Cell bio report PDF

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Illustrated report on cell biology...

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Cell Biology 31/12/2020 Jessica Alston

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Introduction I have produced this illustrated report to demonstrate the basic principles of life and cells. I will show that I understand basic cell structure by: • Discussing the selected characteristics of living cells. • Comparing and contrasting prokaryotic and eukaryotic cells and explaining the impact viruses have on them. • Discussing eukaryotic sub-cellular structure and organelles. I will then go onto show my understanding of cellular metabolism by explaining: • The role of the cell membrane in regulating how nutrients gained and, waste products lost. • How animal cells use nutrients to provide the energy for growth, movement, and cell division. • The role of nucleic acids in the nucleus and cytoplasm. • Discussing the synthesis of proteins. Finally, I will show that I understand how cells grow and divide by explaining: • The generation of specialised tissues from embryonic stem cells. • The process of interphase and factors that initiate cell division and their importance. • How the same genetic information received by each daughter cell. • Comparing and contrasting cancer cells with normal cells. The research I have undertaken has consisted of study materials provided by LearnDirect, reading and gathering information, images, diagrams and tables from educational platforms and online articles, enabling me to present my understanding of cell biology in this illustrated report.

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Contents page Page 1: Title page Page 2: Introduction Page 3: Contents page Pages 4-6: Chapter 1 Cell structure Pages 7-12: Chapter 2 Cellular metabolism Pages 13-15: Chapter 3 Cell growth and reproduction Page 16: Conclusions Page 16: Recommendations Page 17-18: References Page 19: Bibliography

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Cell Structure Selected characteristics of living cells Cells are the basic unit of life. Every living organism contains cells. Living organisms have these seven characteristics in common: • ‘Movement - they can move and change their position. • Reproduction – they can make more of the same kind of organism as themselves. • Sensitivity – they can detect or sense stimuli and respond to them. • Growth - they can permanently increase their size or dry mass by increasing the

number or size of their cells. • Respiration – they can create chemical reactions that break down nutrient molecules

in living cells to release energy. • Excretion – they can excrete toxic materials, waste products of metabolism, and

excess substances. • Nutrition - they can take in and absorb nutrients such as organic substances and

mineral ions. These nutrients contain the raw materials or energy needed for growth and tissue repair.’ (BBC.co.uk, BBC Bitesize – Revision, 2020) MRS GREN – using this acronym is a great way of remembering the characteristics. Prokaryotic and Eukaryotic Cells There are two basic types of cells, prokaryotic cells (bacteria and archaea) and eukaryotic cells (animals, plants, fungi and protists). Both prokaryotic and eukaryotic cells have structures in common. All cells have a cell membrane, ribosomes, cytoplasm and DNA.

Figure 1 – Prokaryotic cell and Eukaryotic cell (microbiologynote.com, 2020)

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By definition, prokaryotic cells are single-celled organisms and do not have a true nucleus or membrane-bound organelles. In contrast, eukaryotic cells have a more intricate structure than prokaryotic cells and contain membrane-bound organelles. A eukaryotic cell is approximately ten times larger in diameter than a prokaryotic cell. Viruses and their impact on cells ‘A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism.’ (Wikipedia, 2020)

Figure 2 – Virus structure (ibiologia.com, 2020) Viruses are non-living particles which depend on host cells they infect to reproduce. The host cells normal functions are hijacked by the virus and, produce more viral protein and genetic material instead of their usual products. There are six key stages in the virus replication cycle; attachment, penetration, uncoating, replication, assembly, and release. The effect viruses have on prokaryotic and eukaryotic cells is different because these cells structures are divergent. Viruses cause several viral diseases in eukaryotic cells, a few examples of these would be; AIDS, the common cold, chickenpox and influenza. The virus has receptors for the cells to attach too. It can then enter and replicate its genetic material in the nucleus, taking control of the cell's metabolism. Before the infection is fully-fledged, the virus has to afflict through many cells. Bacteriophages are viruses that infect and replicate within prokaryotes. They have a lytic cycle (leads to death of host cell) or lysogenic cycle (leads to the integration of phage into the host genome).

