Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

UofG Medicine Question Bank 2020 > Stem Cells/Differentiation/Cell Cycle > Flashcards

Stem Cells/Differentiation/Cell Cycle Flashcards

1
Q

What is the hierarchy of stem cell potency?

A

Totipotent
Pluripotent
Multipotent
Unipotent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name a type of adult tissue stem cell

A

Multipotent Haematopoietic Stem Cell
Mesenchymal Stem Cell
Induced Stem Cell
Neural Stem Cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are some examples of unipotent cells?

A

Epithelial Stem Cells, Neural Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Summarize advantages of using different stem cells in medicine?

A

Adult: harder to culture, easier for transfusing
Embryonic: Ethical problems, rejection, pluritpotent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give examples of pluripotent cells

A

Embryonic stem cells

Pluripotent Primordial Germ Cells (endoderm, mesoderm, ectoderm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Multipotent

A

Adult Stem cells
Haematopoietic Stem Cell
Mesenchymal Stem Cells,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Summarise the advantages and disadvantages of using different stem cells in medicine

A

Adult Stem Cells: Less controversial, Rejection isn’t an issue, multipotent
Embryonic: Controversial, chance of rejection, pluripotent,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Summarise the advantages and disadvantages of using different stem cells in medicine

A

Adult Stem Cells: Less controversial, Rejection isn’t an issue, multipotent
Embryonic: Controversial, chance of rejection, pluripotent,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Summarise current knowledge of the role of stem cells in cancer

A

Looking at cancer therapy that addresses cancers beginning in progenitor stem cells vs somatic cell that moves backwards to acquire stem-cell-like traits
Targeting cancer stem cells (Anti-CD47 treatment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the potential medical applications of stem cells

A

Inducing pluripotent stem cells to differentiate into RBCs
Limbal Stem Cell from eye used in eye to treat injured cornea (Holoclar)
Injections of Colony Stimulating Factor to mobilize stem cells in blood (instead of drawing from bone marrow)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What components are needed for the production of erythrocytes to occur?

A

Iron- (reduced from Fe3+ to Fe2+) needed for haem synthesis,
B12- needed for DNA maturation & condensation of RBC
Folic Acid- needed for DNA maturation & condensation of RBC
Carbohydrates- to make haemoglobin
Fats- to make haeme
Erythropoietin- initiates Myeloid Stem Cell differentiation into erythrocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What events stimulate Erythropoiesis?

A

Hypoxia
Hypoxia allows for release of Hypoxia Inducible Factor, which then stimulates production of Erythropoietin production in Kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where does Erythropoiesis occur?

A

In the red bone marrow at the epiphysis of long bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the process of Erythropoiesis?

A

Haematopoietic Stem Cell -> Myeloid Stem Cell (induced to make erythrocytes when erythropoietin present) -> Pro-erythroblast -> basophilic erythroblast (lots of RNA present make it basophilic- loves blue) -> polychromatic erythroblast (haemoglobin synthesis turns cell red, red/blue (poly colours)) -> orthochromatic erythroblast (loss of nucleus-acid loving, turns it solely red) -> reticulocyte -> erythrocyte (matured reticulocyte)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What initiates the development of platelets?

A

Kidneys/liver release thrombopoietin -> stimulates Myeloid Stem Cell differentiation into Megakaryocytes -> thrombopoietin also stimulates megakaryocyte maturation into platelets -> megakaryocyte produces ~1000-3000 platelets.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where are excess platelets stored?

A

Spleen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is another name for platelets?

