Lecture 1 Genetics Flashcards
Lecture 1 Genetics
Explain William Harvey and the Theory of Epigenesis
NOTE: Genetics started with Harvey!
Structures such as body organs
- Are NOT initially present in the early embryo
- Are formed later
Explain the Theory of Preformation
The fertilized egg contains a complete miniature adult called a “HUMUNCULUS” meaning a tiny human
Explain Schleiden and Schwann: The Cell Theory (1830)
All organisms and every living being contains basic tiny structures called cells
What did Louis Pasteur do?
- Disproved Spontaneous Generation
- Spontaneous Generation: The creation of living organisms from nonliving components.
- Used a swan-necked flask which allowed air to enter but trapped airborne microorganisms in the neck, preventing them from contaminating a nutrient broth inside the flask
- This experiment saying Biogenesis is correct where pre-existing cells must exist.
1859: Darwin published his ideas on the theory of evolution in what?
What two main ideas are included in Darwin’s publication? Define the terms!
- The Origin of Species
- Descent w/ modification: Existing species arose from other ancestral species
- Natural selection: The mechanism for evolutionary change
The Theory of Evolution was independently proposed by Alfred Russel Wallace. Explain it briefly!
Essentially, we overproduced than was needed; then, selection pressure removed those without the best/necessary features to survive.
Modern Genetics is established as 1963 (DNA w/ Watson and Crick) - now.
However, what does it mean when we say “Reverse Genetics”?
Reverse Genetics: We know too much, such as the end products, so now we must work backward by knocking out genes to learn their functions.
In 1866, Mendel published his findings. He worked with peas and used quantitative data to support his ideas. Explain these ideas.
- Traits are passed from generation to generation.
- Transmission of genetic information from parents to offspring.
Mendel’s work forms the FOUNDATION of genetics. What does Genetics mean though?
Genetics: Defined as the branch of biology concerned with the study of heredity and variation
Mendel’s findings also showed what?
Showed VALIDITY! He observed, replicated results, and eventually introduced the word “Trait”
Define Mitosis. Occurs in what type of cells?
- Chromosomes are copied and distributed
- The two resulting daughter cells each receive a diploid set (2n)
- Occurs in SOMATIC cells (aka all cells)
Define Meiosis. Occurs in what type of cells?
- Chromosomes are copied and distributed
- Resulting cells (gametes) receive only half the number of chromosomes that are haploid (n)
- Occurs in Germ-line cells
Easy Q: What does n stand for?
Gene Dosage
Most Eukaryotes have a characteristic number of chromosomes called?
Diploid number (2n)
Chromosomes in diploid cells exist in pairs called?
Homologous chromosomes
Explain the Chromosomal Theory of Inheritance
- Inherited traits are controlled by genes residing on chromosomes
- Genes are transmitted through gametes that maintain genetic continuity from generation to generation
- NOTE: In heredity, EVERYTHING is inherited, but there is variability such as with alleles. Loci and centromere locations in normal cells remain the same.
Explain how many chromosomes are found in men and women such as in the human karyotype.
All 22 chromosomes in men and women are the same, excluding the 23rd chromosome, which is XX in females and XY in males
Define Alleles
- Mutations produce alleles of a gene
- The source of genetic variation
- SAME gene, DIFFERENT product
Define Genotype
The set of alleles for a given trait
Define Phenotype
- Expression of the genotype
- Produces an observable trait or phenotype
Expression = _____ + ______
Transcription + Translation
What is the Central Dogma? What is the ONLY exception?
DNA –> RNA –> PROTEIN
- Retrovirus!
DNA is the carrier of what?
Genetic Information
Research of Avery, MacLeod, and McCarty (1944) published experiments showing what?
DNA was the carrier of genetic information in bacteria