2026 COURSE TIPS FOR Cell Bio 2382B Lecture Notes: Comprehensive
Chapter Review University of Western Ontario
Lecture 1 Review: Introduction to Cell Biology
Why study cells?
➔ It is the fundamental unit of life. Studying the cell allows us to understand how
tissues and organs work
➔ If we can determine the “normal” function of cells, we can study and fix the
“abnormal” function
➔ Win a Nobel Prize! Lol
What is a cell?
➔ Composed of many organelles (know structure)
➔ Ultimate goal: understand how macromolecular systems work and cooperate to
enable cells to function autonomously/independently and in tissues
How do we study cells?
➔ Need a hypothesis to conduct an experiment
➔ Need to isolate and maintain cells in vitro, know how to view cells and what to look
for, how to separate organelles, and finally how to identify and study how proteins
, drive cellular biological processes
Cell culture:
➔ Technique used to grow cells/tissues outside an organism under strict conditions
➔ Step 1, cut up a tissue (break up cell-cell interactions)
➔ Step 2, separate individual cells by breaking the “glue” (cell-matrix) using trypsin
and EDTA (cut proteins and make them less sticky to one another)
➔ Step 3, supply cells with proper nutrients (a.a., minerals, vitamins, etc.) and grow at
37 degrees Celsius in a CO2 incubator
➔ Step 4, culture cells. They can grow adherently (adhere to bottom of dish), or in
suspension (spin container they are in so that cells can’t adhere or settle)
➔ Phenyl red colour = good pH, purple = too basic, yellow = too acidic (may be caused
by bacterial contamination)
➔ Contact inhibition = when cell density is high, cells stop dividing
➔ Passaging = adding trypsin and EDTA to a culture undergoing contact inhibition to
add to a new plate and grow a new culture (even after passaging many times, the
cells will eventually stop growing b/c of telomere length, aka Hayflick limit)
➔ Primary cell culture = cells directly taken from an organism, undergo contact
inhibition and reach a Hayflick limit
, ➔ Cell line = “immortal cells.” They are able to grow indefinitely, and are less likely to
undergo contact inhibition (derived from cancer cells)
Ex. HeLa cells (first human cell line). Derived from cervical carcinoma biopsy
of Henrietta Lacks (these cells grew very fast and did not reach Hayflick limit)
Morphology of normal vs transformed fibroblasts (are specialized cells
that produce collagen and other proteins for connective tissue)
Normal Transformed ex. HeLa cells
Elongated/flat Rounded
Aligned Hairlike processes
Orderly packed Disorganized
Grow in parallel arrays Grow on top of one another
Contact inhibition Loss of contact inhibition (override Hayflick
limit)
Symmetric and asymmetric cell division:
➔ Symmetric: primary cell (normal or transformed) -> divides into two daughter cells
➔ Asymmetric (stem cells): primary cell -> divides into two cells that are different from
each other and parent cell or divides into two cells, one that is different from parent
and one that is identical (stem cell renewal)
➔ Symmetric and asymmetric: stem cell divides into itself and a different cell -> the
different cell can go on to cell death or become a progenitor cell (not a stem or
differentiated cell, but may give rise to different types of cells) -> progenitor cell also
self renews but also goes on to becoming differentiated cells (“end of the line”)
Embryonic stem cells
➔ Blastocyst has an inner cell mass rich in embryonic stem cells, the inner cell mass
is extracted (most die) and cultured (trypsin, EDTA, etc.), eventually creating a cell
line
➔ Embryoid bodies in suspension cultures try to form blastocysts again
➔ As the number of “passages” increases, the risk of cell differentiation increases,
therefore maintain low number of “passages” to lower risk of differentiation
➔ Embryonic stem cells give rise to the three germ layers: endoderm (gut epithelium),
mesoderm (cartilage), ectoderm (neural precursors)
➔ They are pluripotent (undifferentiated cells that can develop into differentiated cells
of three primary germ layers)
, Stem cells can be grown in 3D cultures to create organoids (simplified version of an organ):
➔ ex. brain organoids, have organization and
structure remarkably similar to fetal brain
➔ Organoids cannot advance past fetal
development state (cannot become “adult”)
Adult stem cells:
➔ Most tissues contain adult stem cells, they are required to maintain and repair
tissue
➔ They are capable of generating a limited number of different cell types
➔ Adult stem cell are located in a stem cell niche, adjacent cells send signals to self
renew or differentiate
➔ There needs to be a balance between symmetrical and asymmetrical division to
create new cells but also replenish stem cells
Stem cells to differentiated cells is not a one-way trip!
➔ Sir John B. Gurdon and Shinya Yamanaka discovered that mature cells can be
reprogrammed to become pluripotent
➔ Pluripotent stem cells can be obtained from differentiated normal cells
➔ We can reprogram fibroblasts by introducing the three Yamanaka factor to
differentiated cells: three genes in embryonic stem cells (Oct4, Sox2, Klf4) and one
expressed in cancer cells (c-Myc)
➔ These cells are called induced pluripotent stem cells (differentiated cells into stem
cells) aka iPS cells
➔ iPS cells are the future of transplantation medicine/regenerative medicine
Medical applications of iPS cells:
➔ overall: create cell culture models that more accurately represent the cells you are
trying to target/treat
Chapter Review University of Western Ontario
Lecture 1 Review: Introduction to Cell Biology
Why study cells?
