1. The Cellular Basis of
Reproduction and Inheritance
CHAPTER 8

2. 8.1 Cell Division
___________ is a characteristic of life
 Organism level and cellular level
Cell division – production of 2 identical ‘________’
cells from ‘parent’ cell
Before division, cell needs to _________
chromosomes

3. 8.1 Cell Division
_________ reproduction –
creation of offspring by a single
parent
 Double chromosomes, etc. and split
 Genetically ___________
___________Reproduction –
creation of offspring by the fusion of
a sperm and egg
 Not genetically identical
 Production of sperm/egg involves special

4. 8.1 Cell Division
Cell Division
 _____________ reproduction
 Multicellular reproduction
 Sperm and egg __________
 Development into multicellular organism

5. 8.2 Prokaryote Reproduction
Prokaryotes
 Chromosome of ___________ DNA
 Plasma membrane
 Cell ________
Binary _________ - ‘dividing in half’
2 Identical daughter cells

6. 8.2 Prokaryote Reproduction

7. 8.3 Chromosomes Duplicate
In eukaryotes most genes found in _________
 Exceptions?
Most of the time chromosomes diffuse mass
 ___________ – DNA and protein
 Too thin to see under microscope
As a cell prepares to divide, mass ___________
down
 Distinct ______________

8. 8.3 Chromosomes Duplicate
Humans have _____ chromosomes
 2 copies of each, 1 from each parent
 Dogs have 78 (36 from each parent)
 Cats have 38 (19 from each parent)
Chromatin – thin, long fibers of DNA wound around
____________
 Proteins maintain ___________ and control activity of
genes

9. 8.3 Chromosomes Duplicate
Before division chromosomes
duplicate
Sister _________ – identical
copies joined at ___________
 92 chromatids
Cell __________
 Sister chromatids now called
chromosomes

10. 8.4 Multiplying Cells
Cells divide at different _______
Cell cycle – ordered ____________ from
formation to division
 Interphase –
____________ stage
 _________ phase -
division

11. 8.4 Multiplying Cells
Interphase
 90% of cell cycle (performs its ___________)
 Creates ___________
 Increases ____________
 ______________ duplicate

12. 8.4 Multiplying Cells
G1 – ‘first gap’
 Cell grows
S – ‘_________ of DNA’
 Cell continues to ________
 Chromosomes duplicate
G2 – ‘second gap’
 Cell continues to grow
 Prepares for __________

13. 8.4 Multiplying Cells
Mitotic phase
 Cell divides
 10% of cell cycle
 Mitosis and ___________

14. 8.4 Multiplying Cells
Mitosis – _________ and contents divide
Cytokinesis – __________ divides
Yields 2 daughter cells, _________ to parent
 ‘daughter’ doesn’t have anything to do with ‘sex’
Cycle begins again

15. 8.5 Cell Division
5 stages of mitosis – Figure 8.5 page 130-131
 (Interphase)
 Prophase
 Prometaphase
 Metaphase
 Anaphase
 Telophase

16. 8.5 Cell Division - Interphase
Cell ________
DNA replicates but is
__________ in the nucleus
 After replication, how many
chromatids?
 How many sister chromatids?

17. 8.5 Cell Division - Prophase
In nucleus chromatin condense,
coil into ___________
Duplicated chromosomes are sister
chromatids, joined at _________
In cytoplasm ___________ move
away from each other
___________ grow from
centrosomes, form mitotic spindle

18. 8.5 Cell Division - Prometaphase
Nuclear _________ breaks down
Spindle microtubules attach to each
sister chromatid at
_____________ (region on
centromere)
‘Motor’ proteins move
chromosomes toward center of cell

19. 8.5 Cell Division - Metaphase
Mitotic _______ is fully
formed
Chromosomes line up on
imaginary ___________
plate
Kinetochores of each sister
chromatids face __________

20. 8.5 Cell Division - Anaphase
Centromeres separate, sister
_____________ separate
 Apart: daughter chromosomes
Motor proteins ‘walk’
chromosomes along microtubules
toward _____
Some spindles push, some pull
Cell _________

21. 8.5 Cell Division - Telophase
__________ of prophase
Cell continues to elongate
Nuclear _________forms
around 2 daughter nuclei
Chromatin uncoils
Spindle fibers disappear
__________ furrow forms and 2
cell separate

22. Mitosis Animation

23. 8.6 Cytokinesis
Different for plants and animals
 Why?
In ________ cells cleavage furrow
 Actin microfilaments cause myosin to
___________

24. 8.6 Cytokinesis
In plants cell ________
 ___________ with cell wall material
move to middle
 Fuse to create cell plate

25. 8.6 Cytokinesis

26. 8.7 Factors Affecting Division
__________ of cell division is key for an organism
Influence by ________ and _________ factors
 Growth factors
 Density
 __________ to anchor
 ‘Cell culture’

27. 8.7 Factors Affecting Division
Growth factors
 Secreted _________
 Cause other cells to divide
 Blood __________ release
‘platelet-derived growth
factors’

28. 8.7 Factors Affecting Division
__________ dependence
 Cell must contact a solid surface
Density-dependent inhibition
 ___________ cells stop dividing
 Contact of cell-surface proteins
responsible

29. 8.8 Control System
In an organism cells are __________, receive
nutrients
 Growth factors signal ___________
Cell cycle ________ system
 Like a washing machine
 Triggers/coordinates key
events

30. 8.8 Control System
3 major checkpoints, what
is the cell checking for?
 __________ of stage
 Environmental conditions
 Presence of ____________
molecules
G1 is most important
 G0 is a _______________
state

31. 8.9 Cancer Cells
_________ is a disease of cell cycle
Transformed cells usually killed by ___________
system
__________ – abnormally growing mass; a cancer
cell that proliferates

