Overview of translation, tRNA and codon-anticodon interaction Flashcards Preview

BS2091 Biochemistry I: from genes to proteins > Overview of translation, tRNA and codon-anticodon interaction > Flashcards

Flashcards in Overview of translation, tRNA and codon-anticodon interaction Deck (24):
1

Using an arrow diagram, what happens when genes are expressed?

DNA -> mRNA -> Protein
Nucleus --- || --- cytosol

2

What is the process to get mRNA from DNA?

Transcription

3

What is the process to get protein from mRNA?

Translation

4

How are genes in bacteria arranged?

Closely-packed (with only very short gaps between them) and are commonly co-transcribed to generate polycistronic mRNAs

5

What is meant by 'cistron'?

'mRNA coding sequence or 'open reading frame' (ORF)

6

How are genes in higher eukaryotes such as animals and plants arranged?

'Miles apart' and cannot possibly be co-transcribed. Hence, eukaryotic mRNAs are monocistronic

7

How are genes in lower eukaryotes such as yeast arranged?

Almost as close-packed as in bacteria but they are not co-transcribed

8

How many translation start sites are in prokaryotic mRNA (polycistronic)?

Multiple sites

9

How many translation start sites are in eukaryotic mRNA (monocistronic)?

A single site

10

In all cell types, mRNAs are translated concurrently by..

Multiple ribosomes in structures termed 'polyribosomes'

11

In eukaryotes, where are mRNAs translated?

In the cytosol

12

tRNA contains 'odd' bases and nucleosides such as what?

Uracil (U)
Dihydrouracil (UH2 or DHU)
Thymine (5-methyl-uracil)
Uridine
Pseudouridine
Hypoxanthine
Inosine (I)

13

What type of structure is a 'cloverleaf'?

Secondary structure

14

What type of structure is the co-axial stacking of mini-helices?

Tertiary structure

15

Posttransciptional chemical modification of eukaryotic rRNA mainly involves..

Ribose methylation and pseudouridylation
In contrast, bacterial rRNA is much less heavily modified

16

Chemical modification of tRNA principally involves..

Base methylation including generation of extravagant derivatives ('hyper modification')

17

Describe the interaction between a codon and an anticodon

A triplet base pair interaction via antiparallel strands

18

What happens due to 'Wobble Pairing'?

tRNAs recognise multiple mRNA codons (1, 2 or 3)
mRNA codons can be recognised by multiple tRNAs

19

There is one aaRS per what?

Amino acid

20

What does aaRS stand for?

Aminoacyl-tRNA synthases

21

What are aaRS named specifically after?

The cognate amino acid
e.g. PheRS, AlaRS, LysRS

22

Each E recognises what>

>= 1 x tRNA

23

aaRS has a crucial role in what?

Fidelity of translation

24

tRNA takes what it's given by..

aaRS