Karyotypes

A stain of DNA to visualize it's structure and centromere binding points during reproduction.

Mutant

Rare genes.

Wild Type Normal Genes

Most common.

Homology Homologous Genes

Shared ancestry

Melanosoma

Organelle that stores melanin pigment.

Prokaryote

No nucleus

Arabidopsis Wild Mustard

Food science

E-Coli Bacteria

Pathogenicity

C Elegans Nematode

Development

Saccaromyces Cervisae Baker's Yeast

Biochemistry of cells

Mus musculus House Mouse

Learning/memory

• Don't have histones on DNA
• Relatively small amount of DNA
• dsDNA circular genome with plasmids.
• Plasmids are genes found on smaller, mobile, circles of DNA

Cell Reproduction

Copy, separate, divide

Prokaryotes replicate by binary fission.

• dsDNA linear exists inside cell nucleus.
• dsDNA has histone proteins to form nucleosomes.
• nucleosomes are tightly packed into chromatin.

Nucleosomes

Beads on a string.

Chromatin

Collection of nucleosomes.

Centromere

Holds sister chromatids together.

Division

M Mitosis

Nuclear Division,

Prophase

Anaphase

Metaphase

Telophase

Cytokinesis

Cytoplasm Divides

Interphase

• G0 - cell at rest

G1

Growth, prepares for DNA synthesis.

S Synthesis

Genome replicates

DNA replication

G2

Growth for mitosis

Tumor

Unregulated Cell Cycle

Tumor Suppressor Proteins

Slow down the cell cycle.

Kinase

Add phosphates.

Phosphatase

Removes phosphates.

Three Major Checkpoints

G1/S Checkpoint Restriction Point

The point of no return.

• After this point, the cell will replicate or die.

Regulated by the Rb and p53 tumor-suppressor proteins.

Is the cell cycle ready to start?

Rb protein is regulated by phosphorylation.

• Rb = no-go.

• Rb-P = proceed.

G2/M Checkpoint

Regulated by the Cyclin-B-CDK protein (MPF).

Has the DNA been replicated?

Are chromosomes ready to divide?

M-Phase Spindle Checkpoint

Regulated by the MAD proteins.

Are the centromeres attached to the spindle fibers?

• Chromosome, locus, gene, allele, mutants of genes
  • Alleles are variants of a gene.
  • Locus are stable locations for identifying alleles.
  • Chromosomes are bundles of linear dna stored tightly together for stability.
  • Genes are regions of DNA that code for proteins.
  • Mutants are rare variants of genes.
• Genome, karyotype, idiogram, banding, centromere position (names)
  • Genome is the sum of genetic material for an organism.
  • Karyotypes are a staining visualization of DNA to identify replication abnormalities.
  • Idiograms are a visual representation of chromosomal morphology.
  • Banding is a staining technique that allows visualization of structural abnormalities.
  • Telocentric, Acrocentric, Submetacentric, Metacentric.
• Prokaryote, eukaryote
  • Prokaryotes have ds circular DNA, plasmids, no histones, no nucleus, replicate by binary fission.
  • Eukaryotes have dn linear DNA, chromosomes, cell nucleus, use the cell cycle, large amounts of DNA
• Sister chromatids — note these are "identical copies" and chromatid is not "chromosome"
• Telomere, centromere, kinetochore, tubulin
• Diploid, haploid, 2n, 1n, gamete cell, somatic cell
• Heterozygote, homozygote, dominant, recessive
• P-MAT or PpMAT, meiosis-I, meiosis-II
• Prophase, Prometaphase, Metaphase, Anaphase, Telophase,. Cytokinesis

1. What are the three traditional disciplines in the study of Genetics?
2. Name 3 model organisms used in Genetics, and what type of biology are they used to model (see textbook appendix)!
   • Drosophilia (fruit flies) can model alzheimers and diabetes.
   • C. elegans can model parkinsons and diabetes.
   • Ants can model evolutionary genetics through the homologous HOX genes.
3. Name 3 differences in the DNA of prokaryotes v. eukaryote cells.
   • Prokaryotic DNA is a double stranded circle, don't have histones, have plasmids.
   • Prokaryotic DNA exists in the cytoplasm. Eukaryotic DNA exists in a protected nucleus.
4. Why is DNA packing so important in eukaryotes?
   • Because we have such a large amount of DNA in our cells that we need to compress it for it all to fit.
5. What cells go through the Cell Cycle (Eukaryotes or Prokaryotes?)
   • Eukaryotes go through the cell cycle, but not the mitochondria or chloroplasts.
6. What does homologous mean when we talk about genes - how do we determine if genes are homologous - what do we need to compare?
   • Homologous means the genes are derived from a shared ancestry, I assume we look at the locus of a gene.
7. What is the normal time it takes for a cell to complete one cell cycle? Is there a universal 'normal' time?
   • There is not a universal normal time. Depending on the organism, it varies, within or exceeding the range of 8 min to 1 year.
8. What is the name of the stage of the cell cycle that deals specifically with nuclear division in growing cell populations?
   • Telophase in the M phase of the cell cycle.

8. List the 3 stages of interphase and the major events that take place in each stage.
   • G1 grows for DNA replication, S synthesizes duplicate DNA, G2 grows for cellular division.
9. What is the "resting" (quiescent) stage? Name examples of cells, or biological structures, that have exited the cell cycle, but are not dead?
   • G0 is the resting phase. Nerve cells do not replicate and stay in their resting phase.
10. Know the stages of the Cell cycle (G1, S, G2, M and G0)
11. What are the major cell cycle check points? What do they "check", when do they happen? G1/S checkpoint is the point of no return, ready to start?. G2/M checkpoint verifies DNA replication. Spindle checkpoint verifies spindle attachment.
12. What is cytokinesis, explain the differences in cytokinesis, animals v. plants.
13. What happens at the Restriction Point in the cell cycle? What proteins are involved in the transition between G1/S?
    • Past the point of no return, the cell will either replicate or undergo apoptosis. Rb and the p53 tumor suppressing proteins are involved.
14. Know what the chromosomes look like in G1, G2, and the phases of PMAT of Mitosis: are they replicated or not? Are they unpacked like a mess of spaghetti, and when are they compacted into little "X" shapes? Is that shape a G1 or G2/M chromosome?
15. Know the essential structural elements of eukaryotic chromosome: (what is a CEN, kinetochore, what is a CEN)?
16. Know the three ways you can identify chromosomes in a karyotype.
17. What are microtubules made of? Why do they interact with the CENs, what function do they serve?
18. In what sub-phase of Mitosis (M-phase) are the microtubules growing? In what sub-phase are they shrinking.
19. Explain how Rb, CDK kinase, cyclin function to determine whether a cell divides. What does Rb stand for, and what happens in the disease?
    • Rb blocks the cell cycle from proceeding unless a kinase adds a phosphate to it. When Rb is phosphorylated, it allows the cell cycle to proceed.
20. What is cancer? Does it usually arise from a single mutation? What a Tumor Suppressor?
    • Tumor suppressor proteins halt the cell cycle. Cancer usually involves multiple mutations, affecting multiple tumor suppressing proteins.
21. What are "beads on a string" - what are the "beads" what is the string?
    • Beads on a string refers to dna wrapping twice around chromatin.
22. What are nucleosomes made of?
23. By what factor does DNA get packed, in order to fit into a nucleus?
    • 10,000 to 1