AP Biology: Unit 7 - Chapter 18 & 20
Terms in this set (63)
The regulatory "switch" is a segment of DNa call an ....... usually positioned within the promoter
The entire stretch of Dna that includes the operator, the promoter, and the genes that they control
A protein that can switch off the operon
This prevents gene transcription by binding the operator and blocking RNA polymerase
This is the product of a separate regulatory gene
A molecules that cooperates with a repressor protein to switch an operon off
For example, E. coli can synthesize the amino acid tryptophan
By default, the trp operon is .... and the genes for tryptophan synthesis are transcribed
When tryptophan is present, it binds to the trp repressor protein, which turns the operon off
The repressor is active only in the presence of its corepressor tryptophan; thus the trp operon is turned off (repressed) if tryptophan levels are high
The ....... operon is one that is usually on; binding of a repressor to the operator shuts off transcription
The trp operon is this
Inducible (pt 2. Inducer)
An ....... operon is one that is usually off; a molecule called an inducer inactivates the repressor and turns on transcription
The lac operon is this
By itself, the lac repressor is active and switched the lac operon off
A molecule called an this inactivates the repressor to turn the lac operon on
A molecule called an ....... inactivates the repressor to turn the lac operon in
Inducible enzymes usually function in .........; their synthesis is induced by a chemical signal.
Regulation of the trp and lac operons involves negative control of genes because operons are switched off by the active form of the repressor.
Repressible enzymes usually function in ...... ......; their synthesis is repressed by high levels of the end product.
Regulation of trp and lac operons involves negative control of genes because operons are switched off by the active form of the repressor.
Stimulator proteins, such as catabolite activator protein (CAP), that have the operons be subject to positive control.
When glucose (a preferred food source of E. coli) is scarce, CAP is activated by binding with this.
Activated CAP attached to the promoter of the lac operon and increases the affinity of RNA polymerase, thus accelerating transcription.
Differential gene expression
The expression of different genes by cells with the same genome.
Acetyl groups are attached to positively charged lysines in histone tails
THis process loosens chromatin structure, thereby promoting the initiation of transcription
The addition of methyl groups (methylation) can condense chromatin; the addition of phosphate groups (phosphorylation) next to a methylated amino acid can loosen chromatin
Methylation regulates expression of either the maternal or paternal alleles of certain genes at the start of development
The inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence
Segments of noncoding DNa that help regulate transcription by binding certain proteins
These and the proteins the bind are critical to the precise regulation of gene expression in different cell types
Collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription.
Distal control elements, groups which may be far away from a gene or even located in an intron
Proximal control elements
Elements that are located close to the promoter
Alternative RNA splicing
Different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns
Giant protein complexes that bind protein molecules and degrade them
Small single-stranded RNA molecules that can bind to mRNA
These can degrade mRNA or block its translation
Small interfering RNAs (siRNAs)
One of multiple small, single-stranded RNA molecules generated by cellular machinery from a long, linear, double-stranded RNA molecule.
Similar to miRNAs but form from different RNA precursors
The process by which cells become specialized in structure and function
The physical processes that give an organism its shape constitute
Signal molecules from embryonic cells cause transcriptional changes in nearby target cells
Thus, interactions between cells induce differentiation of specialized cell types
Commits a cell to its final fate
The development of a spatial organization of tissues and organs
The molecules cues that control pattern formation, tells a cell its location relative to the body axes and to neighboring cells
Maternal effect genes
Encode for cytoplasmic determinants that initially establish the axes of the body of Drosophila
These maternal effect genes are also called egg-polarity genes because they control orientation of the egg and consequently the fly
Maternal substances in the egg that influence early development
Nucleotide sequences from two different sources, often two species, are combined in vitro into the same DNA molecule.
The direct manipulation of genes for practical purposes
The manipulation of organisms or their genetic components to make useful products
The process of preparing gene-sized pieces of DNA in identical copies
The production of multiple copies of a specific DNA segment
Small circular DNA molecules that replicate separately from the bacterial chromosome
Involves using bacteria to make multiple copies of a gene
Foreign DNA is inserted into a plasmid, and the recombinant plasmid is inserted into a bacterial cell
Reproduction in the bacterial cell results in cloning of the plasmid including the foreign DNA
This results in the production of multiple copies of a single gene
These cut DNA molecules are specific DNA sequences called restriction sites
The locations for which restriction enzymes must cut along the DNA molecule
Single stranded ends of DNA left after cutting with enzymes
These are fragments of DNA that bond with complementary sticky ends of other fragments after the DNA has been cut by restriction enzymes
An enzymes that seals the bonds between restriction fragments
The original plasmid in gene cloning in bacteria
A DNA molecule that can carry foreign DNA into a host cell and relicate there
The collection of recombinant vector clones produced by cloning DNA fragments from an entire genome
A this that is made using bacteriophages is stored as a collection of phage clones.
Bacterial artificial chromosome
A large plasmid that has been trimmed down and can carry a large DNA insert
A type of vector used in DNA library construction
Complementary DNA (cDNA)
Made by cloning DNA made in vitro by reverse transcription of all the mRNA produced by a particular cell
Represents only part of the genome of complementary DNA-only the subset of genes transcribed into mRNA in the original cells
Nucleic acid probe
A clone carrying the gene of interest, having a sequence complementary to the gene
Nucleic acid hybridization
Base pairing between a gene and a complementary sequence on another nucleic acid molecule.
a cloning vector that contains a highly active bacterial promoter just upstream of a restriction site where the eukaryotic gene can be inserted in the correct reading frame
Applying a brief electrical pulse to create temporary holes in plasma membranes
Polymerase chain reaction (PCR)
A three-step cycle-heating, cooling, and replication-brings about a chain reaction that produces an exponentially growing population of identical DNA molecules
Procedure used to separate and analyze DNA fragments by placing a mixture of DNA fragments at one end of a porous gel and applying an electrical voltage to the gel
A current is applied that causes charged molecules to move through the gel.
Molecules are sorted into "bands" by their size
the electrode at which reduction occurs
The movement to the left (negative) side
the electrode at which oxidation occurs
The movement to the right (positive) side
dideoxy chain termination method
Short DNA fragments can be sequenced by this. Uses dideoxyribonucleotides that are modified nuclotides that attach to synthsized DNA strands of different lengths. Each ddNTP is tagged with flurescent label.
A technique using nucleic acid hybridization with a labeled probe to detect the location of a specific mRNA in an intact organism.
DNA microarray assays
Compared patterns of gene expression in different tissues, at different times, or under different conditions
in vitro mutagenesis
A technique to discover the function of a gene by introducing specific changes into the sequence of a cloned gene, reinserting the mutated gene into a cell, and studying the phenotype of the mutant.
RNA interference (RNAi)
Synthetic double-stranded RNA molecules matching the sequences of a particular gene are used to break down or block the gene's mRNA
A cell that can generate a complete new organism
An unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of one or more types