32. 8.9 Cancer Cells
Benign tumor –
abnormal cells remain at
__________ site
Malignant tumors –
__________ to other
parts of the body

33. 8.9 Cancer Cells
___________ – spread of cancer cells from
their original site
 Circulatory system
 Lymphatic system

34. 8.9 Cancer Cells
Named for original location
 Carcinoma – internal or external ___________ of the body
 ___________ – tissue that supports the body
 Leukemia / Lymphoma – blood-forming tissue and
________ nodes

35. 8.9 Cancer Cells
Treatments
 Surgical ___________
 Radiation – damages _________
 Cancer cells often lose ability to repair
 ______________ – disrupts cell cycle

36. 8.10 Mitosis Review
Growth, cell replacement and asexual reproduction
of multicellular organisms
Yields same chromosome _________ and ______

37. 8.11 Homologous Pairs
___________ cells (all cells in your body except
sperm/egg cells) - 46 chromosomes
 22 pairs of ___________ chromosomes (autosomes)
 1 homolog from mom, 1 from dad – carry genes controlling same
characteristics
 1 pair of sex chromosomes
Other species typically have
__________ homologs

38. 8.11 Homologous Pairs
Example of chromosome 1 during metaphase
Genes at the same ______ (location)
 May be different
types
__________ at the same location

39. 8.11 Homologous Pairs
_____ chromosomes – determine individual’s sex
 Autosomes – other 22 pairs
X and Y chromosomes are exceptions
 Females carry ____
 Males carry ____
Not truly homologous

40. 8.12 Gametes
_________ cell – any cell with 2 homologous
chromosomes (2n=46)
 _________ cells
_________ cell – a cell with 1 set of chromosomes
 Gametes (sperm/egg cells) – 22 autosomes + 1 sex
chromosome
 Sex chromosome is either X or Y

41. 8.12 Gametes
___________ –
sperm and egg fuse
 Zygote is diploid
Mitosis takes over
How are gametes
made? …_________

42. 8.13 From Diploid to Haploid
Meiosis – cell division that _________ the number
of chromosomes
 Single __________ of DNA followed by 2 divisions
 Meiosis I and Meiosis II
 Yields 4 daughter cells, each with _______ the number of
chromosomes as parent cell

43. 8.13 From Diploid to Haploid
8 stages of meiosis
 Prophase I
 Metaphase I Meiosis
 Anaphase I I
 Telophase I and Cytokinesis
 Prophase II
 Metaphase II
 Anaphase II Meiosis II
 Telophase II and Cytokinesis

44. 8.13 From Diploid to Haploid
Chromosomes _________
DNA is a loose mass

45. 8.13 From Diploid to Haploid
Chromatin ____________
___________ – homologous
chromosomes (each 2 sister
chromatids) pair up
 Results in a ___________
 Crossing over – chromatids __________
segments of DNA
Centrosomes move, spindle forms

46. 8.13 From Diploid to Haploid
Tetrads align at imaginary
__________ plate
________ microtubules attach to
kinetochores at the centromeres

47. 8.13 From Diploid to Haploid
Tetrad is ________
Sister chromatids stay _______ at
centromere and move toward
opposite poles together

48. 8.13 From Diploid to Haploid
2 daughter cells are ________, each chromosome
consists of 2 sister chromatids
Meiosis II is the same as _________ just beginning
with haploid cells
TYPO!!

49. Meiosis Animation

50. 8.14 Mitosis vs Meiosis

51. 8.15 Varied Offspring
Genetically __________ from parents and siblings
_____________ assortment/orientation
 Red for maternal,
blue for paternal
 2n Combinations
 223 for humans
 about 8 million

52. 8.16 Different Versions of Genes
Chromosomes each contain many ________
 Homologous chromosomes have genes for same _________
at same __________

53. 8.17 Crossing Over
An exchange of ____________ segments of DNA
between two homologous chromosomes
__________ – where 2 homologous, non-sister
chromatids cross over

54. 8.17 Crossing Over
1. ________ at the same place
2. Rejoin the ________
chromatid
3. ‘Untwist’ and homologs
separate
4. Sister chromatids
_________
Yields 4 different chromosomes

55. 8.19 Altering Chromosome Number
______________ – a pair of chromosomes fail to
separate

56. 8.19 Altering Chromosome Number
Trisomy – having ____ copies
 13, 18 and 21 (Down syndrome)
Monosomy – having ____ copy

57. 8.23 Chromosome Structure
Chromosome structure can be __________
Inversions less likely to have _________ effects
than deletion or duplication

58. You should now be able to…
1. Compare the parent-offspring relationship in asexual and
sexual reproduction.
2. Explain why cell division is essential for prokaryotic and
eukaryotic life.
3. Explain how daughter prokaryotic chromosomes are
separated from each other during binary fission.
4. Compare the structure of prokaryotic and eukaryotic
chromosomes.
5. Describe the stages of the cell cycle.
6. List the phases of mitosis and describe the events
characteristic of each phase.
7. Compare cytokinesis in animal and plant cells.

59. You should now be able to…
8. Explain how anchorage, cell density, and chemical growth
factors control cell division.
9. Explain how cancerous cells are different from healthy cells.
10. Describe the functions of mitosis.
11. Explain how chromosomes are paired.
12. Distinguish between somatic cells and gametes and between
diploid cells and haploid cells.
13. Explain why sexual reproduction requires meiosis.
14. List the phases of meiosis I and meiosis II and describe the
events characteristic of each phase.

60. You should now be able to…
15. Compare mitosis and meiosis noting similarities and
differences.
16. Explain how genetic variation is produced in sexually
reproducing organisms.
17. Describe the causes and symptoms of Down syndrome.