UNIT 5 (2).docx

CELL BIOLOGY
INTRODUCTION
This report will look into the characteristics of cells, how cells survive, structure of a cell and
what impact viruses have on them. It will also provide an analysis into the respiration,
synthesis and movement of what nucleic acid plays in the nucleus and the cytoplasm. Finally,
this report will look into the generation of specialised tissues from embryonic cells,
importance of interphase and factors that initiate cell division, such as mitosis and how
daughter cells are formed from this. This report will compare cancer cells
Characteristics of Living Cells
A cell is a characteristic of life. The cell was first discovered in the 17th
century when a
scientist called Robert Hooke (1665) described the first found cells in cork and that led to
thescientist Anton Can Leuwenhoek (1675) to discover the protozoa cell, which then lead to
bacteria in cells being found nine years later.
This paper will detail my research on the internal organization of eukaryotic and prokaryotic
cells, including their organelles, as well as how they interact with viruses, animal cells, and
cancer cells. Afterwards, analyzing the role that nucleic acids play in the nucleus and
cytoplasm's respiration, synthesis, and mobility.
Characteristics of Living Cells
Life has a feature called a cell. The cell was first identified in the 17th century by a scientist
by the name of Robert Hooke (1665), who subsequently inspired Anton Can Leuwenhoek
(1675) to identify the protozoa cell, which in turn spurred the discovery of bacteria in cells
nine years later.
Here are the main seven characteristics that all cells must follow in order to survive:
1. Movement - a cell's ability to move and change position is essential since it allows the
organism to catch prey and flee from predators.
2. Respiration converts energy from fats and carbohydrates into energy that the cells can
utilise. In multicellular organisms, the respiration mechanism uses oxygen to break
down carbohydrates.
3. Sensitivity - this enables organisms to recognize or sense stimuli and react to
environmental changes in a way that will protect them.

4. Growth - Growth occurs throughout the respiration process because the extra energy it
supplies enables the organism to grow larger and helps the growth of new cells and
tissues.
5. Reproduction - comes in two forms, asexually - the creation of a new organism from
an existing one through cell division or sexually which requires two organisms to
reproduce.
6. Excretion - is vital for the organism to remain healthy; cell and tissue functions
produce waste (dead cells, urine), these waste products must be excreted as if remains
in the organism can become toxic
7. Nutrition is important for survival; food gives us the energy we need and the nutrients
we need for growth and reproduction. (CK-12 Foundation, 2020)
A LIVING CELL
Every cell needs a source of energy, most of which comes from metabolic processes and is
kept in the form of adenosine triphosphate. All cells must be able to reproduce, whether by
binary fusion, mitosis, or meiosis, and they must also be self-sufficient.
PROKARYOTIC AND EUKARYOTIC CELLS
Prokaryotic Cells
Organelles that are members of prokaryotic cells (nucleus and mitochondria). Since they are
composed of only one cell, bacteria are among the most basic of all living things. Their cells
are smaller, with the majority measuring between 0.2 and 2.0 m, and their cell structure is
simpler than that of eukaryotes. Prokaryotic cells are among the simplest in the animal
kingdom. They divide into two identical cells via binary fission, which allows for rapid

reproduction. Prokaryotic cells breathe without the use of oxygen (anaerobic respiration),
which takes place within the cytoplasm. (Bitesize 2020)
PROKARYOTIC CELLS
Eukaryotic Cells
Eukaryotic cells are those that have a nucleus, organelles, and a plasma membrane
surrounding them. Eukaryotic organisms include protozoa, fungus, plants, and mammals. The
other two domains of life, Archaea and Bacteria, contain prokaryotic cells, which are smaller
and less complicated than eukaryotic cells.
EUKARYOTIC CELLS
Comparison
Prokaryotic and Eukaryotic cells are the division of two living organisms. All cells belong
into one of these types; they have many things in common, but each has a distinct structure
and performs in a distinctive way. Animals, plants, and bacteria all contain eukaryotes cells,
just as prokaryote cells do in bacteria. Below is a table I made outlining the main variations
between the two cells:

