Genes and proteins

Question 1

With what does he central dogma of molecular biology deal?

Answer 1

The detailed residue-by-residue transfer of sequential information.

Question 2

What does the central dogma state?

Answer 2

Information cannot be transferred back from protein to protein or nucleic acid.

Question 3

What is the genotype?

Answer 3

The genetic make-up of an individual.

Question 4

What is the phenotype?

Answer 4

The physical traits.

Characteristics expressed by individual.

Question 5

Why do regulatory systems and pathways interact?

Answer 5

To form complex networks.

Question 6

What do complex networks add to most G-P maps?

Answer 6

Additional complexity.

Question 7

Fr what does genotype code?

Answer 7

Phenotype.

Question 8

What did George Beadle and Edward Tatum suggested in 1941?

Answer 8

Genes act through enzyme production.

Each gene is responsible to produce a single enzyme –> affects a single step in metabolic pathway.

Question 9

How was the hypothesis of Beadle and Tatum characterised?

Answer 9

Oversimplification.

Question 10

How is the reformulation of: ‘one gene-one polypeptide’ characterised?

Answer 10

Too simple to describe the relationship between genes and proteins.

Question 11

What did Beadle and Tatum’s experiment found?

Answer 11

Mutations in each of the ‘transformational steps’ between precursor and final products n biosynthesis of arginine.

Question 12

By what was each step in Beadle and Tatum’s experiment undertaken?

Answer 12

By an enzyme encoded by different DNA sections/genes.

Question 13

By what can enzymes be formed?

Answer 13

Multiple protein subunits.

Question 14

What can enzymes include?

Answer 14

Non-protein factors.

Question 15

What do non-protein factors include?

Answer 15

RNA.

Question 16

What can genes produce when they are processed in different ways?

Answer 16

Similar, different proteins.

Question 17

Of what are eukaryote genes composed?

Answer 17

Exons.

Introns.

Question 18

What do exons code for?

Answer 18

Polypeptide sections.

Question 19

What do polypeptide sections make up?

Answer 19

The whole protein.

Question 20

When does splicing occur?

Answer 20

After transcription.

Before translation.

Question 21

What do differences in splicing alter?

Answer 21

Set of exons.

Question 22

What do exons produce once they are translated?

Answer 22

The final protein.

Question 23

What do variations in splicing effect?

Answer 23

Protein structure.

Protein function.

Question 24

Where can modification of key translational controls like start and stop codons result for proteins?

Answer 24

Missing normal N-terminal.

Longer C-terminals.

Question 25

What is the N-terminal of a protein?

Answer 25

Front section.

Question 26

What are C-terminals of a protein?

Answer 26

End sections.

Question 27

For which organism was in vitro transcription first demonstrated?

Answer 27

Escherichia coli RNA Polymerase.

Question 28

Who did first demonstrate in vitro transcription for E. coli?

Answer 28

Sam Weiss. | Jerard Hurwitz.

Question 29

Where could RNA Polymerase be visualised?

Answer 29

On DNA.

Question 30

How could producing 'tails' of RNA by electron microscopy and transcription be followed?

Answer 30

By using 32P. NTPs. | A, C, G, U.

Question 31

Of how many steps does transcription consist?

Answer 31

3.

Question 32

What are the 3 stages of transcription?

Answer 32

1. Initiation. 2. Elongation. 3. Termination.

Question 33

What did analysis of various E. coli mutations found about the 3 steps of transcription?

Answer 33

Any stage could be interrupted to control gene expression. Many antibiotics target one/more of stages.

Question 34

By how many subunits is the Core Enzyme composed?

Answer 34

5.

Question 35

Which are the 5 subunits the Core Enzyme is composed of?

Answer 35

1. 2. 2. α. 3. β. 4. β' . 5. ω.

Question 36

What is the fifth subunit the Holoenzyme includes?

Answer 36

Sigma: σ.

Question 37

What is Sigma factor of Holoenzyme?

Answer 37

A very large protein complex.

Question 38

What does RNAP synthesise?

Answer 38

mRNA. rRNA. tRNA.

Question 39

For which activity is the Core enzyme required?

Answer 39

The polymerization.

Question 40

For what is σ factor required?

Answer 40

Correct initiation of transcription.

Question 41

What does σ target in transcription?

Answer 41

Upstream region of a gene = operator. | -35 and -10 sites.

Question 42

What do bacteria have to regulate different gene groups?

Answer 42

Different Sigma factors.

Question 43

How is the fact that bacteria have f=different genes to regulate different gene groups characterised?

Answer 43

One of the highest-order means of regulating gene expression in bacteria.

Question 44

By what is transcription controlled?

Answer 44

Non-coding DNA sequences.

Question 45

Of what do genes consist?

Answer 45

Central 'coding' sequence.

