1. Chapter 10

2. Three stages of interphase:
Most cells spend most of its life in interphase: between mitotic divisions.
Three stages of interphase:
G1: metabolic activities
S: DNA synthesis
G2: protein synthesis needed for cell division
Mitosis: process of nuclear division that maintains chromosome number
Cells division produces two genetically identical daughter cells
Developmental processes (growth, repair and tissue remodeling)
Eukaryotic asexual reproduction (offspring are produced by one parent)

3. Human body cells are diploid (two of each chromosomes)
Homologous chromosomes: have the same length, shape, and genes
During the cell cycle chromosomes are duplicated
Replicated chromosome copies called sister chromatids
During mitosis, the sister chromatids are pulled apart
Each sister chromatid ends up in separate nuclei

5. Cell divison is controlled by genes
Inhibitors of the cell cycle normally keep cells in G1
“Checkpoint genes” monitor if a cell is ready for division

6. Metaphase: all chromosomes are aligned midway between spindle poles
Prophase
Chromosomes condense
Microtubules forming a spindle (functions to move chromosomes)
Nuclear envelope breaks up
Metaphase: all chromosomes are aligned midway between spindle poles
3. Anaphase: sister chromatids separate and move toward opposite spindle poles
4. Telophase: chromosomes decondense; two new nuclei form

8. In most eukaryotes, cytokinesis (cytoplasmic division) occurs between late anaphase and the end of telophase
Microtubules pull membrane towards the center
Animal cell cytokinesis: Cleavage furrow forms
Plant cell cytokinesis: Disk-shaped cell plate forms and partitions with two new cell walls

10. Telomeres are noncoding repeat DNA sequences found at the ends of eukaryotic chromosomes
Telomeres provide a buffer against the loss of more valuable internal DNA
Telomeres short with each replication
Checkpoint gene halt the cell cycle and if telomere are too short

11. Neoplasm: accumulation of abnormally dividing cells
Tumor: neoplasm that forms a lump
Oncogene: gene that helps transform a normal cell into a tumor cell
Proto-oncogenes: gene that, by mutation, can become an oncogene
Example: growth factors – molecules that stimulate mitosis and differentiation

12. Benign neoplasms such as warts are not usually dangerous
Multiple checkpoint genes mutations are required to form a malignant cell
Metastasis: process in which malignant cells spread from one part of the body to another

13. Chapter 11

14. Cells of eukaryotes normally contain pairs of homologous chromosomes (Diploid – 2n)
Homologous chromosomes carry genes of the same characteristics
Different forms of the same gene are called alleles

15. Sexual reproduction recombines the genes of two parents during fertilization.
Genetic diversity offers a better chance of surviving environmental change than clones
Meiosis: occurs in reproductive cells of eukaryotes
Gametes: cells that are the basis of sexual reproduction
All gametes (egg and sperm) are haploid (n).
Derive from diploid reproductive cells
Fertilization: two haploid gametes fuse - a zygote is formed
The diploid chromosome number is restored

16. Prophase I
Homologous chromosomes condense, pair up, and swap segments
Spindle attach to chromosomes; nuclear envelope breaks up
Metaphase I - homologous chromosome pairs are aligned midway between spindle poles
Anaphase I: The homologous chromosomes separate and begin heading toward the spindle poles
Telophase I: clusters of chromosomes reach the spindle poles; new nuclear envelope forms

18. Meiosis II is more like mitosis
Sister chromatids of the unpaired chromosomes separate during Anaphase II

19. Two events in meiosis introduce novel combinations of alleles into gametes:
Crossing over in prophase I
Segregation of chromosomes into gametes
Creates variation