Chapter 5: DNA, Gene Expression, And Biotechnology Flashcards
DNA
Is a macromolecule that stores information
Nucleotides
Contain a molecule of sugar, a phosphate group, and a nitrogen containing molecule
Genome
The full set of DNA present in an individual organism
Chromosome
One or more unique pieces of DNA that together make up an organisms genome
Gene
A specific sequence of DNA that contains the information necessary to produce all or part of a protein molecule
Alleles
Alternative versions of a gene that code for the same feature
Trait
Any single characteristic or feature of an organism
Introns
A segment of a DNA or RNA molecule that does code for proteins and interrupts the sequence of genes
Junk DNA
The proportion of DNA that codes for proteins or RNA
Genotype
Is the part of the DNA sequence of the genetic makeup of a cell
Phenotype
The physical manifestation of the genotype’s instructions
Transcription
In which a copy of a gene’s base sequence is made
Translation
In which that copy is used to direct the production of a polypeptide folds into the functional protein
Messenger RNA (mRNA)
In transcription which in eukaryotes occurs in the nucleus is copied to make this molecule
Step 1 of Transcription: Recognize and Bind
RNA polymerase binds to the DNA molecule at the promoter site and unwinds it just a bit so that only one strand of the DNA can be read
Step 2 of Transcription: Transcribe
As the DNA strand is processed through the RNA polymerase, the RNA polymerase builds a copy of the gene from the DNA molecule
Step 3 of Transcription: Terminate
When the RNA polymerase encounters a sequence of bases on the DNA at the end of the gene it stops creating the transcript and detached from the DNA molecule
Step 4 of Transcription: Capping and Editting
mRNAs receive extra processing before they can be translated into a protein. A cap and tail may be at the beginning and end of the transcript
Transfer RNA
A special type of RNA molecules holds which translates the language of DNA into the language of proteins
Codon
Each three base sequence in mRNA matches with a tRNA molecule that carries a particular amino acid
Step 1 of Translation: Recognize and Initiate Protein Building
Begins in the cytoplasm when a ribosome recognizes and assembles around a codon on the mRNA transcript called the start sequence
Step 2 of Translation: Elongate
After the mRNA start sequence the next three bases on the mRNA specify which amino acid carrying tRNA molecule should bind to the mRNA
Step 3 of Translation: Terminate
The ribosome arrives at the codon on the mRNA that signals the end of translation. The amino acid is complete and is released from the ribosome
Gene Expression
The production of the protein that the genes sequence codes for
Gene Regulation
A person’s traits depend on whether the gene is turned on or turned off
Promoter
For a gene to be transcribed, RNA polymerase recognizes and binds to the promoter region, the specific sequence of nucleotides in the DNA that signals the beginning of the gene
Operator
A molecule called a repressor protein can bind to the regulatory portion of the DNA and by doing so it blocks RNA polymerase from transcribing the genes necessary for lactose metabolism
Regulatory Gene
Codes for the repressor protein when bound to the operator region does the blocking of RNA polymerase’s binding to the promoter site
If lactose is not present
The regulatory gene produces the repressor protein, the repressor protein binds to the operator region, and RNA polymerase is blocked from transcribing the lactose metabolism genes
If lactose is present
The regulatory gene produces the repressor protein, lactose binds to the repressor protein which alters the shape so it can’t bind to the operator, and with no repressor bound to the DNA, RNA polymerase binds to the promoter and transcribes the genes necessary for lactose metabolism
Positive Control of Transcription Regulation
Activators can initiate or speed up gene expression and enhancer sequences can speed RNA polymerase binding and gene transcription
Negative Controls of Transcription Regulation
Repressors can block or slow down gene expression and chemicals can bind to DNA and block gene expression
Mutation
An alteration of the sequence of bases in an organism’s DNA. Can lead to changes in the structure and function of the proteins produced
Point Mutations
Occur when one base pair in the DNA is substituted for another or when a base pair is inserted or deleted
Chromosomal Abberations
Are changes to the overall organization of the genes on a chromosome
Spontaneous Mutations
Some mutations arise by accident as long strands of DNA are duplicating themselves when cells are dividing. Most are caught by DNA repair enzymes
Radiation Induced Mutations
Is radiation with enough energy to disrupt atomic structure and even break apart chromosomes by removing tightly bound electrons
Chemical Induced Mutations
Many chemicals can react with the atoms in DNA molecules and induce mutations
Steps from Mutation to Illness
A mutated gene codes for a non functioning protein, the non functioning enzyme can’t catalyze a particular reaction as it normally would, the molecule with which the enzyme would have reacted accumulates, and the accumulated chemical causes sickness or death
Biotechnology
The genetic manipulation of organisms for the production of antibiotics, hormones, etc
Genetic Engineering
The manipulation of organisms genetic material by adding, deleting, or transplanting genes from one organism to another
Chop
Chop up the DNA from a donor organism that exhibits the trait of interest
Amplify
Amplify the small amount of DNA into larger quantities
Insert
Insert pieces of DNA into bacterial cells or viruses
Grow
Grow separate colonies of bacteria or viruses each containing some donor DNA
Identify
Identify colonies of bacteria or viruses that have DNA for a trait of interest
Human Growth Hormone
Stimulates protein synthesis, increases the utilization of body fat for energy to fuel metabolism, and stimulates the growth of virtually every part of the body
Erythropoietin
Produced primarily by the kidneys, is a hormone that regulates the production of red blood cells.
Is a given set of parents likely to produce a baby with a genetic disease?
Many genetic diseases occur only if an individual inherits two copies of the disease causing gene, one from each parent
Will a baby be born with a genetic disease?
Once fertilization has occurred it is possible to test the an embryo or developing fetus for numerous genetic problems
Is an individual likely to develop a genetic disease later in life?
DNA technology can also be used to detect disease causing genes in individuals who are currently healthy but are at increased risk of developing an illness later
Gene Therapy
The transplantation of normal genes into cells in place of missing or defective ones in order to correct genetic disorders
Stem Cells
An undifferentiated cell of a multicellular organism that is capable to making more cells of the same type
