Nucleic acids and proteins
What is the monomer of proteins?
Amino acids
Which direction does RNA polymerase synthesise a mRNA molecule from? 5' to 3' or 3' to 5'?
5' to 3'
True or false: Cas9 is a polymerase enzyme.
False, it is an endonuclease
What is the aim of PCR?
To amplify DNA.
Where do plasmids come from (where did humans discover them)?
Bacteria
What are the 3 components of a DNA nucleotide?
1. Deoxyribose sugar
2. Phosphate groups (1 or more)
3. Nitrogenous base (ATGC)
Where does transcription occur and where does translation occur?
Nucleus and ribosome, respectively.
What does CRISPR stand for?
Clustered regularly interspaced short palindromic repeats
Which type of DNA fragments move further through the gel in gel electrophoresis, long or short fragments?
Short fragments
Name two types of enzymes that are involved in makinig recombinant plasmids.
A restriction endonuclease and DNA ligase.
This type of RNA carries the genetic code from DNA to the ribosome, where it is translated into a polypeptide chai
What is mRNA?
What type of protein binds to the operator region of the trp operon when tryptophan levels are high?
A repressor protein.
How do bacteria keep a copy of the viral DNA and where do they keep it?
They use Cas enzymes to cut out a sequence of spacer DNA from the viral DNA and insert it into the CRISPR sequence.
Name the 3 stages of PCR and their associated temperatures.
Denaturation - 90-95 degrees Celsius
Annealing - 50-55 degrees Celsius
Elongation - 72 degrees Celsius
These circular DNA molecules are used as vectors to introduce foreign genes into bacterial cells
What are recombinant plasmids?
This describes the complete set of proteins expressed by an organism, which includes a diverse array of molecules such as enzymes that catalyze biochemical reactions.
What is the proteome?
What does it mean that the genetic code is degenerate?
Multiple codons may code for the same amino acid
True or false: after cutting a DNA sequence using CRISPR-Cas9 technology, the sequence may not always take up new nucleotides introduced by the scientists.
True.
A standard ladder (lane that consists of DNA fragments with known length
Name one ethical and one social implication of GMO use in agriculture.
Ethical - GMOs are unnatural, humans don't have the right to alter the genomes of other organisms
Social - GMO foods that have better disease resistance can improve global food security.
Briefly describe the 4 levels of structure of a protein.
1. Primary structure - sequence of amino acids
2. Secondary structure - shapes of local regions of a polypeptide such as alpha-helix and beta-pleated sheets
3. Tertiary structure - overall 3D shape of a protein
4. Quaternary structure - formed when two or more polypeptides combine to form one functional protein
Briefly outline the process of translation.
- codons on mRNA code for amino acids that are brought into the ribosome on a tRNA molecule with a complementary anticodon
- adjacent amino acids react in a condensation polymerisation reaction, forming a polypeptide chain
What feature of CRISPR-Cas9 makes it a standout DNA manipulation technique?
The use of gRNA to make targeted cuts at specific DNA sequences.
What is the name of the enzyme used in PCR and why is this enzyme used.
Taq polymerase. This enzyme is used as it can withstand high temperatures that are used in PCR to denature the DNA.
This process uses antibiotic resistance genes within plasmids to identify and select bacterial cells that have successfully incorporated recombinant DNA, ensuring only transformed cells survive.
What is antibiotic selection?