Introduction to the Cell - Student PDF

Introduction to the cell September 2024 By Jayne Evans E-mail [email protected] Before we begin, you will need …  By the end of the lecture students will –  Be introduced to the levels of structural organisation within the human body...

Introduction to the cell September 2024 By Jayne Evans E-mail [email protected] Before we begin, you will need …  By the end of the lecture students will –  Be introduced to the levels of structural organisation within the human body  Have an introductory level of knowledge and understanding Learning of the levels of organisation within the human body Aims and Be introduced to the cell and the structures within it  Have an understanding of the main structures within the Objective human cell Be able to recall the key structures s Explore the cell structures and their main function within the cell  Have an introductory level of knowledge and understanding of the functions of the cell structures  Be able to recall the main functions  Characteristics of living things To be characterised as ‘living’, there are said to be 7 key characteristics, often referenced as ‘MRS GREN’ Move – all living things move Respiration – getting energy from food Sense – detect and respond to changes in surroundings Growth – all living things grow Reproduce Excrete- getting rid of waste Nutrition – taking in and using food Believe it or not, you are organised! Well, your body is at least…  Levels of organisation in the human body There are different levels of structural organisation within the human body. The most basic of these is chemical. Atoms combine to form Molecules – of which there are a wide variety within the human body Molecules make up Cells – the smallest units of living matter – there are trillions of them within the body. Each cell type is specialised and carries out a particular function to contribute to what the body needs. Cells with similar structures and functions form tissues Different types of tissues combine to form Organs Organs group together to perform set functions, within a body System. This view may help… Atoms to electrolytes  Starting at the basics… Everything is made from atoms – when the same atoms combine they form an ELEMENT – see periodic table! Common elements would be hydrogen, carbon. A MOLECULE is formed when two or more atoms of a specific element are chemically joined together O². A COMPOUND is two or more types of atom combined, such as water being hydrogen and oxygen H²O. Living tissues are composed almost entirely of just four elements: Carbon, hydrogen, oxygen and nitrogen. Small amounts of others are present (about 4% of body weight) including sodium, potassium, calcium, phosphorus Why do you need to know this? All elements are vital to human body functioning, then any disruption, deficit or excess in relation to their production or use, will affect body function at a cellular level. This ultimately affects tissue-organ-system function  Electrolytes within the body Electrolytes are found within the blood and are essential for cell function. These are basically atoms which have an electrical charge (called ions). In solutions (such as blood), ions are known as electrolytes as they can conduct an electrical charge. They can be found both intracellular and extracellular. They have a positive or negative charge therefore they have the ability to conduct electricity within cells and carry electrical impulses across cell membranes. This is essential for muscle and nerve function: maintaining fluid balance: maintaining pH of body fluids. Electrolytes within the body Some essential electrolytes are: Sodium (Na+) - control of heart rate, muscle movement, nerve impulses Potassium (K-) – heart rate control, nerve and muscles, blood pH Chloride (Cl-) - Fluid balance Within nursing we often check levels of electrolytes through blood tests predominantly. Any excess or lack of electrolytes will affect the bodies functioning at a cellular level – ultimately leading to tissue-organ- system effects without effective treatment. THE CELL  Cell theory Cells were discovered in 1665 by Robert Hooke Schleiden and Schwann proposed the Cell Theory - All organisms consist of one or more cells The cell is the smallest unit of life All cells come from pre-existing cells All living things are made up of cells Cells are the smallest working units of all living things All cells come from pre-existing cells through cell division Types of cells Prokaryotic Example - bacteria Eukaryotic – complex organisms, example animal, plants, fungi plus others  Eukaryotic cells Contain organelles surrounded by membranes Most living organisms Plant cell Animal cell http://library.thinkquest.org/C004535/eukaryotic_cells.html Human Cells Cells are the basic functioning units of the body. Each type of cell has a specific function and they vary in size Over 200 