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1 Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal CellPlant Cell.

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Presentation on theme: "1 Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal CellPlant Cell."— Presentation transcript:

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2 1 Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Animal CellPlant Cell Bacterial Cell

3 2 Number of Cells Organisms may be: Unicellular – composed of one cell Multicellular- composed of many cells that may organize

4 3  Prokaryotes: include bacteria & lack a nucleus or membrane-bound structures called organelles  Eukaryotes: include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals) Cells May be Prokaryotic or Eukaryotic

5 Prokaryote vs Eukaryote Two structural types of cells are recognized: –Prokaryotic –Archaea and bacteria –Eukaryotic: plants, algae, fungi, protists, and animals (variety) Comparing prokaryotic and eukaryotic cells –Prokaryote comes from the Greek words for prenucleus. –Eukaryote comes from the Greek words for true nucleus.

6 ProkaryoteEukaryote Contains plasma membrane Simpler internal structure Absence of nucleus One circular chromosome, not in a membrane No membrane enclosed organelles Peptidoglycan cell walls Binary fission for cell division Smaller Contains plasma membrane Contain nucleus Paired chromosomes, in nuclear membrane Membrane enclosed organelles Simple (polysaccharide) cell walls Cell division by mitosis or meiosis Larger

7 Structure of Prokaryotic vs. Eukaryotic cell

8 7 Prokaryotes – The first Cells Cells that lack a nucleus or membrane-bound organelles Includes bacteria Simplest type of cell Single, circular chromosome copyright cmassengale

9 8 Prokaryotes Nucleoid region (center) contains the DNA Surrounded by cell membrane & cell wall (peptidoglycan) Contain ribosomes (no membrane) in their cytoplasm to make proteins copyright cmassengale

10 9 Eukaryotes Cells that HAVE a nucleus and membrane- bound organelles Includes protists, fungi, plants, and animals More complex type of cells copyright cmassengale

11 EukaryoticProkaryotic Larger Contains membrane bound organelles Contains a nucleus Smaller Does not contain membrane bound organelles No nucleus Differences b/w the 2 types of cells

12 All cells have a: And are grouped into two broad categories: Which are mainly: Some contain yeast and algae Cell walls Which contains unique structures such as: Words you can use: Animals bacteria chloroplasts Eukaryotes a large central vacuole plants plasma membrane prokaryotes

13 All cells have a: Plasma membrane And are grouped into two broad categories: prokaryote s eukaryotic bacteria Which are mainly: plantsanimals Some contain yeast and algae Cell walls chloroplasts A large central vacuole Which contains unique structures such as: Words you can use: Animals bacteria chloroplasts Eukaryotes a large central vacuole plants plasma membrane prokaryotes

14 Viruses Non cellular Obligate intracellular parasites –They must live inside another cell to survive Have only one type of nucleic acid –DNA or RNA (never both) –Single or Double stranded Protein coat (no plasma membrane) Few to no enzymes –Takes enzymes and use host cell metabolic machinery No metabolic activity They require a host cell to exhibit the characteristics of life. Virus diversity –Different viruses have different hosts –Only some viruses cause disease

15 Structure & Organelles VOCABULARY Organelle Plasma Membrane Cytoskeleton Nucleus Nucleolus Golgi Apparatus Endoplasmic Reticulum Chloroplast Mitochondria Lysosome Vacuole Vesicle Cell wall Ribosome Cytosol Cytoplasm

16 15 Organelles Very small (Microscopic) “little organs” that carry out specific functions within each cell Perform various functions for a cell Found in the cytoplasm May or may not be membrane- bound

17 Eukaryotic: Animal Cell

18 Eukaryotic: Plant Cell

19 Prokaryotic Cell

20 Plasma Membrane (AKA cell membrane Function: A flexible boundary that controls the movement of substances in and out of the cell. Key word: Selective permeability. Cell Type: All cells Analogy: __________

21 20 Lies immediately against the cell wall in plant cells Pushes out against the cell wall to maintain cell shape Cell Membrane in Plants Cell membrane

22 21 Nonliving layer Found in plants, fungi, & bacteria Made of cellulose in plants Made of peptidoglycan in bacteria Made of chitin in Fungi Cell Type: Plants Analogy:____________ _________________ Cell wall Cell Wall

23 22 Cell Wall Supports and protects cell Found outside of the cell membrane

24 23 Contains organelles to carry out specific jobs Collective term for cytosol plus the organelles suspended within the cytosol Found in ALL cells Analogy:__________ ____________ More on Cytoplasm cytoplasm

25 Cytosol The fluid surrounding the cytoplasm’s organelles, internal membranes, and cytoskeleton fibers Analogy:_________ ______________ copyright cmassengale24

