Genetics chapter 3
Start Codon
AUG
Ribonucleoside monophosphates are used.
RNA synthesis occurs in a manner similar to DNA synthesis during replication except which of the following is different in RNA synthesis?
two or more polypeptides joined together to form a proten
what is Quaternary structure for a protein.
Linear sequence of amino acids
what is primary structure of a protein
Further folding of 3D structure
what is tertiary structure
Nitrogenous base, pentose sugar, phosphate group
what is the structures of all nucleotides
proofreading
Because of __________, the error rates in DNA replication are as low as one error per 10,000 to 100,000 nucleotides.
Separates the two strands by breaking hydrogen bonds
DNA helicase
one strand runs in a 5' to 3' direction, and the other strand runs in a 3' to 5' direction
DNA in a double helix is antiparallel. What does antiparallel mean?
mainly to repair any damage with DNA, but it also serves to connect Okazaki fragments by deleting RNA primers and replacing the strand with DNA
DNA polymerase I
repair enzyme. enzyme to remove the RNA primer and replace it with DNA.
DNA polymerase I functions as a
It provides the nucleotide sequence that is used to make a complementary, antiparallel strand during replication.
DNA polymerase I requires two different components of DNA, primer and template. What functions does the template component form?
It carries out primer-initiated 5' to 3' polymerization of DNA on a single-stranded DNA template, as well as 3' to 5' exonucleolytic editing of mispaired nucleotides.
DNA polymerase III
each new DNA molecule contains one preexisting strand and one new strand.
DNA replication is said to be semiconservative because
has 146 nucleotide pairs of DNA wrapped around the octamer of histones.
Each nucleosome:
Peptide bonds between phosphate and amino groups
How and where are amino acids joined
sigma factor
In E. coli, which of the following subunits plays no role in chain elongation, only transcription initiation?
mRNA is translated as it is being synthesized.
In prokaryotes, which of the following is true?
must be precisely spliced out in order to be translated to produce the correct polypeptide Correct
Introns:
Addition of 5' methyl cap Addition of 3' polyA tail Removal of introns and keeping of exons
Name three modifications that are made to mRNA molecules in eukaryotic cells before the RNA molecule becomes a mature mRNA.
a nitrogen-containing base a pentose sugar a phosphate group
Nucleotides are composed of:
the same as the nontemplate (coding) strand, except using U instead of T
RNA is
Synthesizes primers
RNA primase
6 member ring connected to a 5 member ring
Structure of a purine
semiconservative
The mechanism of DNA replication where each of the complementary strands from the parental double helix is conserved is termed:
the hydrogen bonds between complementary strands are broken
The process of denaturation involves heating DNA to 100°. What effect does this have on the DNA molecule?
a left-handed structure.
There are several alternate forms of double helical DNA. The Z DNA form is:
Stop Codon
UAA
Stop Codon
UAG
Stop Codon
UGA
the complete replication apparatus moving along the DNA molecule at a replication fork, all of the proteins required for DNA replication in prokaryotes
What is a replisome?
the end of a linear chromosome a structure that keeps the ends of a linear chromosome from fusing with one another sequences that contain short tandem repeats located at the end of a linear chromosome a structure that protects the ends of linear chromosomes from degradation
What is a telomere?
3D structures held together by hydrogen bonds into alpha helices and beta sheets
What is secondary structure of a protein
They have a 6 member ring with Nitrogen at the 1 and 3 positions
What is similar about all 5 bases
ribose has one more alcohol group then deoxyribose
What is the difference between ribose and deoxyribose
synthesize a free 3′ OH for DNA polymerase to use
What is the function of DNA primase in DNA replication in prokaryotes?
to condense the bacterial genome so it will fit into the cell
What is the function of negative supercoiling bacteria?
compact the DNA into the nucleosome
What is the function of the histone proteins in human chromosomes?
G and C have three hydrogen bonds between them
What nucleotide has more hydrogen bonds between them
Hydrogen bonds between nitrogenous bases
What type of bond holds the 2 strands of DNA together.
Phosphodiester bonds, 3' and phosphate group bond together
What type of bonds link nucleotides in nucleic acids, where are they lined
DNA polymerase III
Which DNA polymerase is the true DNA replicase responsible for the semiconservative replication of DNA in E. coli?
DNA ligase
Which enzyme covalently bonds a 3′-OH to a 5′ phosphorous in DNA, such as when DNA is nicked or to link Okazaki fragments together?
Supercoils
Which of the following allows DNA to be collapsed into a tight structure?
50% of the bases are purines
Which of the following is true about double stranded DNA?
Okazaki fragments
Which of the following would you find only on the lagging strand of DNA?
initiation
Which stage of transcription in eukaryotes requires transcription factors?
6 member ring
structure of a pyrimidine
polypeptides
what are proteins made of
Amino group, phosphate group, R group
what are the three groups in an amino acids
amino acids
what are polypeptides made of
