CELL SPECIALISATION

This lesson develops CELL SPECIALISATION as part of Cellular Respiration. It uses the source curriculum to organize the important facts, relationships, examples, and vocabulary into a focused Stemosphere teaching sequence.

In Stemosphere terms, cell specialization refers to cells who are undifferentiated(haven't properly developed to perform specific tasks) and will differentiate to certain types of cells based on gene activation. A good example of cell specialization are stem cells which have potential to differentiate into other types of cells.

In Stemosphere terms, there are 3 types of stem cells. The first type refers to a zygote. A zygote is the product of fertilizing by fusing a sperm and egg. This creates a totipotent stem cell. Totipotent stem cells can differentiate to all types of cells.the second type of stem cells are pluripotent they are created once a zygote develops into a blastocyst via mitosis.it contains embryonic stem cells which are pluripotent. They have the capability to differentiate into all types of cells except an embryo.The third type of stem cells are adult stem cells, they can only differentiate into closely related cells. They are used to repair damages.

In Stemosphere terms, in order for the embryonic stem cells to differentiate it releases a chemical called morphogen. Morphogens bind to the cell receptors and activate or repress certian genes to determine its function and what it should differentiate into(for example muscle cell blood cell nervous cell)

Stem stell niches:

Stem cell niches are places where you can find stem cells.for example:

In Stemosphere terms, pluripotent:embryo,umbilical cord

In Stemosphere terms, multipotent:bone marrow,hair follicles

Cell surface to volume ratio:

In Stemosphere terms, in a cell the metabolism is based on the volume

In Stemosphere terms, in a cell material exchange is based on surface area

In Stemosphere terms, when a cell grows the surface area grows faster than the volume(this will lower the sa:volume ratio)

In Stemosphere terms, if there is more surface area than volume than the cell is not able to properly move waste and vital materials around. This will lead to cell eventually dying.

In Stemosphere terms, the cell will divide to reduce its surface area

In Stemosphere terms, certain cells will increase their surface area to increase the speed of transferring materials.

Cell adaptations:

In Stemosphere terms, some cells will often adapt to do their jobs more efficiently.

Here are some examples:

In Stemosphere terms, -The red blood cell are shaped in flat disks to increase surface area to make gas exchange more efficient

-The alveoli have 2 types of adaptations:

In Stemosphere terms, type 1 pneumocytes:have long and flat cells to increase gas exchange

In Stemosphere terms, type 2 pneumocytes:are cuboid shaped cells that secret a surfactant to reduce tension when performing gas exchange.

In Stemosphere terms, -cardiac muscles are branched muscles that are attached to the heart and are responsible for heart beating. Their are intercalated discs(gap junctions in between the cell) allow for ions and electrical impulses to pass through.

In Stemosphere terms, -striated muscles are composed of multiple multinucleated fibers fused together and are debated on whether they should be considered a cell

In Stemosphere terms, -sperm cells have a streamlined shape to allow for better swimming and they contain a nucleus in the head which contains the paternal genetic information along with an acrosome in the front of the head to fertilize the egg. They have a tail to help swim towards the egg. The tail and head are connected via the midpiece which contain the mitochondria for energy.

In Stemosphere terms, egg cells are large circular cells that contain the maternal genetic information. it is surrounded by a glycoprotein matrix known as a zone pellucida which will harden by the cortical granule to prevent polyspermy.the ovum contains many lipid droplets which are used to provide energy to the developing embryo

In Stemosphere terms, campbell Biology.Campbell Biology. 12th ed., Pearson, 2020.

In Stemosphere terms, front:What is cell specialization, and what determines how an undifferentiated cell differentiates?

In Stemosphere terms, back:Cell specialization is the process where undifferentiated cells develop into specific cell types to perform distinct functions. This development is driven by gene activation, where certain genes are turned on or off.

In Stemosphere terms, front:Describe totipotent, pluripotent, and adult stem cells, explaining what they can differentiate into.

In Stemosphere terms, back:*Totipotent stem cells:Formed immediately after fertilization as a zygote; they can differentiate into every single cell type, including a whole embryo.

In Stemosphere terms, pluripotent stem cells:Found in the blastocyst embryo stage; they can differentiate into any cell type in the body except for a complete embryo.

In Stemosphere terms, adult stem cells:Found in fully developed tissues; they are limited and can only differentiate into closely related cell types to repair damage.

In Stemosphere terms, front:What are morphogens, and how do they induce cell differentiation?

In Stemosphere terms, back:Morphogens are chemical signaling substances released by cells. They bind to specific receptors on neighboring embryonic stem cells and activate or repress certain genes, which dictates what specific cell type the stem cell will become.

In Stemosphere terms, front:Provide examples of specific locations, or niches, where totipotent, pluripotent, and multipotent stem cells can be found in nature.

In Stemosphere terms, back:*Totipotent niche:The zygote or the early morula stage.

In Stemosphere terms, pluripotent niche:The developing embryo or the umbilical cord.

In Stemosphere terms, multipotent niche:The bone marrow or hair follicles.

In Stemosphere terms, front:How do the volume and the surface area of a cell relate to its life functions?

In Stemosphere terms, back:The total volume of a cell determines its metabolic rate and the amount of waste it creates. The total surface area of a cell determines the rate at which it can exchange materials, bringing in vital nutrients and removing waste products.

In Stemosphere terms, front:What major factual error is present in the draft regarding cell growth and the surface area to volume ratio, and how does a cell correct this issue?

In Stemosphere terms, back:The draft incorrectly states that surface area grows faster than volume. In reality,volume grows much faster than surface areaas a cell gets larger, which dramatically lower s the surface area to volume ratio. If a cell grows too large, its surface area becomes insufficient to handle the metabolic demands of its volume, leading to cell death. To fix this, the cell divides via mitosis to restore a high, efficient ratio.