PROKARYOTIC AND EUKARYOTIC CELLS
Prokaryotic Eukaryotic
No Nucleus Nucleus
No Organelles Cytoskeleton
Simple cell structure Complex cell structure
No Membrane organelles Membrane organelles
Nucleoid Chromosomes
Primitive Contains a cell wall
Unicellular Multicellular
DNA is free within nucleus DNA within nucleus
Smaller cells 10x larger prokaryotic cells
Can respire without the use of oxygen Depends on oxygen on whether it can
respire
0.1-5 μm 10-100 μm
Lysosomes and Peroxisomes absent Lysosomes and Peroxisomes present
Cytoskeleton absent Cytoskeleton present

As shown above the differences between each cell i.e. shape, size and how both work
VIRUSES
Since viruses are not living organisms, they are unable to function on their own and cannot
metabolize. A virus would invade the host cell and introduce its genetic material to take over
the functioning of the cell. As a result, the cell would be forced to produce more viral genetic
material and protein than usual. (FS Cohen - 2016)
Eukaryote Sub-cellar Structure and Organelles
The organelles and nucleus of eukaryotic cells are encased in a plasma membrane. This is
because their genetic material is contained within the nuclear envelope. Kingdom Protista,
kingdom Fungi, kingdom Plantae, and kingdom Animalia are the four kingdoms. They have
been characterised by their membrane nucleuses’.
Here is a list of the Eukaryotic cells that contain organelles:
1. Mitochondria (Cellular Energy)
2. Golgi Apparatus (Sectorial Device)

3. Endoplasmic Reticulum (a canal like system of membrane within the cell)
4. Lysosomes (digestive apparatus within many cell types)
I have created an Eukaryote Sub-cellar Structure and Organelles
Cell Membrane
The cell membrane (or plasma membrane) protects the cell. It also maintains a stable
environment within the cell, and that membrane serves various roles. Cells in both unicellular
and multicellular animals are separated from each other and their environment by a barrier
known as the plasma membrane or cell membrane.

Structure of a Cell Membrane
The membrane is divided into two portions that are covered with phospholipids (polar) on the
outside and fatty acid phospholipids (nonpolar) on the inside, both of which are related to the
integral (intrinsic) proteins in the membrane's center. Sugar side chains are distributed across
the top layer of the membrane, as is cholesterol, which runs from the outer layer to the inner
face.
Gained Nutrients and Waste Products
The cell membrane extracts waste and obtains nutrients via transferring substances, which
can happen in a variety of ways depending on the type of the substance. The following are
some of the ways a membrane accomplishes this:
Lipid
Lipid diffusion is used for steroid transportation. The Lipid bilayer allows small substances
such as oxygen, carbon dioxide, and hydrophobic molecules to pass through the cell
membrane and then pass down their concentration gradient into simple diffusion.
Facilitated
Facilitated diffusion is also used through concentration gradient with non-recurring energy
and then classed as a passive transport. Facilitated diffusion is also known for the diffusion of
solutes through transporting proteins in the plasma membrane classed as channels and
carriers.
Passive Transport
Passive transport occurs when chemicals diffuse through the cell membrane via certain
transport proteins. When a high concentration of molecules needs to travel to a lower

concentration, transportation occurs. This uses no energy since it follows the concentration
gradient. (BBC Bite size 2020).
Active Transport
Active transport occurs when chemicals at low concentrations are transported across the cell
membrane by different transport proteins to a greater concentration. Because it goes against
the concentration gradient, its movement costs energy. The breakdown of ATP inside the cell
provides energy. (BBC Bite size 2020)’.
Vesicular transport
Vesicular transport is the predominant exchange of proteins and lipids between membrane-
bound organelles in eukaryotic cells. There are three types of transport vesicles, as shown
below:
1. Clathrin Coated: Vesicles are produced from both the plasma membrane and the
trans-Golgi network.
2. COPI coated: vesicles and COPII-coated vesicles arise from the endoplasmic
reticulum (ER) to export new proteins to the Golgi.
3. COPI vesicles: COPI vesicles are seen in both anterograde and retrograde transport
inside the Golgi complex. COPI is primarily responsible for recycling proteins from
the Golgi to the endoplasmic reticulum (ER).

