Chapter 16 Flashcards
Whose group showed that genes are located on chromosomes?
Thomas Hunt Morgan’s
What are the 2 components of chromosomes that became candidates for the genetic material?
Protein and DNA
Whose research began the discovery of the genetic role of the DNA?
Frederick Griffith
What is the Griffith Experiment?
He mixed heat-killed remains of the pathogenic strain with living cells of the harmless strain, some living cells became pathogenic.
What did Griffith called his experiment?
The transformation
This is the change in genotype and phenotype due to the assimilation of foreign DNA.
Transformation
Who identified the transforming substance as DNA
Oswald Avery, Maclyn McCarty and Colin MacLeod
Were scientists skeptical about the Oswald experiment?
Yes
Who showed that DNA is the genetic material of a bacteriophage known as T2?
Alfred Hershey and Martha Chase
An infectious agent that is mostly made up of a genetic material (DNA or RNA) and a protein coat.
Virus
Who found a relationship among DNA bases that turned out to be an important clue to DNA structure?
Erwin Chargaff and his colleagues
Do DNA vary between species?
Yes
Who used X-ray diffraction to determine 3D structure and measurements of the DNA molecule
Rosalind Franklin
Who applied the information and began to build scale models of DNA components
Watson and Crick
What are the two bases under Purines?
Adenine and Guanine
What are the two bases under Pyrimidines?
Thymine and Cytosine
Which of the bases are equal?
Adenine (A) and Thymine (T), and Guanine (G) and Cytosine (C)
What consists of the pentose sugar deoxyribose, a phosphate, and one of four nitrogenous bases?
DNA Nucleotide
What are the 4 nitrogenous bases?
Adenine, Guanine, Thymine, and Cytosine
The nucleotides are linked by covalent bonds, called____.
Phosphodiester Bonds
Where does DNA replication start?
Origin of replication
What is the type of virus that infects bacteria?
Bacteriophages
This breaks one or both DNA molecules and rejoins them, this prevents the supercoiling of the DNA and relaxing it during replication.
Topoisomerase
An enzyme that destabilize the double helical structure of the DNA by breaking the hydrogen bonds of complimentary bases.
Helicase
This binds to single DNA strands and stabilizes it. This will prevent the double helix from reforming until it is replicated.
Single-strand Binding (SSB) Protein
Synthesizes a short RNA strands to begin the production of new DNA strand.
DNA Primase
What is the short RNA strands called?
primer
This links the nucleotides to form a new DNA strand that is complementary to the template strand
DNA Polymerase
Links the Okazaki fragments together
DNA Ligase
What are the 2 other repair mechanisms
Mismatch Repair & Nucleotide Excision Repair
Enzymes recognize and remove the incorrectly paired nucleotides. Then, DNA polymerases fill in the missing nucleotides.
Mismatch repair
Used to cut and repair DNA lesions which is commonly caused by the UV rays from the sun.
Nucleotide Excision Repair
What can create problems for the linear DNA eukaryotes?
Limitations
a special nucleotide sequence at the end of the DNA
Telomeres
Enzyme that lengthens the telomeres.
Telomerase
Bacterial chromosome’s DNA is associated with a ___ amount of protein.
Small amount
Eukaryotic chromosomes have DNA molecules associated with a ____ amount of protein.
Large amount
In DNA packaging, DNA is precisely combined with proteins in a complex called _____.
chromatin
Proteins called ____ are responsible for the first level of packing in chromatin.
histones
What are the two types of chromatin during interphase?
Heterochromatin & Euchromatin
Highly condensed chromatin. Thus, inaccessible for gene expression.
Heterochromatin
Loosely packed chromatin, making the DNA accessible for gene expression.
Euchromatin
