Honor Bio 8.4 Flashcards
What is a codon?
A sequence of three nucleotides on mRNA that codes for a specific amino acid.
Codons are found in mRNA and are crucial for translating genetic information into proteins.
What is an anticodon?
The three-nucleotide sequence on tRNA that pairs with a complementary mRNA codon during translation.
Anticodons ensure that the correct amino acid is added during translation.
What is translation?
The process by which ribosomes synthesize proteins using the genetic information carried by mRNA
Translation occurs in the cytoplasm and involves mRNA, tRNA, and rRNA.
What is a start codon?
A specific codon (AUG) that signals the beginning of translation
The start codon also codes for the amino acid methionine.
What is a stop codon?
A codon that signals the termination of translation
Stop codons include UAA, UAG, and UGA.
What is a positive transcription factor?
Enhances transcription by helping RNA polymerase bind to the promoter.
Positive transcription factors bind to enhancers and promote gene expression.
What is a negative transcription factor?
Inhibits transcription by blocking RNA polymerase’s access to the promoter.
Negative transcription factors may bind to silencers and inhibit gene expression.
What does affinity refer to in the context of transcription factors?
The strength of the binding between a transcription factor and its target DNA sequence
Higher affinity can lead to more effective regulation of gene expression.
What is a mutation?
A change in the DNA sequence that can affect gene function
Mutations can be caused by various factors including environmental influences and replication errors.
Role of mRNA in translation?
mRNA carries the genetic code from DNA to the ribosome for protein synthesis
It serves as a template for translating codons into amino acids.
Role of tRNA in translation?
tRNA transports specific amino acids to the ribosome based on the codon sequence in mRNA
Each tRNA has an anticodon that pairs with the corresponding mRNA codon.
Role of rRNA in translation?
Forms ribosomes and catalyzes peptide bond formation between amino acids.
rRNA catalyzes the formation of peptide bonds between amino acids.
Identify different types of mutations.
- Point mutation
- Silent mutation
- Missense mutation
- Nonsense mutation
- Frameshift mutation
Each type of mutation has different effects on protein synthesis and function.
What is a point mutation?
A mutation that involves a change in a single nucleotide base pair
Point mutations can lead to silent, missense, or nonsense mutations.
What is a silent mutation?
A mutation that does not change the amino acid sequence of a protein
Silent mutations often occur in non-coding regions or may not affect protein function.
What is a missense mutation?
A mutation that results in the substitution of one amino acid for another in a protein
Missense mutations can affect protein function depending on the properties of the substituted amino acid.
What is a nonsense mutation?
A mutation that introduces a premature stop codon in the protein sequence
Nonsense mutations typically lead to truncated, nonfunctional proteins.
What is a frameshift mutation?
A mutation caused by insertions or deletions of nucleotides that shift the reading frame of the codons
Frameshift mutations often result in significant changes to the resulting protein.
Explain gene regulation and how protein production is affected by positive/negative transcription factors.
Gene regulation involves mechanisms that increase or decrease the expression of genes, influenced by positive and negative transcription factors
Positive factors enhance transcription, while negative factors inhibit it.
How does affinity strength affect gene regulation?
Affinity strength affects how effectively transcription factors bind to DNA, influencing gene expression levels
Higher affinity often leads to stronger regulation of transcription.
