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Inside The Cell.

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Presentation on theme: "Inside The Cell."— Presentation transcript:

1 Inside The Cell

2 Cells Extremely diverse Need microscope to see (few exceptions)
Composed of several hundred cell types Billions of each type Nerve, muscle, gland, bone Specialized to perform particular functions

3 Cell Theory Two Main Types Robert Hooke- English scientist
Studied cork Compound light microscope Discovered small geometric shapes Proposed cell theory All organisms are composed of cells Cell is the basic unit of structure and organization of organisms Cells come from preexisting cells Two Main Types

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5 Prokaryotic Cells First cells on Earth, Archaea and Bacteria
Lack membrane bound nucleus DNA located in nucleoid Smallest and simplest Reproduce quickly Exist in great numbers

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8 Eukaryotic Cell Protists, fungi, animals, plants
Membrane-bound nucleus DNA found in nucleus DNA forms genes, which are located in chromosomes Much larger than prokaryotic cells

9 Eukaryotic Cells Organelles- small structures differing in shape and function Benefit Multiple chemical reactions can be carried out at same time Organelles divided into four categories: Nucleus and ribosomes Organelles of the endomembrane system Energy-related organelles Cytoskeleton

10 Parts of the Cells

11 All Cells Plasma membrane- outer membrane of all cells
Regulates what enters and exits cell Cytoplasm- semi-fluid substance Carry on chemical reactions Genetic information “AKA”- DNA Information for growth and reproduction Ribosomes

12 Plasma Membrane Gate keeper Flexible boundary
Selective permeability- membrane allows some molecules to pass through while keeping others out Flexible boundary Maintains homeostasis- balance between internal and external environment

13 Phospholipid Bilayer Phospholipid- composed of glycerol backbone, two fatty acid chains and a phosphate group Plasma membrane composed of phospholipid bilayer Back to back Nonpolar (hydrophobic) fatty acid tails Polar (hydrophilic) heads

14 Phospholipid Bilayer Water is key component of live
Found inside and outside cells Polar phosphate group allows cell membrane to interact with watery environment 2 layers make a sandwich Nonpolar fatty acid tails inside Polar heads outside Creates water-soluble barrier on outer surface and water-insoluble barrier on inner surfaces

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16 Fluid-mosaic Model Outer layer Inner layer
Phospholipid heads face toward external environment Inner layer Phospholipids heads face toward internal environment

17 Plasma Membrane Components:
Cholesterol- helps stabilize the phospholipids Prevents fatty acid tails from sticking together Proteins- help form selectively permeable membrane Regulates which molecules enter and leave cell 6 main types

18 Membrane Proteins Channel proteins Form tunnels across membrane
Example: aquaporins

19 Membrane Proteins Transport proteins Passage of ions and molecules
Often combine with substances and help it move across membrane Example: sodium and potassium ions across nerve cell membrane

20 Membrane Proteins Cell recognition proteins Glycoproteins
Enable body to distinguish between our cells and cells of other organisms Example: pathogens

21 Membrane Proteins Receptor proteins
Shape allowing specific molecule to bind to it Called- signal molecule Binding causes receptor protein to change shape Brings about cellular response

22 Membrane Proteins Enzymatic proteins
Directly participate in metabolic reactions Allows for degradative and synthetic reactions

23 Membrane Proteins Junction proteins
Assist in cell-to-cell adhesion and communication Example: keeps urine in bladder as it swells

24 Nucleus Most noticeable structure Chromatin- network of strands
Condenses and coils before cell division Forms chromosomes- rod-like structures of condensed chromatin Composed of DNA, protein, RNA Nucleolus- dark structure, produces ribosomes

25 Nucleus Nuclear envelope- double membrane separating nucleus from cytoplasm Nuclear pores- allow communication between nucleus and cytoplasm Size permits ribosomal subunits and mRNA out of nucleus Allows proteins into nucleus

26 Ribosomes Composed of two subunits Sites of protein synthesis
One large One small Sites of protein synthesis Decode instructions of mRNA Some free, some attached to ER

27 Endoplasmic Reticulum
Complicated system of membranous channels and saccules (flattened vesicles) Two types Rough ER Smooth ER

28 Rough ER Studded with ribosomes on cytoplasmic side
Synthesizes polypeptides Modifies polypeptides Forms transport vesicle

29 Smooth ER Doesn’t have attached ribosomes Synthesizes lipids
Phospholipids and steroids Functions dependent on particular cells Forms transport vesicles Particularly to Golgi

30 Golgi Apparatus Named for its discoverer- Camillo Golgi
Consists of 3 to 20 slightly curved, flattened saccules Transfer station Receives transport vesicles Modifies contents Packages them into new vesicle According to destination

31 Lysosomes Vesicles produced by Golgi
Digest molecules and portions of the cell Lysosomal enzymes- aid in digestion of materials

32 Vacuoles Membranous sacs Larger than vesicles Specialized Storage
Contractile- ridding cell of excess water Digestive- break down nutrients Storage Example: plant vacuoles (store pigments)

33 Chloroplasts Plastids- group of organelles used for storage
Store chlorophyll- green pigment Found in plants and algae Use solar energy to synthesize carbohydrates Three membrane system

34 Chloroplasts Stroma- large inner space, contains concentrated mix of enzymes and disc-like sacs called thylakoids Thylakoids- formed from the third membrane Contain pigments that capture solar energy Granum- stack of thylakoids Contain their own DNA and ribosomes Support theory they are derived from photosynthetic bacteria

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36 Mitochondria Breakdown carbohydrates to form ATP
Bound by double membrane Inner membrane- highly convoluted folds called cristae Cristae increase surface area of inner membrane Powerhouse of the cell Produce most of ATP the cell utilizes

37 Mitochondria Inner membrane encloses the matrix
Contains highly concentrated mix of enzymes Contains mitochondrial DNA and ribosomes- evidence that they derived from bacteria Cellular respiration- complete breakdown of carbohydrates

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39 Cytoskeleton Network of interconnected microfilaments and microtubules
Microtubules- thin, hollow protein cylinders Microfilaments- smaller, solid protein fibers Constantly changing Maintain cell shape Anchor organelles, allow for movement Extend from nucleus to plasma membrane

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41 Centrioles Found in animal cells and most protists Occur in pairs
Made of microtubules Play important role in cell division

42 Cell Movement Cilia Flagella Hair-like projections Allow cell to move
Back and forth motion like oars Hair-like projections Allow cell to move Whip-like motion

43 Cell Walls Plants, fungi, bacteria, some protists
Fairly rigid structure located outside plasma membrane Provides additional support and protection Plant cell walls composed of carbohydrate called cellulose Forms thick, tough, porous mesh Not selectively permeable like plasma membrane

44 Plant Cell Walls Plasmodesmata- numerous narrow, membrane-lined channels passing through cell wall Allows for cell to cell communication


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