26 25 Cytoskeleton Helps cell maintain cell shape and supporting structure Also help move organelles around Made of proteins Microfilaments are threadlike & made of ACTIN Microtubules are tubelike & made of TUBULIN Analogy:________________ ____________

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28 Cellular Support Cytoskeleton is made of microtubules  thin, hollow cylinders made of protein, & microfilaments  thin solid protein fibers

29 28 Cytoskeleton MICROTUBULES MICROFILAMENTS copyright cmassengale

30 Nucleus Function: The nucleus contains the cells DNA, stores information used to make proteins –For cell growth, function & reproduction. Key Word: Control Center Cell Type: All Eukaryotic Cells Analogy: ____________

31 30 Nucleolus Inside nucleusInside nucleus Cell may have 1 to 3 nucleoliCell may have 1 to 3 nucleoli Disappears when cell dividesDisappears when cell divides Makes ribosomes that make proteinsMakes ribosomes that make proteins Analogy:________ ____________Analogy:________ ____________ copyright cmassengale

32 31 Endoplasmic Reticulum - ER Two kinds of ER ---ROUGH & SMOOTH Network of hollow membrane tubules Connects to nuclear envelope & cell membrane Functions in Synthesis of cell products & Transport copyright cmassengale Analogy?_______ _____________ _____________

33 32 Rough Endoplasmic Reticulum (Rough ER) Has ribosomes on its surface Makes membrane proteins and proteins for EXPORT out of cell copyright cmassengale

34 33 Smooth Endoplasmic Reticulum Smooth ER lacks ribosomes on its surface Is attached to the ends of rough ER Makes cell products that are USED INSIDE the cell copyright cmassengale

35 34 Functions of the Smooth ER Makes membrane lipids (steroids) Regulates calcium (muscle cells) Destroys toxic substances (Liver) copyright cmassengale

36 35 Ribosomes “ Protein factories” for cell Small particles of RNA and protein found throughout the cytoplasm. Produce proteins by following coded instructions that come from the nucleus. Join amino acids to make proteins Process called protein synthesis Analogy:________  copyright cmassengale

37 Golgi Apparatus Function: It’s a flattened stack of membranes that modifies, sorts & packages proteins into sacs. Key Word: Packing & Sorting Cell Type: All Eukaryotic Cells Analogy: ____________

38 37 Golgi Bodies Look like a stack of pancakes Modify, sort, & package molecules from ER for storage OR transport out of cell copyright cmassengale

39 38 Golgi copyright cmassengale

40 39 Vesicles -small saclike organelles that store and transport materials around the inside of cells

41 Chloroplasts Function: Capture light energy & convert it into chemical energy through photosynthesis. Key Word: Producer of energy Cell Type: Euk. Plant cell Analogy: ____________

42 41 Vacuoles Fluid filled sacks for storage Small or absent in animal cells Plant cells have a large Central Vacuole No vacuoles in bacterial cells Analogy:_____ __________ copyright cmassengale

43 42 Vacuoles In plants, they store Cell Sap Includes storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes copyright cmassengale

44 Mitochondria Function: It converts fuel particles (mainly sugar) into usable energy. Key Word: Powerhouse Cell Type: All Eukaryotic Cells Analogy: ____________

45 44 MITOCHONDRIA CONT Surrounded by a DOUBLE membrane Folded inner membrane called CRISTAE (increases surface area for more chemical Reactions) Has its own DNA Interior called MATRIX copyright cmassengale

46 45 Interesting Fact --- Mitochondria Come from cytoplasm in the EGG cell during fertilization Therefore … You inherit your mitochondria from your mother ! copyright cmassengale

47 Lysosomes Function: Processes enzymes that digest excess or worn out organelles, wastes. Key Word: Gets rid of waste Cell Type: Euk. Animal Cells Analogy: ____________

48 47 Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

49 48 Differences between plant cells and animal cells Animal cellsPlant cells Relatively smaller in size Irregular shape No cell wall Relatively larger in size Regular shape Cell wall present

50 49 Animal cellsPlant cells Vacuole small or absent Glycogen as food storage Nucleus at the center Large central vacuole Starch as food storage Nucleus near cell wall Differences between Plant Cells and Animal Cells

51 50 Cell Movement with Cilia & Flagella copyright cmassengale

52 Cilia & Flagella Cilia  short, numerous, hair-like projections that move in a wavelike motion

53 Flagella  larger projections that move w/ a whip-like motion

54 53 Cilia & Flagella Cilia are shorter and more numerous on cells Flagella are longer and fewer (usually 1-3) on cells copyright cmassengale

55 54 Cilia Moving Away Dust Particles from the Lungs Respiratory System copyright cmassengale

56 55 Cell Size Question: Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse? copyright cmassengale

57 56 Cell Size Question: Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse? About the same size, but … The elephant has MANY MORE cells than a mouse! copyright cmassengale


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