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Eukaryotic sub-cellular structure and organelles Eukaryotic cells contain many organelles. Each one has an important role. See the pictures below for these organelles and their roles:

Figure 3 – Animal cell (course.lumenlearning.org, 2020)

Figure 4 – Plant cell (course.lumenlearning.org, 2020)

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Cellular metabolism The role of the cell membrane Figure 5 – Cell membrane (teachmephysiology.com, 2020)

All living cells need nutrients to be able to sustain life. The cell membrane controls what substances go in and out of the cell. The basic structure of the cell membrane is made up of: • Phospholipids • Proteins • Carbohydrates How substances move across the cell membrane How substances cross the cell membrane depends on the nature of the substance. Below are the different possible methods:

Lipid diffusion

Used for transportation of lipid soluble molecules (water, oxygen, steroids and carbon dioxide). Diffusion occurs in the lipid bilayer, this is where substances move down gradients of concentration levels (no energy is needed to do this).

Figure 6 – Lipid diffusion (flexbooks.ck12.org, 2020) Osmosis

Figure 7 – Osmosis (senecalearning.com, 2020) 7

Diffusion of water molecules across the membrane, from a region of higher to lower concentration. There are 3 types of solutions:

1. Isotonic – concentration is the same as the cell (no water enters or exits). 2. Hypertonic – concentration is higher than the cell (water molecules exit). 3. Hypotonic – concentration is lower than the cell (water molecules enter).

Facilitated diffusion

Figure 8 – Facilitated diffusion (Hughes, 2.1)

Active transport

Figure 9 - Active transport (Hughes, 2.1)

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Uses trans-membrane proteins to help molecules cross the membrane. The transport protein molecules are found in two different forms: 1. ‘Channel proteins which form a pore or channel in the membrane. It is usually charged substances such as ions which make use of these proteins. The channels are often gated to allow the cells to control the entry or exit of these ions. 2. Carrier proteins which have binding sites for specific solutes, such as glucose. They can flip between two states so that the site is alternately open to opposite sides of the membrane. A substance which is to be transported binds on the side where it is more concentrated and released where it is less concentrated.’ (Hughes, 2.1)

Uses a trans-membrane protein (pump-molecule) to transport substances from a region of lower to higher concentration gradient.

Vesicles

Used to transport large molecules. Substances transported into cells are known as endocytosis and transported out are known as exocytosis.

Figure 10 – Exocytosis and endocytosis in vesicles (ck12.org, 2020)

How animal cells use nutrients for growth, movement and cell division For growth, movement and cell division to occur, cells require an energy source. ‘The primary source of energy for animals is carbohydrates, primarily glucose: the body’s fuel.’ (Courses.lumenlearning.com, 2020) Through a series of catabolic reactions the carbohydrates are transformed into glucose molecules. Anabolism occurs in cell growth (synthesis). ‘The anabolic reactions involve complex molecules being manufactured from simpler molecules.’(Hughes, 2.2) Anabolic reactions need energy, this is provided by the hydrolysis of ATP (adenosine triphosphate). ATP is made during respiration, which occurs in two stages: • Glycolysis – breaks down glucose in the cytoplasm. • Kerbs cycle – a series of chemical reactions to release stored energy in the mitochondrion.

Figure 11 – Cellular respiration (Hughes, 2.2) Cellular respiration is the final result of ATP. Movement of nutrients around the cell can involve endocytosis, exocytosis and active transport; these make sure the cell to maintain a steady environment.

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Cell division requires movement of key structures within the cell. There are two types of cell division in animal cells, these are mitosis – process of making new cells and meiosis – cell division that creates egg and sperm cells. These processes happen within the nucleus.

Figure 12 – Cell division (assignmentpoint.com, 2020) Nucleic acids Nucleic acids are macromolecules. They’re chains of nucleotide which provide genetic information. ‘A nucleotide is made up of three parts: a phosphate group, a 5-carbon sugar, and a nitrogenous base.’ (Biologydictionary.net, 2020) In DNA there are 4 nitrogenous bases: adenine, cytosine, guanine and thymine. Instead of thymine, RNA contains uracil. Nucleotides combined form a polynucleotide, DNA or RNA.

Figure 13 – Polynucleotide strands with DNA and RNA molecules (Hughes, 2.4) DNA is a double stranded polymer of nucleotides which is situated in the nucleus. RNA is a single stranded polymer of nucleotides which is situated in the cytoplasm. There are 3 forms of RNA, see picture below:

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Figure 14 – Different types of RNA molecule (loretocollegebiology.weebly.com, 2020)

Synthesis of proteins Proteins, defined as organic macromolecules, are extremely important for growth and repair in eukaryotic cells. A protein structure described in levels, see picture below: Figure 15 – Structure of a protein shown in levels (Hughes, 2.3)

Different chemical bonds hold the whole molecule together.

