Unit 5 - Genetics & Biotechnology Study Guide Flashcards
Explain the Meiosis Cycle
Interphase - Cell grows, DNA replication
Prophase I - DNA coils into Chromosomes, homolougous chromosomes cross-over, Centrosomes move to poles and spindle fibers form
Metaphase I - Chromosomes line up at Metaphase plate and attach to spindle fibers
Anaphase I - Spindle fibers pull chromosomes to centromeres
Telophase I - Nuclear membrane forms, chromosomes uncoil, and cytokinesis forms two cells
Prophase II - DNA coils in chromosomes, centrosomes move to poles and spindle fibers form
Metaphase II - Chromosomes line up at Metaphase plate and attack to spindle fibers
Anaphase II - Spindle fibers pull chromatids to centromeres
Telophase II - Nuclear membrane forms, chromosomes uncoil, and cytokinesis forms two cells
Gregor Mendel
Austrian monk who studied pea plants to see how traits passed. Used:
- Controlled pollination - used a paint brush to control which 2 plants reproduced
- Cross pollination - plants usually self pollinate = they have male and female parts
→Stated that certain “factors” called genes, control traits of the pea plant
Principle of Segregation
when producing sex cells, each sex cell gets 1 of 2 alleles for a trait (ex. Rr; sex cell either gets R or r)
Principle of Independent Assortment
genes for different traits seperate independently from each other
(ex. Rr and Yy seperate into R, r, Y, and y; can combine 4 different ways)
Polygenic traits vs. multiple allelic traits vs. sex-linked traits (with examples)
Polygenic Traits - Traits with large variety controlled by genes located on multiple chromosomes (ex. eye color, hair color, skin color, human height)
Multiple Allelic Traits - traits controlled by 2 alleles; 3+ versions of trait results (ex. human blood types A, B, AB, O)
Sex-Linked Traits - traits controlled by the sex chromosomes (colorblindness, hair ears, hemophilia)
DNA Fingerprinting notes
Use: Paternity determination determine crime suspects body identification
- only identical twins have same DNA sequences
- can make more copies of DNA using PCR (Polymerase chain reaction) so that the original DNA is not damaged or destroyed
Causes + Symptoms of Sickle Cell Anemia, Cystic Fibrosis & Huntington’s
Sickle Cell Anemia
Cause: both incomplete and codominance = abnormal + normal shaped red blood cells
Symptoms: clogged blood cells
Cystic Fibrosis
Cause: recessive genetic disorder
Symptoms: mucus buildup in lungs
Huntington’s:
Cause: dominant gene disorder
Symptoms: slow death of brain cells, coordination issues; fidgety movements
Recombinant DNA (rDNA)
DNA made by connecting, or recombining, fragments of DNA from different sources
Charles Drew
Black physician who established blood banks at Colombia University- seperating blood cells from plasma allowing blood to be stored, longer up to a week.
Steps of Gel Electrophoresis
1. Restriction Enzymes: one or several restriction enzymes are added to a sample of DNA. The enzymes cut the DNA into fragments.
2. The gel: gel is molded so that small wells form at one end. Small amounts of the fragmented DNA are placed into these wells.
3. Electric Field: Gel is placed in a solution and an electric field is applied making one end of the gel positive and other end negative.
4. Fragments move: Negatively charged DNA fragements travel toward the positive end; smaller the fragment, the faster it moves through the gel and away from the well
Gene Splicing
splice in new desirable genetic information that gets passed onto offspring
Benefits of rDNA
1 - insulin produced by E. Coli bacteria
2 - used for anti-viral drug protection
3 - vaccine protection
4 - alter plants to resist cold, drought, etc…
Therapeutic Cloning vs Reproductive Cloning
Therapeutic Cloning: Produces stem cells for tissues
Reproductive Cloning: Produces whole organism
Types of Cloning
- Vegatative propogation - a sexual reproduction without variation
- Grafting - tissues of plants are joined to grow together
- Whole organism - exact copy of organism
Primary problem in bacterial transformation
Both Plasmid DNA and plasma membranes of the E. coli bacteria contain phosphate groups so there both negatively charged (-) and repell each other. Researchers use calcium chloride to neutralize the negative charges.
Types of Plant + Animal Breeding
- Controlled breeding - breading organisms with certain traits to get desirable outcome (ex. larger tomatoe)
- Mass selection - crossing PLANTS with desirable traits for many generations until offspring show traits consistently
-
Cross Breeding/inbreeding - breeding closely related organisms (ex. purebread dog)
- increases strengths of certain traits
- certain diseases with inbreeding
- inability to adapt to environmental changes
- Hybridization - 2 genetically different organisms are crossed resulting in hybrids that have charateristics of both; usually healthier (ex. donkey + horse = sterile mule)
What is the Human Genome Project? How do we use it today?
