Download Study Guide Cell Division Honors

HONORS BIO
Ch. 8 Cell Division
Study Guide
8.1 Mitosis and Asexual Reproduction
a. Asexual reproduction – one parent cell, genetically identical daughter cells
- for growth, maintenance, repair, reproduction in simple organisms
1. prokaryotes – binary fission
2. eukaryotes – chromosomes organized and distributed equally
10.4 DNA Replication – helicase opens helix, polymerase joins free nucleotides
a. semi-conservative - original chains stay intact
- are templates for new strands  two identical molecules
8.6 The Process of Cell Division
A) Chromosomes = DNA + histone proteins, wrap to form nucleosomes
a. chromatin – in non-dividing cell
b. in dividing cell: copied DNA condenses into sister chromatids
B) The Cell Cycle
a. Interphase G1 S (DNA replicates) G2
b. M Phase mitosis – nucleus divides; cytokinesis - cytoplasm divides
1. prophase – cell prepares for cell division:
- spindle forms, centrioles – in centrosomes , organize spindle
- chromatin condenses to chromatids, joined at centromere
2. prometaphase – chromosomes condensed, attach to spindle
2. metaphase – chromosomes on metaphase plate
3. anaphase – sister chromatids go to opposite poles
4. telophase – two new nuclei form, chromosomes unpack
c. Cytokinesis – cleavage furrow in animal cells; cell plate in plants
8.7 Cell Differentiation – stem cells, multipotent, totipotent
Asexual Reproduction – simple animals: budding, regeneration
Plants: runners, bulbs, cuttings, grafts
8.8 Cell Cycle Control systems – chemical signals, cyclins, growth factors
A) checkpoints, anchorage, density-dependent (contact) inhibition
B) Rate of division – some tissues often, others rarely; uncontrolled (cancer)
8.10 Cancer - uncontrolled growth, benign tumors, malignant, metastatic, melanoma
8.12 Meiosis and Sexual Reproduction
Two parents – each gives genes  new gene combination in offspring
A) Diploid and haploid cells
a. Diploid – two sets of chromosomes (2n) –one set from each parent
i. In somatic (body) cells
b. Haploid – one set of chromosomes (n)
i. In sex cells, gametes – egg and sperm
B) Meiosis – two cell divisions, reduces chromosome number by half 2n  n
a. Interphase - DNA replicates
b. Meiosis I – divides homologous pairs of chromosomes
i. Prophase I – pairs match up (synapsis), form tetrads
a. Crossing over – homologous chromatids exchange pieces
b. Increases genetic variation
ii. Metaphase I – pairs line up on equator
iii. Anaphase I – pairs separate (disjunction)
iv. Telophase I – two haploid nuclei form; cytokinesis
c. Meiosis II – sister chromatids separate; cytokinesis again
 four haploid daughter cells
8.14 Independent Assortment – random tetrad arrangement in metaphase I
- increases genetic variation
27.4 Making Sperm and Egg - 2n parent cell  four haploid sperm
a. 2n parent cell  one haploid ovum + 3 polar bodies (die)
A) Fertilization: genetic recombination
a. egg + sperm  zygote n + n  2n
14.2 Problems in Meiosis
A) nondisjunction – pairs or chromatids do not separate correctly
- wrong number (aneuploidy) in daughter cells
a) trisomy – three copies of one chromosome; monosomy – one copy
- Down’s Syndrome is trisomy #21
b) nondisjunction of sex chromosomes: Klinefelter XXY, Turner XO
B) Chromosome mutations – pieces lost, added, misplaced
a) addition, deletion, inversion, translocation
C) Karyotype – picture of paired, sized chromosomes
a) autosomes – numbers 1-22
b) sex chromosomes – X and Y