BIO106 Ch. 12 Molecular Biology of the Gene
Separates double-stranded DNA into single strands
DNA helicase
The enzyme responsible for separating double-stranded DNA into single-stranded DNA is
DNA helicase
Attaches DNA fragments
DNA ligase
Synthesizes DNA, removes RNA and proofreads DNA
DNA polymerase
The enzyme that is used to proofread DNA as it is being synthesized
DNA polymerase
Synthesizes shirt RNA strands
DNA primase
The process of copying a DNA molecule so that there are two copies of the same DNA is called
DNA replication
The synthesis of a new DNA double helix prior to mitosis and meiosis in eukaryotic cells and during prokaryotic fission in prokaryotic cells is called
DNA replication
There is a point on a replicating prokaryotic or eukaryotic DNA strand at which separation of the strands occurs to allow for enzyme activity. What is it called?
Replication fork
The double helix model of DNA resembles a twisted ladder in which the rungs of the ladder are
a purine paired with a pyrimidine
During the final stage of translation, a release factor binds to
a stop codon
Three-base sequence in a transfer RNA molecule base that pairs with a complementary codon in mRNA
anticodon
DNA replication is said to be semiconservative because
both of the new DNA molecules contain one new strand and one old strand
`pre-mRNA is modified or processed before leaving the eukaryotic nucleus by receiving
caps at 5' and 3' end and poly-A tail
In prokaryotes, replication can occur in two directions at once because the DNA molecule is
circular
Prokaryotic cells have _________________ DNA and their DNA replications proceeds in a ________________ direction.
circular, 5' to 3'
Three base sequence in mRNA that during translation directs the addition of a particular amino acid into a protein or directs termination of the process
codon
The hydrogen bonding between particular purines and pyrimdines; responsible for the structure of DNA, and some RNA, molecules is called
complementary base pairing
Middle stage of translation in which additional amino acids specified by the mRNA are added to the growing polypeptide
elongation
What facilitates the binding of tRNA anticodon to mRNA codons?
elongation factors
What are the three tRNA binding sites on ribosomes?
exit, peptide, amino acid
segment of mRNA containing the protein coding portion of a gene that remains within the mRNA after splicing has occurred
exon
The production and usage of a gene's product
gene expression
First stage of translation in which the translational machinery binds an mRNA and assembles
initiation
The first stage of translation, during which ribosomes assemble around mRNA is called
initiation
Intervening sequence found between exons in mRNA; removed by RNA processing before translation, non protein coding regions
intron
A spliceosome uses a ribozyme to cut and remove __________ from pre-mRNA.
introns
The portion of the mRNA transcript that gets removed during RNA processing is the
introns
Eukaryotic organisms have _____________ DNA and DNA replication occurs _________________.
linear; bidirectionally
Type of RNA formed from a DNA template and bearing coded information for the amino acid sequence of a polypeptide
mRNA
Type of nucleic acid bearing codons for the amino acid sequence
mRNA
A modified and finished form of a messenger RNA molecule is called an
mRNA transcript
During protein synthesis, an anticodon on transfer RNA pairs with
messenger RNA nucleotide bases
Transformation occurs when
organisms receive foreign DNA and thereby acquire a new characteristic
facilitates the transport of mRNA out of the nucleus, helps initiate loading of ribosomes and the start of translation and delays degradation of mRNA by hydrolytic enzymes
poly-A tail
How can you increase the efficiency of translation?
polyribosomes
In an operon, a sequence of DNA where RNA polymerase binds prior to transcription, first step in transcription
promoter
Study of the structure, function, and interaction of the complete collection of proteins in a cell
proteomics
Adenine and guanine are
purines
RNA molecule associated most closely with both ribosomes and translation
rRNA
Structural form of RNA found in the ribosomes
rRNA
The process in which DNA is used as a template to produce duplicate molecules of DNA
replication
RNA molecule that functions as an enzyme that can catalyze chemical functions
ribozyme
DNA replication be described as ___________________, because the resulting daughter DNA consists of one parent strand and one daughter strand.
semiconservative
Process of DNA replication that results in two double helix molecules, each having one parental and one new strand
semiconservative replication
Keeps single stranded DNA apart
single stranded binding protein (SSB)
During translation initiation, the small ribosomal subunit and initiator tRNA attach in the vicinity of the
start codon
The central dogma of molecular biology
states that DNA is a template for all RNA production
The process in which DNA is used as a template to produce RNA
transcription
What is the source of particular sequences of tRNA, mRNA and rRNA?
transcription from DNA
Polyribosomes are strings of ribosomes simultaneously
translating an mRNA strand
Polypeptides are created during which process?
translation
The process in which RNA is used to produce a protein
translation
Why must the genetic material be a stable molecule?
-so genetic material can pass from generation to generation - so replication can be accurate
Place the steps of DNA replication in the correct sequence
1. Unwinding the DNA double helix 2. Complementary base pairing 3. Joining nucleotides to the growing DNA strand
List the steps of translation in the correct order
1. initation 2. elongation 3. termination
List the events of termination in order
1. releases factor binds to stop codon 2. protein product is released 3. ribosomal subunits dissociate
List the sequential steps of DNA replication
1. the double helix is separated and unwound 2. DNA polymerase begins the copying process 3. DNA polyermerase meet at the termination region
If 30% of an organism's DNA is thymine, then
20% is guanine
How many different types of DNA nucleotides are there?
4
If each codon were composed of only 1 nucleotide, how many amino acids are possible?
4
The information stored within DNA must be read and is replicated in a
5' to 3' direction
The following rules explain what 1. the amount of A,T,G, and C in DNa varies from species to species 2. In each species the amount of A=T and the amount of G=C
Chargaff's Rules
Who first demonstrated that DNA was the genetic material
Avery, MacLeod, McCarty
Which bacteriologist jump-started the search For DNA in the 1920s
Frederick Griffith
Allow a cell to pick and choose which exons will go into a particular mRNA.
Introns
Which scientists determined that sugars and phosphates formed backbones in the DNA, discovered the double helix shape of deoxyribonucleic acid, determined that nucleotides were paired inside the double helix
James Watson and Francis Crick
Which scientist(s) figured out that the shape of a DNA molecule is a double helix?
Rosalind Franklin
T/F: is it possible to transfer genes from one type of organism to another type of organism?
True
When researchers began their work, they knew that genetic material must be
able to store information, stable, and undergo mutations
The two strands of DNA are held together by
hydrogen bonds
Type of RNA that transfers a particular amino acid to a ribosome during protein synthesis
tRNA
The original parent strand for which a complementary strand is made is called the
template strand
During this phase of translation, a completed polypeptide is released
termination
End of translation that occurs when a ribosome reaches a stop codon on the mRNA that is translating, causing release of the completed protein
termination