1. HW: BRF #28-38 (no #31) 135 Things… (June 2)
Thursday
May 25, 2017
I can:
review the processes of mitosis and meiosis
Agenda
(10) Catalyst
(15) Review Cell Cycle
(20) Quizlet Live!
(25) Trashketball (or more Quizlet Live
(15) Daily Quiz
Catalyst
Grab your computer and go to goo.gl/WQRt54 (type EXACTLY as is)
Familiarize yourself with the flashcard decks and review options.
HW: BRF #28-38 (no #31)
135 Things… (June 2)

2. Biology Released Form

3. Biology Released Form

4. Biology Released Form

5. Biology Released Form

6. Biology Released Form

7. Biology Released Form

8. Biology Released Form

9. Biology Released Form

10. Biology Released Form

11. 65%+ correct shows you’re ready for college-level Biology courses
If you got…
~0-4 right  Level 1
~5 right  Level 2
~6 right  Level 3
~7-8 right  Level 4
~9 right  Level 5
65%+ correct shows you’re ready for college-level Biology courses

12. The cell cycle is the series of four events that cells go through as they grow and divide.
G1 phase
S phase
G2 phase
M phase

13. The cell cycle is the series of four events that cells go through as they grow and divide.
G1 phase
Gap 1 phase: Cells grow in size and make new proteins and organelles.

14. The cell cycle is the series of four events that cells go through as they grow and divide.
S phase
Synthesis phase: DNA replication occurs

15. The cell cycle is the series of four events that cells go through as they grow and divide.
G2 phase
Gap 2 phase: Cell prepares for mitosis.

16. The cell cycle is the series of four events that cells go through as they grow and divide.
M phase
Mitotic phase: Cell divides. Consists of 2 parts:
mitosis – nucleus divides
cytokinesis – cytoplasm and cell membrane divide

17. The cell cycle is the series of four events that cells go through as they grow and divide.
G1 phase
S phase
G2 phase
The first 3 stages of the cell cycle are called interphase. The cell spends most of its time in interphase.

18. (before mitosis) Interphase
Mitosis is the process by which a cell divides itself one time to produce 2 identical daughter cells.
occurs in 4 phases
(before mitosis) Interphase
G1 phase
G2 phase
S phase
Prophase
DNA condenses into chromosomes
nuclear envelope breaks down
Metaphase
chromosomes line up across the center of the cell
spindle fibers attach to chromosomes
Anaphase
sister chromatids split and move apart to opposite ends of the cell
Telophase
chromosomes begin to loosen
nuclear envelope reforms

19. DNA appears in various forms at different stages of the cell cycle.
During interphase, the DNA in a cell is in a loose form called chromatin.
During the S phase, DNA is duplicated, and each copy of DNA is held together at an area of the DNA called the centromere. Each copy is called a sister chromatid.
A chromosome is a tightly coiled molecule of DNA packaged with proteins. Only appears during mitosis.

20. genetic variation! intercourse
Sexual reproduction involves the contribution of genetic
material from two parents, and results in….
genetic variation!
intercourse

21. Human Chromosome Number
Human body cells contain 2 copies of each of 23 chromosomes.
1 copy comes from each parent
2 copies = diploid (2n)
copy from dad
copy from mom
Each set of chromosomes is homologous – they are the same size and contain the same information
chromosome 19

22. Human Chromosome Number
Human body cells contain 2 copies of each of 23 chromosomes.
1 copy comes from each parent
2 copies = diploid (2n)
copy from mom
copy from dad
Each set of chromosomes is homologous – they are the same size and contain the same information
After doubling during the S phase, the homologous chromosomes now form tetrads.
chromosome 19

23. Human Cell Type Somatic Cells Gametes body cells
diploid (2n) = 2 copies of 23 chromosomes
made by mitosis
egg and sperm
haploid (1n) = 1 copy of 23 chromosomes
made by meiosis

24. Just like mitosis, except…
Meiosis (aka reduction division) is the process in which gametes are made.
Just like mitosis, except…
each cell divides two times
each cell produces 4 daughter cells
cells produced are haploid, not diploid
each cell produced is different from the parent

25. There are many ways in which meiosis results in genetic variation, or different combinations of DNA.
1. Crossing-over
During prophase I of meiosis, homologous chromosomes pair up to form a tetrad. Chromatids then cross over each other, and the crossed sections are exchanged. This results in new combinations of genes (DNA).

