Gene Expression Flashcards
1
Q
What makes RNA different from DNA?
A
- single stranded
- uracil (u) instead of thymine (t)
- ribose sugar instead of deoxyribose sugar
2
Q
What are the 3 types of RNA gene expression involves?
A
- messenger RNA
- transfer RNA
- ribosomal RNA
3
Q
What does mRNA do?
A
- carries a copy of DNA code from the ribosome
4
Q
What does tRNA do?
A
- carries specific amino acids to the ribosome
5
Q
What does rRNA do?
A
- forms the ribosome with proteins
6
Q
What is transcription?
A
- the synthesis of mRNA from DNA
7
Q
What is the enzyme involved in transcription?
A
- RNA polymerase
8
Q
How does transcription work?
A
- RNA polymerase move along the unwinding double helix, breaking the hydrogen bonds and adding new nucleotides
- RNA polymerase can only add new nucleotides to the 3’ end of the new mRNA strand
9
Q
What are introns?
A
- non-coding regions of the transcript
- introns are cut out
10
Q
What is translation?
A
- synthesis of a polypeptide from mRNA at the ribosome
11
Q
Where does translation occur?
A
- in the cytoplasm on a ribosome when they mature mRNA transcript passes through nuclear pone
12
Q
What is the first step in translation?
A
- a ribosome attaches to the mRNA at a start codon
13
Q
What happens as the ribosome reads each codon?
A
- complementary tRNA with anti-codon and amino acid attached binds to the codon
14
Q
What bonds the amino acids in translation?
A
- peptide bonds
15
Q
What’s alternative splicing?
A
- different segments of mRNA may be treated as exons and introns. This means the same primary transcript can produce several mature transcripts
