PROTEINS
What are the monomers of proteins?
Amino acid
Which nitrogenous base is found in RNA but not DNA?
Uracil
What enzyme performs transcription?
RNA polymerase
What type of gene produces repressor proteins?
Regulatory gene
Which enzyme acts as molecular scissors?
Restriction endonuclease
What level of protein structure refers to the sequence of amino acids?
Primary structure
DNA strands are described as ______ because they run in opposite directions.
Antiparallel
What is produced directly from transcription in eukaryotes?
Pre-mRNA
Which DNA region does a repressor bind to?
Operator region
Which enzyme joins DNA fragments together?
DNA ligase
Name TWO functions of proteins in living organisms.
enzyme, transport, structural, defence, receptor, hormone, storage, motor/contractile
A DNA molecule contains 40 cytosine bases. How many guanine bases does it contain?
40
What process removes introns and joins exons together?
RNA processing/splicing
In the trp operon, when tryptophan levels are high, does the repressor become active or inactive?
Active
What is the purpose of PCR?
To amplify DNA
A protein contains alpha-helices and beta-pleated sheets. What level of structure is being described?
Secondary structure
Give TWO differences between DNA and RNA.
Any two: ribose/deoxyribose, uracil/thymine, single-/double-stranded
What is the role of tRNA during translation?
Carries amino acids to the ribosome and uses complementary anticodons to pair with codons
Why is gene regulation important?
Conserves energy and prevents unnecessary protein production
Why is Taq polymerase used in PCR?
It is heat-resistant and functions optimally at 72°C
Explain why a change in the primary structure of a protein may alter its function.
A different amino acid sequence changes R-group interactions, altering folding (tertiary/quaternary structure) and potentially changing protein function
A nucleic acid is single-stranded, contains ribose and uracil. Identify it and justify your answer.
RNA
Put these in order: Translation, DNA, Protein, Transcription, mRNA, Pre-mRNA, RNA Processing.
DNA → Transcription → Pre-mRNA → RNA Processing → mRNA → Translation → Protein
Compare what happens in the trp operon when tryptophan levels are HIGH versus LOW.
High: repressor active, transcription inhibited. Low: repressor inactive, transcription occurs.
Why can bacteria produce a human protein after receiving a human gene?
The genetic code is universal