Gene Expression Flashcards
(22 cards)
Gene expression and genetic manipulation cover the three main concepts of…
selective breeding
whole organism cloning
transgenesis
Genes are…
the unit of inheritance found on chromosomes in DNA
Genes found on the same locus on a homologous pair of chromosomes have…
the genetic code fo the same characteristic
Alleles are…
different forms fo a gene with slightly different base sequences of DNA
A gene is that length of DNA that has..
the code for a particular protein with a sequence of a triplet coding for an amino acid
The two processes involving amino acids turning into proteins
Transcription (in the nucleus using codons and mRNA)
Translation (in the cytoplasm with the ribosomes and anticodons)
A metabolic pathway is…
a series of enzyme-controlled steps in which a reactant is converted into a product whcih becomes the reactant for the next step until a final product is produced
Gene mutations (three mutations)
substitution (lest harmful due to code degeneracy)
deletion
insertion
Gene mutations form new alleles so…
provide the raw material for evolution
Mutations can be (four affects of mutations on natural selection)
Beneficial (selected for)
Neutral/silent (selection determined by chance)
Harmful (selected against)
Lethal
DNA coding and non-coding functions
Coding DNA has the bases to make the amino acids.
Non-coding DNA has the instructions for which parts of the DNA are switched ‘on’ or ‘off’
Complete dominance is…
when the presence of a dominant allele masks the presence of a recessive allele so the dominant allele is expressed ifn the phenotype
incomplete dominance is…
neither allele is dominant and creates an intermediate blend of both phenotypes
Co-dominance is…
both alleles are dominant and expressed in the offspring typically in patches of both phenotype
Multiple allles occurs when…
there are more than two possible alleles for a particular gene
Processes fo Genetic manipulation through human control:
selective breeding
transgenesis
whole organ cloning
methylation of DNA is…
the adding of a methyl group that is a common way for a gene to be turned off in a DNA sequence so taht it’s not expressed in the genotype.
epigenetics is…
the regulation of gene expression by factors in the internal environment such as levels of nutrition, hormones, and temperature
Biological implications of gene expression modifications
- unexpected results from the effects on the expression of other genes that may be harmful or benefitial
- effects on biodiversity from the presence of these organisms in natural ecosystems
Selective breeding biological implications
- inbreeding with closely related individuals causing inbreeding depression and genetic disorders (reduced by outbreeding that can cause hybrid vigour)
- reduction in genetic diversity
- selectively bred organisms (IF RELEASED) may outcompete wild types and reduce biodiversity of ecosystems
- Selectively bred organisms have evolution controlled by humans, not natrual selection
- Selectively bred organisms are healthier and live longer
Transgenesis biological implications
- risk of horizontal gene transfer from transgenic organisms into organisms in natural ecosystems that can affect composition and biodiversity
- Transgenetic organisms may outcompete the wild types if released in to natural ecosystems
cloning (whole organisms) biological implications
- cloning produced individuals that are genetically identical and thus have little genetic diversity, and thus as greater risk of extinction
- any genetic disorders within the genome of the parent will be present in offspring
