_____ is the process by which DNA directs the synthesis of proteins (or, in some cases, just RNAs).
Nucleic Acid RNA
The bridge between DNA and protein synthesis is the _____.
Each nucleotide along a(n) _____ strand has A, G, C or T as its base.
Each nucleotide along a(n) _____ strand has A, G, C, or U as its base.
_____ is the synthesis of RNA using information in the DNA.
_____ is the synthesis of a polypeptide using the information in the mRNA.
The sites of translation are _____, complex particles that facilitate the orderly linking of amino acids into polypeptide chains.
The transcription of a protein-coding eukaryotic gene results in _____, and further processing yields the finished mRNA.
The initial RNA transcript from any gene, including those specifying RNA that is not translated into protein, is more generally called a _____.
Cells are governed by a molecular chain of command with a directional flow of genetic information (DNA → RNA → Protein).
This concept was dubbed the _____ by Francis Crick.
The flow of information from gene → protein is based on a _____: The genetic instructions for a polypeptide chain are written in the DNA as a series of non-overlapping, three-nucleotide words.
For each gene, only one of the two DNA strands is transcribed. This strand is called the _____ because it provides the pattern for the sequence of nucleotides in an RNA transcript.
The mRNA nucleotide triplets are called _____, and they are customarily written in the 5' → 3' direction.
There are a total of _____ codons.
There are a total of _____ amino acids.
UAA, UAG, UGA
___, ___, and ___ are the "stop" signals, or termination codons, marking the end of translation.
Our ability to extract the intended message from a written language depends on reading the symbols in the correct groupings – that is, the correct _____.
An enzyme called an _____ pries the two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand, thus elongating the RNA polynulceotide.
5' → 3'
Like the DNA polymerases that function in DNA replication, RNA polymerases can assemble a polynucleotide only in its _____ direction.
The DNA sequence where RNA polymerase attaches and initiates transcription is known as the _____
In bacteria, the sequence that signals the end of transcription is called the ______.
The promoter sequence in DNA is said to be _____ from the terminator.
The stretch of DNA that is transcribed into an RNA molecule is called a _____.
The promoter of a gene includes within it the transcription _____ and typically extends several dozen or more nucleotide pairs upstream from the _____.
In eukaryotes, a collection of proteins called _____ mediate the binding of RNA polymerase and the initiation of transcription. Only after _____ are attached to the promoter does RNA polymerase II bind to it.
Transcription Initiation Complex
The whole complex of transcription factors and RNA polymerase II bound to the promoter is called a _____.
A crucial promoter DNA sequence.
Enzymes in the eukaryotic nucleus modify pre-mRNA is specific ways before the genetic messages are dispatched to the cytoplasm. During this _____, both ends of the primary transcript are altered.
Each end of a pre-mRNA molecule is modified in a particular way. The 5' end is synthesized first; it receives a _____, a modified form of a guanine (G) nucleotide added onto the 5' end after transcription of the first 20-40 nucleotides.
At the 3' end, an enzyme adds 50-250 more adenine (A) nucleotides, forming a _____.
A stage of RNA processing in the eukaryotic nucleus is the removal of large portions of the RNA molecule that is initially synthesized – a cut-and-pase job called _____.
The noncoding segments of nucleic acid that lie between coding regions are called intervening sequences, or _____.
_____ are eventually expressed, usually by being translated into amino acid sequences.
Small Nuclear Ribonucleoproteins (snRNPs)
Particles called _____ recognize splice sites. _____ are located in the cell nucleus are are composed of RNA and protein molecules.
Small Nuclear RNA (snRNA)
The RNA in a snRNP particle is called a _____.
Several different snRNPs join w/ additional proteins to form an even larger assembly called a _____, which interacts with certain sites along an intron, releasing the intron, which is degraded, and joining together the 2 exons that flanked the intron.
RNA molecules that function as enzymes.
