Cell Structure: An Overview

Exploring Cells in Detail By: Mariam Mahmoud Ibrahim Table of Contents What are cells and their discovery Cellular components and their biochemical organization Types of cells and their function  The cell is the smallest building block of What is a cell? a...

Exploring Cells in Detail By: Mariam Mahmoud Ibrahim Table of Contents What are cells and their discovery Cellular components and their biochemical organization Types of cells and their function  The cell is the smallest building block of What is a cell? a living being. It is the fundamental structure of an organism. Plant cell Animal cell Bacterial cell Discovering the Cell Who coined the term ‘cell’ and how did he discover it?  Discovering the Cell Robert Hooke Robert Hooke coined the term ‘cell’ in 1665. The first person to see a cell under the microscope. The first person to tell that a basic unit of life is the cell. The first to invent the compound microscope Guess the Picture  Humans have about 37.2 trillion cells! What is Humans are multicellular organisms. a cell? A living thing may be made Euglena is a of one cell (a unicellular unicellular organism) or many cells (a organism. multicellular organism). Eukaryotic Prokaryotic It has true nucleus It has NO true It has DNA nucleus Cell Division by It has nucleoid mitosis or meiosis instead of DNA Cell Division by binary fission  Cell Growth Cell Growth is achieved by cell metabolism Cell metabolism is divided into catabolism and anabolism Catabolism: the cell breaks down complex molecules to produce energy Anabolism: the cells use the energy to construct the molecules needed and for other biological functions.  Functions of the cells Cell Division Transport Metabolism Cell transport through cell membrane  Cell Organelles The mini organs in our cell in order to make the cell works! Cell membrane Nucleus Ribosomes Rough endoplasmic reticulum Smooth endoplasmic reticulum Golgi Apparatus Centrioles Mitochondria Vacuoles Cytoplasm Cell membrane The cell membrane is a phospholipid bipolar layer. It is a semi-permeable membrane that controls the substance entrance Phospholipid: head H2O soluble +ve charge called hydrophilic tail H2O insoluble -ve charge called hydrophilic Nucleus The nucleus holds the DNA. The DNA is enclosed by double membrane called nuclear envelope/ nuclear membrane The membrane has pores to allow substances inside and out. DNA is wrapped around chromatin. When the cell prepares for division, chromatin condenses to chromosomes. Nucleolus is a small dense region where ribosomes are produced. Ribosomes Proteins are produced by ribosomes as instructed by the DNA Ribosomes are either free in the cytoplasm or attached to the rough endoplasmic reticulum. Rough Endoplasmic Reticulum They are called “rough” for having ribosomes on them. These ribosomes make proteins that are being used in the cell or proteins exported outside the cell. Smooth Endoplasmic Reticulum Being called “Smooth” means it has no ribosomes attached. It synthesize lipids with each enzyme has its specific function: Stuctural lipids (membrane lipids), carrying protein, detoxifying drugs Golgi Apparatus Golgi Apparatus modifies, sorts, packages proteins and other materials made in the endoplasmic reticulum for storage in the cell or secretion from the cell. Lysozymes membrane-bound sack filled with enzymes that breaks down substances either food that the cell can use or waste materials the cell doesn’t need. Centrioles and Vacuoles Vacuoles are membrane bound sacks that stores water, food, enzymes and wastes. Centrioles: help coordinate cell division in animal cells. There are only one pair in each cell. They are also used as transporters inside the cell. Cytoplasm A jelly like material to hold all the organelles in place. Mitochondria They are the powerhouse of the cell. they convert the chemical energy from food to energy that is used by the cell to perform its functions. The mitochondrion (single) consists of two membranes: the outer membrane and inner membrane that folded up inside the mitochondrion. These folds are called Cristae. Cellular respiration occurs inside th mitochondria to provide the energy the cell needs. It has its own DNA? Inherited from the mother only? How to see these Organelles ? Using a Microscope How to Use a Step 1: Microscope Turn the light microscope on, move the mirror to reflect the light up If you have never used a light towards the eyepiece and check microscope before, this handy that the aperture is wide open. guide will explain how it’s done! Step 2: Turn the revolving nosepiece so the lowest objective lens is pointing directly down. How to Use a Microscope Step 3: Place your specimen If you have never used a light onto the stage. microscope before, this handy guide will explain how it’s done! Step 4: Look into the eyepiece and slowly rotate the coarse adjustment wheel to bring your specimen into focus. How to Use a Step 5: Microscope Slowly rotate the fine adjustment wheel until you obtain a clearer If you have never used a light image of your specimen. microscope before, this handy guide will explain how it’s done! Step 6: Examine and explore your specimen, holding still or moving the slide slowly with your thumbs. How to Use a Microscope What are the things you would like to If you have never used a light microscope before, this handy guide will explain how it’s done! observe under a microscope? Step 7: Once you have seen enough, switch to the medium and the high-power objective lens. Use the fine adjustment wheel to bring the specimen into focus as necessary.  Summary How does a microscope work? A microscope magnifies the structure of the specimen. Specimens must be brought into focus to be viewed. This What are cells? is done by moving the coarse and fine adjustment A cell is the smallest unit of a living wheels. thing. An organism may be made of one cell or many cells.  Thank you Any Questions ?