1. Chapter 12. The Cell Cycle A PPT by Mrs
Chapter 12 The Cell Cycle A PPT by Mrs. Morton at Buffalo Acadamy of the Sacred Heart and Andrea Wise of Providence HS

2. Bacterial Cells
Binary Fission
Circular DNA replicates
Cell divides

3. The Cell Cycle Interphase (90% of cycle) Mitotic phase
• G1 phase growth
• S phase synthesis of DNA (Replication)
• G2 phase preparation for cell division
Mitotic phase
• Mitosis nuclear division
• Cytokinesis cytoplasm division

4. Cell Division: Key Roles
Genome: cell’s genetic information
Somatic (body cells) cells
Gametes (reproductive cells): sperm and egg cells
Chromosomes: DNA molecules
Diploid (2n): 2 sets of chromosomes
Haploid (1n): 1 set of chromosomes
Chromatin: uncoiled DNA-protein complex
Chromatids: replicated strands of a chromosome
Centromere: narrowing “waist” of sister chromatids
Mitosis: nuclear division
Cytokinesis: cytoplasm division
Meiosis: gamete nuclear division

5. Chromosomes Chromosomes Contain genetic information. Made of DNA.
Numbers of chromosomes per cell
Humans--46 Total (23 from each parent)
Fruit fly- 8 total
Chicken--78
The # of chromosomes is not correlated with the complexity of the organism

6. MITOSIS Mitosis DEFINITION Division of the Cell’s Nucleus PURPOSE
To ensure that each daughter cell gets an exact copy of the chromosomes

7. Why cells must divide... Why Cells Must Divide
List 3 reasons why cells must divide.
1 Growth of organism
While each cell remains tiny
2 Repair
3 Reproduce
(Mitosis-Asexual, Meiosis Sexual)

8. Mitosis
Prophase
Metaphase
Anaphase
Telophase

9. Prophase Chromosomes visible Nucleoli disappear Sister chromatids
Mitotic spindle forms
Centrioles move to opposite poles

10. Metaphase Centrioles are at opposite poles Centromeres are aligned
Kinetochores of sister chromatids attached to microtubules (spindle)

11. Anaphase Paired centromeres separate; sister chromatids liberated
Chromosomes move to opposite poles
Each pole now has a complete set of chromosomes

12. Telophase Daughter nuclei form Nuclear envelopes arise
Chromatin becomes less coiled
Two new nuclei complete mitosis

15. Cytokinesis Cytoplasmic division Animals: cleavage furrow
Plants: cell plate

16. Cell Cycle regulation Cell cycle control system Checkpoints
Cyclin- cell division protein
Levels of cyclins rise and fall depending on the cycle and cellular conditions

17. Cell Cycle regulation Growth factors Density-dependent inhibition
Mitosis promoting factor (MPF)- a cyclin
Platelet Dervived GF
Grow blood vessels to new tissues
Density-dependent inhibition
Anchorage dependence

18. Cyclins Regulate Cell Cycle
MPF -Mitosis Promoting Factor
Contains the enzyme CDK- Cyclin- Dependent Kinase
Kinase transfers phosphate from ATP to protein (energizes a molecule needed for cell division).

19. Growth Factors G1 Checkpoint (G1/S): External Growth Factors
Platelet Derived GF (PDGF)- stimulates cell division near a wound
G2 Checkpoint (G2/ M)
Checks the DNA for damage
M -spindle checkpoint (before anaphase)
Checks for correct mitosis and that the spindle is correctly anchored to kinetichore

20. Cancer
Transformation of DNA
Tumor: benign or malignant
Metastasis

21. Cancer: breast cancer cell & mammogram

23. Cancer NIH Animations NIH Cancer Resources
Cancer is Caused by a Combination of Genetic Mutations
Proto-oncogene- Healthy cell division gene
Becomes oncogene- mutated form
Tumor Suppressor Gene
p53 is a well-known tumor suppressor gene

24. What phase is this? 24

25. What phase is this?

26. Telophase I and Cytokinesis
Figure 13.8a
MEIOSIS I
Telophase I and Cytokinesis
Prophase I
Metaphase I
Anaphase I
Centrosome (with centriole pair)
Sister chromatids remain attached
Sister chromatids
Chiasmata
Centromere (with kinetochore)
Spindle
Metaphase plate
Cleavage furrow
Homologous chromosomes separate
Homologous chromosomes
Fragments of nuclear envelope
Figure 13.8 Exploring: Meiosis in an Animal Cell
Microtubule attached to kinetochore
Each pair of homologous chromosomes separates.
Two haploid cells form; each chromosome still consists of two sister chromatids.
Duplicated homologous chromosomes (red and blue) pair and exchange segments; 2n  6 in this example.
Chromosomes line up by homologous pairs.
DRAW AND LABEL

27. Telophase II and Cytokinesis
Figure 13.8b
MEIOSIS II
Telophase II and Cytokinesis
Prophase II
Metaphase II
Anaphase II
During another round of cell division, the sister chromatids finally separate; four haploid daughter cells result, containing unduplicated chromosomes.
Sister chromatids separate
Haploid daughter cells forming
Figure 13.8 Exploring: Meiosis in an Animal Cell