Alternative RNA Splicing
Many genes are known to give rise to two or more different polypeptides, depending on which segments are treated as exons during RNA processing; this is called _____.
Proteins often have a modular architecture consisting of discrete structural and functional regions called _____.
The presence of introns in a gene may facilitate the evolution of new and potentially beneficial proteins as a result of a process known as _____.
Transfer RNA (tRNA)
In the process of translation, a cell "reads" a genetic message and builds a polypeptide accordingly. The message is a series of codons along an mRNA molecule, and the translator is called _____.
The function of _____ is to transfer amino acids from the cytoplasmic pool of amino acids to a growing polypeptide in a ribosome.
A tRNA molecule arrives at a ribosome bearing a specific amino acid at one end. At the other, is a nucleotide triplet called an _____, which base-pairs with a complementary codon on mRNA.
The correct matching up of tRNA and amino acid is carried out by a family of related enzymes called _____.
The nucleotide base U at the 5' end of a tRNA anticodon can pair with either A or G in the third position (at the 3' end) of an mRNA codon. The flexible base pairing at this codon position is called _____.
_____ explains why the synonymous codons for a given amino acid most often differ in their third nucleotide base, but not in the other bases.
Ribosomal RNA's (rRNAs)
A ribosome consists of a large subunit and a small subunit, each made up of proteins and one or more _____.
In both bacteria and eukaryotes, large and small subunits join to form a functional ribosome only when they attach to an _____ molecule.
P Site (Peptidyl-tRNA Binding Site)
The _____ holds the tRNA carrying the growing polypeptide chain.
A Site (Aminoacyl-tRNA Binding Site)
The _____ holds the tRNA carrying the next amino acid to be added to the chain.
E Site (Exit Site)
Discharged tRNAs leave the ribosome from the _____.
The _____ stage of translation brings together mRNA, a tRNA bearing the first amino acid of the polypeptide, and the two subunits of a ribosome.
Translation Initiation Complex
The union of mRNA, initiator tRNA, and a small ribosomal subunit is followed by the attachment of a large ribosomal subunit, completing the _____. Proteins called initiation factors are required to bring all these components together.
A _____, a protein shaped like an aminoacyl tRNA, binds directly to the stop codon in the A site. The _____ causes the addition of a water molecule instead of an amino acid to the polypeptide chain.
_____ are found in both bacterial and eukaryotic cells. They enable a cel to make many copies of a polypeptide very quickly.
_____ are suspended in the cytosol and mostly synthesize proteins that stay in the cytosol and function there.
_____ make proteins of the endomembrane system (the nuclear envelope, ER, Golgi apparatus, lysosomes, vacuoles, and plasma membrane) as well as proteins secreted from the cell, such as insulin.
The polypeptides of proteins destined for the endomembrane system or for secretion are marked by a _____, which targets the protein to the ER.
Signal-Recognition Particle (SRP)
The signal peptide is recognized as it emerges from the ribosome by a protein-RNA complex called a _____, which functions as an escort that brings the ribosome to a receptor protein built into the ER membrane.
Changes to the genetic information of a cell (or virus).
Changes in a single nucleotide pair of a gene.
A _____ is the replacement of one nucleotide and its partner with another pair of nucleotides.
A _____ has no observable effect on the phenotype. (They can occur outside genes as well)
Substituions that change one amino acid to another one are called _____. (May have little effect on protein)
A point mutation can change a codon for an amino acid into a stop codon, this is a _____, and it causes translation to be terminated prematurely; the resulting polypeptide will be shorter than the polypeptide encoded by the normal gene.
Insertions / Deletions
_____ and _____ are additions or losses of nucleotide pairs in a gene.
_____ will occur whenever the number of nucleotides inserted or deleted is not a multiple of three.
A number of physical and chemical a gens, called _____, interact with DNA in ways that cause mutations.
A region of DNA that can be expressed to produce a final functional product that is either a polypeptide or an RNA molecule.
The start codon.
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