Golgi-derived COPI-coated vesicles are involved in several vesicular transport steps,
including bidirectional transport within the Golgi and recycling to the ER. (Company of
Biologists 2020)
Animal Cells
Eukaryotic cells, or cells with a membrane-bound nucleus, are animal cells. Animal cells,
unlike prokaryotic cells, contain DNA within the nucleus. Animal cells, in addition to a
nucleus, have additional membrane-bound organelles, or microscopic cellular structures, that
perform specialized roles required for normal cellular activity. Each organelle in the cell is
responsible for a distinct function. Not all organelles are found in all animal cells. Cell
growth is caused by the metabolism process, which is divided into two parts: catabolism and
anabolism. Catabolism begins by breaking down complex molecules into smaller ones,
generating energy that is then stored as Adenosine Triphosphate, or ATP. Catabolism then
boosts ATP concentration by breaking down nutrients and food; cell compounds synthesized
for this activity include proteins, lipids, carbohydrates, and nucleic acids such as DNA and
RNA. Using the energy provided by ATP, the anabolism process converts simpler molecules
into more complex ones. The smaller molecules are combined to form larger and more
diverse molecules known as macromolecules. Anabolisms use macromolecules to create cells
and aid in the formation of new cells, which are required for growth, organ development, and
tissue formation. (BBC Bite size, 2020)
Here are the few functions of Animal Cell:
1. These cells control the processes in the body efficiently.
2. Cells control synthesis and storage of energy.
3. Cells also perform and control the Replication, Translation, and transcription of DNA.
4. Cells are extremely dedicated to carrying out precise responsibilities.

5. Red blood cells encompassed of Hemoglobin. Hemoglobin is the cells which did not
contain any nuclei and its main function is to transfer oxygen throughout the whole
body.
6. Inside the human body, ciliary cells are present in the Digestive Tract which increase
the surface area and help in the process digestion.
7. Numerous cells syndicate and form Tissues. Which perform a specialised function in
the human body.
Animal Cells Structure
Nucleus Acids
Nucleic acids are important biomolecules that are found in all forms of life, from bacteria to
humans. The size of nucleic acids ranges from microscopic molecules to massive
biopolymers. Each nucleic acid has its own distinct form and function within a cell, as seen
below.

RNA
RNA is also present in almost all living cells. RNA is the second most important nucleic acid
present in the living things. It is a polymer of rib nucleotides having ribose as pentose sugar.
Transfer RNA (tRNA)
Transfer RNA transfers amino acids to the ribosomes so that they can be assembled into
proteins. The RNA reads the code on the messenger (mRNA) RNA and carries the specific
amino acids to the ribosomes so it can be transferred to the correct proteins.
Messenger RNA (mRNA)
The messenger RNA is responsible for the messages between the DNA and cytoplasm. It
carries information for the present proteins within the nucleus of DNA to the ribosomes in the
cell cytoplasm.
Ribosomal RNA (rRNA)
Ribosomal RNA is the most prevalent type of RNA found in cells. It is a necessary
component of ribosomes found in both bacterial and eukaryotic cells. Ribosomal RNA
divides into two subunits, the larger ribosomal subunit and the smaller ribosomal subunit.

DNA
DNA is found in all living things. Eukaryotic cells are fully composed of DNA bases such as
adenine, guanine, cytosine, and thymine. Every cell contains the same amount of DNA. The
primary purpose of DNA is to store genetic information.
DNA Replication
Every living thing contains DNA. Eukaryotic cells are fully made up of DNA bases such as
adenine, guanine, cytosine, and thymine. Every cell has the same amount of DNA. The most
crucial function of DNA is to store genetic information.
DNA Replication
Stem Cells
Stem cells are human cells that can develop into a variety of cell types. They can self-renew
by dividing and develop into more mature, specialized cells. Depending on the number of cell
types, stem cells can be unipotent, multipotent, pluripotent, or impotent. It has also been
demonstrated to repair damaged tissues. Stem cells are classified into two types, as seen
below:
Embryonic stem cells - The embryonic stem cells come from unused embryos. These are
found from an in vitro fertilization procedure. These embryonic stem cells can turn into more
than one cell.

