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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

http://www.youtube.com/watch?v=BTicXXxzQA4&feature=related

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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

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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

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Cell History Continued The real importance of

cells not recognized until the 1830s

1838-1839 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

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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

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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 reactionsSum 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 ClassesProkaryotic Cells Eukaryotic CellsConsidered 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

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Cell Parts and Functions Cell is composed of

many structures and parts with various functionsThese 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

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Plant Cell

Animal Cell

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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 OrganellesCell Membrane

Forms a protective barrier around the cell

Made of a double layer of lipidsLipid is a fat-like molecule that does not dissolve in water

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Designed to allow movement of certain substancesOne form of movement

is called diffusion

Diffusion relies on the amount of dissolved particles present, the concentration, to occurParticles 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 OrganellesCytoplasm

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 OrganellesNucleus

Control centre organelle of the cellControls everything (e.g. growth and reproduction)

Surrounded by a nuclear envelopeMovement 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 OrganellesVacuoles VesiclesMembrane bound organelleHelp with storage of nutrients, wastes and other substances used by cells

Important in plants as often have central vacuoleMainly stores water, causing cells to swell, making the plant become firm

Membrane bound organelleAlso helps with storage

Bigger role in the transport of the stored substances throughout the cell

Common OrganellesMitochondria

Provides the supply of energy for the cell

Does this by converting chemical energy in sugars into usable for the cell, ATPATP=Adenosine Triphosphate

Powerhouses of the cell

Common OrganellesLysosomes

Organelles where digestion takes place

Are small organelles packed with enzymesEnzymes are proteins that speed up chemical reactions in a cell

Also help break down invading bacteria and damaged organellesWork as the clean up system

In the image the purple structures are lysosomes

Common OrganellesGolgi Apparatus

Receives proteins from endoplasmic reticulumFunction is to modify, sort, and package these proteins for delivery throughout the cell or outside the cellLooks like a stack of flattened membranesResembles stack of pancakes

Common OrganellesCytoskeleton 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 ReticulumOrganelle made of series of interconnected small tubes that carry materials through the cellFound in 2 forms:

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Plant vs Animal CellsOrganelles that are only

found in Plant cellsOrganelles that are only

found in Animal cells

Cell Wall

Chloroplasts

Centrioles

Plant CellsChloroplasts

Contains chlorophyllChlorophyll uses energy from the Sun to convert carbon dioxide and water into sugar and oxygen through photosynthesis

Made of little sacs called thylakoidsStack in fashion that resembles a coin stackA stack of thylakoids is called a granumChloroplasts 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

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Other Differences Between Plant and Animal Cells

Compounds / ChemicalPlants cells have specialized chemical compound

called chlorophyll, a pigment that allows photosynthesis

Animal cell have some specialized compounds like hemoglobin in red blood cells

VacuolesPlant cells have large central vacuoleAnimal cells vacuoles tend to be small

Energy storagePlants cells store energy in the form of starch or oilsAnimal cells store energy in the form of glycogen (a

carbohydrate) or as lipids in the form of fats

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