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Bio 104 Final
Partin
55
Biology
Undergraduate 1
12/13/2006

Additional Biology Flashcards

 


 

Cards

Term
The Future Isn’t What It Used to Be: Biotechnology
Definition
The DNA of two people of the same sex is 99.9% identical
Term
What Is Biotechnology?
Definition
–Any use of living organisms to create products or facilitate processes
–Example—HGH (human growth hormone)
Secreted by pituitary
Necessary for childhood growth
Missing in some individuals
In the past, replaced by extraction of hormone from cadavers
Costly and unsafe
–Now, gene for HGH is isolated, inserted into E. coli, and expressed by the vats-full.
Term
Tools of Biotechnology
--Restriction Enzymes
Definition
–Cut DNA into pieces (designed to cut invading viral DNA)
–At highly specific sequences of bases called recognition sequence
–Example—BamHI cuts only at GGATCC
–“Sticky ends” can reseal, thus pasting two pieces together like DNA Velcro.
–1000 Identified!
Term
Tools of Biotechnology
--Plasmids
Definition
–Extra-chromosomal rings of bacterial DNA
–Replicate independently of bacterial chromosome
–Inherited by both daughter cells
–Bacteria take up plasmids from surroundings (transformation)
Term
Getting Human Genes into Plasmids
-Recombinant DNA
Definition
Two or more segments of DNA that have been combined by humans into a sequence that does not exist in nature.
Term
Cloning: Make an Exact Genetic Copy
Definition
–Sheep Dolly cloned in 1997 (Ian Wilmut at PPL Therapeutics)
Spark added to two cells
Udder and egg cells fused
Mimicked by the stimulation by sperm
Surrogate mother
Now has her own offspring
Aging problems
–DNA from 6 yr old
–Arthritis
Dead in 2003
Term
Benefits of Cloning
Definition
–Combine cloning with recombinant DNA technology.
–Creating livestock that contain human genes needed to treat genetic disorders like hemophilia B (Factor IX) in Polly.
Clone & Human gene!
Factor IX in milk!
–More useful chemical form than bacteria.
Term
Xenotransplantation
Definition
Creating livestock to serve as organ donors, or blood donors.
Pigs
Remove DNA coding for proteins that are recognized as foreign by human immune system
Then, clone and harvest organs
Term
Human Cloning
Definition
–U.S. Prof. & Italian doctor
–Realian sect in Canada already proposed to start
Cells from baby before dying
–Clones already exist—identical twins
Began as one cell
–Ethical considerations:
When is it OK—To replace child who died? To create mini-me? For infertile couples?
What about the number of attempts that may fail?
Term
PCR—Polymerase Chain Reaction
Definition
–Use primers—short sections of DNA complementary to both ends of the DNA to be copied
–Primers signal DNA polymerase to copy
Term
PCR—Uses
Definition
–“Amplifies” a specific piece of DNA from small samples
Crime scene investigation
–Medical—Lyme disease diagnosis
–Archeology—5,200-year-old Iceman compared to modern Europeans
More closely related to northern and central
–Invented in 1983 by Kary Mullis
Nobel prize in Chemistry
Term
Visualizing DNA Sequences
Definition
–How do we compare DNA?
–Restriction enzymes cleave DNA into manageable pieces.
–Gel electrophoresis—DNA moves in an electric field through a gel matrix.
–Larger pieces are more easily retarded by holes in the gel, so they travel less than smaller pieces.
–Dyes are used to visualize DNA as bands
Term
Sequencing DNA
Definition
–Characterizing a stretch of DNA by the order of As, Gs, Cs, and Ts
–Regularly performed by machine
Term
DNA in the Courtroom
Definition
–Police are making DNA data banks
Cold Hits
–Free wrongly accused
Term
The Human Genome Project
Definition
–Locate and catalogue human genome.

1990—Publicly funded Human Genome Project
1998—Craig Venter (biotech company, Celera) sought sequence of entire genome by 2001.
Sequence published in February 2001.
Genes for sale

–Surprised that human genome contains only 26,000 to 40,000 total genes—not 100,000.
–Benefit—finding disease genes at increasing rate.

