Ch. 17 From Gene to Protein
RNA molecules is synthesized in an_direction to the template strand of DNA
antiparallel
Eukaryotes have _types of RNA polymerase in their_
at least 3 types nuclei
Using the genetic code in biotechnology
bacteria can be programmed by the insertion of human genes to synthesize certain human proteins for medical use (insulin)
nucleic acids and proteins contain information written in two different_
chemical languages
a mRNA molecules is_to its DNA template, why?
complementary because RNA nucleotides are assembled on the template according to base-pairing rules
the series of words in a gene is transcribed into a_, which is then translated into a _
complementary series of nonoverlaping, three-nucleotide words in mRNA chain of amino acids
ribososmes
complex particles that facilitate the orderly linkage of amino acids into polypeptide chains
The codons of the_are identical in sequence to mRNA, except that they have_instead of _
nontemplate strand T U
Who is the bridge between DNA and proteins synthesis?
nucleic acid RNA
Where does the instructions for assembling amino acids into a specific order are encoded?
nucleic acids
what polymers have specific sequences of monomers that convey information?
nucleic acids and proteins
The information content of genes is in the form of specific sequences of
nucleotides along strands of DNA, the genetic material
Bacteria has a _type of RNA polymerase that synthesizes_
single synthesizes not only mRNA but also other tupes of RNA that function in protein synthesis (ribosomal RNA)
what marks where transcription of a gene begins and ends?
specific sequence of nucleotides (codons)
The DNA inherted by an organism leads to
specific traits by dictating the synthesis of proteins and of RNA molecules involved in protein synthesis.
RNA molecules can act as
templates for DNA synthesis
Which stage of transcription is different between bacteria and eukaryotes?
termination
The cell must translate the nucleotide sequence of an mRNA molecule into
the amino acid sequence of a polypeptide
Messenger RNA
the carrier of information from DNA to the cell's protein-synthesizing machinery
During transcription what happens?
the gene determines the sequence of nucleotide bases along the length of the RNA molecule that is being synthesized
Why the protein is faulty?
the gene that codes for it contains incorrect information
who are the monomers in DNA and RNA? what differ between each other?
the monomers are four types of nucleotides, which differ in nitrogenous bases
Gene expression
the process by which the information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs
Messenger RNA is transcribed from
the template strand of a gene
Usually the codons that show redundancy (code for the same amino acid) differ only in the _
the third nucleotide base of the triplet
Because codons are nucleotides triplets, the number of nucleotides making up a genetic message must be_times the number of amino acids in the protein product.
three times
In eukaryotes, the other RNA polymerases, besides RNA polymerase II, what they do?
transcribe RNA molecules that are not translated into protein
mRNA is a faithful
transcript of the gene's protein-building instructions
Genes specify proteins via
transcription and translation
In eukaryote, the RNA transcript must_
undergo processing
Molecular biologists cracked the genetic code of life in the early _ when a series of elegant experiments disclosed the _
-1960s -amino acid translations of each of the RNA codons
Primary transcript
-An initial RNA transcript from any gene; also called pre-mRNA when transcribed from a protein-coding gene -Including those RNA that is not translated into protein
Flow of genetic information in bacteria? (transcription and translation)
-Because bacteria does not have nuclei, its DNA is not separated by nucelar membranes from ribosomes and the other protein synthesizing equipment -This allows translation of an mRNA to begin while its transcription is still in progress.
reading frame
-On an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis -the ability to extract the intended message from a written language depends on reading the symbols in the correct groupings
Differences between DNA and RNA?
-RNA contains ribosa insteadof deoxyrobose sugar -RNA has the nitrogenous base uracil -DNA has the nitrogenous base thymine -DNA is a double helix strand -RNA is a single strand -nucleotides in DNA: A, G, C, or T -nucleotides in RNA: A, G, C, or U
Template strand
-The DNA strand that provides the pattern, or template, for ordering, by complementary base pairing, the sequence of nucleotides in an RNA transcript -For any given gene,the same strand is used as the template every time the gene is transcribed -However, for other genes on the DNA molecule, the opposite strand may be the one that always functions as the template.
what is the difference of the base-pairing rules between DNA synthesis and transcription? other difference between both?
-Uracil (U) takes the place of Thymine (T) in RNA (transcription) -mRNA nucleotides contain ribose instead of deoxyribose
Evolution relationship between organisms?
-all the organism share the genetic code -CCG (RNA codon) is translated into the amino acid proline in all organisms whose genetic code has been examined
RNA polymerase
-an enzyme that links ribonucleotides into a growing RNA chain during transcription, based on complementary binding to nucleotides on a DNA template strand -it pries the 2 strands of DNA apart and joins togetherRNA nucleotides complementary to the DNA template strand, thus elongating the RNA polynucleotide
terminator
-in bacteria -the sequence of nucleotides in DNA that signals the end of transcription -signals RNA polymerase to release the newly made RNA molecule - RNA polymerase detach from DNA
Stages of transcription
-initiation -elongation -termination
Flow of genetic information in eukaryotes? (transcription and translation)
-nuclear envelope separates transcription from translation in space and time. -Transcription occurs in nucleus, and mRNA is then transported to the cytoplasm, where translation occurs.
transcription unit
-stretch of DNA that is transcribed into an RNA molecule
Promoter
-the DNA sequence,specific nucleotide sequence, where RNA polymerase attaches and initiates transcription -Positioning RNA polymerase to start transcribing RNA at the appropriate place
AUG codes for...
