Base-ically Brilliant
What are the monomers that make up nucleic acids called?
Nucleotides
What is the process of making an RNA molecule from a DNA template called?
Transcription
What is the name of the enzyme that cuts DNA during CRISPR-Cas9 gene editing?
Cas9
What type of enzyme recognises and cuts DNA at specific nucleotide sequences?
Endonuclease
Which organelle is the main site of photosynthesis in plant cells?
Chloroplast
What are the three components of a RNA nucleotide?
Phosphate group; ribose sugar; nitrogenous base
What is the name of the organelle where proteins are modified, sorted and packaged for secretion?
Golgi apparatus
What is the role of guide RNA in CRISPR-Cas9?
Directs Cas9 to a complementary target DNA sequence.
What is the term for DNA formed by joining genetic material from different sources?
Recombinant DNA
What pigment absorbs light energy for photosynthesis?
Chlorophyll
What type of bond joins complementary nitrogenous bases between the two DNA strands?
Hydrogen bonds
In the trp operon, what molecule activates the repressor protein when tryptophan levels are high?
Tryptophan
What does CRISPR stand for?
Clustered Regularly Interspaced Short Palindromic Repeats
What is the purpose of gel electrophoresis when analysing DNA fragments?
Separates DNA fragments by size
What are the two main stages of photosynthesis?
Light-dependent reactions; Light-independent (Calvin cycle)
Identify two structural differences between DNA and RNA.
DNA contains deoxyribose; RNA contains ribose;
DNA uses thymine; RNA uses uracil;
DNA is usually double-stranded; RNA is usually single-stranded.
A protein is destined to be secreted from a cell. Name the two organelles it passes through after leaving the ribosome and before reaching the cell surface.
Rough endoplasmic reticulum; Golgi apparatus
After Cas9 cuts a target gene, which cellular process can introduce insertions or deletions that disrupt the gene?
DNA repair
Name the three main stages of a PCR cycle.
Denaturation; annealing; extension
Where does the Calvin cycle occur, and what molecule does it use as its carbon source?
Location: Stroma of the chloroplast. Carbon source: Carbon dioxide (CO₂).
A DNA molecule contains 30% adenine. What percentage of its bases are cytosine?
20%
A mutation changes one nucleotide in the coding DNA sequence, resulting in a different amino acid being incorporated into the protein. What type of mutation has occurred, and name one possible effect on the protein.
Missense mutation.
Altered protein folding/changed function/reduced function or loss of function
A researcher uses CRISPR-Cas9 to disable a gene. Identify a possible reason why the experiment might not produce the intended outcome.
- DNA repair does not disrupt gene function
- Cas9 cuts an unintended DNA sequence (off-target effect)
- the edit does not sufficiently reduce gene expression or protein function
Identify two features required for a plasmid to function as a vector in bacterial transformation.
origin of replication; selectable marker (e.g. antibiotic resistance gene); suitable restriction site that matches target gene
A plant is exposed to high light intensity, but its rate of photosynthesis does not increase. Explain how another limiting factor could be responsible.
Any two relevant points: CO₂ concentration, temperature or water availability is limiting; increasing light alone cannot increase the rate while that factor remains limiting.