U.1 K.A.3 Gene Expression Flashcards
(26 cards)
Describe three differences between DNA and RNA.
- DNA is double stranded while RNA is single stranded
- DNA has deoxyribose sugar in its nucleotides while RNA has ribose sugar in its nucleotides
- The base partner for adenine in DNA is thymine while it is Uracil in RNA
Name the two stages involved in gene expression.
Transcription and Translation
In which region of the cell does transcription take place?
Nucleus
Name the region of 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 sequence
What name is given to the strand formed initially after transcription?
Primary transcript of mRNA
What process follows the formation of the primary transcript of mRNA?
Splicing
Where does the process splicing occur?
Nucleus
During splicing what parts are cut out?
Introns (non-coding regions)
During splicing what regions are retained?
Exons (coding regions)
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 an 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. 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 bond forms between adjacent amino acids?
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?
It 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