types of Genetic material – cell within the in a nucleoid or human body nucleus All cells have Cytoplasm – a certain structures semifluid matrix in common – Plasma membrane – a phospholipid bilayer Cell membrane Semi-permeable or selective permeability Controls what enters and leaves cell Made up of two layers of phospholipids (fats) Double bi-phospholipid layer Forms a barrier between cell contents and surroundings How a substance enters the cell depends on its size and solubility Proteins within membrane provide channels to allow passage of certain substances. How do substances move across the cell membrane? Passive processes Simple diffusion Osmosis Facilitated diffusion Active processes – ATP used Active transport Endo/Exocytosis Inside the cell - Organelles Nucleus largest organelle within the cell. Has a membrane. Contains chromosomes (DNA) which direct all activities of the nucleus, 46 (23 pairs). Control centre of cell – directs cells activities. Pores in nucleus membrane allow movement from inside nucleus into the What is a Nucleus?- Structure and Fun cell cytoplasm ction of Nucleus (byjus.com) Chromosomes Situated in the nucleus Made of Deoxyribonucleic acid (DNA) Contains instructions for traits and characteristics  Cytoplasm The cytoplasm functions to support and suspend organelles and cellular molecules in a gel like mixture that is surrounded by the cell membrane. Many cellular processes also occur in the cytoplasm, such as protein synthesis, the first stage of cellular respiration (known as glycolysis), mitosis, and meiosis. The cytoplasm helps to move materials, such as hormones, around the cell and also dissolves cellular waste.  Endoplasmic Reticulum Overall functions Synthesis, folding, modification and transportation of proteins Regulates many cellular process Communicates with other organelles to co-ordinate the cells metabolism to maintain homeostasis Two types – Rough Endoplasmic Reticulum – Rough ER Rough outer surface due to ribosomes Quality control – ensures the proteins produced by the attached ribosomes are folded correctly to perform their assigned function Smooth endoplasmic Reticulum – Smooth ER Makes lipids Detoxifies the cell  Ribosomes Every cell contains thousands of ribosomes Produced by the nucleolus Manufacture proteins for use by the cell Found on the endoplasmic reticulum and floating in the cytoplasm Ribosomes - Structure And Functions | A-Le vel Biology Revision Notes (alevelbiology.c o.uk) Mitochond ria Produces energy through chemical reactions – breaking down fats and carbohydrates Controls the level of water and other materials in the cell Recycles and decomposes proteins, fats and carbohydrates Anaerobic and Aerobic Anaerobic aerobic respiration Oxygen Needed Not needed Glucose breakdow Complete Incomplete n Aerobic respiration releases 19 times End Carbon more energy than anaerobic product(s dioxide and lactic acid. ) water respiration from the same amount of glucose. Energy Relatively Relatively large released small amount amount  Golgi bodies Protein packaging plant Move materials within the cell Move materials in and out of the cell Golgi apparatus | Definition, Function, Location, & Facts | Britannica lysosome Lysosomes are membrane- enclosed organelles that contain an array of enzymes capable of breaking down all types of biological polymers—proteins etc. Diagram of Lysosomes and Typ es - Biology Brain Cytoskelet on Network of protein fibres which provide structural support, maintain cell shape and facilitate movement (eg muscle cell contraction) https://directorsblog.nih.gov/ 2015/04/02/snapshots-of-life-cell-  At the end of the lecture have/are you? –  Been introduced to the levels of structural organisation within the human body  Developed an introductory level of knowledge and understanding of the levels of organisation within the Learning human body Aims and Been introduced to the cell and the structures within it Objectives –  Developed an understanding of the main structures within the human cell How did we  Able to recall the key structures do? Explored the cell structures and their main function within the cell  able to demonstrate an introductory level of knowledge and understanding of the functions of the cell structures  Able to recall the main functions Thank you for listening and participating This Photo by Unknown Author is licensed under CC BY-SA Further reading/ references Cook, Boore, J. R. P., Shepherd, A., McCormack, B., & McCance, T. (2021). Essentials of anatomy and physiology for nursing practice (2nd edition.). SAGE Publications. Tortora, G.,J. and Derrickson, B. (2023) Principles of anatomy and physiology. (16th ed.) Wiley Waugh, A., & Grant, A. (2022) Ross & Wilson Anatomy and Physiology in Health and Illness. (14th ed.) Elsevier. Website – create an account with your student email address – free https://www.khanacademy.org