Intro to Bio 2-Chapter 12
lagging strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork.
DNA ligase
A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end of a growing chain.
In the 1940s, scientists had concluded that the genetic material was most likely either _____ or _____
DNA or protein
Transfer RNA (tRNA)
An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA
Which of the following were direct contributions of the work of James Watson and Francis Crick?
Deduced the double helix shape of deoxyribonucleic acid Determined that nucleotides were paired inside the double helix Determined that sugars and phosphates formed backbones in the DNA
gene expressions
genes are expressed when the polypeptides are modified into their structure to become functioning proteins
process of translation
initiation, elongation, termination
translation
the mRNA transcript is read by a ribosome and converted into the sequence of amino acids in a polypeptide
The process of synthesizing an RNA strand from a DNA template strand is called
transcription
What comes first, transcription or translation?
transcription
What is the source of particular sequences of tRNA, mRNA, and rRNA?
transcription from DNA
For a protein, gene expression requires _______in the nucleus and ______at the ribosome to take place.
transcription; translation
gene expression
transfer of information from the genetic material (DNA) to RNA and onto a protein. transcription and translation
The process which uses mRNA, tRNA, and ribosomes to synthesize proteins is called
translation
wat does replication result in?
two double helix molecules, each having 1 parent & 1 new strand
ribosomal RNA
type of RNA that makes up the major part of ribosomes
proetomics
understanding the structure of proteins and how they functions in metabolic pathways
Error rate in eukaryotes
varies depending on the size of the genome
introns
Noncoding segments of nucleic acid that lie between coding sequences. removed by splicesomes
Which of the following are components of a nucleotide?
Phosphate 5-carbon sugar Nitrogen-containing base
does RNA have a double helix?
no
the ribosome 3D structure
Two subunits made of ribosomal RNA and proteins; can be free in cytosol or bound to ER
characteristics of the genetic code
Universal, redundant, specific
what is each parent DNA for new DNA?
a template
nitrogenous bases of RNA
adenine, guanine, cytosine, uracil
many RNA transcripts on one DNA molecule....
allows cell to better respond to chaining environmental conditions
Incorporating new nucleotides into DNA can provide it with the ability to code for a greater number of
amino acids
what does the end of the molecule have in translation?
an anticodon-group of 3 bases
what is a replication bubble
an unwound and open region of a DNA helix where DNA replication occurs
what are the strands of DNA?
antiparallel
rRNA strands are transcribed from a template strand of DNA found in the _______.
nucleolus
what is transformation of bacteria?
bacterial cells absorb and incorporate pieces of DNA from environment (usually dead bact. cells).
How are nucleotides joined together?
by linking the 5' phosphate of one nucleotide to a free hydroxy located at the 3' position on the sugar of the preceding nucleotide
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'
the genetic code
collection of codons of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis
what is DNA?
deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.
The building blocks of DNA are
nucleotides
joining in replication
nucleotides are connected/bonded to each other (sugar-phosphate covalent bond)
complementary base pairing in replication
nucleotides move into position and pair with those on the template
What did Watson and Crick discover?
double helix structure of DNA
The coding portions of a gene that are joined during mRNA processing are called
exons
saying for introns and exons
exons are expressed and introns are in the way
what is synthorax
expanded genetic alphabet creating two new world of bases called X & Y
exons
expressed sequence of DNA; codes for a protein
The production and usage of a gene's product is called gene____
expression
Thymine and cytosine are nitrogen-containing bases called
pyrimidine
what is RNA
ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins,
R strain bateria
rough appearance, mice did not die
replication is ______
semiconservative
How did Rosalind Franklin contribute to determining the structure of DNA?
she used x-ray diffraction patterns to show the DNA double helix
dna primase
short complementary sequences of RNA (primers) are laid down to initiate synthesis
polyribosome
string of ribosomes simultaneously translating regions of the same mRNA strand during protein synthesis
what does mRNA codon determine
the amino acid
what does tRNA transport?
the correct amino acid to the ribosome
what are the steps in replication?
1. Unwinding 2.Complementary base pair 3. Joining
process of transciption
1. initiation- RNA polymerase bonds to the promote region of the gene= DNA unwinds 2.elongation- RNA polymerase moves along the DNA template and synthesizes RNA 3. termination-RNA polymerase encounters the terminator sequence
Error rate in prokaryotes
1/100million pairs
what is the structure of DNA
-composed of polynucleotides -- have a phosphate group, deoxyribose sugar and a nitrogen containing bases (adenine, thymine, cytosine and guanine) -Has a doubled helix that is formed by hydrogen bonds between polynucleotides -Densely compacted into chromosomes to fit into nucleus
prokaryote replication
1 circular chromosome, in the nucleoid region of prokaryote, 1 origin, in 2 directions (leading & lagging strands) very fast
replication fork
A Y-shaped region on a replicating DNA molecule where new strands are growing.
the codon
A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid
The two purines bases in DNA are:
Adenine and Guanine
Which of the following are similarities between prokaryotic and eukaryotic DNA replication?
Both result in 2 copies from one parent molecule Both involve DNA polymerase Both are semiconservative Both happen from the 5' to 3' direction
What does guanine pair with?
Cytosine
Central Dogma of Molecular Biology
DNA -> RNA->AA sequence ->specific polypeptide -> Protein
dna polymerase
Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
messenger RNA
RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell
Transcription
RNA molecules are produced by copying part of the nucleotide sequence of DNA into a complementary sequence in RNA
Unwinding in replication
Requires helicase activity. The dsDNA is unwound producing a replication bubble made of open ssDNA.
when does replication occur in the cell cycle?
S phase of interphase
S strain bacteria
Strain of Streptococcus pneumoniae that causes pneumonia (it would be SO BAD to be infected by this one)
leading strand
The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' to 3' direction.
What does adenine pair with in DNA?
Thymine