Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemical Engineering > The Central Dogma > Flashcards

The Central Dogma Flashcards

1
Q

What are the three processes involved in the central dogma?

A
  1. DNA replication
  2. Transcription
  3. Translation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where is information stored in the cell?

A

It is stored on the DNA molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the 4-letter alphabet for the information storage and exchange?

A

A, T, C and G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How long are each of these ‘words’?

A

Each word consists of 3 letters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many possible words are there?

A

There are 64 possible words

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the order of these words represent?

A

A particular amino acid or “stop” protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are these “three-letter” words called?

A

Codons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does each word correspond to?

A

An amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does each gene code for?

A

A protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does replication usually start?

A

At a predetermined site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What binds to the DNA at the origin of replication?

A

Initiator proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The steps involved in DNA replication

A
  1. The initiator sequence is detected and the DNA strands are separated by breaking the hydrogen bonds between the strands.
  2. The synthesis of an RNA polymer which is made by RNA polymerase
  3. Once the short RNA strand is made, DNA is synthesised using DNA polymerase (pol III)
  4. RNA is degraded by (Pol I)
  5. DNA is synthesised in it’s place by Pol I
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In which direction is the DNA strand read?

A

From 3’ to 5’ of the DNA template. From 5’ to 3’ in newly synthesised strands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of RNA polymerase in DNA replication?

A

To mediate the synthesis of the RNA primer to initiate DNA replication.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the function of Pol III in DNA replication?

A

To mediate the formation of bonds between nucleotides and RNA primer?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the functions of Pol I in DNA replication?

A

To hydrolyse the RNA primer and to control the linking of DNA nucleotides to replace the primer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Does DNA replication require or produce energy?

A

The enzymatic reaction requires energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is the energy supplied for in DNA replication?

A

The activated monomers are the nucleoside triphosphates. The formation of the 5’ to 3’ phosphodiester bond to link a nucleotide with the growing DNA molecule results in the release of a pyrophosphate which provides energy for biosynthesis reactions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Is DNA replication conservative, semi-conservative or non-conservative and why?

A

DNA replication is semi-conservative because each newly synthesised DNA molecule consists of a daughter strand and an original strand.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the three primary products in transcription?

A
  • Messenger RNA, m-RNA - chemical “blueprint” for a protein product. mRNA is transcribed from a DNA template
  • Transfer RNA - recognises three letter codes and provides the corresponding amino acid
  • Ribosomal RNA - rRNA is the central part of the ribosome equipment for producing proteins
21
Q

Which enzyme mediates RNA synthesis from DNA?

A

RNA polymerase

22
Q

What are the two major subcomponents of RNA polymerase?

A
  • core enzyme: contains the catalytic site

- sigma factor - a protein which is essential for locating the appropriate beginning for the message

23
Q

What are the two parts of the RNA polymerase called together?

A

Holoenzyme

24
Q

In which direction does RNA polymerase read from?

A

3’ to 5’ direction

25
Q

The three stages of the transcription process?

A
  1. initiation
  2. elongation
  3. propagation
26
Q

Describe initiation in transcription

A

The sigma factor recognises a specific sequence of nucleotides on a DNA strand called the promoter region.

27
Q

How is the rate of transcription linked to the affinity of the promoter region to the holoenzyme?

A

A strong promoter has a high affinity for the holoenzyme. They are directly linked.

28
Q

Where does the energy for propagation in transcription come from?

A

Activated triphosphate monomers

29
Q

When is the transcript made until?

A

The RNA polymerase encounters a stop signal (transcriptor terminator).

30
Q

What happens when the RNA polymerase encounters the stop signal in transcription?

A

The RNA polymerase dissociates from the DNA template and the RNA transcript is released. The sigma factor and rho protein are released.

31
Q

What additional protein is sometimes required in transcription for termination?

A

A rho protein. The rho protein binds to the DNA.

32
Q

The differences between transcription in prokaryotes and eurkaryotes?

A
  • In prokaryotes no physical separation of chromosome from cytoplasm and ribosomes. This means that m-RNA can bind to a ribosome and be translated immediately even when being transcribed. Eukaryotes have a nuclear membrane and this acts as a physical barrier.
  • DNA in eukaryotes can code for a transcript with an intervening sequence (an intron) in the middle of the transcript. The intron is cut out and remains spliced together (RNA splicing).
  • RNA capping and polyadenylation occur in eukaryotes but not prokaryotes
33
Q

What are the three primary stages of translation?

A
  • Initiation
  • Elongation
  • Termination
34
Q

What codon does protein synthesis always start with in translation?

A

AUG or CUG codon on m-RNA

35
Q

What is required for the initiation of polymerisation in prokaryotes?

A
  • 30 s ribosomal unit and a 50s ribosomal unit
  • three proteins called initiation factors (IF 1, IF 2, IF 3)
  • phosphate bond energy from GTP
36
Q

What is on each end of a t-RNA molecule?

A

One end contains the anticodon which is complementary to the codon on m-RNA and the other end of t-RNA binds to a specific amino acid.

37
Q

When is the t-RNA molecule called charged?

A

The t-RNA molecule is charged when it is carrying an amino acid.

38
Q

Where does the energy from the binding of the amino acid to t-RNA come from?

A

The energy from two phosphate bonds and enzymes known as aminoacyl t-RNA is also required.

39
Q

What are the two sites of the ribosome?

A
  • P or peptidyl site

- A or aminoacyl site

40
Q

Which site is occupied by the growing protein?

A

The A site

41
Q

What mechanism moves the m-RNA down one codon from the A site to the P site?

A

The t-RNA associated with the P site is released and a rachet mechanism then moves the m-RNA down one codon. A charged t-RNA with the correct anticodon then is inserted into the A site to be complementary to the m-RNA codon.

42
Q

In total, how many phosphate bonds need to be broken to add one amino acid to the polypeptide chain in translation?

A

There would be four phosphate bonds that need to be broken (two in charging the t-RNA and two for elongation).

43
Q

What happens when a stop codon is reached in translation?

A

A stop codon is UAA, UAG, UGA. When the stop codon is reached, the protein is released from the ribosome with the aid of a protein release factor. The 70s ribosome then dissociates into 30s and 50s sub-units.

44
Q

Why is post-translational processing important?

A

Because the newly formed polypeptide chain is not useful yet.

45
Q

What is the first stage of post-translational processing?

A

The newly formed chain must fold into a proper structure.

46
Q

What is the difference between the pre-form and mature form of a protein?

A

A pre-form is what is synthesised from m-RNA but the mature form is the actually active form of the protein.

47
Q

Give examples of further processing that may be required.

A

Addition of non-amino acid components (sugars, lipids) and phosphorylation. Glycolysation refers to the addition of sugars. Many proteins are subject to extensive processing after the initial polypeptide chain is made.

48
Q

Do all codons code for an amino acid?

A

No some code for stop signals.

Biochemical Engineering (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions