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Bio Ch.10
Biological Processes Test
60
Biology
Undergraduate 1
04/09/2012

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Term
Molecular biology
Definition
the study of heredity at the molecular level
Term
Bacteriophages
Definition
viruses that exclusively infect bacteria
Term
Phages
Definition
short for bacteriophages (virus that infects bacteria)
Term
Nucleotides
Definition
a building block of nucleic acids, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and one or more phosphate groups
Term
Polynucleiotide
Definition
a nucleotide polymer chain
Term
Sugar-phosphate backbone
Definition
a repeating patterns of sugar-phosphate-sugar-phosphate (the nitrogenous bases are arranged like ribs that project from a backbone)
Term
Deoxyribonucleic acid
Definition
A double-stranded helical nucleic acid molecule consisting of nucleotide monomers with deoxyribose sugar and the nitrogenous bases adenin (A), cytosine (C), guanine (G), and thymine (T). Capable of replicating, DNA is an organism's genetic material
Term

Thymine

Cytosine

&

Adenine 

Guanine

Definition

T & C - single ring structures called pyrimidines

 

A & G - larger, double-ring structures called purines

Term
Uracil (U)
Definition
RNA's nitrogenous base (replaces the thymine from DNA)
Term
Double helix
Definition
helix made up of two polynucleiotide strands
Term
Semiconservative model
Definition
type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand 
Term
DNA polymerase
Definition
a large molecular complex that assmbles DNA nucleotides into polynucleotides using a preexisting strand of DNA as a template
Term
DNA ligase
Definition
an enzyme, essential for DNA replication, that catalyzes the covalent bonding of adjacent DNA polynucleotide strands; used in genetic engineering to paste a specific piece of DNA containing a gene of interest into a bacterial plasmid or other vector
Term
Transcription
Definition
the synthesis of RNA under the direction of DNA
Term
Translation
Definition
the synthesis of protein under the direction of RNA
Term
Triplet code
Definition
a set of 3-nucleotide-long "words" that specify the amin acids for polypeptide chains
Term
Codons
Definition
A 3 nucleotide sequence in mRNA that specifies a particuar amino acid or polypeptide termination signal; the basic unit of the genetic code
Term
Genetic code
Definition
set of rules that relate codons in RNA to amino acids in proteins
Term
RNA polymerase
Definition
a large molecular complex that links together the growing chain of RNA nucleotides during transcription, using a DNA strand as a template
Term
Promoter
Definition
a specific binding site for RNA polymerase and determines which of the 2 strands of the DNA double helix is used as the template in transcription
Term
Terminator
Definition
sequence of bases in the DNA template; signals the end of the gene; at that point, the polymerase molecule detaches from the RNA molecule and the gene
Term
Messenger RNA
Definition
RNA that encodes amino acid sequences; conveys genetic messages from DNA to the translation machinery of the cell
Term
Introns
Definition
internal non-coding regions in plants and animals; "intervening sequences"
Term
Exons
Definition
coding regions; parts of the gene that are expressed 
Term
Transfer RNA
Definition
ribonucleic acid that functions as an interpreter in translation; each has a specific anticodon, picks up a specific amino acid, and conveys the amino acid to the appropriate codon on mRNA
Term
RNA splicing
Definition
cutting and pasting process 
Term
Anticodon
Definition
On a tRNA molecule, a specific sequence of 3 nucleotides that is complementary to a codon triplet of mRNA
Term
Ribosomes
Definition
structures in the cytoplasm that position mRNA and tRNA close together and catalyze the synthesis of polypeptides
Term
Ribosomal RNA (rRNA)
Definition
type of ribonucleic acid that, together with proteins, makes up ribosomes; the most abundant type of RNA in most cells
Term
Start codon
Definition
On mRNA, the specific 3-nucleotide sequence (AUG) to which an initiator tRNA, molecule binds, starting translation of genetic information
Term
P site (P stands for peptidyl tRNA)
Definition
 1 of 2 ribosomes binding sites for tRNA during translation; holds the tRNA carrying the growing polypeptide chain 
Term
A site (A stands for aminoacyl tRNA)