Project started in 1990 to sequence the 3 billion base pairs of human DNA (finished in 2001) and to map our 20,000 genes (still ongoing)
Uses:
- Prenatal diagnosis of genetic disorders
- genotherapy
- develop new techniques in crime scene investigation
Chromosome Theory
1882 - Walther Flemming discovered dark thread-like objects in the nucleus with a compound light microscope.
1902 - Walter Sutton saw chromosomes seperate during mitosis.
→Stated that genes are sections of chromosomes that control specific characteristics or traits
What are the 4 human blood types?
Human blood types: A, B, AB, O
A and B are both dominant while O is recessive, making AB codominant.
What are GMO’s? What is the benefit of genetically modifying organisms?
GMO - Genetically Modified Organism
Benefits:
- Use less fertilizer/pesticides
- Better nutritional value
- Climate, disease, & pest resistance
Polyploidy
two or more complete sets of chromosomes to get desired trats
How does probability relate to genetics?
Probability determines the likelihood the offspring will get certain traits (ex. Genes R or r = 1/2 chance from each parent); shown in Punnet squares
Differentiate between asexual and sexual reproduction
Asexual Reproduction: 1 parent ÷ into 2 identical cells (ex. Mitosis, Bacteria, Budding)
Sexual Reproduction: Offspring produced through meiosis or when egg and sperm join
- Genetically different from parents because of NEW combination of genes
- Variations allow organisms to adapt to environment faster
Mitosis vs. Budding vs. Binary Fission
Mitosis: 1 body cell ÷ into 2 body cells
Budding: New offspring made from parts of the parent body; in plants
Binary Fission: “Mitosis” in prokaryotes like bacteria
Define karyotype and explain how amniocentesis is involved in the making of it.
Karyotype - picture of cells chromosomes lined up neatly for anaylsis
→In amniocentesis, a small amount of amniotic fluid surrounding the baby is removed. This amniotic fluid is used to create a Karyotype to detect birth defects BEFORE birth.
Results of meiosis in males vs. females
Male: Produces 4 identical spermatid cells that all develop into sperm
Female: Produces 4 polar bodies and 1 develops into an egg cell
Diploid or Haploid before meiosis I, created by Meisos I, and created by meiosis II.
Before Meiosis I: Diploid
After Meiosis I: Haploid
After Meiosis II: Haploid
Why is meiosis considered to be a form of “sexual reproduction”?
Meiosis produces sex cells that are genetically different than there parent
Dominant vs recessive alleles
Dominant: stronger allele; overshadows recessive
Recessive: weaker allele; sometimes hidden
How do we designate Dominant vs. Recessive alleles?
Dominant = uppercase
Recessive = lowercase
Homozygous/pure genotype vs. Heterozygous/hybrid genotype
Homozygous: 2 of the same allele (ex. RR, rr)
Heterozygous: 2 different alleles (ex. Rr)
Phenotype vs. Genotype
Phenotype: Physical description of trait (ex. blue eyes, brown hair)
Genotype: Genetic description of trait (ex. RR, Rr, rr)
Principle of Dominance
when the dominant allele overshadows the recessive (ex. Bb = brown eyes)
2 exceptions to the Principle of Dominance
1) Incomplete Dominance: neither gene is dominant; results in blending of two traits (ex. red + white = pink)
2) Codominance: equally dominant; results in both traits being shown (ex. red + white = spotted)
If a heterozygous parent crossed with a homozygous recessive parent (brown/blues example)…
What is the phenotypic percentage and ration? What is the genotypic percentage and ratio?
Heterozygous parent - Rr
Homozygous recessive parent - rr
Phenotype: 50% brown eyes, 50% blue eyes; 1/2 brown eyes, 1/2 blue eyes
Genotype: 50% Rr, 50% rr; 1/2 Rr, 1/2 rr
Autosomes vs. sex chromosomes
Autosomes - chromsomes that DON’T determine gender
Sex Chromsomes - chromsomes that DO determine gender
Pedigree symbols
Pedigree - Chart used to trace family genetics and show normal, carrier, and affected offspring
□ / ◯ = normal
◨ / ◑= carrier
■ / ● = affected
Which genotypes produce the various human blood types?
Alleles:
A → AA, AO
B → BB, BO
AB → AB
O → OO
Gene therapy
Replacing “bad” genes with “good” genes to cure disease
Universal Blood Type
O- (i RH-)
