What is Palmitate?

Answer 53

A fatty acid that has provides energy.

Question 54

What are phospholipids?

Answer 54

Fatty acids with structural functions.

Question 55

What is oestrogen?

Answer 55

A steroid hormone that has signalling properties.

Question 56

What are the 3 main membrane lipids?

Answer 56

Phospholipids, glycolipids, cholesterol. They're are all structural.

Question 57

Does altering the side R chain alter the properties of an amino acid?

Answer 57

Yes

Question 58

What proteins catalyse chemical reactions?

Answer 58

Enzymes

Question 59

Which proteins have the function of communication?

Answer 59

Receptors and peptide hormones

Question 60

Which proteins have the function of defence?

Answer 60

Antibodies and the proteins involved in blood clotting

Question 61

Which proteins are involved in transport?

Answer 61

Haemoglobin and albumin

Question 62

Which proteins have structural functions?

Answer 62

The cytoskeleton and collagen

Question 63

Which proteins have control functions?

Answer 63

Transcription factors and chaperones

Question 64

Nucleotides are joined to form....

Answer 64

Nucleic acids

Question 65

What is another name for the polarity found in DNA?

Answer 65

Directionality

Question 66

Describe which bases pair with which?

Answer 66

Adenine pairs with Thymine Guanine pairs with cytosine

Question 67

Is it true that some RNA molecules are catalytic?

Answer 67

Yes. These are called ribozymes.

Question 68

Is it true that DNA sequences are conserved between organisms?

Answer 68

Yes

Question 69

LEARN THIS

Answer 69

Conserved gene sequences are those that remain similar across different species because they are critical for basic cellular functions. By comparing these gene sequences, scientists can determine the relatedness of different species and build a phylogenetic tree, which shows their evolutionary relationships. The implication is that there is a common ancestor, potentially LUCA, who existed 3.5 - 3.8 billion years ago

Question 70

Is it true that 'Studying mutants provides insight into normal molecular functions and evolutionary adaptations.'?

Answer 70

Yes

Question 71

How many hydrogen bonds do Adenine and Thymine form?

Answer 71

2

Question 73

In which direction are proteins synthesised ?

Answer 73

From N to C

Question 74

What is at the 5' end and the 3' end of DNA and RNA?

Answer 74

- At the 5' end, there is a phosphate group. - At the 3' end, there is a hydroxyl group.