Biology Week 19 & 20 Cell Structures and Organelles PDF

Module 7: Cell Structure and Function Br. Farhan Kamili  Lesson 4 Cell Structures and Organelles Br. Farhan Kamili Focus Question What are the structures and their functions in prokaryotic and eukaryotic cells? Moving into the cell Prokaryote...

Module 7: Cell Structure and Function Br. Farhan Kamili  Lesson 4 Cell Structures and Organelles Br. Farhan Kamili Focus Question What are the structures and their functions in prokaryotic and eukaryotic cells? Moving into the cell Prokaryote We talked about the outside of the cell (plasma membrane) and how the cell brings materials into and out of the cell (cellular transport) Plasma membrane Now we will go inside of the cell and talk about the structures and organelles found on the inside The insides of prokaryotes and eukaryotes are very different but they do have some similarities Eukaryote Common Structures Common structures between cell types Prokaryote and eukaryote cells are distinct but have some cell structures in common All prokaryotes and all eukaryotes have: ○ Plasma membrane ○ Cytoplasm ○ Cytoskeleton ○ Ribosomes All prokaryotes and some eukaryotes have: ○ Cell wall Only eukaryotes have membrane-bound organelles Common structures – Plasma membrane We did a whole two sections on this Biology Week 14: Cell Theory and Plasma membrane Common Structures – Cytoplasm The environment enclosed by the plasma membrane is semifluid material called cytoplasm. In prokaryotes, all the chemical processes of the Cytoskeleton cell take place directly in the cytoplasm. In eukaryotes, these processes take place within organelles in the cytoplasm. – The organelles are located within the cytoplasm  Common Structures - Cytoskeleton The cytoskeleton is a supporting network of long, thin protein fibers that form a framework for the cell. Microtubules are long, hollow protein cylinders that form a rigid skeleton for the cell and help Cytoskeleton move substances within the cell. (not pictured) Microfilaments are thin protein threads that help give the cell shape and enable it to move. Centrioles are bundles of microtubules that are important during cell division. Common Structures – Ribosomes Ribosomes are organelles that manufacture proteins. ○ Proteins are like workers of the cell Unlike other organelles, ribosomes are not membrane-bound. Recall: Only eukaryotes have membrane-bound organelles Membrane-bound means that the organelle is surrounded by a layer that separates it from the rest of the cytoplasm (like a phone case) Common structures – Cell wall All prokaryotes and some eukaryotes have cell walls The cell wall of a is a thick, rigid mesh of fibers that surrounds the outside of the plasma membrane. Plant cell wall Prokaryote cell wall Protects the cell and gives it structure It is made from a carbohydrate ○ Cellulose in plants ○ Peptidoglycan in prokaryotes Common structures – Flagella Flagella are external structures made up of microtubules that help cells move around Flagella are found in some prokaryotes and some eukaryotes Some eukaryotes have cilia that also in aid in movement Some prokayotes have pili filament structures that help in adhesion, movement, and DNA transfer Prokaryote Structures Some prokaryotes also have pili and capsules Pili filament structures that help in adhesion, movement, and DNA transfer Capsules are made up of a stick carbohydrate that helps cells adhere to surfaces and prevent drying out Eukaryote Structures Eukaryotes have additional membrane bound organelles: Nucleus Mitochondria Chloroplast Endoplasmic reticulum (ER) Golgi apparatus Vacuole Lysosome Nucleus – Controlling Cell Activities The nucleus of a cell contains most of the cell’s DNA, which stores information used to make proteins that determine a cell’s growth, function, and reproduction. The nucleus is surrounded by a double membrane called a nuclear envelope. Mitochondria – Processing Energy Mitochondria (singular: mitochondrion) convert sugar particles into usable energy in the form ATP They have an outer membrane and a highly folded inner membrane that provides surface area for breaking the bonds in sugar molecules. Chloroplasts – Processing Energy Plant cells and some other eukaryotes also contain chloroplasts, which capture light and convert it into chemical energy in a process called photosynthesis. Chloroplasts are composed of multiple thylakoids, which contain the light-capturing pigment called chlorophyll. Endoplasmic Reticulum – Manufacturing Proteins The endoplasmic reticulum (ER) is a membrane system of folded sacs and interconnected channels that serves as the site for protein and lipid synthesis. There are two parts of endoplasmic reticulum: Rough ER–has ribosomes attached to it, location of protein production; Smooth ER–no ribosomes, location of carbohydrate and lipid production Both–sites of production of compounds that the cell needs Golgi Apparatus – Processing, Transporting, and Storing Molecules The Golgi apparatus is a flattened stack of membranes that modifies, sorts, and packages proteins. Proteins are packaged into sacs called vesicles, which can fuse to the plasma membrane and release the proteins to the environment. Vacuole – Processing, Transporting, and Storing Molecules A vacuole is a membrane-bound sac used for temporary storage. Vacuoles store food, enzymes, or waste. Vacuoles are also used in endocytosis Vacuoles are found only in plant cells. Lysosomes – Processing, Transporting, and Storing Molecules Lysosomes are vesicles that contain substances that digest excess or worn-out organelles and food particles. They also digest bacteria or viruses that invade the cell. Comparing Cells Only plant cells have: ○ Chloroplasts/chlorophyll ○ Vacuoles ○ Cell walls Animal cells generally do not have these features. Organelles at Work Knowledge of organelles allows for an increased understanding of cellular processes. Protein synthesis begins in the nucleus with DNA. ○ RNA and ribosomes leave the nucleus and produce a protein on the endoplasmic reticulum. ○ Proteins produced in the ER are sent to Golgi apparatus for packaging. ○ Packaged proteins are delivered to other organelles, where they serve a variety of functions. ○ We'll talk more about this process later Do Nows / TWS 156. Which structure is found in both plant and animal cells? A. Chloroplast B. Vacule C. Ribosome D. Cell Wall Do Nows / TWS 157. In which structure would you expect to find a cell wall? A. Human skin cell B. Leaf cell from a tree C. Blood cell from a cat D. Liver cell from a mouse Do Nows / TWS 158. Which structures synthesize protein that will be used in the cell in all cells? A. Chromatin B. Nucleolus C. Ribosome D. Endoplasmic Reticulum Do Nows / TWS 159. Which is not a component of the cytoskeleton? A. Microtubule B. Microfilament C. Cell wall D. Centriole Do Nows / TWS 159. Which of the following is a site of protein synthesis? A. Nuclear pore B. Chromatin C. Endoplasmic reticulum D. Nucleolus