Question 46

To what is the central 'coding' sequence translated?

Answer 46

The sequence of amino acids. An up-stream promoter region. Down-stream terminator region.

Question 47

What do amino acids make?

Answer 47

The protein.

Question 48

What do the up-stream promoter region and the down-stream terminator region control?

Answer 48

Gene expression.

Question 49

What is the difference between eukaryote gene structure and prokaryote genes?

Answer 49

Eukaryote is more complex.

Question 50

What is the similarity between eukaryote gene structure and prokaryote genes?

Answer 50

Coding. | Non-coding sections.

Question 51

When does initiation of transcription begin?

Answer 51

When RNAP binds promoter region of double-stranded DNA.

Question 52

What happens in transcription?

Answer 52

Two strands melt apart. | Base-pairing first nucleotide to coding strand.

Question 53

How do transcription and translation occur in prokaryotes?

Answer 53

Tightly coupled.

Question 54

How do ribosomes exist in prokaryotes?

Answer 54

Lining up along nascent mRNA.

Question 55

What do ribosomes produce in prokaryotes?

Answer 55

Proteins.

Question 56

What does RNAP produce when going along DNA?

Answer 56

mRNA.

Question 57

What did tight coupling of transcription and translation in prokaryotes meant?

Answer 57

In vitro transcription-translation was possible with 3H production. 14C labelled proteins allow protein functions to be investigated. (could not in cells/with cell lyses.

Question 58

What does eukaryotic mRNA undergo?

Answer 58

Modifications.

Question 59

Where does eukaryotic mRNA undergo modifications?

Answer 59

In nucleus.

Question 60

When does eukaryotic mRNA undergo modifications?

Answer 60

Before being exported and translated.

Question 61

What are some modifications eukaryotic mRNA undergoes?

Answer 61

5' capping. 3' poly-A-tailing. Splicing.

Question 62

Where do alternative splicing patterns to remove exons and link introns result?

Answer 62

Expression of related proteins.

Question 63

What do proteins consist of?

Answer 63

Amino acid chains linked together in a specific order.

Question 64

How is the specific order of linked amino acid chains known?

Answer 64

The primary structure. | From N-terminus to C-terminus.

Question 65

What can the peptide chain then adopt?

Answer 65

Different structures.

Question 66

How do different structures of peptide chain occur?

Answer 66

Fold around itself.

Question 67

How is the final protein formed by different peptides?

Answer 67

When they interact with one another.

Question 68

How can amino acids be categorised?

Answer 68

By: Polarity. Charge. Size.

Question 69

How many levels of polypeptide chains folding and interacting with each other exist?

Answer 69

4.

Question 70

Why do polypeptide chains fold and interact with each other?

Answer 70

To produce the final three-dimensional shape of the mature protein.

Question 71

What does the genetic code use?

Answer 71

Triplets of DNA bases.

Question 72

Why does the genetic code use triplets of DNA bases?

Answer 72

To encode the amino acids in a peptide chain.

Question 73

What is the code of amino acids?

Answer 73

Almost universal.

Question 74

How many combinations of A, C, G and T ecist?

Answer 74

>20.

Question 75

What do some amino acids have?

Answer 75

>1 triplet.

Question 76

As what are some triplets used?

Answer 76

Stop signals.

Question 77

What happens to amino acids in the ribosome?

Answer 77

They are matched to base triplets by tRNAs.

Question 78

What does the universal code link?

Answer 78

RNA triplets to amino acids. | DNA triplets with amino acids. (more helpful).

Question 79

What does the expression of reading frame produce?

Answer 79

A protein.

Question 80

What must the reading frame have?

Answer 80

An appropriate start codon. | An in-frame stop codon.

Question 81

What is usually the start codon?

Answer 81

AUG.

Question 82

What are usually the stop codons?

Answer 82

UAA. UAG. UGA.

Question 83

What happens in translation?

Answer 83

Genetic information encoded by DNA, transcribed into mRNA --> converted into amino acid sequences/polypeptides.

Question 84

By which factor is the template strand of DNA double-stranded helix used?

Answer 84

By RNAP.

Question 85

What does the template strand of DNA produce when used by RNAP?

Answer 85

mRNA.

Question 86

What does the amino acid sequence follow?

Answer 86

The coding strand sequence.

Question 87

What are transfer RNAs?

Answer 87

Short RNA molecules.

Question 88

Into what structure do tRNAs fold?

Answer 88

't'. | 'L'.

Question 89

Where is the neck of tRNAs linked?

Answer 89

To a specific amino acid.

Question 90

Where is the bulging foot of tRNA matched?

Answer 90

To the mRNA triplet.

Question 91

Of what is anticodon composed?

Answer 91

Three bases that interact with mRNA.

Question 92

Where do ribosomes shuffle?

Answer 92

Along mRNA transcript.