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Stonebridge Natural Science Pathway
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Stonebridge Natural Science Pathway modules 5-20
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Within this essay I am going to touch on subject such as, how stem cells differ fromnormal/abnormal cells, cellular metabolism and how cells grow and divide. This will be
conducted through describing a plethora of subjects revolving around these key points stated
above. To begin we start with describing stem cells through understanding living cells,
prokaryotic and eukaryotic cells and eukaryotic sub-cellular structure and organelles.
Living Cell Characteristics
Cells share a wide range of common characteristics and require 7 biological characteristics of
life. All cells are capable of cell division, in exception of red blood cells, and depending on the
type of cell, cell division can occur in the shape of binary fission, mitosis and meiosis. These
three different forms of how cells divide have differences such as, uses by simple organisms like
bacteria, uses of chromosomes by skin cells, as an example, and uses by sex cells in fertilisation
where chromosome numbers are halved to be restored, known as sexual reproduction. Other
shared characteristics are: Using enzymes as catalysts for speeding up chemical reaction rates,
known as cell metabolism. The requirement of an energy source which is used as fuel for
metabolism, also known as respiration. The capability of adaption, which is in response to a
variety of stimuli. Also, the ability to be self-sufficient which is the use of cell membrane to
control the input and output of key substances. Cells are diverse and allow a wide range of
characteristics these are biological characteristics of life. This is explained in an article on “Living
Cell Characteristics” written by Ho-Diep Dinh (2019), where he explains that “no matter how
different cells may appear, there are many shared characteristics of living cells.” The 7
different biological characteristics are: Movement which is the ability to alter the organism’s
position within the environment. Respiration which is the ability to produce energy. Growth
which is the ability to enlarge in complexity and size, known as development. Reproduction,
the ability to produce offspring. Excretion which is the possession of the ability to eradicate
toxic metabolic waste products. Finally, nutrition which is the ability to make use of, acquire
food and feed. Knowing these characteristics tell us truly which cells are living and which
aren’t and how to use this in scenarios of specific cells and knowing how they can be
affected by numerous factors.
Prokaryotic and Eukaryotic Cell Comparison
Knowing the living characteristics of a cell we need to know how viruses may be able to affect
them. However, knowing the differences between prokaryotic and Eukaryotic cells will help us
understand even further. There are a number of differences between these cells but most
importantly they have different forms of a nucleus. Most notably a prokaryotic cell doesn’t have
a true nucleus, but a eukaryotic cell does. A prokaryotic cell is the most primitive form of cell
and their DNA is coiled into a region known as the nucleoid. A eukaryotic cell contains its DNA
in its nuclear membrane within the true nucleus. Another key difference is the size, and a
eukaryotic cell is 10. Times larger in diameter than a prokaryotic cell. Two more main
differences are their cell division forms and their respirations methods, a eukaryotic cell can use
either mitosis or meiosis. This cell can use either mitosis to create an identical copy of itself or
, meiosis which is a sexual reproduction form of cell division which involves the restoration of
chromosome numbers when male and female gametes fuse together. A prokaryotic cell will use
binary fission which is a DNA replication which created identical daughter cells. The variation in
respiration methods means eukaryotic cells use mainly aerobic respiration which makes use of
the mitochondrion organelle, a prokaryotic cell will use anaerobic respiration which occurs in
the cell cytoplasm. Viruses can infect cells in categories such as plant or bacteria, depending on
the nature of the cell the specific virus needs. A virus shares no commons with these cells as
they are made of DNA coated in a RNA shell, they use the sell to lock to the cells and infect the
host cell in order to make copies of their DNA. In the article “Viruses”, Douglas Wilkin, (2019)
writes, “viruses also do not have their own metabolism or maintain homeostasis.” Due to this
factor, most scientists consider viruses not to be living things. In the article, “Cell Organelle
Exploitation by Viruses During Infection”, Parikshit Bagchi (2021) writes, “viruses exploit
different cell organelles and their associated proteins.” This is key as eukaryotic cells have many
organelles with many functions.
Eukaryotic Sub-cellular Structure and Organelles
The eukaryotic sub-cellular structure helps the cell survive in a number of ways and contains a
number or organelles. The best way to understand this cells structure is through diagram taken
from the article, “Cell Biology”, written by Steve Hughes,
This diagram shows the organelles the eukaryotic sub-cellular structure holds. Starting with
cytoplasm, also known as cytosol, it’s a solution containing enzymes, sugars, amino acids, salts
and nucleotides in the cell membrane which is required for the cells function. Another organelle
is the nucleus, this is the largest organelle encased in a double nuclear membrane which has
pores to control the exit of RNA and ribosomes, the interior contains nucleoplasm which has
DNA in the form of chromatin granules, these contain genes. The mitochondrion organelle has
the shape of a sausage and is the location of aerobic respiration. It has Cristea, which is a
structure on the latter of the outer smooth and inner folded membrane, that increases the
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