A

Thrombocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the name of the division a stem cell undergoes?, and what type of daughter cells are produced? (RK)

A

Asymmetric division. Two daughter cells are produced, one is identical to the mother stem cell + the other is a slightly specialised cell (progenitor/precursor) which has a reduced proliferative capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When and where are totipotent cells found? (RK)

A

Early stages of development in the embryo, examples include zygote (fertilized cell) and morula (early stage embryo consisting of 16 cells called blastomeres)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are induced pluripotent stem cells (iPSCs)? (RK)

A

Pluripotent stem cells generated directly from adult somatic cells (e.g. skin fibroblasts) by genetic reprogramming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are cancer stem cells and what are 2 hypotheses in which they arise? (RK)

A

Sub-population of stem-like cells that exist within tumour cells that exhibit both characteristics of cancer cells and stem cells. They are thought to arise from normal stem cells or progenitor cells that acquire cancerous characteristics, or from normal adult somatic cells that acquire both stem cell and cancer cell characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Do all cells undergo life cycles?

A

No, i.e. Granulosome cells of the epidermis do not replicate and divide, red blood cells & neutrophils dont divide
Leukocytes only sometimes divide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is G nought, ir quiesence?

A

When cells are not replicating,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How long does the cell cycle typically take in a human?

A 
About 1 day
G1- 11 hours
S- 8 hours
G2- 4 hours
M`-1 hour
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What happens in G1?

A

Cells grow back to their organelle size

Monitor external environment for optimal time to replicate, and looking for growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What happens in G2?

A

Cells prepare for cell division

Duplication of cell organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What happens in M phase?

A

Mitosis and Cytokinesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the stages of mitosis?

A

Prophase- chromosome strands shorten and thicken, nuclear envelope disappears, centrioles move to poles
Prometaphase- spindle extends into nucleus to attach to the chromosome
Metaphase- all chromosomes consist of sister chromatids attach to spindles
Anaphase- sister chromatids are moved to either end of cell
Telophase- Chromatids arrive at either end of pole, spindles disappear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

In what stage of the cell cycle is DNA Polymerase most active?

A

S Phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is a cyclin?

A

Short lived protein that regulate CDK activity

Vital in regulating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Why is the cell cycle regulated?

A

We would have uncontrollable growth without it (tumours)

Necessary to ensure DNA replication is done correctly and at the right time

32
Q

What are Cyclin-Dependent Kinases?

A

A protein that functions at different stages of cycle to allow progression once forming a complex with cyclin

33
Q

What are some pairings of CDKs and Cyclins and the stages of the cell cycle they regulate?

A

CDK 4/6 and Cyclin D- regulates G1 progression
CDK 2 and Cyclin E- Regulates movement into S phase
CDK 2 and Cyclin A- Regulates movement into G2 and Mitosis
CDK 1 and Cyclin B- Regulate movement past Metaphase

34
Q

What is a Cyclin-Dependent Kinase Inhibitor?

A

Regulates CDK and Cyclin activity in response to environmental factors or damaged DNA by forming inactive complex or acting as competitive ligand

35
Q

What is Maturation Promoting Factor?

A

Another name for CDK 1/ Cyclin B

36
Q

How do Cyclins regulate CDK?

A

A CDK isn’t active unless cyclin is bound to it.
Cyclin is produced when cell cycle progression is needed, and automatically binds CDKs
cyclin is destroyed afterwards

37
Q

What determines if a cell moves forward in the cell cycle?

A

Cyclins

38
Q

What are the types of Cyclin-Dependent Kinase Inhibitors?

A

p21 CIP- offer extra level of control (can inhibit all CDKs, but primarily associated with CDK2)
p27 KIP- Directly inhibits Cyclin D/CDK4 & E/CDK 2
p16 INK- Encodes inhibitor of Cd/ CDK 6 & 4

39
Q

How does CDK 1/ Cyclin B work to encourage cell cycle progression?

A

Cyclin B, synthesized during G2, associates with CDK1- now active- known as Maturation Promoting Factor (MPF)
CDK1 now phosphorylates lamins (lamins are intermediate filaments that are part of nuclear lamina) to aid in break down of nuclear envelope
Also phosphorylates histones and condensins which aids in condensation of chromosomes
Phosphorylates Microtubules Associates Proteins (MAPs) that are needed for microtubule assembly

40
Q

When is the restriction Checkpoint of the cell cycle?

