1. Mitosis & Meiosis

2. Key Vocab Chromosome- long thread of DNA that consists of many genes
Humans have 46 chromosomes (23 pairs)
Gametes- sex cells such as egg and sperm (meiosis)
Somatic cells- body cells (mitosis)
Homologous chromosomes- two chromosomes; one from mom and other from dad
Diploid- a cell has two copies of each chromosome (cells at end of mitosis) (46)
Haploid- a cell has only one copy of each chromosome (cells at end of meiosis) (23)
Sexual reproduction- type of reproduction that requires 2 parents ( an egg and a sperm) to produce offspring (young/baby)
Asexual Reproduction- Type of reproduction needing only ONE single parent. Offspring is Identical to the parent. No genetic variation. Cloning.

4. Mitosis Uses: growth, cell replacement, healing and repair
Asexual reproduction: one parent produces offspring that are identical to parent
Cell division- one cell separates into two cells
Each new cell contains the SAME amount of chromosomes as the original cell
The DNA is copied before the cell divides
One copy of the genetic information is distributed to each new daughter cell

5. Process of Mitosis DNA REPLICATES- DOUBLES
Double-stranded chromosomes (replicated) line up at the center of the cell before division.
Double-stranded chromosomes split into 2 identical single strands and move toward opposite ends of the cell
The cytoplasm divides resulting in two smaller, but genetically identical cells
Cells are diploid at beginning and end of mitosis

6. Phases of Mitosis

7. Microscopic View of Mitosis

9. Cancer Uncontrolled cellular division.
Cancerous cells keep dividing; crowding out and stealing nutrients from healthy tissue.
Cancer “kills” when a mass of cancer cells called a tumor interferes with the functions of major organs.
The spreading of cancer to other organs and tissues is known as metastasis.
Tumor

10. Asexual Reproduction One parent No genetic variation
Identical to parent
Offspring has the same # of chromosomes as parent
RESULTS IN 2 IDENTICAL Cells

11. Types of Asexual Reproduction
MITOSIS
BINARY FISSION
BUDDING
VEGETATIVE PROPAGATION
SPORULATION
REGENERATION

12. Binary Fission- EQUAL DIVISION --Examples: bacteria, amoeba, paramecium

13. Budding- a cell of a parent develops a bud
Budding- a cell of a parent develops a bud. - Uneven division Examples: yeast, hydra

14. Sporulation- each spore contains DNA
Sporulation- each spore contains DNA --each spore can develop into a new organism --Examples: Bread Mold

15. Regeneration- Replacement of lost or damaged body parts Examples: lobster, starfish, planaria, some reptiles

16. Vegetative Propagation- new plant develops from part of a parent plant Examples: onion, potato, tulip

18. Let’s Practice!
1. The diagrams represent a cell process. If the cell in Diagram 1 contains 4 chromosomes, what is the total number of chromosomes in each cell in Diagram 3? 8 2 16 4

19. 2. Which process is represented by the series of diagrams?
photosynthesis
fertilization
mitotic cell division
meiotic cell division

20. 3. Normal mitotic cell division results in each daughter cell having
half the number of chromosomes as the parent cell
the same number and kinds of chromosomes as the parent cell
the same number but different kinds of chromosomes as the parent cell
twice the number of chromosomes as the parent cell

21. 4. A colony of red bacteria is allowed to reproduce for 16 generations
4. A colony of red bacteria is allowed to reproduce for 16 generations.  A scientist examines the colony at the end of this time and notes that all the individuals are almost identical in all characteristics.  This evidence suggests that the bacteria
did not receive the proper nutrients
reproduced sexually
exchanged genetic material
reproduced asexually

22. 5. Which phrases best identify characteristics of asexual reproduction?
one parent, union of gametes, offspring similar to but not genetically identical to the parent
one parent, no union of gametes, offspring genetically identical to parents
two parents, union of gametes, offspring similar to but not genetically identical to parents
two parents, no union of gametes, offspring genetically identical to parents

23. 6. Which activity most directly involves the process represented in the diagram below?
a gamete reproducing sexually
a white blood cell engulfing bacteria
a zygote being produced in an ovary
an animal repairing damaged tissue

24. 7. Which statement regarding this process is correct?
Cell B contains the same genetic information that cells A and C contain.
Cell C has DNA that is only 50% identical to cell B.
Cell A has DNA that is only 75% identical to cell B.
Cells A, B, and C contain completely different genetic information.