Adult stem cells - Adult stem cells are classified into two categories. One sort of cell is
derived from completely grown tissues like the skin, brain, and bone marrow. These tissues
contain a limited amount of stem cells. (BBC Bite size 2020)
Cell Division and Daughter Cells
Mitosis and meiosis are two types of cells that divide during cell division. Cell division is the
reproductive mechanism via which all living entities develop and reproduce.
Actively dividing eukaryote cells go through the cell cycle, which consists of two gap phases
(G1 and G2), a S (for synthesis) phase in which the genetic material is duplicated, and a M
phase in which mitosis partitions the genetic material and the cell divides.
Mitotic: At the end of the mitosis cell cycle, the cell divides into two daughter cells.
Mitosis cells produce two identical body cells that are used for growth and repair (when body
becomes damaged it creates more cells).
Mitosis and has 4 stages.
Prophase - During early prophase, chromosomes appear as coiled threads that condense to
grow shorter and thicker. The centrioles travel to opposing poles of the nucleus as prophase
develops. The nuclear membrane contracts and disappears.
Metaphase - During metaphase, the spindle becomes fully formatted, with chromosomes
aligning at the equator and pairs of chromatids attaching to it via their centromere. Anaphase
occurs when the chromatids are pulled apart by the movement of the spindle fibers, resulting
in freshly separated chromatids, which are then referred to as chromosomes. Sister
chromatids will travel away from the pole in the opposite direction.
Telophase - Telophase is the final step of mitosis, when chromatids uncoil and become
visible as they reach the spindle poles. As the nucleolus reforms in each nucleus, the nuclear
membrane reforms around each group.

There are two main steps of the cell cycle, interphase where the growth of the cell takes
place, it is also the longest phase, where the dividing cell spends 90-95% of its time in
preparation for mitosis phase which are G1 phase, S phase M phase, G2 phase, DNA
synthesis
Interphase is divided into three sub-phases. Gap 1 (G1) new cells grow normally and produce
a lot of protein as they prepare to duplicate DNA. Some organelles are generated, and the cell
grows and expands in size. Only after the cell has produced enough ribosomes can it proceed
to the next phase. Synthesis (S) is the time when DNA replicates and the number of
chromosomes doubles. Gap 2 (G2) is the final stage, during which the cell continues to grow
in size and replenish its energy stores.
This is the cell cycle as shown starting with cell growth, then DNA synthesis after that further
growth occurs and the DNA is checked for errors.
Cancer Cells
All cancer cells begin as normal cells and then develop into damaged versions of normal
cells, which is usually due to defects rather than a single mutation. Cancer is caused by
alterations to a person's DNA caused by carcinogens, which are chemicals or other factors.
Because cancer is a non-communicable disease, carcinogens create DNA mutations, which
disrupt the cell cycle and prevent correct signals from being sent to cells. When cells do not

need to divide, the mitotic stage becomes unregulated. It is at this moment that cancer cells
can form; cells gain control of their own growth and divide uncontrollably, forming a lump of
cells known as a tumour, whereas normal cells (seen in the top figure) remain tightly
controlled and do not expand at an abnormal rate or form clusters. The table below illustrates
the distinction between a cancer cell and a normal cell.
Organelles and
Characteristics
Normal Cell Cancer Cell
Nucleus Single Multiple
Shape Regular Irregular
Death Can self-destruct No only able to perform
apoptosis
Energy Obtained by glucose and the ATP
molecule Presence of oxygen
Obtained in the absence of
oxygen
Function Abnormality Normal
Nucleous Single Multiple and darker coloured
Reproduction Normal Reproduces massively
Conclusion
All cells in most living things, from humans to animals to plants and organs, are alive. It's
astonishing how cells proliferate in a variety of ways and can repair and function even after
being damaged. Understanding cell biology is critical to understanding how our bodies work

and reproduce. Cell biology has greatly benefited the way we live our lives through research
with medicine and disease detection over the years.
Recommendations
As indicated in prior units, employing the pomodoro approach allowed me to accomplish this
unit much faster than I would have otherwise because I was taking rests in between studies to
avoid becoming exhausted. For this unit, I primarily used BBC Bite size and a few more
websites from general research. I've also watched countless cell-related videos on YouTube
and through BBC Bite size.

