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2 Link Between Our Knowledge and Technology  As in all fields of science, or any other field of study our knowledge increases as technology improves  Result of the fact that new technologies provide new perspective and allow observations that were not possible before  A clear example of this in Biology is the development of the Microscope  4&feature=related 4&feature=related

3 Microscope Development  First developed in the mid-1600s  With the development allowed a once invisible world to now be visible The World of Cells  This world of cells was first described by Robert Hooke  Hooke used his primitive microscope to view cork and the structures he saw, he called “cells” Called the structures cells because they reminded him of the cells inhabited by monks living in a monastery

4 Cell History Continued  Next came Anton van Leeuwenhook Made his own more advanced microscopes Used his microscopes to be the first to observe drop of pond water and various bacteria samples  People were skeptical of his findings so Robert Hooke sent to confirm his findings His findings were confirmed and Anton became a worldwide celebrity soon after

5 Cell History Continued  The real importance of cells not recognized until the 1830s  Matthias Schleiden and Theodor Schwann work with cells made the first two tenets of the cell theory  The final tenet of the cell theory came in 1855 from the work of Rudolf Virchow

6 Cell Theory  Made of the following three tenets: 1. All organisms are composed of 1 or more cells 2. The cell is the structural unit of life 3. Cells can arise only by division from a preexisting cell

7 Basic Properties of Cells  Cells are highly complex and organized  Cells possess a genetic program and a means to use it  Cells are capable of producing more of themselves  Cells acquire and utilize energy Cells carry out a variety of chemical reactions Sum total of the reactions in a cell represent the cell’s metabolism Cells engage in numerous mechanical activities Cells are able to respond to stimuli Cells are capable of self regulation Cells evolve

The Cell Classes Prokaryotic Cells Eukaryotic Cells Considered to be structurally simpler Findings suggest started to exist approximately 2.7 billion years ago Considered to be structurally more complex Findings suggest started approximately 2 billion years ago

9 Cell Parts and Functions  Cell is composed of many structures and parts with various functions These functional parts of cells are called organelles  These functions allow cells to survive in unicellular (single- celled) and multicellular organisms The functions a cell must carry out include: Intake of nutrients Movement Growth Response to stimuli Exchange of gases Waste removal Reproduction

10 Plant Cell

Animal Cell 11

Organelles Common to Both Plant and Animal Cells  Cell Membrane  Cytoplasm  Nucleus  Vacuoles and Vesicles  Mitochondria  Lysosomes  Golgi Apparatus  Cytoskeleton  Ribosomes  Endoplasmic Reticulum (ER) Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum

Common Organelles Cell Membrane Forms a protective barrier around the cell Made of a double layer of lipids Lipid is a fat-like molecule that does not dissolve in water

14  Designed to allow movement of certain substances One form of movement is called diffusion Diffusion relies on the amount of dissolved particles present, the concentration, to occur Particles will diffuse, or move, across the membrane from area of high concentration of that substance to areas of low concentration of that substance. Cell Membrane

Common Organelles Cytoplasm Jelly-like substance that fills the cell and surrounds the organelles Contains the nutrients to allow the cell to carry out its life processes Allows things to move within the cell

Common Organelles Nucleus Control centre organelle of the cell Controls everything (e.g. growth and reproduction) Surrounded by a nuclear envelope Movement across this occurs through nuclear pores Most have a small dense area called the nucleolus Contains all the cell’s DNA DNA= Deoxyribonucleic Acid

Common Organelles Vacuoles Vesicles Membrane bound organelle Help with storage of nutrients, wastes and other substances used by cells Important in plants as often have central vacuole Mainly stores water, causing cells to swell, making the plant become firm Membrane bound organelle Also helps with storage Bigger role in the transport of the stored substances throughout the cell

Common Organelles Mitochondria Provides the supply of energy for the cell Does this by converting chemical energy in sugars into usable for the cell, ATP ATP=Adenosine Triphosphate Powerhouses of the cell

Common Organelles Lysosomes Organelles where digestion takes place Are small organelles packed with enzymes Enzymes are proteins that speed up chemical reactions in a cell Also help break down invading bacteria and damaged organelles Work as the clean up system In the image the purple structures are lysosomes

Common Organelles Golgi Apparatus Receives proteins from endoplasmic reticulum Function is to modify, sort, and package these proteins for delivery throughout the cell or outside the cell Looks like a stack of flattened membranes Resembles stack of pancakes

Common Organelles Cytoskeleton Ribosomes Internal network of fibres Made of protein filaments Helps maintain cell’s shape Small, dense-looking organelles Either free floating in cytoplasm or attached to the rough endoplasmic reticulum Site of protein assembly

Common Organelles 1. Smooth Endoplasmic Reticulum 2. Rough Endoplasmic Reticulum Associated with the production of fats and oils Associated with making proteins Considered rough due to presence of ribosomes Endoplasmic Reticulum Organelle made of series of interconnected small tubes that carry materials through the cell Found in 2 forms:

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Plant vs Animal Cells Organelles that are only found in Plant cells Organelles that are only found in Animal cells Cell Wall Chloroplasts Centrioles

Plant Cells Chloroplasts Contains chlorophyll Chlorophyll uses energy from the Sun to convert carbon dioxide and water into sugar and oxygen through photosynthesis Made of little sacs called thylakoids Stack in fashion that resembles a coin stack A stack of thylakoids is called a granum Chloroplasts have many grana Stack of thylakoids surrounded by thick fluid called stroma Thylakoids are “solar collectors”

Plant Cells Cell Wall Rigid frame around the cell that provides: Strength Protection Support

Animal Cells Centrioles Paired structure Involved in cell division

28 Other Differences Between Plant and Animal Cells  Compounds / Chemical Plants cells have specialized chemical compound called chlorophyll, a pigment that allows photosynthesis Animal cell have some specialized compounds like hemoglobin in red blood cells  Vacuoles Plant cells have large central vacuole Animal cells vacuoles tend to be small  Energy storage Plants cells store energy in the form of starch or oils Animal cells store energy in the form of glycogen (a carbohydrate) or as lipids in the form of fats

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