-the amino acid methionine (Met) -functions as "start" signals, or initiation codons, that signals the protein-synthesizing machinery to begin translating the mRNA at that location
Getting from DNA to protein requires two major stages:
-transcription -translation
the expresion of genes that code for proteins includes two stages:
-transcription -translation
Exeptions to the universality of the genetic code include
-translation systems in which a few codons differ from the standard ones (unicellular eukaryotes and organelle genes of some species )
describe the first step of transcription
1) Initiation: -After RNA polymerase binds to the promoter, the DNA strands unwind. -Polymerase initiates RNA synthesis at the start point on the template strand
coding strand
nontemplate DNA strand
When and by who was the first codon deciphered? what was this codon?
1961 Marshall Nirenberg UUU (poly-U)
describe the second step of transcription
2) elongation: -The polymerase moves downstream, unwinding the DNA and elongating the RNA transcripts 5'->3'. -In the wake of transcription, the DNA strands re-form a double helix
The _ codons of the 64 that do not designate amino acids are_, or_, marking the _. These codons are:
3 "stop" signals Termination codons the end of translation These codons are: UAA, UGA, UAG.
How many nucleotides correspond to an amino acid?
3 (triplets of nucleotide bases)
How many nucleotides along the mRNA do we need to produce a protein with 100 amino acids long?
300 nucleotides
codons are customarily written in the_direction
5'->3'
the codons are read by the translation machinery in what direction along the mRNA?
5'->3'
what direction does RNA polymerase can assemble a polynucleotide only?
5'->3'
If each arrangement of 3 consecutive nucleotide bases specifies an amino acid there can be_possible code words. what is the formula to determine this?
64 4^3
messenger RNA (mRNA)
A type of RNA, synthesized using a DNA template, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein. (In eukaryotes, the primary RNA transcript must undergo RNA processing to become mRNA.)
genetic messages on mRNA usually begin with which codon?
AUG
the UUU codon specifies what amino acid?
Phenylalanine
The term codon is also used for the DNA nucleotide triplets along the _strand
nontemplate strand
The messenger RNA is called like this because,,,
Because it carries a genetic message from the DNA to the protein-synthesis machinery of the cell.
Central dogma
Concept that said that cells are governed by a molecular chain of command with a directional flow of genetic information, which is DNA-> RNA-> Protein
what is the genetic materia?
DNA
Cells are governed by a molecular chain of command with a directional flow of genetic information, which is:
DNA --> RNA --> Protein
who created and in what year the central dogma?
Francis Crick 1956
Summarize protein synthesis.
Genes program protein synthesis via genetic messages in the form of messenger RNA
Transcriptions and translation occur in which organisms?
In all organisms. Eukayotes and prokaryotes
Does genes build proteins directly?
NO they do not, they only provided the information
in eukaryotes, the type of RNA polymerase used to mRNA synthesis is called...
RNA polymerase II
What is the difference between DNA polymerase and RNA polymerase used in transcription?
RNA polymerase are able to start a chain from scratch; they do not need a primer
Transcritption
Synthesis of RNA using information in the DNA. The two nucleic acids are written in different forms of the same language, and the information is simply transcribed, or "rewritten", from DNA to RNA.
What is the difference between the mechanism of transcription and translation between bacteria and eukaryotes?
The flow of genetic information within the cells
triplet code
The genetic instructions for a polypeptide chain are written in the DNA as a series of nonoverlapping, three-nucleotide words.
Just as DNA strand provides the template for making a new complementary strand during DNA replication, it can also serve as
a template for assembling a complementary sequence of RNA nucleotides
Codon
a three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.
The flow of information from gene to protein is based on
a triplet code
How reading frame applies to translating process?
The poypeptide will be made correctly only if the mRNA nucleotides are read in the direction of 5'->3' and reading the message of mRNA as a series of nonoverlapping three-letter words. (EX. UGG UUU GGC UCA).
translation
The synthesis of polypeptide using the genetic information encoded in an in the mRNA molecule. There is a change of "language" form molecule nucleotides to amino acids.
Each polypeptide of a protein also has monomers arranged in a particular linear order, but its monomers are_
amino acids
what happens before mRNA leaves the nucleus?
They are modified in various ways to produce the final, functional mRNA
what is the smallest unit of uniform length that can code for all the amino acids (20)?
Triplets of nucleotide bases (3)
the trait of albinism is caused by
a recessive allele of a pigmentation gene
molecular biologist refer to the direction of transcription as_and the other direction as_. This terms are also used to describe _. Ex?
downstream upstream the positions of nucleotides sequence withing DNA or RNA Ex: the promoter sequence in DNA is said to be upstream from the terminator
What does the codons specify?
each codon specifies which one of the 20 amino acids will be incorporated at the corresponding position along a polypeptide
Albino deer has a _version of a key protein, an
faulty enzyme required for pigment synthesis
Inherited traits are determined by
genes
who provides the information to create specific proteins?
genes
In bacterium, the RNA transcript is _ usable as mRNA
immediately
During translation what happens to the sequence of codons along an mRNA molecule?
it is decoded, or translated, into a sequence of amino acids making up a polypeptide chain
Polypeptide chains usually begin with what amino acid? why? Does this amino acid stay or is removed after synthesis?
methionine because AUG codes for it usually removed
For each gene how many of the strands is or are transcribed?
only one of the two DNA strands is transcribed
The transcription of a protein-coding eukaryotic gene results in_, and further processing yields the
pre-mRNA finished mRNA
who are the link between genotype and phenotype?
proteins
Codons show_because_;however they do not show _ because
redundancy because multiple codons code for the same amino acid. ambiguity because neither of the codons specify any other amino acid
The site of translation are_.
ribosomes
during translation, the mRNA is read as a
sequence of nucleotide triplets, codons
A_is a reminder of the kinship that bonds all life on Earth
shared genetic vocabulary