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There are stages that occur in protein synthesis, these are: transcription (in the nucleus), activation (in the cytoplasm) and translation (at the ribosome).

Figure 16 – Protein synthesis (dreamstime.com, 2020)

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Cell growth and division Specialised tissues from stem cells By definition, a stem cell is an undifferentiated cell capable of giving rise to indefinitely more cells of the same type and other cells can arise from it by differentiation. (Hughes, 3.1) There are three types of stem cells: • Embryonic – derive from embryos (able to become any other type off cell in the body). • Foetal – found in the tissues of developing foetus. • Adult stem cells – found in the tissues of adults, for example: bone marrow (used to treat blood diseases and blood cancer. Embryonic stem cells are pluripotent. They evolve from a fertilised egg (zygote), which later develops into the blastocyst. The blastocyst has an inner mass of cells (embryoblast) which become the embryo and an otter mass off cells (trophoblast) which becomes the placenta. Usually, embryos used are ones that haven’t been used in IVF treatment clinics.

Figure 17 – Pluripotent stem cell (medicinenet.com) In controlled environments, the stem cells are allowed to divide and multiply. ‘The next step in the process is to actually collect healthy, dividing and undifferentiated cells, which is known as a stem cell line.’ (Hughes, 3.1) Stem cells have the ability to treat diseases such as, heart disease, cancer and Parkinson’s disease.

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Interphase and factors that initiate cell division Interphase is what a cell goes through when it divides, it is a part of the cell cycle.

Figure 18 – Cell cycle (www2.le.ac.uk, 2020) Interphase has different phases: G1 (the cell grows), S (synthesis of new DNA), and G2 (prepares for mitosis). Mitosis is broken down into 4 stages: prophase, metaphase, anaphase and telophase. See diagram below: Figure 19 – Summary of mitosis and it’s different stages (Hughes, 3.3)

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During the cell cycle, mitosis is where the cell divides , making two identical daughter cells ensuring they contain the same chromosomes and DNA as the parental cell. Mitosis is also used in organisms that reproduce sexually and for growth and repair in animal cells. Cancer cells Cancer cells are physically different and have different characteristics to normal cells. They are produced by uncontrollable division which then damages the healthy cell.

Figure 20 – Normal vs cancer cell (Hughes, 3.4) As you can see from the diagram above the structure of cancer cells differ from normal. Normal cells have a large cytoplasm, one nucleus, one nucleolus and fine chromatin. In contrast, cancer cells have a small cytoplasm, multiple nuclei, large and multiple nucleoli and coarse chromatin.

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Conclusions The cell is a complex living organism. Each and every organism is made up of equally complex microorganisms. They work in harmony to sustain life. Without intervention, cells grow, metabolise and divide. Cells are the smallest structural and functional unit of life. It is important cells are kept healthy in order for them to go through their routine functions efficiently. Cell biology allows us to be able to understand life, which has enabled us to find ways to preserve and create life with science and medicine. The study of cells has led to the treatment of many diseases, illnesses and fix issues with fertility.

Recommendations To begin with all the terminology was a bit beyond me, but I soon found by writing things down and what they mean my confidence grew as I was able to refer back to my ‘help sheet’ for clarity. In the future I will use more videos when researching as they are more easy to follow. I also need to allow more time for researching and revising.