A

During G1 phase, a point of commitment to replication, or not

41
Q

When is the DNA Damage Checkpoint in the cell cycle?

A

During the G1 transition and G2 phases

42
Q

What is the last checkpoint in the cell cycle and what is it checking for?

A

The Metaphase checkpoint

Ensures chromatids are secured to mitotic spindles

43
Q

What are growth factors?

A

Secreted signalling molecules that act on cells, impacting their growth and behaviour

44
Q

What are some common growth factors?

A

EGF, VEGF, PDGF

45
Q

What is the retinoblastoma protein?

A

The gate-keeper to the cell cycle

46
Q

How does the RB protein typically work?

A

Found bound to E2F
This binding of RB to E2F disallows E2F from allowing transcription of DNA and initiating the production of proteins needed for the cell cycle
Phosphorylation of RB causes dissociation of RB from E2F

47
Q

What is E2F?

A

A transcription factor that allows the initiation of transcription of proteins (i.e. DNA Polymerase) needed for the cell cycle

48
Q

What is an example of a tumour suppressor gene?

A

Retinoblastoma, P53, BRCA1

49
Q

What do tumour suppressor genes do?

A

They halt the cell cycle until appropriate conditions are met by initiating production of proteins that will stop the progression of the cycle

50
Q

How does p53 respond when it detects damaged DNA?

A

Damaged DNA is detected by P53 causing

CKI P21 production -> binds to CDK 2 Cyclin E/A and/or CDK 1 Cyclin B, halting progression

51
Q

How does the p53 gene respond to extensive DNA damage?

A

Transcribe genes that cause cell apoptosis

52
Q

What is done at the metaphase checkpoint?

A

Spindle Assembly Checkpoint
Delays onset to anaphase until all chromosomes are correctly attached to spindle fibres, inhibition is removed once all chromosomes are correctly bound to spindles.

53
Q

What does p53 do for cell regulation/transcription?

A

It increases in quantity in response to cell damage, acts as transcription factor to regulate cells that regulate cell growth
i.e. regulates transcription of p21cip that halts the cell cycle, will initiate transcription of apoptotic factors if cell DNA is too damaged

54
Q

Describe the receptors, transduction, and response of the Ras pathway.

A

Growth Factor stimulates tyrosine kinase receptor -> dimerization -> autophosphorylation of intracellular component of receptor -> GRB2 can now bind intracellular receptor-> SOS binds GRB2 -> SOS catalyses RAS phosphorylation -> Ras phosphorylates B-RAF -> B-RAF phosphorylates MEK 1/2 -> MEK 1/2 phosphorylates ERK 1/2 -> activation of transcription factors of AP1 family (Fos, Jun) -> transcription of cyclin D -> complex CD / CDK4 &6 formation -> progression past G1 phase

55
Q

What is an example of an enzyme linked receptors and what is the typical ligand?

A

Tyrosine kinase and Growth Factors

56
Q

What is a G-protein linked coupled receptors and its typical ligand?

A

Large, trimeric, transmembrane receptor that is activated by hormones, chemicals, (i.e. serotonin, adrenalin) to stimulate an intracellular secondary messenger

57
Q

What is an ion-channel linked receptor and its typical ligand?

A

A transmembrane receptor which, when activated by ions, will allow ions into cells to alter electrical properties.
I.e. glutamate neurotransmitter

58
Q

What are the categories of receptors, and their types?

A

Intracellular receptors- Hydrophobic or Gases

Extracellular receptors- Ion-Channel Linked, G-Protein Linked Couple Receptor, Enzyme Linked

59
Q

What is an example of a hydrophobic receptor ligand?

A

Oestrogen, testosterone

Bind hormone receptor intracellularly, and travel and complex into the nucleus

60
Q

What is an example of a gaseous receptor ligand?

A

Nitric Oxide diffuses through the plasma membrane of smooth endothelial muscle cells in blood vessels of the corpus cavernosum of the penis to bind Guanylate Cyclase.

61
Q

What are the types of intracellular transduction pathways as well as an example?

