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What did Griffith's experiment demonstrate about genetic material?
Something can be transmitted from a dead virulent bacterium to a non-virulent one, transforming it into a virulent strain.
What was the key finding of Avery's experiments regarding DNA?
Transformation does not occur when DNA-digesting enzymes are added, indicating that DNA is the genetic material.
What conclusion did Hershey and Chase reach about DNA?
DNA is the agent that causes the manufacture of viral DNA and proteins in bacteria.
What are the components of a nucleotide?
Nitrogenous base, 5-carbon sugar (ribose or deoxyribose), and phosphate group.
What is the key difference between DNA and RNA nucleotides?
DNA contains Thymine (T), while RNA contains Uracil (U).
What are the two groups of nitrogenous bases in nucleotides?
Pyrimidines (T, C, U) and Purines (A, G).
What was Chargaff's finding regarding DNA base pairing?
Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).
What is the structure of DNA?
A double helix resembling a twisted ladder, with sugar-phosphate backbones as uprights and nitrogenous bases as rungs.
How does DNA replication occur in terms of templates?
Parental DNA strands separate, and each strand serves as a template for the creation of a new strand.
What enzyme is responsible for adding nucleotides during DNA replication?
DNA polymerase.
What is the significance of the semiconservative model of replication?
Half of the parent DNA is retained in each new DNA strand.
What are the three main types of RNA?
Messenger RNA (mRNA), Transfer RNA (tRNA), Ribosomal RNA (rRNA).
What is the main role of mRNA?
To carry genetic instructions from the nucleus to the cytoplasm for protein synthesis.
What is the central dogma of molecular biology?
DNA --> RNA --> Protein.
What is a codon?
A sequence of three nucleotides on mRNA that specifies an amino acid.
What role do ribosomes play in protein synthesis?
They facilitate the translation of mRNA codons into a polypeptide chain.
What happens during the initiation phase of translation?
mRNA binds to the small ribosomal subunit, and tRNA binds to the start codon.
What occurs during the elongation phase of translation?
tRNA anticodon pairs with mRNA codon; polypeptide bond forms as ribosome moves along the mRNA.
What is the outcome of reaching a stop codon during translation?
Termination of protein synthesis, releasing the completed polypeptide.
What is the primary role of tRNA during translation?
To transport specific amino acids to the ribosome based on mRNA codons.
Why is gene expression regulation important in eukaryotes?
It allows cells to differentiate and respond to environmental signals.
What characterizes the lac operon in E. coli?
It regulates the production of enzymes needed for lactose digestion depending on lactose presence.
What are three levels of gene control in eukaryotes?
Pretranscriptional, transcriptional, and posttranscriptional controls.
What types of mutations can occur on DNA sequences?
Point mutations and frame shift mutations.
What is a point mutation?
A substitution of a single nucleotide that can result in silent, missense, or nonsense mutations.
How do frame shift mutations alter protein synthesis?
They alter the reading frame, potentially changing all subsequent amino acids in the protein.
What can the mutation of the p53 gene lead to?
It can lead to uncontrolled cell division and various types of cancer.
What is the central dogma of molecular biology?
DNA __ RNA __ Protein.
The process where DNA is copied into RNA is called __.
Transcription.
The type of RNA that carries amino acids to the ribosome is called ___.
tRNA.
The enzyme that unwinds DNA during replication is called __.
Helicase.
Each amino acid is specified by a sequence of __ nucleotides on the mRNA.
Three.
The sequence of nucleotides in DNA is read by RNA polymerase during __.
Transcription.
The part of the gene that is transcribed into mRNA is called __.
Exon.
The region of the DNA where transcription begins is known as the ___.
Promoter.
When a stop codon is reached during translation, __ occurs.
Termination.
The structures that facilitate translation are called ___.
Ribosomes.