Biology Pres - Cells & Tissues

The Role of Cells and Tissues Within the Body

PRESENTATION By Aiden Roberts

This interactive slideshow will include these topics:

• Description of the difference between prokaryotic cells and eukaryotic cells
• An examination of the role of cell organelles
• An explanation of the process and function of cell division
• Analysis of the structure and function of animal tissues

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Prokaryotic Cells vs. Eukaryotic cells

What's the difference?

(Testbook, 2023)

(Buckley, 2020)

(Mokobi, Microbe Notes, 2023)

Prokaryotic cells are the simplest form of a living organism. They have no membrane bound organelles and so these cells have no nucleus. They are unicellular or single-celled. Prokaryotes are classified as bacteria and archaea. Within the cell’s plasma membrane, contains loose DNA and ribosomes which, after the necessary biochemical reactions happen, produce the proteins needed to reproduce and gather nutrients. All other living organisms are composed of eukaryotic cells, multicellular organisms. As these prokaryotic cells are simpler than eukaryotic cells, they are much smaller than them, measuring at 0.1 to 5.0 micrometres in diameter (μm).

Eukaryotic cells, on the other hand, are cells that have membrane bound organelles and so they contain a nucleus. All the organisms within the Plantae, Animalia, Fungi and Protist kingdoms are composed of eukaryotic cells. The only organelle both prokaryotes and eukaryotes have in common are ribosomes, whose role is to synthesise proteins, which is a necessary function for all cells. Both eukaryotes and prokaryotes contain cytoplasm, whose function is to protect inner organelles against damage and both have an exterior plasma membrane which controls what substances enter and exit the cell. The main difference between these types of cells is that only eukaryotic cells possess a nucleus, which contains genetic material such as DNA and RNA. Prokaryotic cells contain a nucleoid instead, essentially a very simplified nucleus. A nucleus is essentially a control centre for the cell, determining all activities across the cell such as protein synthesis, growth, metabolism, reproduction and more.

Function of each organelle

This page examines the role and functions of eukaryotic cell orgnelles.

Watch this video linked above, then tick which properties prokrayotic and eukarutoic cells have in common

The differences are..

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Examination of the roles of cell organelles

Read this article from Anatomy & Physiology then answer these questions.

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The Process and functions of cell division

What are the key differences between the two processes of cell division?

Meiosis

Mitosis

Meiosis is the process of cell division that produces four haploid cells by halving the number of chromosomes in the original parent cell to ensure each cell is genetically distinct. All organisms that reproduce sexually must utilise the process of meiosis. Whereas, organisms that reproduce asexually utilise the mitosis approach. There are two stages of this process, the first where homologous chromosomes are separated and the second, where the sister chromatids are separated. Each stage has four steps. Meiosis ensures all organisms created via sexual reproduction contain the correct number of chromosomes.

• Mitosis splits a cell into 2 genetically identical daughter cells to the parent cell. This is vital to GROWTH and REPAIR within the body as without this process, cells would simply die and so the organisms would die. Mitosis is the only way an infant/baby can grow into an adult. All animal and plant life would cease to exist without it.

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Mitosis stages

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• Prophase (early prophase)

• Prometaphase (late prophase)

• Metaphase

• Anaphase

• Telophase

The first stage of mitosis, the chromosomes within the cell start to condense. The mitotic spindle starts to form and the nucleolus starts to disappear.

The transition period between prohase and metaphase. The chromosomes compact so much so that the nuclear envelope begins to break down. The mitotic spendle grows larger and begins to catch chromosomes.

Subtitle

The mitotic spindle has caught all of the chromosomes and lines them up in what's termed the 'metaphase plate'. The kinetochores of each chromosome attaches to a microtubule from opposite side spindle poles.

The sister chromatids seperate from each other as the protein glue breaks down. Chromosomes from each pair are pulled to oppoiste ends of the cells. The microtubules not attached to any chromosomes start to seperate the poles and ultimately make the cell longer, by elongating themselves and pushing apart.

Two new nuclei form, one from each set of chromosomes. New nuclear membranes and nucleoli appear. The cell is almost finished dividing as the mitotic spindle is broken down into its building blocks. The chromosomes expand and and return to their original stringy form.

