Biology 101: Unit 5 First few days: Cell Cycle, Asexual vs Sexual Reproduction, Chromosome Number THE ANSWER TO YOUR QUESTION IS: YES!
Mar 31, 2015
Biology 101: Unit 5
First few days: Cell Cycle, Asexual vs Sexual Reproduction, Chromosome Number
THE ANSWER TO YOUR QUESTION IS: YES!
GENETICS II:
• Cell Cycle• Asexual vs Sexual Reproduction• Meiosis (friday)• Mon- finish meiosis- Reebops Lab• DNA Mutations• Genetics Disorders
IMPORTANT DATES TO KNOW:
• Benchmark: USA TEST PREP: Thurs 10/17
• MIDTERM: 10/18: will include all information up to this point on this test
Getting Started…
• If you were the prosecutor in this criminal case, who would you want arrested? Why?
• What is the DNA Technology that is used in this situation called?
How does cell division differ in uni and multicellular organisms?
• Unicellular: reproduce by binary fission, budding, fragmentation= asexual reproduction
• Multicellular: involves the production of sex cells
Compare internal/external fertilization
• Fertilization- joining of sex cells• External fertilization- gametes are
released into the environment• Internal fertilization- sperm are deposited
inside female’s body
What are chromosomes?• Carriers of genetic
material found in nucleus
• Made up of DNA
What is involved in Chromosome structure?
• Chromosomes are made up of two chromatids which are held together with a centromere
• Human chromosome number is 46 in body cells; 23 in sex cells
Compare haploid/diploid number
• Haploid number- (n) “half-number” typically found in gametes only
• Diploid number- (2n) “double-number” found in somatic cells (body cells)
How is gender determined in humans?
• Females have XX as last set of chromosomes (sex chromosomes)
• All eggs are X
• Males have XY as last set of chromosomes• Half of sperm are X sperm; half are Y
sperm• Males determine gender of offspring
Activity:
• Chromosome Worksheet: Chromosome Number practice
What is the cell cycle?
• Sequence of growth and division in the cell
1. Interphase is the growth period where replication occurs
2. Mitosis
What is mitosis?
• division of cells producing two cells with the same number of chromosomes
• Ex: 46 chromosomes in human body cells, so ALL body cells should have 46
What is involved in Prophase?• Chromatin (normal
form of DNA) coils into chromosomes
• The nucleus disappears
• Centrioles form and move to opposite poles of cell
• Spindle fibers form from centrioles and begins to cross cell
What is involved in Metaphase?
• Chromosomes line up in the middle of the cell
• Spindle forms across the cell from centrioles
What is involved in Anaphase?
• Spindle fibers begin to shorten
• Chromosomes pulled apart
• Move to opposite poles
What is involved in Telophase?
• Chromosomes unwind into chromatin
• Spindle fibers break down
• Nucleolus and nuclei reform
• Plasma membrane begins to pinch in
What is Cytokinesis?• Division of cytoplasm• In animal cells: cell membrane
continues to pinch in until two cells are formed
• In plant cells: cell plate forms in center of cell and eventually splits cells
• At the end of mitosis, two new cells are produced; called “daughter” cells
Thurs: 10/10 Quick Quiz 11. Which part of the cell cycle involves the copying of the
DNA? a. interphase b. mitosis
2. What is the division of the cytoplasm called? a. cytolysis b. cytofission c. cytokinesis
A. Prophase B. Metaphase C. Anaphase D. Telophase
3. Which phase involves the splitting of the chromosomes?4. Which phase involves the chromosomes lining up in the
center of the cell?5. Which phase involves the formation of chromosomes?6. In which phase does a cell plate form in a plant cell?7. The nucleus begins to disappear and spindle fibers begin to
form across the cell?
Review of The Cell Cycle: Mitosis
• Chromosome Structure/Number• Gender• Interphase• Mitosis- P-M-A-T-Cyto• Review Mitosis and Cancer Reading
Activity 1: Cell Cycle
• Using supplies available in class, create a Cell Cycle Flipbook:
MUST INCLUDE:
1) ALL steps of the cell cycle: Interphase-Cytokinesis
2) Show LABELED diagrams and a description of what is happening in each stage
Activity 2: Mitosis Lab
• Onion Root Tip Lab
1) Complete lab in lab area;
2) Use caution with microscope slides and the microscope
Asexual vs. Sexual Repoduction• Asexual Reproduction
– No sperm or egg are used– Newly produced cells are
genetically identical to parent cell- clones
– If it occurs in… • human body cells (like the
skin)- called mitosis• single-celled organisms like
bacteria or protists- called binary fission
• simple animals (like sponge)- called budding
• Sexual Reproduction– Sperm and egg are
produced & fused– Newly produced cells are
genetically different from each other and the parent cell.
– This creates genetic diversity
– If it occurs in• human body cells- called
meiosis• Single-celled organisms like
bacteria or protists- called conjugation.
Homework: Thurs 10/10
HW: Why Sex is Good Case Study- ALL
**If needed: Mitosis matching WS for practice with stages