U1: 3- Gene Expression Flashcards
Describe three differences between DNA and RNA.
- DNA is double stranded, RNA is single stranded
- DNA has deoxyribose sugar in it’s nucleotide, RNA has ribose sugar in it’s nucleotide
- in DNA adenine pairs with thymine (A-T), in RNA adenine pairs with uracil (A-U)
Name the two stages involved in gene expression.
Transcription and translation
In which part of the cell does transcription take place?
Nucleus
Name the region on the DNA strand where transcription begins.
Promoter region
Name the enzyme involved in transcription.
RNA polymerase
Name the region on the DNA strand where transcription ends.
Terminator region
What name is given to the strand formed initially after transcription?
Primary transcript of mRNA
Which process follows the formation of the primary transcript of mRNA?
Splicing
Where does the process of splicing occur?
Nucleus
During splicing what parts are cut out?
Non-coding regions called introns
During splicing what parts are retained?
Coding regions called exons
The same piece of DNA can be used to make several proteins due to the fact that on occasions different regions can act as introns and exons. What name is given to this?
Alternative RNA splicing
In which part of the cell does translation occur?
Ribosome
Where are tRNA molecules found?
In the cytoplasm
What name is given to every three bases on mRNA?
Codon
What name is given to the three bases at one end of a tRNA molecule?
Anticodon
The anticodon acts as a codeword to attach something to the other end of the tRNA molecule. What is it that attaches?
An amino acid
How many different amino acids exist?
20
An mRNA strand attaches at a ribosome binding site. Where does the process of translation begin?
Start codon
What type of bonds form between the codons and anticodons as they pair up?
Hydrogen bonds
Amino acids start to align with one another when tRNA anticodons join up with mRNA codons. What type of bonds form between adjacent amino acids?
(Mainly) peptide bonds
When does the process of translation stop?
When a stop codon is reached
What happens to the tRNA and mRNA at the end of translation?
The tRNA is discharged and the mRNA detaches from the ribosome and is released back into the cytoplasm for reuse
What other type of bond can be found between a polypeptide apart from peptide bonds?
Hydrogen bonds
