AP BIO EXAM REVIEW: Ch. 17 Lecture Notes Flashcards

Terms Definitions
the information content of DNA is in the form of specific sequences of __________ along the DNA strand.
The DNA inherited by an organism leads to specific traits by dictating the sythesis of ____________.
transcription; translation
Gene expression, the process by which DNA directs protein synthesis, includes two stages called ____________ and ___________.
__________ are the links between genotype and phenotype.
genes; enzymes
In 1909, Archibald GARROD was the first to suggest that __________ dictate phenotype through _________ that catalyze specific chemical reactions in the cell.
inborn; metabolism
Archibald Garrod referred to such diseases as "__________ errors of ___________."
The bridge between DNA and protein synthesis is the nucleic acid ________.
ribose; thymine
RNA is chemically similar to DNA, except that is contains _______ ribose as its sugar and substitutes the nirtrogenous base uracil for _______.
An RNA molecule almost always consists of a ______ strand.
During _________, a DNA strand provides a template for the synthesis of a complementary RNA strand.
messenger RNA
Transcription of many genes produces a __________ __________ molecule. (mRNA)
the site of translation is the ________ complex particles that facilitate the orderly assembly of amino acids into polypeptide chains.
The use of an RNA intermediate provides ___________ for DNA and its genetic information.
more; orderly
Using an RNA intermediate allows ______ copies of a protein to be made simutaneously, since many RNA transcripts can be made from one gene. Also, each gene transcript can be translated _________.
The basic mechanics of transcription and translation are ____________ in eukaryotes and prokaryotes.
Because bacteria lack nuclei, their DNA is not segregated from ribosomes and other protein- synthesizing equipment. This allows the __________ of transcription and translation.
primary transcript
The initial RNA transcript of any gene is called a ________ ________.
RNA Processing
________ __________ yields the finished mRNA.
DNA, RNA, protein
The molecular chain of command in a cell is _______ - ______ - _______.
triplet code
During transcription, one DNA strand, the __________ ________ , provides a template for ordering the sequence of nucleotides in an RNA transcript.
the complementary RNA molecule is synthesized according to base-pairing rules, except that _______ is the complementary base to adenine.
The mRNA base triplets are called _______, and they are written in a 5' - 3' direction.
61; start
By the mid 1960s, the entire code was deciphered. ____ of 61 triplets code for amino acids. The codon AUG not only codes for the amino acid methionine, but also indicates the "_____" of translation.
termination; end
_____________ codons do not indicate amino acids but are "stop" signals marking the __________ of translation.
same; 1
Several codons may specify the ______ amino acid, but no codon specifies more than ___ amino acid.
reading frame
To extract the message from the genetic code requires specifying the correct starting point. This establishes the _________ ________.
In summary, genetic information is ________ as a sequence of nonoverlapping base triplets, or codons, each of which is translated into a specific amino acid during protein synthesis.
The genetic code is nearly ________, shared by organisms from the simplest bacteria to the most complex plants and animals.
The evolutionary significance of the near _______ of the genetic code is clear.
A _______ genetic vocabulary is a reminder of the kinship that confs all life on Earth.
RNA polymerase
_______ __________ separates the DNA strands at the appropriate point and bonds the RNA nucleotides as they base-pair along the DNA template.
Unlike DNA polymerases, RNA polymerases are able to start a chain from scratch; they don't need a _______.
RNA polymerase attaches and initiates transcription at the __________.
In prokaryotes, the sequence that signals the end of transcription is called the _________.
transcription unit
The stretch of DNA that is transcribed into an RNA molecule is called a _________ ________.
initation, elongation, termination
Transcription can be separated inot three stages: _________, ________, and ___________ of the RNA chain.
transcription factors
In eukaryotes, proteins called __________ ______ mediate the binding of RNA polymerase and the initation of transcription.
transcription initation complex
The completed assembly of transcription factors and RNA polymerase II bound to a promoter is called a _______ _________ ________
TATA box
A crucial promoter DNA sequence is called a _______ _______.
As RNA polymerase moves along the DNA, it _______ the double helix, 10 to 20 bases at a time.
Behind the point of RNA synthesis, the double helix _____ and the RNA molecule peels away.
Transcription proceeds until after the RNA polymerase transcribes a _______ sequence in the DNA.
falls off
Transcription is terminated when the polymerase eventually ______ ______ the DNA.
5' cap
At the 5' end of the pre-mRNA molecule, a modified form of guanine is added, the ____ _________.
poly-a tail
At the 3' end, and enzyme adds 50 to 250 adenine nucleotides, the ____-__ ________.
export; protect; ribosomes
These modifications share several important functions. They seem to facilitate the _______ of mRNA from the nucleus. They help ______ mRNA from hydrolytic enzymes. They help the _____________ attach to the 5' end of the mRNA.
RNA splicing
The most remarkable stage of RNA processing occurs during the removal of a large portion of the RNA molecule in a cut-and-paste job of _____ ___________.
Noncoding segments of nucleotides called intervening regions, or ______, lie between coding regions.
the final mRNA transcript includes coding regions, _______, which are translated into amino acids sequences, plus the leader and trailer sequences.
Each snRNA is about _____ nucleotides long.
