Biology Chapter 12 Flashcards Preview

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Flashcards in Biology Chapter 12 Deck (70):
1

Mitosis is a type of cell division that

leaves two identical copies of a cell

2

In mitosis, the chromosome number is

Unchanged

3

Most cells divide by

Mitosis (skin, blood, kidney)

4

Why is nerve and brain damage usually permanent?

Nerve and brain cells rarely divide after childhood

5

Interphase

The cell grows and DNA replicates

6

Interphase is followed by

Mitosis

7

Mitosis

The cell divides into two

8

What are the stages of mitosis?

Prophase,
metaphase,
anaphase,
telophase

9

Prophase

The spindle forms. The chromosomes are visible scattered at random

10

What is the spindle, that forms during prophase, made of?

Microtubules

11

Metaphase

Chromosomes line up in the center of the cell

12

Anaphase

Centromeres divide. The chromosomes move to opposite ends of the cell (V shape)

13

Telophase

Two nuclei form. The cytoplasm divides (cytokinesis)

14

During telophase in animals, how does it divide?

The cell membrane pushes inwards from the outer edge making a cleavage furrow, so the center is the last part that divides

15

During telophase in plants, how does it divide?

The cytoplasm separates from the center of the cell towards the outside by forming a cell plate

16

When do normal cells divide?

When the correct growth factor is present.

When each cell is not completely surrounded by other cells.

17

What do proteins inside the cell control?

The cell cycle

18

What do cyclins in the nucleus control?

The replication of DNA

19

The 2001 Nobel prize was awarded to

The people who discovered cyclins

20

What do protein kinases switch on?

Proto-onco genes that start mitosis

21

A mutation in a proto-onco gene can turn it into

An oncogene that causes cancer (uncontrolled cell division)

22

Tumor suppressor genes

Prevent mitosis and make abnormal cells kill themselves

23

What is an example of a tumor suppressor gene?

p53

24

Why is cancer more common in older people?

Most cancers have mutations in the tumor suppressor genes and as you get older the chance of mutation increases

25

Cancer cells keep dividing even if

Surrounded by other cells

26

A benign tumor

Is limited to one site and cannot spread

27

A malignant tumor

Cancer cells spread around the body in the blood

28

Metastasis

The cancer has spread

29

What is cell division needed for?

Growth, reproduction, and to replace dead cells

30

What are causes of cancer?

Environment,
Genetics

31

Environment

* Carcinogens (chemicals which cause cancer)
* Radiation
* Ultra-violet (UV) light causes skin cancer
* Virus (the virus HPV causes cancer of the cervix)

32

Genetics

Some cancers have a high genetic risk

33

What are high risk cancers?

Prostate, colon, breast, skin, ovary

34

What are low risk cancers?

Lung, pancreas, testicles, uterus

35

What are some cancer treatments?

Surgery, chemotherapy, radiation

36

Surgery

Removes cancer cells. Best for benign tumors

37

Chemotherapy

Chemicals that kill dividing cells. Standard for malignant tumors

38

What is a problem with chemotherapy?

Side effects. Kills all cells that are dividing.

39

Radiation

Kills all the cells in one spot. Standard for malignant tumors

40

What are problems with radiation?

Kills all cells in the area, whether cancerous or not, causes side effects.

Can cause new cancer to start.

41

Prostate cancer

39,000 annual deaths

93% 5 year survival rate

Early detection through exam and blood

42

Breast cancer

44,000 annual deaths

85% 5 year survival rate

Early detection through self exam and mammogram

43

Colon cancer

57,000 annual deaths

62% 5 year survival rate

Early detection through exam and blood

44

Lung cancer

160,000 annual deaths

14% 5 year survival rate

No early detection

45

What are cancer survival rates from lowest to highest?

Lung,
Colon,
Breast,
Prostate

46

Most cancer research is done using human cells grown in the lab called

HeLa cells

47

Who are HeLa cells named for?

Henrietta Lacks

48

What cells have telomerase?

Cancer cells

49

Telomerase

An enzyme that repairs the telomeres on the ends of the chromosomes

50

Cancer researchers are developing

Inhibitors against telomerase

Inhibitors that stop cancer cells from producing new blood vessels

Medications that boost the immune system

51

Asexual reproduction

Offspring are identical (clones)

Only one parent

Cells divide by mitosis

52

What are examples of asexual Reproduction?

Bacteria, banana

53

Sexual reproduction

Offspring vary

2 parents

Sex cells have one set of chromosomes, compared to two sets in a normal cell

54

What are sex cells called?

Gametes

55

Gametes are produced by

Meiosis

56

Diploid cells

Have 2 sets of chromosomes (2n)

57

Examples of diploid cells

Skin, stomach, liver

58

Regular body cells are also called

Somatic cells

59

In humans, diploid cells have how many chromosomes?

46 chromosomes

60

Haploid cells

Have one set of chromosomes (n)

61

Examples of haploid cells

Sperm and egg (called the gametes or sex cells)

62

In humans, haploid close have how many chromosomes?

23 chromosomes

63

What are sources of genetic variations?

Independent assortment

Crossing over

Random fertilization

64

Independent assortment

Picking 23 chromosomes from 46 in humans

65

In a species with 3 chromosomes in gametes it gives

8 genetic combinations

66

How many independent assortment combinations are in humans?

8 million

67

Crossing over

Changes the combinations of genes that are inherited. May give thousands of different combinations (exact number is unknown)

68

Random fertilization

The sperm that fertilizes the egg is chosen at random

69

In a species with 3 genetically different gametes it gives

9 combinations

70

How many random fertilization combinations are in humans?

70 trillion