BME 80H Exam 1
Terms in this set (58)
All parts of the body, particularly the brain, produce substances "humors" that get collected together to provide the material for heredity. Humors from the male and female were blended to produce the offspring.
Argued against Hippocrates.
-traits sometimes skip a generation
-lost limbs in adulthood are not inherited.
HOMUNCULUS = tiny preform child
BUT!! Offspring has traits of both parents
Formulated "Doctrine of Inheritance of Acquired Characteristics"
-traits acquired in the adult are passed to the next generation
-humor-like substances = genmules
Showed that traits are not inherited by cutting off the tails of mice (20 generations of mice)
Laid to rest the "Doctrine of Inheritance of Acquired Characteristics
Significance of Mendel's findings
His experiments with pea plants revealed how a trait is passed through the inheritance of "factors" now known to be genes.
Definition of species
variants that, when crossed, produce a fertile offspring
John Fredrich Miescher
isolated DNA from white blood cells in human pus. Discovered NUCLEIC ACID
Flemming and Strasburger
-describes the separation of chromosomes to daughter cells
Proposed Chromosome Theory
-"Mendel's 'factors' are located on chromosomes
T.H. Morgan and Sturtevant
Proved genes are carried on chromosomes in a specific order.
Beadle and Tatum
"one gene, one enzyme" Each gene produces a particular substance.
Showed that DNA stores genetic information.
Identified "jumping genes" that can change their location on chromosomes= transposons
discovers the molecular basis of sickle cell anemia. Started Human Molecular Genetics.
X-ray diffraction images of DNA provide valuable information and DNA structure.
Watson and Crick
(1953) Discover the structure of DNA
Crick and Gamov
(1957) Propose the "Central Dogma of Molecular Biology" explains how genes in DNA get made into proteins.
Meselson and Stahl
(1957) describe the mechanism of DNA repliction
(1961) work on "cracking the genetic code"
(1972) Isolated restriction enzyme and utilized it with an enzyme called ligase, made first recombinant DNA
Cohen and Boyer
(1974) express a foreign gene in bacteria, shows that a segment of DNA can be reproduced in bacteria.
Meeting of Molecular Biologists at Asilomar
(1975) Focused on the containment of recombinant organisms in the lab.
What are Eugenics?
Science of improving a human population by controlled breeding to increase the occurrence of desirable heritable characteristics
Social policies affected by Eugenics
Buck v.s. Bell failed attempt to sue, lead to other states gaining the right to forcibly sterilize
What did Eugenics lead to?
A loss of genetic diversity, over 60,000 people sterilized in the United States
Scientific fallacies in Eugenics
Expression of traits, including behavior and intelligence are affected by genes.
Natural science teacher, grant for research rejected, performed experiments at the Monastery
Why were garden peas a good choice?
self fertilization and controlled crosses.
Significance of having true-breeding lines and how Mendel ensured he had these
-2 years spent making sure his pea lines bred true for a characteristic
-multiple rounds of self fertilization
How to determine if plants with the same phenotype are heterozygous or homozygous dominant
trace the lineage
Results and setup of Mendel's Monohybrid Cross
Mendel crossed a pure bred wrinkled and smooth pea plants to see which was dominant. All the peas were round, meaning round seeded peas were dominant.
Conclusions based on results of Mendel's Monohybrid Cross
-traits are inherited as distinct, unchanged units
Mendel's Law of Dominance
If 2 different genes are present only the dominant one will be expressed
Phenotype v.s. Genotype
Phenotype="form shown" (ex. color)
Genotype=genetic makeup (ex. Ss or SS or ss)
Nomenclature for designation of genotypes
Gene-3 letter designation (an abbreviation for the pathway or phenotype of mutants)
Allele number-each mutation in the pathway is consecutively
Mendel's Law of Segregation
Each parent carries a pair of factors and contributes one factor from this pair to the next generation.
Mendel's Law of Independent Assortment
Inheritance of one trait had has no effect on the inheritance of another one
Chromosome Therapy of Inheritance
genes are found at specific places on chromosomes (fruit fly eye color found on X chromosome)
-repeat sequence DNA
-location o genes
-made up of Heterochromatin
-one of two identical copies of a replicated chromosome
-made up of Heterochromatin
Cell cycle stages
1.Interphase= DNA Synthesis (replication)
2.Mitosis=division of the nucleus
3.Cytokinesis= cytoplasmic division (results in daughter cells)
Four phases of Mitosis
2.Metaphase: chromosomes line up single-file along a "metaphase plate"
3. Anaphase: sister chromatids seperate from each other and move towards opposite poles of the cell.
4.Telophase: chromosomes reach the poles of the cell (nuclear envelope reforms)
Meiosis v.s. Mitosis
Mitosis- produces 2 daughter cells (somatic)
Meiosis- Produces 4 daughter cells (gamete)
What are genes?
make up stretches of particular nucleotide sequence
What is the basis of most recessive alleles?
Both alleles are disrupted
How does meiosis reveal the biology behind Mendel's Law of Segregation and of Indep. Assortment?
Segregation-one member of each homologous pair of chromosomes, each with their genetic alleles, segregates into the gamete.
Indep. Assortment-orientation of each pair of homologous chromosomes has no effect on the pairing orientation of another pair of homologues
Where are linked genes?
close together on the same chromosome
Codominance and inheritance of blood type
Codominance=each allele is expressed equally in the phenotype.
lethal during development
probability that an individual will show a disease phenotype given that they have disease-related genotype.
Having more than one phenotypic effect.
One gene masks the phenotypic effects of another
Polygenic and Multifactorial Inheritance
Inheritance is influenced by environmental factors
determining the distance between linked genes (further apart the more likely they are to recombine)
Genes located on the X chromosome
Mitochondrial and maternal inheritance
mtDNA passed down maternally. Mutations can leave offspring effected with disease. Affects brain, heart, liver, and kidneys.
Thickened mucus in the airway. Lungs, airways, reproductive ducts degenerate over time.
Sickle Cell Anemia
RBCs form a sickled shape
Cured by bone marrow transplant