The Human Cell PDF

T H E HUMAN CELL GUASA, J. T., INOY, PALAD, J. N. K.& LIMUEL S. INOY, L. S.  THE HUMAN CELL Introduction Fundamental unit of life Self-replica...

T H E HUMAN CELL GUASA, J. T., INOY, PALAD, J. N. K.& LIMUEL S. INOY, L. S.  THE HUMAN CELL Introduction Fundamental unit of life Self-replicating structure The first cell was observed and named by Robert Hooke in 1665 from a slice of cork Some organisms consist of a unicellular organism, while others are multicellular Diameter 2 – 120 µm  THE HUMAN CELL Introduction CELLS are often called the microscopic building blocks of the body. They are active and dynamic, they continually grow and specialize, function, die, and replenish themselves by millions every second. The whole body contains about 37.2 trillion (37,200,000,000,000) of cells There are 226 different kinds of body cell  THE HUMAN CELL Why are cells so small? Cells need sufficient surface area to allow adequate transport of nutrients in and wastes out. As cell volume increases, so does the need for the transporting of nutrients and wastes. However, as cell volume increases the surface area of the cell does not expand as quickly. If the cell’s volume gets too large it cannot transport enough wastes out or nutrients in. Thus, surface area limits cell volume/size.  THE HUMAN CELL They also contain the body’s hereditary material in the form of DNA and make copies of themselves. Cells are extremely small, typically only about 0.01 millimeters (.0004 or 4 ten- thousandths of an inch) across – even our largest cells are no bigger than the width of a human hair.  THE HUMAN CELL Parts of the Cell Each living cell carries out the tasks of taking food, transforming food into energy, getting rid of wastes, and reproducing. Most of our body cells have three main parts: Cell outer Membrane Cytoskeleton structure inside to keep its shape The nucleus  THE HUMAN CELL Cell Membrane maintaining the integrity of the cell, regulating the passage of substances, facilitating communication, and contributing to various cellular processes essential for life.  THE HUMAN CELL Cytoskeleton Structures provides support, enables movement, and participates in a wide range of cellular functions. Its organization and activities are tightly regulated, contributing to the overall integrity and functionality  THE HUMAN CELL Nucleus houses genetic material and serves as the control center for many cellular activities. Its functions are vital for the proper growth, development, and functioning of eukaryotic cells.  THE HUMAN CELL Cell Diversity – Internal Organization The Nucleus of each cell contains DNA(deoxyribonucleic acid) which directs the activity of the cell. Eukaryotes have a true nucleus, where the genetic material (linear DNA) is enclosed within a nuclear membrane. Prokaryotes lack a distinct nucleus and membrane-bound organelles.  THE HUMAN CELL Structure and Function of Organelles An organelle is a tiny cellular structure that performs specific functions within a cell. Organelles are embedded within the cytoplasm (liquid) of our cells and are held in there by an outside membrane. –Cell Membrane –Mitochondria –Nucleus –Lysosomes –Cell Wall –Peroxisomes –Cytoplasm –Cilia and Flagella –Cytoskeleton –Basal Bodies –Ribosomes –Centrioles –Endoplasmic Reticulum –Vacuoles –Golgi Apparatus –Plastids  THE HUMAN CELL Multicellular Organisms Cells in multicellular organisms often specialize (take on different shapes & functions)  THE HUMAN CELL Specialized Human Cells Muscle cells Red Blood Cells Cheek cells THE HUMAN CELL THE HUMAN CELL  THE HUMAN CELL History of Cell Theory mid 1600s – Anton van Leeuwenhoek - improved microscope, observed many living cells mid 1600s – Robert Hooke - observed many cells 1850 – Rudolf Virchow - proposed that all cells come from existing cells  THE HUMAN CELL History of Cell Theory Cells were discovered in 1665 by Robert Hooke. Early studies of cells were conducted by - Mathias Schleiden (1838) - Theodor Schwann (1839) Schleiden and Schwann proposed the Cell Theory.  THE HUMAN CELL The Cell Theory Proposed by Matthais Schleiden and Theodor Schwann in 1839 1. All living things are composed of one or more cells. 2. Cells are an organisms’ basic units of structure and function. 3. Cells are the smallest working unit of all living things. 4. Each cell maintains homeostasis at the cellular level. 5. Homeostasis at the level of the tissue, organ, organ system, and organism, reflects the combined and coordinated actions of billions of cells. Cell Theory Virchow  THE HUMAN CELL Cell Size 1 nm = nanometer = 1 billionth of a meter µm = 1 micron = 1 millionth of a meter  THE HUMAN CELL Cell Size Diversity Smallest cell Longest cell Biggest cell THE HUMAN CELL Cell  THE HUMAN CELL In passive processes concentration or pressure differences drive the movement. In active processes the cell provides energy (ATP) to power the transport process.  THE HUMAN CELL Membrane Transport Passive - doesn’t use energy - molecules are moving from high concentration to low Active - requires energy - molecules are moving from low concentration to high - done with the help of proteins called pumps  THE HUMAN CELL Types of Diffusion Diffusion – helps in the movement of substances in and out of the cells. ❖ Simple diffusion - ions or molecules diffuse from an area of high concentration to an area of low concentration. ❖ Osmosis– transport of solvent molecules (water) ❖ Facilitated diffusion – transport of solute with help from membrane proteins: channels and transporters  THE HUMAN CELL Factors that may affect Diffusion Temperature Molecular size Distance Pressure THE HUMAN CELL Diffusion  THE HUMAN CELL Osmosis Osmosis is the diffusion of water molecules (solvent) until the concentration of the solute is equal on both sides of the membrane. Direction of water flow is: - from a higher concentration of free water molecules to a low - Or from a low concentration of solute molecules to a high  THE HUMAN CELL Active transport Active transport Moving molecules Against their concentration gradient; can be done only using energy (ATP). Proteins in the membrane called pumps can use ATP to push chemicals from low concentration to high concentration. Example: NA/K-pump  THE HUMAN CELL Active transport The sodium-potassium pump moves potassium and sodium ions across the plasma membrane. credit: modification of work by Mariana Ruiz Villarreal)  THE HUMAN CELL References Marieb, E. Human Anatomy & Physiology Laboratory Manual. (11th edition). Illinois, USA: Pearson Education, Inc. 2014. Marieb, E and Keller, S. Essentials of Human Anatomy and Physiology. (12th edition). London, UK: Pearson Education Ltd. 2018. END