The idea of a catalytic role for snRNA arose from the discovery of __________, RNA molecules that function as enzymes.
Some introns play a ______ role in the cell.
alternative RNA splicing
_____ ________ _________ gives rise to two or more different polypeptides, depending on which segments are treated as exons.
Proteins often have a modular architecture with discrete structural and functional regions called _______.
exon shuffling
The presence of introns in a gene may facilitate the evolution of new and potentially useful proteins as a result of a process known as ______ _________.
The presence of introns _________ the probability of potentially beneficial corssing over between genes.
Introns increase the ______- for recombination between two alleles of a gene.
Either way, exon shuffling can lead to ____- proteins through novel combinations of functions.
transfer RNA
The interpreter is ________ ______, which transfers amino acids from the cytoplasmic pool to a ribosome.
The ribosome adds each amino acid carried by ___ to the growing end of the polypeptide chain.
During translation, each type of tRNA links an _____ codon with fine appropriate amino acid.
Each tRNA arriving at the ribosome carries a specific amino acid at one end and has a specific nucleotide triplet, an ________, at the other.
The tRNA molecule is a __________, because it can read a nucleic word and translate it to a protein word.
The rules of base pairing between the third base of the codon and anticodon are relaxed (called __________)
aminoacyl- tRNA synthetase
Each amino acid is joined to the correct tRNA by ___________ ________ ___________.
ribosomal rRNA
The subunits of ribsomes are composed of proteins and ____________, the most abundant RNA in the cell.
P site
The ___ ______ holds the rRNA carrying the growing polypeptide chain.
a site
The ____ ________ carries the rRNA with the next amino acid to be added to the chain.
E (exit) site
Discharged tRNAs leave the ribosome at the ____ ______.
exit tunnel
As the polypeptide becomes longer, it passes through an _____ __________ in the ribosomes large unit and is released to the cytosol.
rRNA; protein
Recent advances in our understanding of the structure of the ribosome strongly support the hypothesis that ______, not ______, carries out the ribosome's function.
All three phases require ________ "factors" that aid in the translation process.
_____ brings together mRNA, tRNA with the first amino acid, and the two ribosomal subunits.
initiation factors
proteins called ________ ________ bring in the large sununit so that the initiator tRNA occupies the P site.
_______ involves the participation of several protein elongation factors, and consist of a series of three-step cycles as each amino acid is added to the proceeding one.
codon recongnition; codon factor
During _______ _________, an ______ _________ assists hydrogen bonding between the mRNA codon under the A site with the corresponding anticodon of tRNA carrying the appropriate amino acid.
peptide bond formation
During _________ _______ _________, and rRNA molecule catalyzes the formation of a peptide bond between the polypeptide in the P site with the new amino acid in the A site.
During _________, the ribosome movies the tRNA with the attached polypeptide from the A site to the P site.
_______ occurs when one of the three stop codons reaches the A site
release factor
A ________ _______ binds to the stop codon and hydrolyzes the bond between the polypeptide and its tRNA in the P site.
Multiple ribosomes, __________, may trail along the same mRNA.
post tranlational modifications
In addition, proteins may require ______ _________ __________ before doing their particular job.
free; bound
Two populations of ribosomes, _____ and ______, are active participants in protein synthesis.
signal peptide
Translation in all ribosomes begins in the cytosol, but a polypeptide destined for the endomembrane system or for export has a specific _______ _________ region at or near the leading end.
signal recongnition particle
A ________ ________ __________ (SRP) bind to the signal peptide and attaches it and its ribosome to a receptor protein in the ER membrane
_______ proteins are released entirely into the cisternal space, but membrane proteins remain partically embedded in the ER membrane
hydrogen bonds
The diverse functions of RNA are based, in part, on its ability to form ________ ______ bonds with other nucleic acid molecules ( DNA or RNA)
small nucleolor
A type of RNA called ______ __________ (snoRNA) asids in processing pre-rRNA transcripts in the nucleolus, a process necessary for ribosome formation.
same gene; diffuses.
One major difference is that prokaryotes can transcribe and translate the _______ ____-simultaneously. The new protein quickly ________ to its operating site.
__________ are changes in the genetic material of a cell (or virus).
point mutation
A chemical change in just one base pair of a gene causes a ________ __________
base- pair substition
A point mutation that results in the replacement of a pair of complementary nucleotides with another nucleotide pair is called a _______-_____ ______________.
silent mutations
In _______ ________, altered nucleotides still code for the same amino acids because of redundancy in the genetic code.
missese mutation
________ _____ are those that still code for an amino acid but a different one.
nonsense mutations
_______ ________ change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein.
insertions; deletions
_________ and ________ are additions or losses of nucleotide pairs in a gene.
frameshift mutations
Unless insertions or deletions mutations occur in multiples of three, they cause a _______ ________.
spontaneous mutations
Mutations can occur in a number of ways. Errors can occur during DNA replication, DNA repair, or DNA recombination. These can lead to base-pair substitutions, insertions, or deletions, as well as mutations affecting longer stretches of DNA. These are called ______ __________.
________ are chemical or physical agents that interact with DNA to cause mutations.
DNA; polypeptide; RNA
A gene is a region of ______ whole final product is either a ___________ or an ________ molecule.
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