26. 2. Random (or Independent) Assortment
There are many ways in which meiosis results in genetic variation, or different combinations of DNA.
2. Random (or Independent) Assortment
Chromosomes are separated into gametes randomly. That is why you inherit traits by chance, and you get a mix of traits from each parent.

27. There are many ways in which meiosis results in genetic variation, or different combinations of DNA.
3. Mutation
Sometimes there is a mistake in the DNA that is not caught.

28. There are many ways in which meiosis results in genetic variation, or different combinations of DNA.23 46 23
4. Fertilization
Reproduction that requires 2 parents results in variation because any combination of egg and sperm is possible. Fertilization (when an egg and sperm combine) restores the correct chromosome number.

29. There are many ways in which meiosis results in genetic variation, or different combinations of DNA.
5. Nondisjunction
Nondisjunction is when chromosomes don’t separate correctly in meiosis. It leads to the wrong number of chromosomes. It results in genetic disorders like Down Syndrome.

30. The genetic variation produced by meiosis ensures that there is a wide variety of traits in offspring.

31. Quizlet Live!

32. It’s time for…
Trashketball!

33. gametes Write On Your Board
What type of cell are egg and sperm? (gamete or somatic)
gametes

34. somatic cells Write On Your Board
What type of cell is a skin cell? (gamete or somatic)
somatic cells

35. haploid, 23 Write on Your Board
What type of cell is a gamete (diploid or haploid), and how many chromosomes does it contain?
haploid, 23

36. diploid, 46 Write on Your Board
What type of cell is a somatic cell (diploid or haploid), and how many chromosomes does it contain?
diploid, 46

37. somatic cells Write on Your Board
What kind of cell is made by mitosis?
somatic cells

38. Write on Your Board
What kind of cell is made by meiosis?
gametes

39. Write on Your Board
A skin cell has 36 chromosomes. How many chromosomes are in the same organism’s sperm? 18

40. Write on Your Board
A nerve cell has 102 chromosomes. How many chromosomes are in the same organism’s eggs? 51

41. Write on Your Board
An egg cell has 48 chromosomes. How many chromosomes are in the same organism’s liver cell? 96

42. Write on Your Board
A sperm cell has 22 chromosomes. How many chromosomes are in the same organism’s bone cells? 44

43. Write on Your Board
Mitosis or meiosis:
produces 2 cells
mitosis

44. mitosis Write on Your Board
Mitosis or meiosis:
produces cells that are identical to the parent
mitosis

45. meiosis Write on Your Board
Mitosis or meiosis:
produces cells that are genetically different from the parent
meiosis

46. Write on Your Board
Mitosis or meiosis:
produces 4 cells
meiosis

47. mitosis Write on Your Board chromosome # is the same as parent
Mitosis or meiosis:
chromosome # is the same as parent
mitosis

48. meiosis Write on Your Board
Mitosis or meiosis:
has half as many chromosomes as parent cell
meiosis

49. meiosis Write on Your Board increases genetic diversity
Mitosis or meiosis:
increases genetic diversity
meiosis

50. meiosis Write on Your Board chromosome number is divided in half
Mitosis or meiosis:
chromosome number is divided in half
meiosis

51. Write on Your Board
Mitosis or meiosis:
results in clones
mitosis

52. Write on Your Board
Mitosis or meiosis:
crossing-over occurs
meiosis

53. Write on Your Board
Mitosis or meiosis:
asexual reproduction
mitosis

54. Write on Your Board
Mitosis or meiosis:
makes gametes
meiosis

55. meiosis Write on Your Board part of sexual reproduction
Mitosis or meiosis:
part of sexual reproduction
meiosis

56. Write on Your Board
Mitosis or meiosis:
makes somatic cells
mitosis

57. meiosis Write on Your Board
Mitosis or meiosis:
occurs in reproductive organs (ovaries, testes)
meiosis

58. mitosis Write on Your Board occurs in somatic cells
Mitosis or meiosis:
occurs in somatic cells
mitosis

59. different combinations of DNA (genes)
Write on Your Board
What does crossing-over result in?
different combinations
of DNA (genes)

60. What stage?

61. What stage?

62. What stage?

63. What stage?

64. What stage?

65. The cell spends most of its time in…
what stage?

66. Which is a result of mitosis? A. four sex cells B. four haploid cells
C. two diploid daughter cells
D. two haploid daughter cells
2 pts.