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References o BBC.co.uk, BBC Bitesize – Revision – characteristics [online] Available at: https://www.bbc.co.uk/bitesize/guides/zr46fg8/revision/1 (Accessed December 2020) o Microbiologynote.com – Prokaryotic and eukaryotic cell [image] Available at: https://microbiologynote.com/prokaryotic-cell-and-eukaryotic-cell/ (Accessed December 2020) o Wikipedia – Viruses [online] Available at: https://en.m.wikipedia.org/wiki/Virus (Accessed December 2020) o Ibiologia.com – Viruses [image] Available at: https://ibiologia.com/virus-structureclassification508-2/ (Accessed December 2020) o Course.lumenlearning.com – Animal cell [image] Available at: https://courses.lumenlearning.com/boundless-biology/chapter/eukaryotic-cells/ (Accessed December 2020) o Course.lumenlearning.com- Plant cell [image] Available at: https://courses.lumenlearning.com/boundless-biology/chapter/eukaryotic-cells/ (Accessed December 2020) o Teachmephysiology.com – Cell membrane [image] Available at: https://teachmephysiology.com/histology/cell-structures/cell-membrane/ (Accessed December 2020) o Flexbooks.ck12.org – Lipid diffusion [image] Available at: https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook2.0/section/2.11/primary/lesson/diffusion-bio (Accessed December 2020) o Senecalearning.com – Osmosis [image] Available at: https://senecalearning.com/enGB/definitions/osmosis/ (Accessed December 2020) o Hughes, S. – ePearl, facilitated diffusion [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/8NiGlr32qCyF3C4W4iFUQXsJd6UgOiS C (Accessed December 2020) o Hughes, S. – ePearl, facilitated diffusion [online] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/8NiGlr32qCyF3C4W4iFUQXsJd6UgOiS C (Accessed December 2020) o Hughes, S. – ePearl, active transport [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/8NiGlr32qCyF3C4W4iFUQXsJd6UgOiS C (Accessed December 2020) o Hughes, S. – ePearl, vesicles [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/8NiGlr32qCyF3C4W4iFUQXsJd6UgOiS C (Accessed December 2020) o Ck12.org – Exocytosis and endocytosis [image] Available at: https://www.ck12.org/c/biology/exocytosis-and-endocytosis/lesson/Exocytosis-andEndocytosis-BIO/ (Accessed December 2020) o Lumenlearning.com – Animals energy source [online] Available at: https://courses.lumenlearning.com/boundless-biology/chapter/nutrition-and-energyproduction/

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o Hughes, S. – ePear, anabolic reactions [online] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/bM6YXZw7MHKT4hLjg9uYW_w1tSO PPbde (Accessed December 2020) o Hughes, S. – ePearl, cellular respiration [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/bM6YXZw7MHKT4hLjg9uYW_w1tSO PPbde (Accessed December 2020 o Biologydictionary.net – Nucleotides [online] Available at: https://biologydictionary.net/nucleotide/ (Accessed December 2020) o Assignment point.com – Cell division [image] Available at: https://www.assignmentpoint.com/science/biology/cell-division.html (Accessed December 2020) o Hughes, S. – ePearl, polynucleotide strands [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/0rbJjmRypsE9dwIS_QxXXKYcfCiesT0 n (Accessed December 2020) o Loretocollegebiology.weebly.com – RNA molecules [image] Available at: http://loretocollegebiology.weebly.com/rna-structure.html (Accessed December 2020) o Hughes, S. – ePearl – protein structure [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/Nz01NES1c2DVCAK54Br4MgWZEq2h XGGc (Accessed December 2020) o Dreamstime.com – Protein synthesis [image] Available at: https://www.dreamstime.com/protein-synthesis-vector-illustration-transcriptiontranslation-protein-synthesis-vector-illustration-labeled-transcriptionimage129145976 (Accessed December 2020) o Hughes, S. – ePearl, stem cells [online] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/NC-Aw1IB-PnFeXZbQYEZ4aOaPHVJk9m (Accessed December 2020) o Medicinenet.com – Pluripotent stem cell [image] Available at: https://www.medicinenet.com/human_pluripotent_stem_cell/definition.htm (Accessed December 2020) o Hughes, S. – ePearl – stem line [online] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/NC-Aw1IB-PnFeXZbQYEZ4aOaPHVJk9m (Accessed December 2020) o Www2.le.au.uk – cell cycle [image] Available at: https://www2.le.ac.uk/projects/vgec/highereducation/topics/cellcycle-mitosis-meiosis (Accessed December 2020) o Hughes, S. – ePearl, mitosis [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/gQG2HoqSZkuaC1lsIZNQ6o7YM4c8M OVw (Accessed December 2020) o Hughes, S. – ePearl, normal vs cancer cell [image] Available at: https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/index.html#/lessons/R7MXn7QyXQlXTlMGPsx0m6cEcw8h HkDg (Accessed December 2020)

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Bibliography o https://ldatom.epearl.co.uk//vle/_store/scorm/1604424138-cell-biology-scorm2004-4l459oaha/scormcontent/i...