Week 6

Question 1

Cytokinesis

Answer 1

the physical process of cell division, which divides the cytoplasm of a parental cell into two daughter cells.

Question 2

Transit-amplifying cells (TACs)

Answer 2

an undifferentiated population in transition between SCs and differentiated cells

Question 3

PET scans

Answer 3

detects metabolically active regions including tumours but also normal kidneys

Question 4

ionizing radiation

Answer 4

radiation that has enough energy to break an electron away from an atom

Question 5

Cell fates

Answer 5

1. Survive
2. Grow and Divide
3. Differentiate
4. Die

regulated by chemical signalling

Question 6

necrosis

Answer 6

Cell death by pathogens, poisons, damage,
hypoxia (insufficient oxygen), starvation (lack of
glucose and other nutrients), boiling, dehydration

Question 7

cytochrome c

Answer 7

one of the mitochondrial proteins that is released into the cytosol when the cell is activated by an apoptotic stimulus.

Question 8

release of cytochrome c will…

Answer 8

stop ATP synthesis - this stops cell metabolism

• initiates destruction of cell proteins

Question 9

skin peeling from sunburn

Answer 9

excessive uv exposure damages dna in basal cells and TACs - if dna cannot be repaired, cells stop dividing and die by apoptosis … dead cells detach

Question 10

whole body imaging - ionizing radiation

Answer 10

x-ray, pet

Question 11

whole body imaging - non-ionizing radiation

Answer 11

ultrasound, mri

Question 12

srsi

Answer 12

sense, report, stop and initiate

molecules interacting with molecules

Question 13

Mitotic spindle defective

Answer 13

chromosomes not attached or not aligned

Question 14

mitogen

Answer 14

a small bioactive protein or peptide that induces a cell to begin cell division, or enhances the rate of division (mitosis).

Question 15

word breakdown : mitogen

Answer 15

“Mito” mitosis; “gen” agent or substance similar to
“carcinogen”, a cancer-causing substance.

Question 16

egf

Answer 16

epidermal growth factor

Question 17

exposing babies to ionizing radiation…

Answer 17

results in greater risk of gene
mutations and therefore cancer, because they have more stem cells dividing more
often than in adults (due to baby growth and development)

Question 18

myc gene

Answer 18

stimulates cell division

(named for a cancer in birds in which
this gene and its protein were found to be mutated)

Question 19

EGF binding to EGR-R changes

Answer 19

EGF-R shape
This shape change enables EGF-R to bind and activate
other proteins (not shown)

Question 20

when a protein shape changes

Answer 20

its function changes

Question 21

Ras

Answer 21

named for Rat sarcoma where this protein and
its gene were discovered to be mutated

Question 22

MAP kinase

Answer 22

a mitogen-activated protein
kinase; “-ase” indicates a protein with enzymatic
activity

Question 23

protooncogenes and protooncoproteins

Answer 23

cancer promoting

Question 24

Ras gene(s) are mutated in

Answer 24

30% of all human cancers

(Ras gene mutations promote tumor growth)

• Mutant Ras protein stimulates cell growth
  and division even when there is no external
  EGF binding to EGF-R

Question 25

Let-7

Answer 25

a microRNA (miRNA) that regulates many processes in the body

Question 26

“Post transcriptional”

Answer 26

means that microRNA acts on mRNAs, not on
genes to control protein production

Question 27

how miRNA (microRNA) work

Answer 27

microRNA (miRNA) bind to
complementary parts of mRNAs.
This region of double stranded RNA
blocks ribosome translation of mRNA
to make protein. No RAS protein is
synthesized

• A region of double stranded RNA cannot be translated by ribosome into protein
  The affected mRNA is degraded (broken down)

Question 28

MRI stands for

Answer 28

magnetic resonance imaging

Question 29

microRNA

Answer 29

short strands of RNA

• non-coding
• regulates gene expression

ex. Let-7

Question 30

let-7 found in

Answer 30

present day nematodes