Modern Genetics 2 Flashcards
What is the basic structure of DNA?
DNA is a double helix composed of two strands of nucleotides.
What are the four nucleotide bases in DNA?
Adenine, Thymine, Cytosine, and Guanine.
Which base pairs with Adenine in DNA?
Thymine.
What type of bond holds the two strands of DNA together?
Hydrogen bonds.
What is the process of DNA replication?
The process by which DNA makes a copy of itself.
True or False: DNA replication is semi-conservative.
True.
What enzyme unwinds the DNA during replication?
Helicase.
What is the role of DNA polymerase?
It synthesizes new DNA strands by adding nucleotides.
Fill in the blank: The leading strand is synthesized _____ during DNA replication.
continuously.
What is the function of ligase in DNA replication?
It joins Okazaki fragments on the lagging strand.
What is protein synthesis?
The process by which cells generate proteins from amino acids.
What are the two main stages of protein synthesis?
Transcription and translation.
Where does transcription occur in eukaryotic cells?
In the nucleus.
What is the role of mRNA in protein synthesis?
It carries the genetic information from DNA to the ribosome.
What is the function of ribosomes in translation?
They facilitate the assembly of amino acids into proteins.
True or False: The lac operon is involved in the metabolism of lactose in bacteria.
True.
What are the three structural genes of the lac operon?
lacZ, lacY, and lacA.
What is the role of the repressor in the lac operon?
It inhibits transcription when lactose is not present.
Fill in the blank: The presence of _____ induces the lac operon.
lactose.
What is transformation in biology?
The process by which a cell takes up foreign DNA from its environment.
True or False: Transformation can occur naturally in some bacteria.
True.
What is a mutation?
A change in the DNA sequence of an organism.
What are the three types of mutations?
Substitution, insertion, and deletion.
What is a point mutation?
A mutation that affects a single nucleotide.
Fill in the blank: A _____ mutation changes one amino acid in a protein.
missense.
What is a frameshift mutation?
A mutation that shifts the reading frame of the genetic message.
True or False: Mutations can be beneficial, harmful, or neutral.
True.
What is the role of the promoter in gene expression?
It is a DNA sequence that initiates transcription.
What is the difference between prokaryotic and eukaryotic transcription?
Eukaryotic transcription occurs in the nucleus, while prokaryotic transcription occurs in the cytoplasm.
What is an operon?
A group of genes regulated together.
Fill in the blank: The _____ is a regulatory protein that can turn off the lac operon.
repressor.
What is the purpose of the operator in an operon?
It controls access of RNA polymerase to the genes.
What is the first step of transcription?
RNA polymerase binds to the promoter.
What is the role of tRNA in translation?
It brings amino acids to the ribosome based on codon recognition.
What is a codon?
A sequence of three nucleotides that encodes an amino acid.
Fill in the blank: The start codon for protein synthesis is _____
AUG.
What is the significance of the 5’ cap and poly-A tail in mRNA?
They protect mRNA from degradation and assist in translation.
What is the process by which RNA is converted into a protein?
Translation.
What does the term ‘gene expression’ refer to?
The process by which information from a gene is used to synthesize a functional gene product.
What is the role of the terminator in transcription?
It signals the end of transcription.
True or False: All mutations lead to changes in protein function.
False.
What is an example of a mutagen?
Radiation, chemicals, or viruses.
