Dit portaal werkt voor & door studenten. Heb je recent een examen gemaakt? Help je medestudenten en stuur je vragen in!
Examenjaren TimelineAlle jaren getoond
Examenjaar 2021-2022
2de Semester1 item
Examen Vragen
Geen datum
Stem Cell Biology and Reprogramming
Examen 2021-2022
Deel Björn Heindryckx:
- How are iPSCs and SCNT-ESCs generated? What are the key differences in their reprogramming mechanisms?
👁️ Klik om verborgen antwoord / sectie te tonen
- iPSCs: Somatic cells transduced with defined transcription factors (Oct4, Sox2, Klf4, c-Myc); gradual, stochastic transcription factor-driven reprogramming over weeks.
- SCNT-ESCs: Somatic cell nucleus transferred into an enucleated MII oocyte; rapid, maternal cytoplasmic factor-driven epigenetic reprogramming within hours.
- A 33-year-old woman has defective oocytes. How can you generate de novo oocytes?
Deel Jolanda van Hengel:
- Explain the CRISPRi (CRISPR interference) experiment presented in the lectures.
- A schematic figure is provided displaying iPSCs with arrows towards CRISPR, another culture dish, diseased cells, drug screening, and a mouse model:
- a. Fill in the empty boxes and explain the workflow.
- b. Which other pluripotent stem cells exist, and could they be used in this assay?
- c. What are the disadvantages and limitations of using iPSCs?
- Spinal cord disease in a patient leads to the degeneration of nerve cells. What can be a clinical approach to help this patient? (Figure provided with numbers 1–6 to identify).
Deel Susana Chuva de Sousa Lopes:
- Explain genomic imprinting and the role of DNA methylation.
Mondelinge vragen:
- What is the name of the long non-coding RNA (lncRNA) responsible for X-chromosome inactivation?
- What is the difference between random and imprinted X-chromosome inactivation?
- Which histone modifications are involved in genomic imprinting? Give an example of a silencing and an activating histone modification.
👁️ Klik om verborgen antwoord / sectie te tonen
- Silencing modification: $\text{H3K9me3}$ or $\text{H3K27me3}$.
- Activating modification: $\text{H3K4me3}$ or $\text{H3/H4}$ acetylation.
Examenjaar 2020-2021
2de Semester1 item
Examen Vragen
Geen datum
Stem Cell Biology and Reprogramming
Examen 2020-2021
Deel Jolanda van Hengel:
- Spinal cord disease in a patient leads to the degeneration of nerve cells. What can be a clinical approach to help this patient? (A figure was provided with numbers 1–6 indicating steps/cell types to be identified).
- What is the biological function of transmembrane proteins?
- What do you know about mechanobiology? How is this related to stem cell differentiation?
👁️ Klik om verborgen antwoord / sectie te tonen
- Definition: An interdisciplinary field investigating how physical forces and changes in mechanical properties influence cell behavior, fate, and development.
- Cellular effects: Mechanical cues regulate cell morphology, lineage specification, migration, organelle and nuclear remodeling, and stretch-activated ion channels.
- Substrate stiffness:
- In hESCs:
- $< 0.1\text{ MPa}$ (soft) $\rightarrow$ ectoderm differentiation
- $0.1 - 1\text{ MPa}$ (intermediate) $\rightarrow$ endoderm differentiation
- $1.5 - 6\text{ MPa}$ (stiff) $\rightarrow$ mesoderm differentiation
- $> 6\text{ MPa}$ $\rightarrow$ maintenance of undifferentiated state
- In MSCs:
- Soft matrix ($\sim 0.1 - 1\text{ kPa}$) $\rightarrow$ neurogenesis / adipogenesis
- Stiff matrix ($\sim 30 - 40\text{ kPa}$) $\rightarrow$ osteogenesis
- In hESCs:
- Micropatterned topography & cell shape:
- High cytoskeletal tension (star-shaped, spread out) $\rightarrow$ osteogenesis
- Low cytoskeletal tension (round, confined area) $\rightarrow$ adipogenesis
- Dynamic mechanical forces:
- Fluid shear stress: Endothelial differentiation.
- Cyclic mechanical strain: Osteogenic differentiation.
- Hydrostatic pressure: Chondrocyte differentiation.
- Uniaxial stretch: Myogenic or tenogenic differentiation.
Deel Björn Heindryckx:
- How can you reset mESCs to the ground state? Compare the properties of mESCs and mouse epiblast stem cells (mEpiSCs).
👁️ Klik om verborgen antwoord / sectie te tonen
- Resetting to the ground state is achieved by culture in 2i medium (supplemented with LIF):
- PD0325901: MEK/ERK inhibitor (blocks differentiation signals).
- CHIR99021: GSK3$\beta$ inhibitor (activates Wnt signaling to promote self-renewal).
- Comparison:
- mESCs: Naïve state, dome-shaped colonies, survive single-cell dissociation, high chimera-forming capacity.
- mEpiSCs: Primed state, flat colonies, sensitive to single-cell passaging, do not integrate efficiently into blastocysts.
- A 33-year-old woman presents at the fertility clinic without functional oocytes. How can you clinically/experimentally generate de novo oocytes from stem cells?
Deel Susana Chuva de Sousa Lopes:
- What is X-chromosome inactivation (XCI)? Discuss the differences between males and females.
- What are bivalent chromatin domains? Give two examples of histone modifications involved.
👁️ Klik om verborgen antwoord / sectie te tonen
- Bivalent domains are promoter regions of developmentally important genes that simultaneously carry activating and repressing epigenetic histone marks, keeping the gene silenced but primed for rapid activation upon differentiation.
- Activating mark: $\text{H3K4me3}$ (histone H3 lysine 4 trimethylation).
- Repressive mark: $\text{H3K27me3}$ (histone H3 lysine 27 trimethylation).
Mondeling Examen:
- Jolanda van Hengel: Look at the figure provided and identify which mechanobiological mechanisms are displayed.
- Björn Heindryckx:
- What are interspecies chimeras? What are they used for and are they efficient?
- How can SCNT efficiency be improved?
- What is an artificial embryo?
- History of cloning: which cells were used first for nuclear transfer?