REFERENCES
• A Biology (2016) Stem Cells available at: http://astarbiology.com/edexcel/stem-cells/
• Alevelnotes.com. (2017). Organelle Structure and Function | A Level Notes. [online]
Available at: https://alevelnotes.com/Organelle-Structure-and-Function/111
• BBC Bitesize (2020) Prokaryotes - Prokaryotic and eukaryotic cells, Available at:
https://www.bbc.co.uk/bitesize/guides/zy28h39/revision/6
• BBC Bitesize (2020) Animal cells and plant cells available at:
https://www.bbc.co.uk/bitesize/guides/z9hyvcw/revision/3#:~:text=Animal%
• BD Editors, (2017) cell cycle, biology dictionary https://biologydictionary.net/cell-cycle/
• Diffen.com. (2017). Eukaryotic Cell vs Prokaryotic Cell - Difference and Comparison
|Diffen. Available at:
http://www.diffen.com/difference/Eukaryotic_Cell_vs_Prokaryotic_Cell
• En.wikipedia.org. (2017). Cell (biology) Available at:
https://en.wikipedia.org/wiki/Cell_(biology)
• Khan Academy (2020) Protein synthesis, available at:
https://www.khanacademy.org/partner-content/nova/nova-labs-
topic/rnawondermolecule/a/protein
• Mr Pollock (2014), The Fluid Mosaic Model of the Cell Membrane [Online video]
Available at:hFps://www.youtube.com/watch?!me_con!nue=6&v=jEY9Bie92aM
• Nature.com. (2017). Cell Membranes | Learn Science at Scitable. Available at:
https://www.nature.com/scitable/topicpage/cell-membranes-14052567
• Science-of-aging.com. (2017). Robert Hooke and The Discovery of the Cell. Available at:
https://www.science-of-aging.com/timelines/hooke-history-cell-discovery.php
BIBLIOGRAPHY
• A Biology (2016) Stem Cells available at: http://astarbiology.com/edexcel/stem-cells/
• Act for libraries (2018) Causes or Initiation of Cell Division available at:
http://www.actforlibraries.org/causes-or-initiation-of-cell-division/
• Alevelnotes.com. (2017). Organelle Structure and Function | A Level Notes. [online]
Available at: https://alevelnotes.com/Organelle-Structure-and-Function/111
• BBC Bitesize (2020) Animal cells and plant cells available at:
https://www.bbc.co.uk/bitesize/guides/z9hyvcw/revision/3#:~:text=Animal%
• BBC Bitesize (2020) Stem Cells available at
http://www.bbc.co.uk/schools/gcsebitesize/science/21c/genes/cloning_stem_cellsrev2.sht

• BBC Bitesize (2020) growth in cells available at:
http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/growth_developme
nt/singlecellrev1.sh
• BD Editors, (2017) cell cycle, biology dictionary https://biologydictionary.net/cell-cycle/
• BD Editors (2019) Daughter Cells, Biology Dictionary available at:
https://biologydictionary.net/daughter-cells/
• BD editors (2019) facilitated diffusion, Available at:
https://biologydictionary.net/facilitated-diffusion• BD editors (2019) Krebs cycle,
Available at: https://biologydictionary.net/krebs-cycle/ (Accessed 15.9.20)
• Biology.arizona.edu. (2017). Prokaryotes, Eukaryotes, & Viruses Tutorial. Available at:
http://www.biology.arizona.edu/cell_bio/tutorials/pev/page4.html
• Biology-online dictionary (2020) Anabolism definition and examples, Available at:
https://www.biologyonline.com/dictionary/anabolism
• Biology wise (2019) Similarities Between Prokaryotic and Eukaryotic Cells available at:
https://biologywise.com/similarities-between-prokaryotic-eukaryotic-cells
• CK-12 Foundation (2020) Characteristics of Life available at:
https://www.ck12.org/biology/Characteristics-of-Life/lesson/Characteristics-of-Life-
Advanced-BIO-ADV/
• Diffen.com. (2017). Eukaryotic Cell vs Prokaryotic Cell - Difference and Comparison
|Diffen. Available at:
http://www.diffen.com/difference/Eukaryotic_Cell_vs_Prokaryotic_Cell
• Hughes, S., ePearl Cell Biology Assignment [Online] Available at:
hFps://www.epearl.co.uk/assignment/4790 • Jennifer Stearns, Michael Surette (2019)
available at: https://www.dummies.com/education/science/biology/synthesizing-protein/
• Khan Academy (2020) Protein synthesis, available at:
https://www.khanacademy.org/partner-content/nova/nova-labs-
topic/rnawondermolecule/a/protein

UNIT 5 (2).docx

More Related Content

Similar to UNIT 5 (2).docx (20)

Recently uploaded (20)

UNIT 5 (2).docx