Library analogy
Give genes descriptive names
Only 1.5% of your DNA codes for proteins!
Term
Multifunctional genes
Definition
–code for more than one protein
–Exons are rearranged before translation
Term
Genomics
Definition
the study of genome data; like mining to find gene functions
Term
Proteomics
Definition
the study of protein expression and function.
Term
Genetics’ Next Phase: Genomics and Proteomics
Definition
–Unimaginable complexity must be solved using computer technology “bioinformatics.”
Bio & computers
30,000 genes
100’s of thousands of proteins
Term
Alternative mRNA splicing
Definition
–Splice exons together in alternative ways to make different proteins
Term
Genetically Modified Foods: Protests
Definition
–1998—European Union restricts approval of new GM foods.
–2000—U.S. genetically modified corn approved only for animal feed ends up in taco shells
Term
Genetically Modified Foods: Promise
Definition
–Golden Rice
Genes from bacterium and daffodil to make beta-carotene.
Enrich diets of 124 million children worldwide who are lacking Vitamin A.
–1/2 million blind each yr
–2 million die each yr.


–Bananas
Resistant to fungal infections
Produce edible vaccines (maybe
Term
Genetically Modified Foods: Concerns
–Allergic Reactions
Definition
No evidence of harm to humans.
Considered “low probability.”
American Medical Assoc. said no justification for special labeling, recommends continued research into safety
Term
Genetically Modified Foods: Concerns
–Environmental Contamination
Definition
Threat of hybridization with wild relatives, sharing genes and thus creating super weeds.
Study in England from 1990—in 12 locations, not one of various varieties of GM crops spread beyond the growth plots.
Term
Genetically Modified Foods: They’re Here…
Definition
–In United States, 54% soybeans, 48% cotton, 25% of all corn are GM.
–Most contain Bt gene, with no harm.
Bacteria gene that produces a protein that kills bugs
–Reduced chemical insecticide use on cotton in the Southeast by 72%.
–Suggested use with buffer zone to prevent development of resistance.
Term
Human Gene Therapy
Definition
Human gene therapy is a recombinant DNA procedure that seeks to treat disease by altering the genes of the afflicted person
Term
Microevolution Leads to Macroevolution
Definition
–Macroevolution
•grand scale
•new species
•major changes in family lines
Term
–Microevolution
Definition
•Darwin
•minor changes in the genetic composition of a population
Term
–Adaptation
Definition
•results from microevolution
•changes that increase likelihood of survival and reproduction

–Adaptation by natural selection is responsible for evolution
•accumulation of small changes leads to new species (macroevolution).
Term
Pace of Evolution
Definition
Rate
–Mammals evolve slowly
–Fish (Coelacanth) even slower.
Spurts?
Term
–Gradualism
Definition
•macroevolution occurs at a constant, gradual pace
Term
–Punctuated Equilibrium
Definition
•Major environmental changes trigger bursts of rapid speciation, followed by periods of gradual change.
–“Radiation” after mass extinction
–Niles Eldredge & Stephen Jay Gould
•Fossil record supports both hypotheses
Term
The Fossil Record
Definition
Evidence of macroevolution
Fossils
–The preserved remains, traces, or tracks of once-living creatures.

Dating Fossils
–Relative age of rock was determined by its position relative to other rocks.
–Today, measuring the rate of decay of certain radioisotopes w/in the rock.
•1/2 life
–Time for 1/2 to decay into new


History
–fossils lined up by age show successive evolutionary change.
–Strongest evidence

Gaps in the Fossil Record
–Very complete w/ few gaps
–Among vertebrates
•fossils link all major groups
•Ex. Archaeopteryx, lungfish
Term
Vestigial Organs
Definition
–served a function in an ancestor
–no function now
–evidence for evolution
•Ex. appendix
•Dew claw on dogs
•Dolphin and Whale hind legs
Term
The Molecular Record
Definition
Evolution is linked to changes in DNA