25. 8. The diagram can be used to illustrate a process directly involved in
tissue repair
meiosis
cellular respiration
sexual reproduction

26. 9. Warts result when certain viruses cause skin cells to reproduce at a high rate. This rapid reproduction of skin cells is due to the viruses stimulating
cellular digestion 
mitotic cell division 
synthesis processes
meiotic cell division

27. Meiosis Sexual reproduction
Occurs in gametes or sex cells (eggs and sperm) ONLY
Meiosis produces haploid cells that have one half the chromosomes of the original cell
Gametes or sex cells (sperm/eggs) have one half the amount of chromosomes as the original cell

28. Phases of Meiosis
First Phase of Meiotic Division- double stranded chromosomes line up in pairs in the center and then divide into two cells
Second Phase of Meiotic Division- division of the two newly formed cells
Each chromosome in the two cells still consists of two strands that will separate resulting in 4 cells

29. Phases of Meiosis

30. Meiosis in Testes of Males

31. Meiosis in Ovaries of Females
Egg Cell
(Nonfunctioning Cells)

32. Meiosis Comparison

33. Meiosis: Source of Variation
During meiosis, genetic variation occurs.
Sources of Variation
Crossing over
Genetic Recombination- during fertilization (Egg and Sperm)
Random fertilization of Gametes-

34. 1. Crossing Over- Random exchange of chromosome pieces (genetic information between chromosomes)

35. 2. Genetic Recombination- during fertilization (Egg and Sperm)
2. Genetic Recombination- during fertilization (Egg and Sperm) --Different combinations of chromosomes can be produced (about 8 million different combinations)

37. Random Fertilization of Gametes- random combination of gametes or egg and sperm --About 70 trillion possible combinations of the egg and sperm

38. Mitosis Meiosis Produces 2 genetically identical cells
Produces 4 genetically unique/ different cells
Results in diploid cells
Results in haploid cells
Takes place in body cells or somatic cells only
Takes place only in sex cells or gametes
Sperm and egg
Involved in asexual reproduction
Involved in sexual reproduction

40. Let’s Practice!
1. Each body cell of a chimpanzee contains 48 chromosomes. How many chromosomes would normally be present in a gamete produced by this chimpanzee? 24 36 48 96

41. 2. Which process is represented by the diagram?
fertilization
production of gametes
cloning
evolution

42. 3. The process of meiotic cell division in a human male usually forms
one diploid cell, only
four diploid cells
one monoploid cell, only
four monoploid cells

43. 4. Cell with a diploid chromosome number of 12 divided two times, producing four cells with six chromosomes each. The process that produced these four cells was most likely
internal fertilization
external fertilization
mitotic cell division
meiotic cell division

44. 5. Most cells in the body of a fruit fly contain eight chromosomes
5. Most cells in the body of a fruit fly contain eight chromosomes.  How many of these chromosomes were contributed by each parent of the fruit fly? 8 2 16 4

45. 6. Which diagram best represents part of the process of sperm formation in an organism that has a normal chromosome number of eight? 1. 3. 2. 4.

46. 7. The diagram below shows a process that can occur during meiosis
7. The diagram below shows a process that can occur during meiosis. The most likely result of this process is
a new combination of inheritable traits that can appear in the offspring
an inability to pass either of these chromosomes on to offspring
a loss of genetic information that will produce a genetic disorder in the offspring
an increase in the chromosome number of the organism in which this process occurs

47. 8. A particular species of shark normally reproduces sexually
8. A particular species of shark normally reproduces sexually. In captivity, it was found that a female could also reproduce asexually. One negative result from asexual reproduction is
increased gene recombinations
increased number of males produced
decreased number of eggs used
decreased biodiversity within the species

48. References
McDougal Littell Biology Living Environment Textbook