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
Describe the structure of DNA
- Antiparallel
- Double-stranded helix
Made of nucleotides - “Steps”=bases with H bonds
- “Rail/Backbone” = Sugar + Phosphate
Describe the monomer of DNA
- Nucleotide consisting of a sugar (deoxyribose)
- Bonded to a phosphate
- Also, bonded to the bases adenine, cytosine, guanine, and thymine
Compare Nucleotides and Nucleosides
Nucleotides: Sugar + Base + Phosphate
Nucleosides: Sugar + Base (NO phosphate = NOT energized!)
Where does Chargaff’s Law come into play with DNA?
- Nucleotides form A-T and G-C in equal amounts
- AKA, complementary base pairing across the helix
How is RNA different from DNA?
- Usually single-stranded
- It has uracil (U) in place of thymine (T)
- The sugar in RNA nucleotides is ribose instead of deoxyribose
Explain to which carbon the sugar is attached. What about the phosphate?
LOOK AT NOTES FOR DIAGRAMS + TEMPLATE STUFF
- Carbon 1 = Sugar attached
- Carbon 5 = Phosphate attached
All Polymerases synthesize from what end?
From 5’ end to 3’ end
Define codons.
- Triplet nucleotides present in mRNA
- The genetic code
- Each triplet encodes for insertion of a specific amino acid into a growing protein chain
What does each triplet encode for?
Insertion of a specific amino acid into a growing protein chain
Define Proteins
- End product of gene expression
- Protein activation or location in a cell produces phenotype(s)
- Diversity of proteins are from 20 different amino acids
T/F: Enzymes are proteins
TRUE!
Provide examples of Structural and Enzymatic/Functional Proteins
- Structural: Actin and Microtubules
- Enzymatic/Functional Proteins: Biological catalysts
Explain how Sickle-Cell Anemia is caused. Also, what type of therapy exists for it to correct the incorrect base?
- Caused by a mutant form of hemoglobin
- Hemoglobin: The protein that transports oxygen from the lungs to cells in the body
- There is a single-nucleotide change (MISSENSE MUTATION) leading to an altered mRNA codon and the insertion of a different amino acid
- Specifically, Glutamic Acid is changed to Valine in the Beta-Globin
- CRISPR-CAS therapy
Genetic Diseases = _____
Ex.) If I smoke and get lung cancer is this a genetic disorder?
- Inherited/ Heredity
- NO! My parents did not have it, so no familiar ties
Define Restriction Enzymes (1970s) and what they allowed the advent of
- Restriction enzymes in bacteria CUT viral DNA at specific cites.
- Allowed the advent of Recombinant DNA and cloning EX.) Dolly the Sheep
Define Biotechnology
Using biology concepts to produce something typically using DNA, RNA, or Proteins
Provide places where Biotechnology is now used
- Health Care
- Supermarket Products
- Agriculture
- Court System (Paternity and Forensics)
Biotechnology has now been used for the genetic modification of crop plants for what 3 things
- Increased herbicide, insect, and viral resistance
- Nutritional Enhancement (Vitamin B3 rice or Golden Rice)
- Water use reduction
Thinking Question: How can we SAFELY use this Biotechnology?
We are quick to judge, but you MUST analyze the COST-BENEFIT ratio
Define Genomics
- Study of ALL things genes
- Studies the structure, function, and evolution of genes and genomes
Define Proteomics
- Identifies a set of proteins present in cells under a given set of conditions
- Studies their functions and interactions
Define Bioinformatics
- Uses hardware and software for processing nucleotide and protein data
What does L.U.C.A stand for? What does this mean?
- Last Universal Common Ancestor
- All life has a common origin
- Genes with similar functions in different organisms are similar in structure and in DNA sequence
What is Classical or Forward Genetics?
Identifying the genes that caused mutant phenotypes
What is Reverse Genetics?
DNA sequence of a particular gene of interest (GOI) is known, but its function is not
Define Gene Knockout
Allows scientists to render genes nonfunctional to investigate the possible role of that gene
Model organisms for genetic study meet these criteria. List all 4!
- Easy to Grow
- Short Life Cycle
- Produce many offspring
- Genetic analysis is straightforward
Understand which organism is used to study human diseases
- E. coli
- S. cerevisiae
- D. melanogaster (Fruit Fly)
- C. elegans (Nematode)
- D. rerio (Zebrafish)
- M. musculus (mouse)
- E. coli: Colon Cancer and other cancers
- S. cerevisiae: Cancer, Werner syndrome
- D. melanogaster (Fruit Fly): Disorders of the nervous system, cancer
- C. elegans (Nematode): Diabetes
- D. rerio (Zebrafish): Cardiovascular disease
- M. musculus (mouse): Lesch-Nyhan disease, cystic fibrosis, fragile-X syndrome, and many other diseases
What are some of the Modern Model Organisms
- Viruses: T phages and Lambda phages
- Bacteria: E. coli
- Yeast: S. cerevisiae
- Gram (+): Bacillus subtilis
- Plants: Arabidopsis thaliana (watercress)
Future of Genetics: Society is faced with a host of sensitive genetics-related issues including these 3 examples:
- Prenatal Testing
- Ownership of Genes
- Access to/safety of gene therapy
