What is the correct order of the central dogma of gene expression?
DNA--> Translation-->RNA--> Transcription-->Protein
DNA--> Transcription-->RNA-->Translation-->Protein
RNA-->Transcription-->DNA-->Translation-->Protein
RNA-->Translation-->DNA-->Transcription-->Protein
What are components of a nucleotide?
Sugar
Nitrogen containing base
Phosphate
Carbon
RNA and DNA differ in the sugar component of one of the bases
What contains the sugar ribose?
RNA
DNA
mRNA
tRNA
Purines are
Adenine and Guanine
Adenine and Cytosine
Guanine and thymine
Cytosine and thymine
Pyrimidines are
Adenine and guanine
Adenine and thymine
Cytosine and adenine
Nucleic acid sequences are written in what direction?
One end has a phosphoryl group attached to the 3'carbon atom of the sugar and one end has a free hydroxyl attached to the 5' carbon of the sugar
One end has a phosphoryl group attached to the 5' carbon atom of the sugar and one end has a free hydroxyl attached to the 3' carbon of the sugar
A base bound to a sugar is called a
Nucleoside of DNA are
Deoxyadenosine, deoxyguanosine, deoxycytidine, and deoxythymidine
Adenine, guanine, cytosine, thymine
deoxyadenosine, deoxyguanosine, deoxycytosine, deoxyuracil
Deoxythymidine, rarely occurs in RNA, simply called thymidine
Nucleoside of RNA are
deoxyadenosine, deoxyguanosine, deoxycytidine, and deoxythymidine
adenosine, guanosine, cytidine, and uridine
adenosine, guanosine, cytidine, thymidine
deoxyadenosine, deoxyguanosine, deoxycytidine, and deoxyuracil
A nucleotide is a nucleoside with only 1 phosphoryl group attached
Nucleotide triphosphates Adenosine trisugars( triphosphates, Adenosine, trisugars ) are the building blocks of DNA tRNA mRNA( DNA, tRNA, mRNA ) and RNA mRNA tRNA( RNA, mRNA, tRNA )
DNA molecules are very long some consisting of more than nucleotides
The double helix is stabilized by hydrogen bonds and van der Walls interactions
Adenine always forms hydrogen bonds with thymine cytosine( thymine, cytosine ) while guanine forms hydrogen bonds with cytosine thymine( cytosine, thymine )
The helix is stabilized by hydrogen bonds between base pairs as well as hydrophobic interactions called
stacking forces
semiconservative replication
Van der Walls interactions
Because of the base pair rules, the sequence of one strand determines the sequence of the partner strand
Because the two daughter helices have one parent strand one newly synthesized strand, the replication process is called
Stacking forces
Semiconservative replication
Conservative replication
DNA polymerase
What are the key characteristics of DNA synthesis
Four deoxynucleoside triphosphates and Mg2+ are required
A template strand is used to direct RNA synthesis
A primer from which the new strand grows must be absent
Many DNA polymerases have nuclease activity that allows for the removal of mismatched bases
Some viruses, such as tobacco mosaic virus, have genomes that are replicated by -directed polymerases
Retroviruses, such as HIV-1, have single-stranded RNA genomes that are converted into DNA double helices by the action of
Transcriptase
Translation
Reverse transcriptase
Reverse translation
All cellular RNA is synthesized by RNA polymerases
The synthesis of RNA from a DNA template is called translation, a process catalyzed by RNA polymerase
RNA polymerase has the following requirements
Template
The sequence of the newly-synthesized RNA is complementary to the DNA template
coding strand
Activated precursors in the form of the 4 ribonucleoside
Divalent metal ions
Base pair
RNA polymerase initiates and elongates the RNA product, with the chain growing in the to direction
Several kinds of RNA play a role in gene expression, what are three most abundant classes of RNA
Ribosomal RNA
Messenger RNA
Transfer RNA
Translate RNA
RNA polymerases take instructions from DNA templates
Transcription begins near the sites and ends at sites
Promoters are
Specific DNA sequences that direct RNA polymerase to the proper initiation site
Specific RNA sequences that direct DNA polymerase to the proper initiation site
Specific DNA sequences that direct RNA polymerase to the proper terminator site
Specific RNA sequences that direct DNA polymerase to the proper terminator site
The average of variation in the sequence of a promoter for different genes is called sequence
The RNA complement of the DNA stop signal forms a hairpin structure, followed by several thymine residues
What is required for transcription termination
Protein rho
Protein thy
Protein gly
Protein leu
In eukaryotes,
The 3' end of mRNA is modified by the attachment of a cap structure while the 5' end acquires a poly(A)tail
The 5' end of mRNA is modified by the attachment of a cap structure while the 3' end acquires a poly(A)tail
The 5' end of tRNA is modified by the attachment of a cap structure while the 3' end acquires a poly(A)tail
The 3' end of tRNA is modified by the attachment of a cap structure while the 5' end acquires a poly(A)tail
Transfer RNA molecules react with
specific amino acids in a reaction catalyzed by aminoacyl-tRNA synthetases
one amino acids in a reaction catalyzed by aminoacyl-tRNA synthetases
specific amino acids in a reaction catalyzed by aminoacyl-mRNA synthetases
Specific amino acids in a reaction catalyzed by aminoacyl-rRNA synthetases
Transfer RNA molecules also contain a template recognition site, called
the anticodon
the codon
the initiator
the terminator
Anticodon consist of
2 bases
3 bases
complementary 3 base sequence in the rRNA
complementary 3 base sequence in the mRNA
Protein synthesis is the process of translation
Characteristics of the genetic code are
three nucleotides, called a codon
code is overlapping
code is nonoverlapping
code has punctuation
code has no punctuation
Code is read from 5' end of the mRNA to the 3' end
code is degenerate in that some amino acids are encoded by more than one codon
Degeneracy
amino acids encoded by 1 codon
amino acids encoded by more than 1 codon
minimizes deleterious effects of mutations
maximizes deleterious effects of mutations
Messenger RNA is translated on ribosomes
The genetic code is nearly universal
Eukaryotic genes are discontinuous
with coding regions called exons, interrupted by noncoding regions called introns
with noncoding regions called introns, interrupted by coding regions called exons
with coding regions called introns, interrupted by noncoding regions called exons
with interrupted regions called exons, coding regions called introns
Many exons encode
protein domains
amino acids
rRNA
Introns almost always begin with GU and end with an AG
The gene for the β- chain of human hemoglobin has exons and introns
RNA processing generates mature RNA
Pre-messeneger tRNA mRNA rRNA( Pre-messeneger, tRNA, mRNA, rRNA ) RNA contains exons and introns
