Test questions

Question 1

Label the a site, p site, e site

Answer 1

Ribosome Sites

1. A Site (Aminoacyl-tRNA Binding Site):
   
   • Function: This is where tRNA carrying an amino acid enters the ribosome.
   • Remember: A for “Arrives” (tRNA with amino acid arrives here).
2. P Site (Peptidyl-tRNA Binding Site):
   
   • Function: This is where the growing polypeptide chain is held as peptide bonds form.
   • Remember: P for “Peptide” (chain grows here).
3. E Site (Exit Site):
   
   • Function: This is where the empty tRNA leaves the ribosome after delivering its amino acid.
   • Remember: E for “Exit” (empty tRNA exits here).

Visualization Order:
1. A Site: tRNA enters with an amino acid.
2. P Site: Polypeptide chain is built.
3. E Site: Empty tRNA exits.

Simple mnemonic: Arrive, Produce, Exit!

Question 2

What if, during transcription, termination goes wrong: what will happen?

Answer 2

1. RNA is too long: The RNA keeps being made past where it should stop.
2. Wrong proteins: Extra RNA might make faulty or too many proteins.
3. Wastes energy: The cell uses energy for unnecessary work.

Question 3

mutations (point mutation): write two things abt it and why it’s not gna change, genetically negligible (insignificant)

Substitution

Answer 3

1. Point mutations change a single base in the DNA sequence.
2. They can be silent mutations, where the change doesn’t affect the amino acid sequence due to the redundancy in the genetic code.

Why it’s genetically negligible:
Silent mutations don’t change the protein, so they have no effect on the organism’s traits or functions.

Question 4

lac operon and trp operon: is it an inducer or compressor (know which one it is between the two questions to choose from)

Insertion and deletion

Answer 4

• Lac Operon: Uses an inducer (lactose turns it ON).
• Transcription is active when lactose is present
• Trp Operon: Uses a corepressor (tryptophan turns it OFF).
• Transcription stops when tryptophan is present

Question 5

Each gene mutation, and effect:

Answer 5

Here are the key things to know about common types of gene mutations:

1. Point Mutation:
   
   • Definition: A change in a single base pair of DNA.
   • Types:
     
     • Silent Mutation: No change in the protein (due to redundancy in the genetic code).
     • Missense Mutation: Changes one amino acid in the protein, which might affect its function.
     • Nonsense Mutation: A stop codon is introduced, leading to a shortened, nonfunctional protein.
2. Insertion Mutation:
   
   • Definition: A base pair is added to the DNA sequence.
   • Effect: Shifts the reading frame (frameshift), altering all amino acids downstream and usually creating a nonfunctional protein.
3. Deletion Mutation:
   
   • Definition: A base pair is removed from the DNA sequence.
   • Effect: Similar to insertion, it causes a frameshift and often leads to a nonfunctional protein.
4. Frameshift Mutation:
   
   • Definition: Insertion or deletion of a number of base pairs not divisible by three, shifting the reading frame.
   • Effect: Changes the entire amino acid sequence from the mutation onward, usually resulting in a nonfunctional protein.
5. Duplication Mutation:
   
   • Definition: A section of DNA is copied and inserted into the genome.
   • Effect: Can lead to repeated proteins, which might disrupt normal cell functions.
6. Inversion Mutation:
   
   • Definition: A segment of DNA is reversed within the chromosome.
   • Effect: This can disrupt the function of the gene or cause abnormal protein function.
7. Translocation Mutation:
   
   • Definition: A piece of DNA from one chromosome is transferred to another chromosome.
   • Effect: Can disrupt the genes involved or lead to unregulated gene expression, causing diseases like cancer.

Each mutation can have different effects, depending on the type and where it occurs in the gene.