➔ It is the fundamental unit of life. Studying the cell allows us to understand how
tissues and organs work
➔ If we can determine the “normal” function of cells, we can study and fix the
“abnormal” function
➔ Win a Nobel Prize! Lol
What is a cell?
➔ Composed of many organelles (know structure)
➔ Ultimate goal: understand how macromolecular systems work and cooperate to
enable cells to function autonomously/independently and in tissues
How do we study cells?
➔ Need a hypothesis to conduct an experiment
➔ Need to isolate and maintain cells in vitro, know how to view cells and what to look
for, how to separate organelles, and finally how to identify and study how proteins
, drive cellular biological processes
Cell culture:
➔ Technique used to grow cells/tissues outside an organism under strict conditions
➔ Step 1, cut up a tissue (break up cell-cell interactions)
➔ Step 2, separate individual cells by breaking the “glue” (cell-matrix) using trypsin
and EDTA (cut proteins and make them less sticky to one another)
➔ Step 3, supply cells with proper nutrients (a.a., minerals, vitamins, etc.) and grow at
37 degrees Celsius in a CO2 incubator
➔ Step 4, culture cells. They can grow adherently (adhere to bottom of dish), or in
suspension (spin container they are in so that cells can’t adhere or settle)
➔ Phenyl red colour = good pH, purple = too basic, yellow = too acidic (may be caused
by bacterial contamination)
➔ Contact inhibition = when cell density is high, cells stop dividing
➔ Passaging = adding trypsin and EDTA to a culture undergoing contact inhibition to
add to a new plate and grow a new culture (even after passaging many times, the
cells will eventually stop growing b/c of telomere length, aka Hayflick limit)
➔ Primary cell culture = cells directly taken from an organism, undergo contact
inhibition and reach a Hayflick limit
, ➔ Cell line = “immortal cells.” They are able to grow indefinitely, and are less likely to
undergo contact inhibition (derived from cancer cells)
Ex. HeLa cells (first human cell line). Derived from cervical carcinoma biopsy
of Henrietta Lacks (these cells grew very fast and did not reach Hayflick limit)
Morphology of normal vs transformed fibroblasts (are specialized cells
that produce collagen and other proteins for connective tissue)
Normal Transformed ex. HeLa cells
Elongated/flat Rounded
Aligned Hairlike processes
Orderly packed Disorganized
Grow in parallel arrays Grow on top of one another
Contact inhibition Loss of contact inhibition (override Hayflick
limit)
Symmetric and asymmetric cell division:
➔ Symmetric: primary cell (normal or transformed) -> divides into two daughter cells
➔ Asymmetric (stem cells): primary cell -> divides into two cells that are different from
each other and parent cell or divides into two cells, one that is different from parent
and one that is identical (stem cell renewal)
➔ Symmetric and asymmetric: stem cell divides into itself and a different cell -> the
different cell can go on to cell death or become a progenitor cell (not a stem or
differentiated cell, but may give rise to different types of cells) -> progenitor cell also
self renews but also goes on to becoming differentiated cells (“end of the line”)
Embryonic stem cells
➔ Blastocyst has an inner cell mass rich in embryonic stem cells, the inner cell mass
is extracted (most die) and cultured (trypsin, EDTA, etc.), eventually creating a cell
line
➔ Embryoid bodies in suspension cultures try to form blastocysts again
➔ As the number of “passages” increases, the risk of cell differentiation increases,
therefore maintain low number of “passages” to lower risk of differentiation
➔ Embryonic stem cells give rise to the three germ layers: endoderm (gut epithelium),
mesoderm (cartilage), ectoderm (neural precursors)
➔ They are pluripotent (undifferentiated cells that can develop into differentiated cells
of three primary germ layers)
, Stem cells can be grown in 3D cultures to create organoids (simplified version of an organ):
➔ ex. brain organoids, have organization and
structure remarkably similar to fetal brain
➔ Organoids cannot advance past fetal
development state (cannot become “adult”)
Adult stem cells:
➔ Most tissues contain adult stem cells, they are required to maintain and repair
tissue
➔ They are capable of generating a limited number of different cell types
➔ Adult stem cell are located in a stem cell niche, adjacent cells send signals to self
renew or differentiate
➔ There needs to be a balance between symmetrical and asymmetrical division to
create new cells but also replenish stem cells
Stem cells to differentiated cells is not a one-way trip!
➔ Sir John B. Gurdon and Shinya Yamanaka discovered that mature cells can be
reprogrammed to become pluripotent
➔ Pluripotent stem cells can be obtained from differentiated normal cells
➔ We can reprogram fibroblasts by introducing the three Yamanaka factor to
differentiated cells: three genes in embryonic stem cells (Oct4, Sox2, Klf4) and one
expressed in cancer cells (c-Myc)
➔ These cells are called induced pluripotent stem cells (differentiated cells into stem
cells) aka iPS cells
➔ iPS cells are the future of transplantation medicine/regenerative medicine
Medical applications of iPS cells:
➔ overall: create cell culture models that more accurately represent the cells you are
trying to target/treat
