Ch20 Stem and Cancer

Question 1

Tumor cells

Answer 1

1. irregular shape
2. larger and darker nucleus
3. uncontrolled growth

Question 2

Tumor supressor gene

Answer 2

1. slow cell division
2. repair mistakes in DNA
3. controls programmed cell death(apoptosis)

Question 3

Proto-oncogene

Answer 3

1. produce proteins
2. stimulate cell division

Question 4

Hypermethylation of tumor supressor gene

Answer 4

1. gene cannot be transcribed
2. no longer inhibits mitosis
3. uncontrolled cell division
4. tumor develops

Question 5

Hypomethylation of proto-oncogene

Answer 5

1. oncogene
2. stimulates uncontrolled cell division
3. tumor develops

Question 6

Malignant tumor

Answer 6

1. cancerous
2. uncontrolled cell growth
3. spreads around body(metastasis)
4. invades and destroys surrounding tissue

Question 7

Benign tumor

Answer 7

1. not cancerous
2. localised
3. cause blockages and put pressure on organs

Question 8

Oncogene

Answer 8

1. permanently activated receptor on csm
2. codes for excessive amount growth factor

Question 9

Oestrogen

Answer 9

1. binds to receptor on breast cells
2. promotes transcription in gene that controls cell growth
3. uncontrolled cell growth

Question 10

Epigenetics

Answer 10

1. heritable changes in gene functions
2. without change to base sequence of DNA

Question 11

Stem cell

Answer 11

1. undifferentiated
2. specialises into other cells

Question 12

Totipotent cell

Answer 12

1. differentiates into any body cell
2. embryo and placenta
3. all genes in nucleus are activated

Question 13

Pluripotent cell

Answer 13

1. differentiate into almost any cell
2. embryo

Question 14

Multipotent

Answer 14

1. differentiate into limited number of specialised cells
2. adult or umbilical cord

Question 15

Unipotent stem cells

Answer 15

1. differentiate into single type of cell
2. adult
3. e.g. cardiomyocytes

Question 16

Induced pluripotent cells

Answer 16

1. unipotent genetically altered in lab
2. genes and TF switched on or off
3. more ethical than embryos
4. capable of self-renewal

Question 17

Stem cell differentiation

Answer 17

1. certain genes expressed
2. certain genes switched off
3. proteins produced control cell processes and cell shape
4. modify cell- specialised

Question 18

Oestrogen

Answer 18

1. diffuses through phospholipid bilayer
2. binds to oestrogen receptor TF in cytoplasm (oestrogen-oestrogen receptor complex)
3. DNA binding site on TF changes shape
4. activated TF enters nucleus
5. binds to specific complementary base sequence
6. stimulates RNA polymerase
7. transcription of gene occurs

Question 19

Transcription factor

Answer 19

1. regulates expression of genes
2. stimulates RNA polymerase to regulate transcription

Question 20

Active transcriptional factor

Answer 20

1. binds to specific complementary base sequence of DNA
2. stimulates RNA polymerase
3. gene is transcribed
4. mRNA produced
5. translation occurs
6. protein produced

Question 21

Inhibitory transcription factor

Answer 21

1. bind to complementary base sequence at beginning of gene
2. prevent RNA polymerase binding
3. transcription can’t occur

Question 22

Decreased acetylation of histones

Answer 22

1. increase + charge on histone
2. increased attraction to DNA phosphates
3. stronger association between DNA and histone
4. DNA can’t be transcribed
5. gene isn’t expressed

Question 23

Increased methylation of DNA

Answer 23

1. binds to cytosine on DNA
2. prevents binding of TF
3. attracts proteins that condense DNA-histone complex
4. can’t be transcribed

Question 24

Small interfering RNA

Answer 24

1. enzyme cuts RNA into single-stranded siRNA
2. siRNA binds with enzyme
3. siRNA binds to complementary base sequence on mRNA
4. enzyme cuts mRNA into fragments
5. mRNA can’t be translated
6. gene can’t be expressed

Question 25

Epigenetic cancer treatment

Answer 25

1. inhibit enzymes involved in histone acetylation
2. inhibit DNA methylation