Chapter 12 Flashcards
Who tested on mice?
Griffith.
What did Griffith discover?
Griffith discovered that when a harmless bacteria strain was combined with a harmful heat-killed bacteria strain the harmless bacteria would become virulent. This is an example of transformation
What does virulent?
Virulent means able to cause disease.
What is transformation?
Transformation is when there is a change in a phenotype caused when bacterial cells take up foreign genetic material.
What did Avery discover?
Avery found that DNA is the material responsible for transformation.
What did Hershey and Chase discover?
Using bacteriophages Hershey and Chase discovered DNA, not proteins is the source of genetic material.
What is a bacteriophage?
Bacteriophages are viruses that infect bacteria
What is the shape of DNA?
A double helix of nucleotides
What does DNA do?
Controls the production of proteins.
What is a nucleotide?
The monomer of DNA.
What are a nucleotide’s three parts?
Five Carbon Sugar, A phosphate group, and one nitrogen base.
What are the four options of nitrogen base for a nucleotide?
Adenine, Guanine, Cytosine, or Thymine.
Who discovered the Laws of Base-Pairing?
Erwin Chargaff.
Which nitrogen bases pair together?
Adenine pairs to Thymine and Cytosine pairs to Guanine.
How are nitrogen bases paired?
Hydrogen bonds.
Who ‘discovered’ the double helix?
Watson and Crick.
Who actually discovered the double helix, but died because they were exposed to radiation?
Rosalind Franklin.
What does DNA look like?
A twisted ladder.
What are the ‘sides’ of the ‘ladders’ of DNA?
Alternating Sugar and Phosphate groups.
What are the ‘rungs’ of the ‘ladder’ of DNA
The base pairing Adenine to Thymine and Guanine to Cytosine nitrogen bases.
How many hydrogen bonds do the Adenine and Thymine pair have?
Adenine and Thymine have two hydrogen bonds.
How many hydrogen bonds do the Cytosine and Guanine pair have?
Cytosine and Guanine have three hydrogen bonds.
What do chromosomes contain?
Chromatin, which contains tightly packed DNA and histones.
What is a histone?
A protein that DNA wraps around.
What are DNA and histones combined called?
Nucleosome.
What is DNA replication and when does it occur?
The process of making a copy of DNA during the S phase. One strand of DNA acts as a template on which the other strand is built.
What is the name of the enzyme that unwinds the double helix?
DNA Helicases.
What is a complex basic summary of DNA replication?
The double helix strands split and DNA polymerase adds replaces the bases for each strand. DNA polymerase then detaches from the strands.
What is a replication fork?
The point where DNA splits during DNA replication.
What is DNA polymerase?
DNA polymerase adds new nitrogen bases during DNA replication and proofreads during DNA replication.
What is RNA?
Ribonucleic acid, or RNA, is basically just one strand of DNA.
What are the three kinds of RNA?
Messenger RNA (mRNA), Ribosomal RNA (rRNA), and Transfer RNA (tRNA).
What nitrogen base does RNA have that DNA doesn’t?
Uracil.
What kind of sugars does RNA have?
Ribose sugar.
What kind of sugar does DNA have?
Deoxyribose.
What is messenger RNA?
mRNA is an RNA produced by transcription that transmits information for protein synthesis. mRNA passes the message of DNA to ribosomes.
What is transfer RNA?
tRNA is a single strand of RNA that temporarily carries a specific amino acid on one end while the other has an anticodon.
What is ribosomal RNA?
rRNA is a part of the structure of ribosomes.
What is transcription?
When the instructions for making proteins are passed from a gene to tRNA, which occurs inside the nucleus.
What is a codon?
A codon is three nucleotides put together.
What is translation?
When the instructions on the RNA molecule are used to put together amino acids and make proteins. Translation occurs in the cytoplasm on ribosomes.
What are mutations?
Changes in genetic material.
What are point mutations?
Point mutations are when one or just a few nucleotides in a gene are changed.
What are frameshift mutations?
Frameshift mutations change the entire reading frame of the genetic message.
What is a promoter?
The binding site for RNA polymerase.
What is an operator?
A piece of DNA that overlaps the promoter site and serves as the on-off switch for RNA polymerase.
What is an operon?
Operons are found in prokaryotes and are both the promoter and the operator.
What is a repressor?
Repressors are proteins that bind to the operator in an operon to switch off transcription.
