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Biology > Biology Chapter 12 > Flashcards

Biology Chapter 12 Flashcards

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1
Q

Mitosis is a type of cell division that

A

leaves two identical copies of a cell

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2
Q

In mitosis, the chromosome number is

A

Unchanged

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3
Q

Most cells divide by

A

Mitosis (skin, blood, kidney)

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4
Q

Why is nerve and brain damage usually permanent?

A

Nerve and brain cells rarely divide after childhood

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5
Q

Interphase

A

The cell grows and DNA replicates

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6
Q

Interphase is followed by

A

Mitosis

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7
Q

Mitosis

A

The cell divides into two

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8
Q

What are the stages of mitosis?

A

Prophase,
metaphase,
anaphase,
telophase

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9
Q

Prophase

A

The spindle forms. The chromosomes are visible scattered at random

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10
Q

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

A

Microtubules

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11
Q

Metaphase

A

Chromosomes line up in the center of the cell

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12
Q

Anaphase

A

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

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13
Q

Telophase

A

Two nuclei form. The cytoplasm divides (cytokinesis)

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14
Q

During telophase in animals, how does it divide?

A

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

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15
Q

During telophase in plants, how does it divide?

A

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

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16
Q

When do normal cells divide?

A

When the correct growth factor is present.

When each cell is not completely surrounded by other cells.

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17
Q

What do proteins inside the cell control?

A

The cell cycle

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18
Q

What do cyclins in the nucleus control?

A

The replication of DNA

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19
Q

The 2001 Nobel prize was awarded to

A

The people who discovered cyclins

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20
Q

What do protein kinases switch on?

A

Proto-onco genes that start mitosis

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21
Q

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

A

An oncogene that causes cancer (uncontrolled cell division)

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22
Q

Tumor suppressor genes

A

Prevent mitosis and make abnormal cells kill themselves

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23
Q

What is an example of a tumor suppressor gene?

A

p53

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24
Q

Why is cancer more common in older people?

A

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

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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

Biology (19 decks)

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