67. Why is cytokinesis important in cell division? A. The cell grows
B. The nucleus divides
C. Chromosomes are duplicated
D. The cytoplasm and cell membrane split, forming two daughter cells
2 pts.

68. Before the process of mitosis can start, which must occur?
A. DNA replication
B. RNA transcription
C. Protein translation
D. Microtubule formation
2 pts.

69. A. Gametes are being produced B. Cells are undergoing cytolysis
Which is most likely occurring when animal cells undergo mitosis at an abnormally high rate?
A. Gametes are being produced
B. Cells are undergoing cytolysis
C. Haploid cells are being created
D. Cancerous tumors are developing
4 pts.

70. Some species of starfish can reproduce by breaking off an arm or splitting in half. Each arm or half then becomes a whole new organism genetically identical to the parent. Which type of cell division occurs in this process?
A. Meiosis
B. Mitosis
C. Budding
D. Conjugation
4 pts.

71. Why does meiosis promote genetic variability?
A. Meiosis undergoes one cell division producing diploid cells.
B. Meiosis undergoes one cell division producing haploid cells.
C. Meiosis undergoes two cell divisions producing diploid cells.
D. Meiosis undergoes two cell divisions producing haploid cells.
4 pts.

72. An individual has three number 21 chromosomes
An individual has three number 21 chromosomes. Which is most likely the cause?
A. Disjunction
B. Crossing over
C. Gene mutation
D. Nondisjunction
4 pts.

73. A. Meiosis produces identical daughter cells.
Which explains the significance of meiosis in the development of gametes?
A. Meiosis produces identical daughter cells.
B. Meiosis reduces the chromosome number by one-half.
C. Meiosis combines an egg and a sperm to form a zygote.
D. Meiosis increases the number of offspring an organism can produce.
4 pts.

74. What is a result of crossing over during meiosis? A. Genetic variation
B. Extra chromosomes formed
C. Loss of chromosomes
D. Production of gametes
4 pts.

75. How does crossing over contribute to greater genetic diversity?
A. It results in the exchange of proteins.
B. It produces new combinations of alleles. C. It reduces the number of chromosomes in each cell.
D. It separates the chromosomes at the centromeres.
6 pts.

76. A. assortment and alignment B. alignment and crossing over
During which actions can an exchange of genetic information occur during meiosis, rather than during mitosis?
A. assortment and alignment
B. alignment and crossing over
C. crossing over and replication
D. assortment and crossing over
6 pts.

77. B. fertilization C. nondisjunction D. spermatogenesis
Meiosis produces cells in the haploid state. In which process is the chromosome number restored to the diploid state?
A. ovulation
B. fertilization C. nondisjunction D. spermatogenesis
6 pts.

78. Which best describes the purpose of sexual reproduction?
A. to produce offspring that are non­viable
B. to produce offspring that are genetically identical C. to produce offspring that exhibit greater genetic variations D. to produce offspring that are genetically identical to their parents
6 pts.

79. Nondisjunction during meiosis results in an abnormal number of chromosomes in one or more gametes. In some cases of nondisjunction, a single chromosome fails to separate. In others, none of the chromosomes separate. Suppose an egg is produced in which none of the chromosomes separate during meiosis II. What is the chromosome number of the zygote that results if this egg is fertilized by a normal sperm? A. 1n B. 2n C. 2n+1 D. 3n
6 pts.

80. 20 autosomes and 1 X chromosome 20 autosomes and 1 Y chromosome
The skin cells of an adult female rat has 40 autosomes and 2 sex chromosomes. A healthy egg cell would contain which number and type of chromosomes?
20 autosomes and 1 X chromosome
20 autosomes and 1 Y chromosome
40 autosomes and 2 X chromosomes
40 autosomes and 2 Y chromosomes
6 pts.