Definition
1 of 2 ribosomes binding sites for tRNA during translation; holds the tRNA that carries the next amino acid in the polypeptide chain 
Term
Codon recognition
Definition
the anticodon of an incoming tRNA molecule, carrying its amino acid, pairs with the mRNA codon in the A site of the ribosome
Term
Peptide bond formation
Definition
the polypeptide separates from the tRNA in the P site and attaches by a new peptide bond to the amino acid carried by the tRNA in the A site; the ribosome catalyzes formation of the peptide bond, adding one more amino acid to the growing polypeptide chain
Term
Translocation
Definition
1) During protein synthesis, the movement of a tRNA molecule carrying a growing polypeptide chain from the A site to the P site on a ribosome (mRNA travels with it) 2) A change in a chromosome resulting from a chromosomal fragment attaching to a nonhomologous chromosome; can occur as a result of an error in meiosis or from mutagenesis
Term
Stop codon
Definition
(UAA, UAG, UGA) do not code for amino acids but instead act as signals to stop translation 
Term
Mutation
Definition
any change in the nucleotide sequence of DNA
Term
Silent mutation
Definition
mutation in a gene that changes a codon to one that encodes for the same amino acids as the original codon; the amino acid sequence of the resulting polypeptide is thus unchanged
Term
Missense mutations
Definition
change in the nucleotide sequence of a gene that alters the amino acid sequence of the resulting polypeptide; a codon is changed from encoding one amino acid to encoding a different amino acid
Term
Nonsense mutations
Definition
change an amino acid codon into a stop codon
Term
Reading frame
Definition
the way a cell's mRNA-translating machinery groups the mRNA nucleotides into codons
Term
Mutagenesis
Definition
the creation of a change in the nucleotide sequence of an organism's DNA
Term
Mutagen
Definition
a chemical or physical agent that interacts with DNA and causes a mutation
Term
Virus
Definition
microscopic particle capable of infecting cells of living organisms and inserting its genetic material; generally not considered to be alive because they do not display all of the characteristics associated with life
Term
Capsid
Definition
the protein shell that encloses a viral genome
Term
Lytic cycle
Definition
type of viral replication cycle resulting in the release of new viruses by lysis (breaking open) of the host cell
Term
Lysogenic cycle
Definition
type of bacteriophage replication cucle in which the viral genome is incorporated into the bacterial host chromosome as a prophage; new phages are not produced, and the host cell is not killed or lysed unless the viral genome leaves the host chromosome
Term
Prophage
Definition
phage DNA that has inserted by genetic recombination into the DNA of a bacterial chromosome
Term
AIDS
Definition
acquired immunodeficiency syndrome
Term
HIV
Definition
human immunodeficiency virus; RNA virus
Term
Reverse transcriptase
Definition
enzyme that catalyzes the synthesis of DNA on an RNA template; characterizes "retrovirus)
Term
Retrovirus
Definition
reproduces by means of a DNA molecule; RNA > DNA; inserts DNA into a cellular chromosome, then transcribes more copies of the RNA from the viral DNA 
Term
Viroids
Definition
small circular RNA molecules that infect plants
Term
Prions
Definition
cause a number of degenerative brain diseases in various animal species
Term
Transformation
Definition
incorporation of new genes into a cell from DNA that the cell takes up from the surrounding environment
Term
Transduction
Definition
transfer of bacterial genes from one bacterial cell to another by phage
Term
Conjugation
Definition
the union of two bacterial cells or protist cells and the transfer of DNA between 2 cells
Term
F factor
Definition
a piece of DNA that can exist as a bacterial plasmid; carries genes for making sex pili and ther structures needed for conjugation, as well as the site where DNA replication can start (F = fertility)
Term
Plasmid
Definition
small ring of independently replicating DNA separate from the main chromosomes; found in prokaryotes and yeasts
Term
R plasmid
Definition
bacterial plasmid that carries genes for enzymes that destroy particular antibiotics; thus making the bacterium resistant to the antibiotics
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