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Cell Biology Final Exam 2382 Correct answers 2024/2025
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Cell Biology Final Exam 2382 Correct answers 2024/2025
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Solution 2024/2025Pepper
Cell Biology Final Exam 2382
Ultimate Goal of Studying Cells ANS✔✔ to understand how macromolecular systems and organelles work and corporate
to enable cells to function autonomously any in tissues.
- 75 trillion cells in the body
cell culture ANS✔✔ the technique used to grow cells or tissues outside the organism under strictly controlled conditions
How are cells isolated from any tissue? ANS✔✔ breaking down the cell-cell and cell-matrix interactions -- using
mechanical fragmentation, trypsin, EDTA (seives into clumps of 1000s, trypsin enzyme chews up protein)
Healthy cell environment for a cell culture has to have: ANS✔✔ proper nutrients (amino acids, salts, minerals, vitamins,
glucose, etc), serum (insulin GF), and gown at 37ºC in a CO2 incubator (ensures pH is maintained).
primary cell culture ANS✔✔ Cell culture grown from cells taken directly from a tissue in an organism.
Hayflick limit ANS✔✔ limited number of times a cell can divide (~50 generations)
contact inhibition ANS✔✔ a process that stops additional cell growth when cells become crowded
cell line ANS✔✔ Cells which are transformed and able to grow indefinitely *less likely to exhibit contact inhibition*
- also known as immortal cells
HeLa cells ANS✔✔ first human cell line, first immortalized cell line
- given to pharm companies to test cancer medicine
Morphology of normal fibroblasts ANS✔✔ - elongated
, Solution 2024/2025
Pepper
- aligned
- orderly packed
- grow in parallel arrays
- contact inhibition
(valuable for understanding normal physiological state)
Morphology of transformed fibroblasts ANS✔✔ - rounded
- hair like processes
- disorganized
- grow one atop other (form clumps)
- loss of contact inhibition
(better for reproductivity BUT does not necessarily translate into normal physiological state)
How to make a transformed fibroblast ANS✔✔ infect with virus oncogene to cancerous state -- allow cell to adapt a new
phenotype
What types of cell division do adult stem cells exhibit? ANS✔✔ symmetric and asymmetric
Symmetric cell division ANS✔✔ daughter cells identical to mother cell after division -- important for self renewal
asymmetric cell division ANS✔✔ daughter cells different from one another after division -- important for cells that need
to specialize to have different functions
Stem cell ANS✔✔ don't function as is, give rise to one stem cell (renewal) and one differentiated cell. Sometimes give
rise to two differentiated cells (no renewal).
, Solution 2024/2025
Pepper
differentiated cell ANS✔✔ a cell that has reached final cellular state (will function as this)
embryonic stem cells ANS✔✔ embryonic cells, which can develop into any type of body cell (differentiate)
- can be maintained in culture and can form differentiated cell types.
- are pluripotent and can be grown indefinitely in culture under appropriate conditions.
inner cell mass ANS✔✔ high number of pluripotent stem cells; giving rise to three germ layers: all body tissues
(endoderm, mesoderm, ectoderm)
How to establish embryonic stem (ES) cell cultures? ANS✔✔ - Put inner cell mass on a plate with fibroblasts to receive
nutrients
- Most cells die, some survive
- Use trypsin to dissociate and then put them back on fibroblast feed cells.
- individual cells divide, creating colonies
- Pick colonies and characterize to see if pluripotent
- Check for pluripotency by growing in a suspension culture
-- Will create embryoid bodies with features of 3 germ cell layers.
Organoids can be generated from ANS✔✔ pluripotent stem cells
Organoids ANS✔✔ - brain organoids have organization and structure very similar to fetal brain.
- advance to the fetal development state, but do not proceed to the organization seen in adult cells
---- can make organized structures (like fetal brain from ESC)
adult stem cells ANS✔✔ undifferentiated cells found among differentiated cells in a tissue or organs throughout the
body
- required to maintain and repair the tissue
- capable of generating a limited number of cell types
, Solution 2024/2025
Pepper
- located in stem cell niche (adjacent cells which provide signals to either self renew or differentiate)
Adult stem cells in intestine ANS✔✔ in crypt of villi give rise to intestinal epithelial cells (migrate and die at the top)
What type of cell differentiation do cancer cells exhibit? ANS✔✔ symmetric differentiation ONLY
induced pluripotent stem cells (iPs) ANS✔✔ Obtaining pluripotent stem cells from differentiated normal cells
(backwards)
How to make iPS cells ANS✔✔ Reprogramming of fibroblasts can be accomplished by into the Yamanaka Factors into
differentiated cells: three genes that are characteristics of ES cells (Oct4, Sox2, Klf4) and one frequently expressed in
cancer (c-Myc)
- Introduce transcription factors that are highly expressed in ESC and over-express them.
Problem with c-Myc ANS✔✔ has potential to dissregulate cell cycle (safety concern)
patient specific treatment ANS✔✔ use their own stem cells (no rejection, better integration)
Primary Cell:: ANS✔✔ Division: symmetric
Differentiation Capability: differentiated
Therapeutic Potential: limited
Transformed Cell:: ANS✔✔ Division: symmetric
Differentiation Capability: differentiated
Therapeutic Potential: No (cancerous)
Embryonic Stem Cell:: ANS✔✔ Division: symmetric/asymmetric
Differentiation Capability: pluripotent
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