1. Bellringer 10.15
1. Put the following phases of cell division in the correct order: anaphase telophase metaphase G2 G1 cytokinesis S prophase 2. Describe what occurs in each of the phases above.

2. Bellringer 4/29 Describe the phases of meiosis.
2. How does meiosis differ from mitosis?

3. G1  S  G2  P  M  A  T  Cytokinesis

4. Sexual Reproduction

5. Sexual reproduction Uses genetic information from more than one source
Offspring are different from parents (lots of variation because of genetic recombination)
May use gametes (sex cells)

6. Advantages Disadvantages
When an environment is changing an organism group (species) may be able to adapt because so much variation
Disadvantages
When an environment is stable, variation is not as necessary
Reproduction cannot occur as quickly as asexual

7. How are gametes made? ... MEIOSIS
Cell division that reduces the number of chromosomes in half
Makes haploid cells from diploid cells
Produces gametes (sperm and egg)

8. Interphase Period of cell growth and chromosome replication
Precedes meiosis

9. Steps of Meiosis Meiosis I Prophase I: 4 phases: P I, M I, A I, T I
Nucleolus and nuclear membrane fade, chromatin condenses and becomes chromosomes
Homologous chromosomes pair up (called synapsis).
Homologous chromosomes = chromosomes that have the same type of genes (one from each parent)

10. During synapsis, CROSSING OVER occurs
Homologous chromosomes cross over each other
Exchange of genetic information
Produces genetic recombination, which increases variations in offspring

12. RESULT: TWO haploid cells
Metaphase I:
Homologous chromosomes line up in center of the cell
Anaphase I:
Homologous chromosomes separate
Telophase I:
Nuclear membrane reforms
RESULT: TWO haploid cells

13. RESULT: FOUR haploid cells
Meiosis II:
Separates the copied chromosomes
4 phases: P II, M II, A II, T II
RESULT: FOUR haploid cells
PROPHASE II:
Nuclear membrane and nucleolus disappear, chromatin condenses into chromosomes, centrioles appear
METAPHASE II:
Chromosomes line up at center of cell
ANAPHASE II:
Centromeres break at center of chromosomes, chromosomes are divided into two chromatids; chromatids are pulled to opposite poles of cell
TELOPHASE II:
Nuclear membrane and nucleolus reappear, chromosomes uncoil into chromatin

14. Trait
Mitosis
Meiosis
Chromosome Number
Same (diploid)
Half (haploid)
Genetic Similarities
Same
Diverse
Type of Cell
Somatic cells (any cell other than sperm/egg)
Sex cells (egg & sperm)
Number of Divisions
1(one)
I and II (two)
Type of Reproduction
Asexual
Sexual
Role/Function
Produce cells for growth & repair
Produce sex cells

17. April 28, 2015 TO TURN IN!  Bellringer:
List the phases of mitosis in the correct order and describe what occurs in each phase.
Read section 10.2 (pg 263) in the blue Biology book.
Answer section questions 1-4 (pg 273)
Define the review and new vocabulary (pg 263)
TO TURN IN! 

18. Mendel’s Pea Plant Experiment Questions
If the round seed shape is dominant to the wrinkled seed shape, what would the genotype be of the parent plants in the P generation of the cross between pure round seeds vs pure wrinkled seeds? What are the possibilities of genotypes in the F1 generation? F2 generation?
Repeat #1 the green/yellow cross, purple/white cross, and the tall/short cross.
What is the ratio of:
Round : wrinkled
green : yellow
Purple : white
Tall : short