Cell Structure and Function

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Cell Structure and Function

• Life
• Science

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Two Categories of Cells

• Prokaryotes
• Small and simple cells
• Do NOT contain a nucleus
• Do NOT contain organelles
• All bacteria are prokaryotes
• Eukaryotes
• Large and complex cells
• Contain a nucleus
• Contain organelles
• Animals, plants, fungi, etc.

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Cell Structures
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Prokaryotic Cell
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Plant Cell
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Animal Cell
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Dont forget that all cells have all these
things!!!

• Cell membrane
• Cytoplasm
• Genetic material (almost all contain DNA)
• Have ribosomes, sites of protein synthesis
  (dehydration synthesis happens here!)

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Cell Membrane

• Structure
• Phospholipid bilayer with proteins and
  carbohydrates
• Functions
• Thin, flexible barrier
• Separates cell from surroundings
• Regulates molecules into/out of cell (food,
  water, wastes, etc.)
• Selectively Permeable

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Cell Wall

• Structure
• Made of cellulose (a carbohydrate) and proteins
• Rigid wall outside of cell membrane
• Only in plants
• Function
• Support and protect
• Allows water, oxygen, carbon dioxide and other
  substances to pass through
• Found only in plant, fungi, and algae cells,
  NOT in animals

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Nucleus

• Function
• Stores DNA (chromatin), hereditary info for cell
• Controls cell activities
• Components (Structure)
• Nuclear Envelope bilayer lipid membrane that
  surrounds nucleus and has pores or holes to allow
  materials to move in/out of nucleus
• Nucleolus Small dense region that makes ribosomes

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Cytoskeleton

• Structure
• Network of long protein strands called
  microfilaments and microtubules
• Function
• Microtubules movement inside cells
• Microfilaments Maintain shape and size of cell

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Ribosomes

• Most numerous organelle
• Structure
• Made of RNA and protein
• Function
• Synthesis of Proteins (make proteins)

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Endoplasmic Reticulum (ER)

• Structure
• Internal membrane system
• Stacks of flattened sacs
• Rough has ribosomes- gives a bumpy appearance
• Smooth no ribosomes- looks smooth
• Function
• Intracellular highwaymoves molecules around the
  cell
• Rough prepares and sends proteins to Golgi for
  export
• Smooth synthesizes lipids and cell membrane
  parts, detox (breaks down drugs and toxins)

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Golgi Apparatus

• Structure
• Stacks of flattened membranes
• Function
• Processing, packaging, and secreting proteins
• Send proteins to their final destinations
• Works with Rough ER

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Lysosome

• Structure
• Small sac which contains enzymes
• Not in plants
• Function
• Breaks down food digest proteins, carbs, and
  lipids, DNA or RNA in cell
• Removes debris digests old organelle or viruses
  and bacteria

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Vacuole

• Structure
• Large sac filled with enzymes, water, and
  wastes
• In plants VERY large takes up most of cell
• In animals small store extra materials
• Function
• Storage
• Vesicles small vacuoles involved in transporting
  substances within cells

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Centrioles

• Paired cylindrical organelles near the nucleus
• Structure
• composed of bundles of microtubules at right
  angles to each other
• Function
• involved in cell division

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Chloroplast

• Structure
• Saclike structure that contains chlorophyll (a
  green pigment)
• Function
• Photosynthesis Changes sunlight energy to
  organic chemicals (sugars)
• Found in plants, algae, and some bacteria
• NOT found in animals

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Mitochondria

• Structure
• Has 2 membranes
• Cristae folds of the inner membraneincreases
  surface area
• Function
• Powerhouse of the cell
• Cellular Respiration releases energy from food
  molecules to power cell (growth, movement,
  development, etc.)

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Organelle DNA

• Chloroplasts and mitochondria contain some of
  their own genetic information or DNA
• Lynn Margulis scientist who suggested that
  mitochondria and chloroplasts are actually
  descendants of ancient prokaryotes
• Endosymbiotic Theory eukaryotic cells formed
  from a symbiosis among several different
  prokaryotic organisms

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A Cell Is Like A CityAs a pair, match each
structure with the city part that has the same
function. Write 1-2 sentences for each structure
to explain why you have made this analogy.

• Cell Membrane ?
• Cell Wall ?
• Nucleus ?
• Ribosome ?
• ER ?
• Golgi Apparatus ?
• Lysosome ?
• Vacuole ?
• Chloroplast ?
• Mitochondrion ?

• trucking company
• power plant
• recycling center
• storage company
• fence surrounding city
• post office
• factory
• border patrol
• city hall
• restaurant

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A Cell Is Like A City

• Cell Membrane
• Cell Wall
• Nucleus
• Ribosome
• ER
• Golgi Apparatus
• Lysosome
• Vacuole
• Chloroplast
• Mitochondrion

• border patrol
• fence surrounding the city
• city hall
• factory
• trucking company
• post office
• recycling center
• storage company
• restaurant
• power plant