28. Sister chromatids Diploid germ-line cell Chromosome duplication
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sister
chromatids
Diploid
germ-line
cell
Chromosome
duplication
Centromere
Synapsis:
homologues
closely
associated,
and crossing
over can
occur
Meiosis I
Meiosis II
Homologue
Haploid gametes
Homologue

29. Figure 13.9
MITOSIS
MEIOSIS
Parent cell
Chiasma
MEIOSIS I
Prophase
Prophase I
Chromosome duplication
Chromosome duplication
PAGE
256
Duplicated chromosome
Homologous chromosome pair
2n  6
Metaphase
Metaphase I
Anaphase Telophase
Anaphase I
Telophase I
Haploid n  3
Daughter cells of meiosis I 2n 2n
MEIOSIS II
Daughter cells of mitosis n n n n
Daughter cells of meiosis II
SUMMARY
Figure 13.9 A comparison of mitosis and meiosis in diploid cells.
Property
Mitosis
Meiosis
DNA replication
Occurs during interphase before mitosis begins
Occurs during interphase before meiosis I begins
Number of divisions
One, including prophase, metaphase, anaphase, and telophase
Two, each including prophase, metaphase, anaphase, and telophase
Synapsis of homologous chromosomes
Does not occur
Occurs during prophase I along with crossing over between nonsister chromatids; resulting chiasmata hold pairs together due to sister chromatid cohesion
Number of daughter cells and genetic composition
Two, each diploid (2n) and genetically identical to the parent cell
Four, each haploid (n), containing half as many chromosomes as the parent cell; genetically different from the parent cell and from each other
Role in the animal body
Enables multicellular adult to arise from zygote; produces cells for growth, repair, and, in some species, asexual reproduction
Produces gametes; reduces number of chromosomes by half and introduces genetic variability among the gametes

30. Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fig. 12.8(TE Art)

31. Fig. 12.9(TE Art)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Homologues do not pair; kinetochores of sister chromatids remain separate; microtubules attach to both
kinetochores on
opposite sides of the
centromere.
Chiasmata hold homologues together. The kinetochores of sister chromatids fuse and
function as one. Microtubules
can attach to only one side of
each centromere.
Meiosis I
Mitosis
Metaphase I
Metaphase
Chiasmata
Microtubules pull the
homologous chromosomes
apart, but sister
chromatids are
held together.
Microtubules pull sister
chromatids apart.
Anaphase I
Anaphase

32. Count cells in the zone of cell division

35. CROSSING OVER- RECOMBINATION FREQUENCY
KARYTYPE C C E e
CROSSING OVER- RECOMBINATION FREQUENCY

36. Fig. 13.32(TE Art) Five characters on X chromosome Wild type y
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fig (TE Art)
Five characters on
X chromosome
Wild type y
Yellow body color w
White eye color v
Vermilion eye color m
Miniature wing y w v m r r
Rudimentary wing
.01
.31
.34
.58

37. Human X chromosome Ichthyosis, X-linked
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Ichthyosis, X-linked
Placental steroid sulfatase deficiency
Kallmann syndrome
Chondrodysplasia punctata,
X-linked recessive
Hypophosphatemia
Aicardi syndrome
Hypomagnesemia, X-linked
Ocular albinism
Retinoschisis
Duchenne muscular dystrophy
Becker muscular dystrophy
Chronic granulomatous disease
Retinitis pigmentosa-3
Adrenal hypoplasia
Glycerol kinase deficiency
Norrie disease
Retinitis pigmentosa-2
Ornithine transcarbamylase
deficiency
Incontinentia pigmenti
Wiskott-Aldrich syndrome
Menkes syndrome
Androgen insensitivity
Sideroblastic anemia
Aarskog-Scott syndrome
PGK deficiency hemolytic anemia
Charcot-Marie-Tooth neuropathy
Choroideremia
Cleft palate, X-linked
Spastic paraplegia, X-linked,
uncomplicated
Deafness with stapes fixation
Anhidrotic ectodermal dysplasia
Agammaglobulinemia
Kennedy disease
PRPS-related gout
Pelizaeus-Merzbacher disease
Alport syndrome
Fabry disease
Lowe syndrome
Lesch-Nyhan syndrome
HPRT-related gout
Immunodeficiency, X-linked,
with hyper IgM
Lymphoproliferative syndrome
Hunter syndrome
Hemophilia B
Hemophilia A
G6PD deficiency: favism
Drug-sensitive anemia
Chronic hemolytic anemia
Manic-depressive illness, X-linked
Colorblindness, (several forms)
Dyskeratosis congenita
TKCR syndrome
Adrenoleukodystrophy
Adrenomyeloneuropathy
Emery-Dreifuss muscular dystrophy
Diabetes insipidus, renal
Myotubular myopathy, X-linked
Albinism-deafness syndrome
Fragile-X syndrome