Meiosis stages

In the first stage during prophase 1, chromosomes condense to become visible inside the nucleus. Each chromosome pairs itself with its homologous partner chromosome. Chromosomes then cross over, exchanging parts of their DNA to form unique combinations of alleles. Metaphase 1 Spindles capture chromosomes and move them towards the centre of the cell or metaphase plate. Each chromosome attaches to one pole of the spindle but homologous binds to microtubules from opposite poles. The homologous pairs line up at the metaphase plate for separation. The orientation of the pairs are random to allow for different formations within the gametes. Anaphase 1 Homologues are separated and moved to opposite sides of the cell. Telophase 1 The chromosomes are at opposite poles of the cell. Cytokinesis occurs, which forms two haploid cells. Prophase 2 Chromosomes condense and the nuclear envelope breaks down. Centrosomes move away from each other, a spindle forms between, then spindle microtubules capture the chromosomes. The sister chromatids are captured from opposite poles of the spindle. Metaphase 2 The chromosomes line up along the metaphase plate. Anaphase 2 The sister chromatids seperate and get moved to opposite poles of the cell. Telophase 2 New nuclear membranes form around each set of chromosomes. Cytokinesis splits the sets of chromosomes into new cells: four haploid cells where each chromosome contains only one chromatid.

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Analysis of the Structure and Functions of Animal Tissues

Epithelial Tissue

Structure and Function

Epithelial tissue - functions

Extra iNFO

The function of epithelial tissue differs depending on where it is located in the body. Protection - for example, the epidermis/outer layer of skin protects the deep tissue within the body such as blood vessels, muscle and internal organs. Another example is the cilia on the epithelial cells in the lining of the small intestine help protect against intestinal bacteria. Secretion - glandular epithelium secretes enzymes, hormones, and fluids of different types. Absorption - the epithelial lining of internal organs e.g. liver and lungs, allow the abortion of certain substances. For example, the internal epithelial lining of the intestines absorbs nutrients from the food eaten. Excretion - e.g. the epithelial tissue is the kidneys excrete waste. E.g. the epithelial tissue in sweat glands are responsible for excreting sweat. Filtration - the epithelium of the respiratory tract filters out particles and dirt, cleaning the air inhaled. Another example is the epithelial tissue in kidneys filtering blood. Diffusion - simple squamous epithelial cells form a membrane that allows selective diffusion of materials to pass through. Sensory reception - sensory nerve endings embedded within epithelial tissue allows the body to receive outside sensory stimuli. E.g. taste buds are embedded within the stratified squamous epithelium of a person's tongue. E.g. the stereocilia on the surface of the epithelial tissue in the inner ear help with hearing and balance. Text paraphrased from Professor Dave Explains (2018), Types of \tissue Part 1: Epithelial Tissue. Available at: https://www.youtube.com/watch?v=oe-Z9t0KBfU

Connective Tissue

Answer these questions to test your knowledge!

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Conective Tissue - Video Summary

This video summarises and explains key basic aspects of the different structures and roles of the different types of connective tissues.

Muscle tissue

There are 3 categories of muscle tissues, all structured differently and perform different functions vital to the survival of an animal's body!

Skeletal Muscle

Smooth Muscle

Cardiac Muscle

Muscle tissue

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Main Properties of the Different Types of Muscle Tissue

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Cardiac muscle

Skeletal muscle

Smooth muscle

Nervous tissue

Structure and Function of Nervous Tissue

Structure: Composed of 2 types of cells - neurons and glial cells. The neurons are electrically active and responsible for the communication within the nervous system. Neurons release chemical signals to target certain cells. Glial cells support the neurons within the nervous system. Some of these cells are phagocytic and help to protect against invasion by bacteria and others help to bind blood vessels to neurons to ensure nutrients are provided. Functions:Responsble for controlling and coordinating body activites The brain, spinal cord and nerves are made up of nervous tissue. Neurons are what makes the brain active and produce thoughts, as well as interpret information from outside stimuli. The cells have 3 main components - dendrites, cell body and axon.

Do you know what this 2% stands for?

2%

Helpful links to learn more

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References

https://training.seer.cancer.gov/anatomy/cells_tissues_membranes/tissues/nervous.html https://opentextbc.ca/biology/chapter/14-2-animal-primary-tissues/#:~:text=Multicellular%2C%20complex%20animals%20have%20four,specialized%20functions%20within%20the%20body. https://open.oregonstate.education/aandp/chapter/4-4-muscle-tissue/ https://pressbooks-dev.oer.hawaii.edu/biology/chapter/animal-primary-tissues/#fig-ch33_02_12 References https://www.khanacademy.org/test-prep/mcat/cells/eukaryotic-cells/a/organelles-article https://biologydictionary.net/prokaryotic-cell/ – G. Buckley, 2020. https://www.khanacademy.org/science/biology/structure-of-a-cell/prokaryotic-and-eukaryotic-cells/a/prokaryotic-cells#:~:text=Typical%20prokaryotic%20cells%20range%20from,from%2010%20to%20100%20%CE%BCm. – Khan Academy https://testbook.com/biology/diagram-of-animal-cell – animal cell diagram https://byjus.com/biology/cell-organelles/#plasma_membrane https://byjus.com/biology/difference-between-nucleus-and-nucleoid/#:~:text=A%20nucleus%20is%20a%20spherically,not%20found%20in%20a%20nucleoid. https://my.clevelandclinic.org/health/articles/22062-epithelium

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