–organisms more distantly related have more genetic changes in DNA.
–English in: US, Austrailia, England
Term
Molecular Clocks
Definition
–longer ago the diverged, the differences in the nucleotide sequence
•cytochrome c gene
–(codes for a protein that plays a key role in oxidative metabolism).
–Change occurs at a constant rate; thus a clock
Term
Proteins Evolve at Different Rates
Definition
–Not all proteins evolve at the same rate.
–Cytochrome c and hemoglobin have changed at relatively constant rates, but other proteins, like the fibrinopeptides, evolve considerably faster
Term
Phylogenetic Trees
Definition
–relatedness of organisms
•Fossil
•Molecular evidence
•Both give similar results
Term
Phylogenetic Trees
Definition
–relatedness of organisms
•Fossil
•Molecular evidence
•Both give similar results
Term
Anatomical Record
Definition
Development
–Many go through the same stages of embryologic development
–Evidence for evolution
–Debated during Darwin’s ti
Term
Sharing Parts
Definition
–Homologous Structures
•similar structure
•Dif. function
•Divergent Evolution

–Vert forelimbs
•diverged to perform different functions
•consist of the same bone structure
•indicates common ancestry
Term
–Analogous Structures
Definition
• Same function
• Different lineage
•Convergent Evolution
–similar structures in animals
–same solution to a problem
–NO common ancestor.
•Ex. Icthyosaur, dolphin, & shark;
•crocodile vs phytosaurs
-Semi-aquatic predator niche
•Marsupial vs placentals
Term
The Hardy-Weinberg Principle
Species
Definition
–A group of interbreeding populations, reproductively isolated from other populations.
•Horse & Donkey = Mule?
Term
The Hardy-Weinberg Principle
Population
Definition
–members of species that occupy the same geographical region
Term
The Hardy-Weinberg Principle
Population genetics
Definition
–The study of the properties of genes in populations.
Term
Genes Within Populations
Definition
–The proportion of alternative forms of a gene (alleles) in a population can be calculated and the allele frequencies determined
Term
Alleles
Definition
–Alternate forms of a gene
Term
Allele Frequencies
Definition
–The proportion of alleles of a given gene
–Ex. # of blue eyes vs # of brown eyes
Term
Hardy Weinberg Equilibrium
Definition
•Dominant alleles do not replace recessive ones
•The proportions stay the same!
•A population that is in Hardy-Weinberg equilibrium is not evolving.
•Assumptions
–Population size is infinite
–Mating is random
–No mutation
–No input of new copies of any allele from any extraneous source (such as
from a nearby population or from mutation).
–All alleles are replaced equally from generation to generation (natural selection is not occurring)
Term
Why Do Allele Frequencies Change
Definition
Change in the population
–Mutation, migration, genetic drift, nonrandom mating, selection

–Mutation
•alterations in DNA nucleotide sequences
•add new combinations to the genetic makeup of a population.

–Migration
•movement of individuals into or out of the population can be a source of new genetic variation.

–Genetic Drift
•In small populations, by random chance alone, it is possible for the allele frequencies to change from one generation to the next.
•As local subgroups are isolated from the main population, genetic drift occurs in them as well.

•The Founder Effect
–a few individuals are separated from the rest and give rise, over time, to a new population
–this effect often occurs on oceanic islands where a species may have descended form one or two founders.

•Bottleneck Effect
–a few members of a population of species are all that are left to give rise to the next generations of that species.
–limits the genetic diversity of a population and can lead to the appearance of recessive mutations.
–Cheetahs are all practically genetically identical and may have passed through a genetic bottle-neck.
–Nonrandom Mating
•Nonrandom mating and inbreeding (mating with relatives) also lead to changes in gene frequencies from one generation to the next.
–Inbreeding produces more homozygous individuals than predicted by the Hardy-Weinberg Rule.
•-Ex. Self fertilizing plants
•More likely to receive Homozygous defects!

–Selection
•Some individuals leave behind more progeny than others.
–Artificial Selection
•Breeder selects desirable traits
–Natural Selection
•Nature
•Operates to select certain fit phenotypes, which add more genes to successive generations.
Term
Forms of Selection
Definition
Selection changes the population when genotypes are favored.
Term
Stabilizing Selection
Definition
–individuals toward the middle of the range are selected.
•Ex. Humans born with intermediate birth wait have the the highest survival rates
Term
Directional Selection
Definition
–Directional selection favors a phenotype at one extreme or the other of the population.
•Ex. Phototropism in Drosophila
Term
Disruptive Selection
Definition
–both extremes are favored to the demise of the middle phenotype.
–less common than other types
Term
human gene therapy
Definition
Is a recombinant DNA procedure that seeks to treat disease by altering the genes of the afflicted person.
The mutant version of a gene is replaced with a properly functioning one.
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