Biology 11 - Cell Structure

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Cellular Structure
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Types of Cells

• All cells from any of the 5 kingdoms are either
  Prokaryotic Cells or Eukaryotic Cells

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Types of Cells

• Prokaryotic Cells
• Usually bacteria
• Lack a nucleus (bag containing DNA) organelles
• Eukaryotic Cells
• Compromise 4 of 5 kingdoms
• Has a nucleus organelles

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Types of Cells
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Types of Cells

• There are key differences between prokaryotic and
  eukaryotic cells
• Create a table with 3 columns (see below)

Trait Prokaryotic Cells Eukaryotic Cells

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Types of Cells
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Types of Cells
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Types of Cells
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Eukaryotic Cells
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Plasma Membrane(cellular membrane)

• Outer boundary of cell
• Separates the cytoplasm from the extracellular
  fluid (fluid outside the cell)
• Functions
• Protects the cell
• Controls what enters and leaves the cell

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Plasma Membrane(cellular membrane)
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Plasma Membrane (cellular membrane)

• Plasma membrane is selectively permeable so only
  certain things can pass through

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Plasma Membrane(cellular membrane)
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Cytoplasm

• The inside of the cell
• Cytoplasm consists of
• Cellular Structures (organelles)
• The cystol
• Cystol
• A thick soup of salts, organic molecules and
  ezymes for reactions
• Makes up 70 of the cell

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Cytoplasm
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Cell Wall

• Only found in plant cells (exceptions)
• Structure
• Rigid wall made of cellulose
• Fibers of cellulose are interlocked leaving
  spaces

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Cell Wall

• Complete Permeable
• Allows any small thing to pass through freely
• Passes through spaces in the cell wall
• Functions
• Protection from physical injury
• Provides support in conjunction with the vacuoles

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Cell Wall
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The Nucleus

• Found in all Eukaryotes (1 per cell)
• A complex organelle (structure having its own
  membrane)
• Brain of the cell which regulates cell activity
  
• Ie. Contains cells DNA (genetic material)

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The Nucleus
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The Nucleus

• Nucleus Structure
• Nuclear Envelope
• Nucleoplasm
• Nucleolus
• Chromatin

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The Nucleus (a closer look)
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The Nucleus

• Nuclear Membrane
• Double membrane of nucleus
• Separates nucleus contents (DNA) from rest of
  cell
• Selectively Permeable regulates what enters or
  leaves the nucleus through nuclear pores
• Outer part of membrane is connected to the rough
  ER

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Nuclear Envelope (a closer look)
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The Nucleus

• Nuclear Pores
• Passages in nuclear envelope
• Allows substances to pass in/out of nucleus
• Examples
• Materials for DNA (go in)
• Molecules for energy (go in)
• Ribosomal subunits made inside (go out)

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The Nucleus

• Chromatin
• DNA (genetic material) is wrapped around histones
  (a protein) to reduce size

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The Nucleus (a closer look at chromatin)
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The Nucleus

• Nucleolus
• Membrane lacking structure in the nucleus
• Makes ribosomal subunits

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The Nucleus
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Endoplasmic Reticulum (ER)

• Folded system of membranes
• Has large surface area (allows for increased
  chemical reactions)
• ER manufactures, processes, and transports
  various compounds for use OUT OF THE CELL
• Spreads throughout the cell

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Endoplasmic Reticulum (ER)

• Rough ER
• Surface is covered with ribosomes
• Involved in production processing of proteins
  that will be exported, or secreted, from the cell
  

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Endoplasmic Reticulum (ER)

• Smooth ER
• Primarily involved in production of lipids
• Also involved in detoxification of drugs
  poisons
• Lacks ribosomes, but receives proteins from rough
  ER

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Endoplasmic Reticulum (ER)
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Endoplasmic Reticulum (ER)
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Ribosomes

• Cell structure made of RNA and protein
• Has no membrane
• Location
• On rough ER
• Floating free throughout the cell

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Ribosomes

• Functions
• Makes protein by assembling amino acids

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Ribosomes
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Golgi Apparatus

• Saclike membranes, pinched off at ends
• The packaging and shipping department of the
  cell

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Golgi Apparatus

• Functions
• Receives chemicals (from ER)
• Chemicals are modified to make them functional
• Chemicals are released in vesciles
• Note chemicals can also be stored

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Golgi Apparatus
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Lysosomes

• Found in/with Golgi Bodies
• Structure
• Membrane bound bag containing hydrolytic enzymes
• Hydrolytic Enzymes
• A digestive enzyme
• i.e. using water to split chemical bonds

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Lysosomes

• Functions
• Breakdown of large molecules into simpler ones
• Breakdown uses water molecules
• Also involved in helping white blood cells to
  destroy bacteria

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Lysosomes

• Typically found in Golgi bodies
• Contain digestive enzymes to digest/breakdown
  unwanted particles into basic compounds
• Help white blood cells to destroy bacteria

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Lysosomes
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Mitochondra

• Powerhouse of the cell
• Structure
• Has a double membrane
• Cristae - Inside folds studded with proteins

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• Notice the studding

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Mitochondria

• Functions
• Site of cellular respiration
• Cellular Respiration
• The release of chemical energy from food
• Glucose Oxygen ? Carbon Dioxide Water
  Energy (ATP)

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Mitochondria

• Plant Cells
• Provides energy when no sunlight
• Converts stored glucose (sugar) to energy

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Mitochondria

• Animal Cells
• Main energy produce for the cell
• Energy comes from glucose (sugar) from food
• Cells with higher energy needs have more
  mitochondria

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Mitochondria
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Chloroplasts (plants only)

• Energy powerplant of plant cells
• Structure
• Composed of double membrane
• Grana Thylakoid inner layers which contain
  chlorophyll

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Chloroplasts(plants only)

• Functions
• Contain chlorophyll
• Provide energy for plants through photosynthesis
• Photosynthesis
• Process through which plants obtain energy from
  the sun

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Chloroplasts(plants only)
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Vacuoles(plants mainly)

• Structure
• A single layer of unit membrane
• Enclosing fluid in a sack

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Vacuoles(plants mainly)

• Generally, stores water, waste, or materials
• Structure
• A single layer of unit membrane enclosing fluid
  in a sack

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Vacuoles(plants mainly)

• Functions
• Produces turgor pressure against cell wall for
  support in plants
• Provides 80 of a plants support
• Stores water and various chemicals
• May store insoluble wastes

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Vacuoles(plants mainly)
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Centrioles

• Structure
• Barrel shaped organelles called centrioles
• Made of microtubules
• Functions
• Involved in mitosis (cell division)
• Releases spindle fibres to move chromosomes

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Centrioles(animation mitosis)
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Centrioles(animation mitosis)
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Centrioles
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Cytoskeleton
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Cytoskeleton

• Cellular skeleton / scaffolding
• Found in the cytoplasm (In all eukaryotic cells,
  some prokaryotic cells)
• Composed of different filaments (actin,
  intermediate) and microtubles
• Functions
• Maintain cell shape
• Enable cell motion
• Involved in intra-cellular transport (movement of
  organelles vesicles)
• Involved in cellular division

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Comparing Plant Animal Cells
Plant Cells Animal Cells
Possess rigid Cell Walls No Cell Walls
Have green Chloroplasts No Chloroplasts
Thin lining of Cytoplasm Most of cell is Cytoplasm
Vacuole filled with cell sap No vacuole