Transcription and Translation Flashcards
What type of bond holds complementary base pairs together?
Hydrogen bonds.
What type of bond links adjacent nucleotides in a DNA strand?
Phosphodiester bonds.
State two differences between the structure of tRNA and mRNA.
- tRNA is clover-shaped
mRNA is a linear chain - tRNA has an anticodon and binds to specific amino acids; mRNA carries genetic code from the nucleus.
How is the structure of mRNA different from pre-mRNA in eukaryotes?
Pre-mRNA contains introns; mRNA is formed after splicing, where introns are removed.
How is one amino acid added to a polypeptide at the ribosome?
tRNA with the anticodon binds to mRNA codon, bringing a specific amino acid. Ribosome forms a peptide bond using ATP and enzyme.
Describe how mRNA is produced from a DNA template strand.
RNA polymerase joins free RNA nucleotides using base pairing rules to form a complementary pre-mRNA strand.
What is the proteome of a cell?
The complete set of proteins the cell is able to produce.
Starting from mRNA in cytoplasm, how is a polypeptide formed?
Ribosome binds to mRNA start codon. tRNA anticodon binds, bringing amino acid. Peptide bonds form. Process repeats until stop codon.
What is meant by the term ‘degenerate code’?
More than one triplet codes for the same amino acid.
What two types of molecule make up a ribosome?
rRNA and protein.
What is the role of a ribosome in translation?
Ribosome reads mRNA, aligns tRNA anticodon with codon, and joins amino acids into a polypeptide chain.
Why might mRNA be different from pre-mRNA in a eukaryotic cell?
Because introns are removed during splicing.
How is mRNA produced in a plant cell?
RNA polymerase joins free RNA nucleotides complementary to the DNA template to form pre-mRNA, which is then spliced to form mRNA.
Describe how mRNA is formed by transcription in eukaryotes.
Enzymes unzip the DNA, exposing bases. RNA polymerase joins RNA nucleotides to make pre-mRNA using base pairing rules. Introns are removed via splicing to produce mature mRNA.
Describe how a polypeptide is formed by translation of mRNA.
Ribosome binds to mRNA start codon. tRNA anticodon binds, bringing amino acid. Peptide bonds form between amino acids. Ribosome moves along mRNA until stop codon is reached, releasing polypeptide.
Give two structural differences between mRNA and tRNA.
- mRNA is a long single helix; tRNA is a small cloverleaf-shaped molecule. 2. mRNA carries genetic code; tRNA has an anticodon and binds specific amino acids.
