week 2: Human cells, cancer

Question 1

what is gametogenesis?

Answer 1

the production of the gametes

Question 2

what is spermatogenesis?

Answer 2

the formation of sperm. it is continuous and prolific

hundreds of millions produced each day. each sperm takes about seven weeks to develop.

Question 3

oogenesis

Answer 3

the development of a mature egg.

this is a prolonged process.

immature eggs form in the female embryo but do not complete their development for years later.

Question 4

what is fertilization?

Answer 4

it is the formation of a diploid zygote from the haploid egg and sperm.

Question 5

what is the cleavage

Answer 5

a period with rapid mitotic division without growth.

Question 6

what is a morula

Answer 6

the compact mass of cells after fertilization.

Question 7

what is gastrulation?

Answer 7

the cells of the blastula (fluid filled cell) are rearranged into a three layered embryo called the gastrula.

Question 8

What are the three germ layers produced during gastrulation?

Answer 8

1. ectoderm
2. mesoderm
3. endoderm

Question 9

describe the ectoderm germ layer

Answer 9

the epidermis of the skin, the nervous system (including brain) and sensory organs.

Question 10

describe the mesoderm germ layer

Answer 10

the skeleton, muscles, blood vessels, heart, blood and kidneys

Question 11

describe the endoderm germ layer

Answer 11

lining of internal organs; including those of the digestive system, respiratory system, liver and pancreas.

Question 12

what happens during the first trimester?

Answer 12

all the major structures are present by 8 weeks, and the embryo is called a fetus

Question 13

what happens during the second trimester

(3 point)

Answer 13

1. the fetus grows and is very active
2. the mother may feel fetal movements.
3. the uterus grows enough for the pregnancy to become obvious

Question 14

what happens during the third trimester

Answer 14

the fetus grows and fills the space within the embryonic membranes.

Question 15

what are the 4 adult tissue types

Answer 15

1. epithelial tissue
2. connective tissues
3. muscle tissue
4. nerve tissue

Question 16

describe epithelial tissue

Answer 16

tightly packed cells, covers internal and external surfaces

Question 17

describe connective tissue

Answer 17

loosely packed cells surrounded by abundant extracellular matrix

Question 18

describe muscle tissue

Answer 18

specialized for movement

Question 19

what is nerve tissue for?

Answer 19

used for the transmission of nerve impulses

Question 20

what type of cell has the ability to continuously divide and differentiate into various other kinds of cells/tissues

Answer 20

Stem cells.

Question 21

what are embryonic stem cells?

Answer 21

• cells taken from the inner cell mass of the blastocyst
• they are pluripotent

Question 22

what are Adult stem cells?

Answer 22

-stem cells from adults needed for normal growth and repair.
-adult stem cells are multipotent.

Question 23

describe and give examples of totipotent cell type

Answer 23

each cell can develop into a new individual

cells from early embryos (1-3 days)

Question 24

describe and give examples of pluripotent cell type

Answer 24

cells can differentiate into any cell type

some cells of the blastocyst (5-14 days)

Question 25

describe and give examples of multipotent cell type

Answer 25

have the ability to differentiate into all cell types within one particular lineage/cell group fetal tissue, cord blood, and adult stem cells

Question 26

explain Induced Pluripotent Stem Cells (IPS's)

Answer 26

obtained from adult somatic cells reprogrammed to act like embryonic stem cells created in 2007 the cells are "dedifferentiated" by genetic modification

Question 27

why is stem cell research important? (3 points)

Answer 27

1. stem cells can replace diseased or damaged cells 2. stem cells allow us to study development and genetics 3. stem cells can be used to test different substances (drugs and chemicals)

Question 28

explain the process of reproductive cloning

Answer 28

Genetic material (nucleus from embryonic, fetal, or adult cell) is removed and placed into an unfertilized egg or embryo, whose nucleus has been removed.

Question 29

what is the result if the genes that regulate cell growth and division mutate?

Answer 29

cancerous cells may develop

Question 30

what are the three types of cancer?

Answer 30

carcinomas, sarcomas, leukemias and lymphomas.

Question 31

what type of cancer constitutes 90% of cancers and are cancers of epithelial cells

Answer 31

carcinomas

Question 32

what type of cancer is rare and consist of tumors of connective tissues (connective tissue, muscle, bone etc.)?

Answer 32

sarcomas

Question 33

what are the characteristics of lymphomas and leukemias?

Answer 33

constitutes 8% of tumors. Leukemias arise from blood forming cells lymphomas arise from cells of the immune system (T and B cells).

Question 34

describe a benign tumor

Answer 34

do not spread from their site of origin but can crowd or squash surrounding area (eg brain tumor)

Question 35

describe malignant tumor

Answer 35

can spread from the original site and cause secondary tumors. this is called metastasis

Question 36

what is a somatic mutation?

Answer 36

mutations that occur in any cell of the body except from the germ cells. this form of cancerous gene is not passed on to offspring.

Question 37

what are the two types of cancer critical genes?

Answer 37

- tumor suppressor genes - oncogenes

Question 38

what ways can proto-oncogenes be converted to oncogenes? (3 points)

Answer 38

- movement of DNA within genome - amplification of proto-oncogene - point mutation in the proto-oncogene or its control elements

Question 39

what is the Ras protein?

Answer 39

acts as a signaling protein at an early stage of a pathway which stimulates cell proliferation.

Question 40

what prevents a cell from passing on mutations due to DNA damage?

Answer 40

the p35 gene.

Question 41

name 5 treatments for cancer

Answer 41

surgery combined with radiation or chemotherapy immunotherapy cancer fighting vaccines gene therapy stem cell research