A

Kinase Cascades- involves amplification, and kinases and phosphotases
i.e. Mitogen Activated Protein Kinases (MAPKKK activates MAPKK which activates MAPK which acts on effector molecule).
Secondary Messengers- involves transmission and amplification of signal. Production of many secondary messengers
i.e. • Cyclic AMP (cAMP) - produced by the enzyme adenylyl cyclase
• Inositol triphosphate (IP3)and Diacylglycerol (DAG) - produced by the enzymephospholipase C
• Calcium ions - released from intracellular stores by IP3, or flow into cell upon ion channel activation

62
Q

What responses can signal transduction cause?

A
  1. Altered targetprotein activity
    e. g. phosphorylation alters the activity of many metabolic enzymes
  2. Altered targetprotein binding
    e. g. blocks, or causes, binding of a target protein to an inhibitor or activator protein
  3. Alteredprotein localization
    e. g. movement of a transcription factor from nucleus to cytoplasm stops it acting on DNA
    e. g. causes co-localisation of an enzyme with its substrates, allowing the enzyme to function
63
Q

What are two exceptions to the central dogma of molecular biology?

A

Reverse transcriptase

Non-coding RNAs (tRNA, rRNA, miR)

64
Q

How do transcription factors affect transcription?

A 
Bind to very small sequences of DNA
Can increase (activator) or decrease (repressor) rate of transcription
65
Q

What are some examples of transcription factors?

A

Nuclear Hormone Receptors- Ligand-dependent transcription factors
-glucocorticoid, oestrogen, testosterone, and retinoic acid receptors
p53 and E2Y

66
Q

What is an example of a drug impacting transcription factors?

A

Steroid act on transcription factor to impact gene expression

67
Q

What form the transcription initiation complex?

A

6 primary transcription factors (TF) involved, RNA Polymerase II, TATA Box.
RNA polymerase binds to TFIIB which is bound to TATA box sitting on DNA
TATA binds to promoter

68
Q

What is the CCAAT Box?

A

CAT Box is used to stabilize the other transcription factors

69
Q

What are gene enhancers or silencers?

A

Aid or deplete the transcription of genes.

They therefore can alter the expression of genes over time

70
Q

How does p53 act as a promoter and repressor of cell survival?

A

Activator- p53 activates transcription of p21 leading to cell cycle arrest, allowing for DNA repair
Repressor- inhibits transcription of survivin gene, leading to apoptosis

71
Q

How does Oct-1 act as a transcription promoter or repressor?

A

Oct1 represses transcription of thyroid stimulating hormones in all cells apart from thyrotrophs in the pituitary

72
Q

How does E2F work to either promote/repress transcription?

A

Promotes transcription of genes for S phase

73
Q

How does Snail work as a transcription repressor or promoter?

A

Promotes the repression of E-cadherin in epithelial cell cancers (allows for epithelial to mesenchymal transition during embryological development)
No E-cadherin means less rolling adhesion, but better invasive capabilities

74
Q

What is a super-enhancer locus control region?

A

Locus control region areas that when a transcription factor binds, will open tightly wound chromatin, allowing for transcription factors bind
i.e. locus control region ahead of globin gene in erythrocytes.

75
Q

What is constitutive gene expression?

A

Expressed in all cells at all time, maintain cell function
i.e. beta-actin (microfilaments of cells), or ribosomal proteins, or GAPDH (needed in 6th stage of glycolysis), and general transcription factors needed for gene transcription

76
Q

What is are inducible gene expression?

A

Only expressed in certain tissues or at certain times.
i.e. Almost all protein, CD4, CD8, collagen 1 by fibroblasts needing to make fibroblasts, globin only in erythrocytes, myelin in myelin producing cells.
Time: Cyclins are present in any cell but only during cell replication, inflammatory cytokines, foetal development ones. Foetal-globin expression during development, which declines after birth. Beta-globin then begins to be more highly expressed in cells expressing haemoglobin after birth.

UofG Medicine Question Bank 2020 (42 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions