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Chapter 22 Part 3 Cells and cell structure For this part read 22.2 (pg 478) through 22.6 (pg.487)

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Presentation on theme: "Chapter 22 Part 3 Cells and cell structure For this part read 22.2 (pg 478) through 22.6 (pg.487)"— Presentation transcript:

1 Chapter 22 Part 3 Cells and cell structure For this part read 22.2 (pg 478) through 22.6 (pg.487)

2 I. Cell Theory- history Anton van Leeuwenhoek- dutch biologistAnton van Leeuwenhoek- dutch biologist Called the ‘father of the microscope’Called the ‘father of the microscope’ Developed first truly usable microscopeDeveloped first truly usable microscope Made detailed drawings of life in pond waterMade detailed drawings of life in pond water Robert Hooke- english biologistRobert Hooke- english biologist Named ‘cells’ while studying corkNamed ‘cells’ while studying cork Opened up the study of cellsOpened up the study of cells Robert Brown- scottish 1833Robert Brown- scottish 1833 Named ‘nucleus’ as center of cellsNamed ‘nucleus’ as center of cells

3 Cell Theory Contributors Matthias Schleidan- 1838Matthias Schleidan- 1838 All plants made of cellsAll plants made of cells Theodor Schwann- 1839Theodor Schwann- 1839 All animals made of cellsAll animals made of cells Rudolf Virchow- 1855Rudolf Virchow- 1855 All cells arise from the division of preexisting cellsAll cells arise from the division of preexisting cells

4 Current Cell Theory 1.All living things are made up of cells 2.Cells are the basic units of structure and function in living things 3.All cells come from preexisting cells

5 II. Two Types of Cells Prokaryotic- simplistic cells found in bacteriaProkaryotic- simplistic cells found in bacteria Eukaryotic- more sophisticated cells found in all other living thingsEukaryotic- more sophisticated cells found in all other living things

6 Prokaryotes- original cells Have existed on the planet for 3.5-4 billions years ago and were the only living things on the planet for several billion years.Have existed on the planet for 3.5-4 billions years ago and were the only living things on the planet for several billion years. Are single-celled organismsAre single-celled organisms All bacteria are prokaryotesAll bacteria are prokaryotes Are much smaller than eukaryotesAre much smaller than eukaryotes Have very simplistic structuresHave very simplistic structures

7 Prokaryotes do not have membrane enclosed organelles The main difference between prokaryotes and eukaryotes is that prokaryotes do not contain the sophisticated structures that eurkayotic cells contain.The main difference between prokaryotes and eukaryotes is that prokaryotes do not contain the sophisticated structures that eurkayotic cells contain.

8 More They do not contain a nucleus- their DNA is contained in a single circular chromosome.They do not contain a nucleus- their DNA is contained in a single circular chromosome. They also do not have structures that are found in eukaryotic cells: mitochondria, chloroplasts, endoplasmic reticulum, golgi apparatus, etc.They also do not have structures that are found in eukaryotic cells: mitochondria, chloroplasts, endoplasmic reticulum, golgi apparatus, etc. Their structures are much more simpleTheir structures are much more simple

9 Very important Although they do not contain the sophisticated structures found in eukaryotes, prokaryotes carry on all the functions that eukaryotes do.Although they do not contain the sophisticated structures found in eukaryotes, prokaryotes carry on all the functions that eukaryotes do. For example: just because they do not contain a nucleus does not mean that they don’t have DNA- it is just not contained in a nucleus.For example: just because they do not contain a nucleus does not mean that they don’t have DNA- it is just not contained in a nucleus.

10 Typical prokaryote Generally prokaryotic cells have a cell wall and cell membrane that form their outside capsule They also have a nucleoid which is a single circular piece of DNA Ribosomes Perhaps flagella or cilia which aid in movement

11 III Cell Structure Enormous variety in the size and shape of cellsEnormous variety in the size and shape of cells Smallest cells- the bacteria Mycoplasma - 0.2 micrometersSmallest cells- the bacteria Mycoplasma - 0.2 micrometers Micrometer- one millionth of a meterMicrometer- one millionth of a meter Largest unicellular organisms- amoeba (protist) Chaos chaos – 1000 micrometersLargest unicellular organisms- amoeba (protist) Chaos chaos – 1000 micrometers Largest single cell- egg yolks of birdsLargest single cell- egg yolks of birds Average cell size – 5-50 micrometersAverage cell size – 5-50 micrometers

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13 Basic Structures- common to many cells- but not all Cell membrane- outer boundary of cellCell membrane- outer boundary of cell Nucleus- control centerNucleus- control center Cytoplasm- material between cell membrane and nucleusCytoplasm- material between cell membrane and nucleus

14 Cell Membrane FunctionFunction Regulates what enters and exits the cellRegulates what enters and exits the cell Aids in the protection and support of the cellAids in the protection and support of the cell

15 Cell Membrane StructureStructure Bilayer of phospholipids with protein molecules and carbohydrate chains that help with cell identification and channels through which molecules passBilayer of phospholipids with protein molecules and carbohydrate chains that help with cell identification and channels through which molecules pass

16 Cell Wall – plants, algae and some bacteria Lies outside of cell membraneLies outside of cell membrane Helps support the cellHelps support the cell Very porous- allows water, carbon dioxide, oxygen and other things to easily pass throughVery porous- allows water, carbon dioxide, oxygen and other things to easily pass through

17 Cell wall formation The first layer to form develops when two plant cells meet- contains pectin-a gluey substance that helps hold cells togetherThe first layer to form develops when two plant cells meet- contains pectin-a gluey substance that helps hold cells together Each cell then forms a primary cell wall made of celluloseEach cell then forms a primary cell wall made of cellulose In woody cells, a secondary cell wall forms made of cellulose and ligninIn woody cells, a secondary cell wall forms made of cellulose and lignin Lignin makes cellulose more rigid- wood consists mainly of secondary cell wallsLignin makes cellulose more rigid- wood consists mainly of secondary cell walls Note: The cell wall found in prokaryotic bacteria is a totally different structureNote: The cell wall found in prokaryotic bacteria is a totally different structure

18 Nucleus- found in eukaryotes Eukaryotes- organisms whose cells contain nuclei and other membrane enclosed organellesEukaryotes- organisms whose cells contain nuclei and other membrane enclosed organelles Protists, fungi, plants, animalsProtists, fungi, plants, animals Prokaryotes- organisms whose cells lack nuclei and any other membrane enclosed organelles (mitochondria, chloroplasts, etc)Prokaryotes- organisms whose cells lack nuclei and any other membrane enclosed organelles (mitochondria, chloroplasts, etc) bacteriabacteria

19 Nucleus-function Information center of the cellInformation center of the cell Contains DNA (deoxyribonucleic acid) which contains the genetic information to make thousands of different moleculesContains DNA (deoxyribonucleic acid) which contains the genetic information to make thousands of different molecules Directs all the cell’s activitiesDirects all the cell’s activities

20 Nucleus- Structure Nuclear membrane or envelope A double layer of membranes that surrounds the nucleus regulating what enters and exits through the nuclear pores or openings in the membraneA double layer of membranes that surrounds the nucleus regulating what enters and exits through the nuclear pores or openings in the membraneNucleolus Made up of RNA and proteinMade up of RNA and protein Structure in which ribosomes are madeStructure in which ribosomes are madeChromosomes The DNA in the nucleus is attached to special proteins and forms large structures called chromosomesThe DNA in the nucleus is attached to special proteins and forms large structures called chromosomes Chromosomes contain the genetic information that must be passed to each new generation of cellsChromosomes contain the genetic information that must be passed to each new generation of cells

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22 Cytoplasm FunctionFunction Holds organelles (small cell structures) in placeHolds organelles (small cell structures) in place Helps with intracell communication and transportHelps with intracell communication and transport StructureStructure Gel-like substanceGel-like substance

23 IV. Cytoplasmic Organelles Organelle- a tiny structure that performs a specialized function in the cellOrganelle- a tiny structure that performs a specialized function in the cell Types and number of organelles will vary depending on the type of cell involved and the function of the cellTypes and number of organelles will vary depending on the type of cell involved and the function of the cell

24 Power Stations: Mitochondria and Chloroplasts All living things require a dependable energy sourceAll living things require a dependable energy source Mitochondria and chloroplasts are key organelles that change energy from one form to anotherMitochondria and chloroplasts are key organelles that change energy from one form to another Mitochondria change the chemical energy in food into compounds that are more convenient for the cell to useMitochondria change the chemical energy in food into compounds that are more convenient for the cell to use Chloroplasts trap the energy of sunlight and convert it into chemical energyChloroplasts trap the energy of sunlight and convert it into chemical energy

25 Mitochondria (mitochondrion- singular) Two sets of membranesTwo sets of membranes An outer membraneAn outer membrane An inner folded membrane that increases the inner surfaceAn inner folded membrane that increases the inner surface of the mitochondriaof the mitochondria

26 Chloroplast- only in photosynthetic cells- plants, algae Surrounded by two envelope-like membrane and contains a third kind of membrane where the radiant energy of the sun is actually changed into chemical energy (photosynthesis).Surrounded by two envelope-like membrane and contains a third kind of membrane where the radiant energy of the sun is actually changed into chemical energy (photosynthesis).

27 Protein factories- Ribosomes Structures in which proteins are madeStructures in which proteins are made Composed of RNA and protein- made in the nucleolusComposed of RNA and protein- made in the nucleolus Some are attached to membranes, some are found free floating in the cytoplasmSome are attached to membranes, some are found free floating in the cytoplasm Among the smallest organelles- 25 nanometers (1 nm – 1 billionth of a meter)Among the smallest organelles- 25 nanometers (1 nm – 1 billionth of a meter)

28 ribosome

29 Packaging and shipping: Endoplasmic Reticulum and Golgi Apparatus Endoplasmic reticulum (ER) A complex network of sacs that transports materials through the inside of the cell Two types: Smooth ER Rough ER – have ribosomes stuck to its surface

30 Golgi Apparatus –named after Camillo GolgiGolgi Apparatus –named after Camillo Golgi Will modify proteins and package them for distribution and shipment to other parts of the cellWill modify proteins and package them for distribution and shipment to other parts of the cell

31 Clean-up Crew: Lysosomes Not found in plant cellsNot found in plant cells Also called suicide sacsAlso called suicide sacs Small membrane bordered structures that contain strong chemicals and enzymes needed to digest certain materialsSmall membrane bordered structures that contain strong chemicals and enzymes needed to digest certain materials Involved in breaking down old, used up or damage cell partsInvolved in breaking down old, used up or damage cell parts Don’t work properly in people that have Tay-Sachs diseaseDon’t work properly in people that have Tay-Sachs disease

32 Storage containers: Vacuoles and Plastids Vacuoles- store water, salts, proteins and carbohydratesVacuoles- store water, salts, proteins and carbohydrates Plant cells have huge water vacuoles that help give plant structure when filled up (wilt)Plant cells have huge water vacuoles that help give plant structure when filled up (wilt) Plastids- plant storage for pigments and foodPlastids- plant storage for pigments and food Chloroplast –where photosynthesis occursChloroplast –where photosynthesis occurs Leukoplasts- starch storageLeukoplasts- starch storage Chromoplasts- contain colored pigment molecules (tomatoes)Chromoplasts- contain colored pigment molecules (tomatoes)

33 Framework: Cytoskeleton Composed of a variety of filaments and fibers that support cell structure and drive cell movementComposed of a variety of filaments and fibers that support cell structure and drive cell movement Microtubules-hollow tubules made of proteinMicrotubules-hollow tubules made of protein Provide shape for the cell, help move organelles through the cell, form centrioles in animal cell, can form cilia and flagella (used in the movement of some cells)Provide shape for the cell, help move organelles through the cell, form centrioles in animal cell, can form cilia and flagella (used in the movement of some cells) Microfilaments- long, thin fibersMicrofilaments- long, thin fibers Involved in the moving of the cytoplasm and in cytoplasmic streaming (amoeba movement)Involved in the moving of the cytoplasm and in cytoplasmic streaming (amoeba movement)


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