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The cell Cell theory: All living things contain cells.
All cells come from other cells.
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Viruses Are viruses living? According to cell theory no.
However they do contain organic molecules (DNA or RNA & protein) and can replicate themselves using a host cell, so some biologists say yes. This demonstrates the rule, that for every rule in biology, we can usually find at least 1 exception Influenza virus (an Orthomyxovirus)
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Escherichia coli bacteria
Prokaryotic cells Do they have a nucleus? Do they have organelles? How big are they? Examples include no no Very small - usually 1 – 10 m Bacteria, blue green bacteria Escherichia coli bacteria Streptococcus pnemoniae
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Eukaryotic cells Do they have a nucleus? Do they have organelles?
How big are they? Examples include yes yes Larger than bacteria – usually 20 – 500 m Plants, animals, fungi, Protista
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Cell membrane Main function Controls entry and exit of substances
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Cell wall Main function Provides structure and support
Only found in plant cells
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Cytoplasm Main function
Provides a medium for reactions & site for organelles
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Nucleus Control centre – contains the genetic blueprint (genes) for coding proteins, hence controls all cell activities Main function
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Nucleolus Main function Site of RNA production & storage
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Nuclear membrane Main function Keeps DNA within nucleus
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Endoplasmic reticulum
Main function Transport system, site for reactions to occur
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Ribosomes Main function Site of protein synthesis
Some are found free in the cytoplasm Most are found attached to the endoplasmic reticulum
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Mitochondria Main function
Site of aerobic respiration – energy production
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Plastids
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Chloroplasts Main function Site of photosynthesis
Only found in plant cells
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Golgi body Main function Packaging for secretion
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Vacuoles Main function Storage of food and water
In plants provides strength and structure to cell Plant cells usually have 1 large one Animal cells usually have several smaller ones
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Lysosomes Main function Storage of wastes
Most contain enzymes that break down substances Main function
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Contractile vacuole Main function Pumps out excess water,
hence maintaining water balance in the cell Only found in some unicellular organisms
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Centrioles Main function Forms spindle during cell division
Only found in animal cells
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Cytoskeleton Microfilaments are thin fibres that are made mostly of the protein actin. Microfilament fibres can change length when supplied with energy by ATP, and so they allow cells to change shape. They also guide the movements of organelles within the cell. Interactions of actin and the protein myosin are important in contraction of muscle cells. Intermediate fibres (intermediate filaments) are somewhat larger in diameter than are microfilaments, and are made of several different proteins. Intermediate fibres form a 3-D network throughout the cell that forms much of the framework of the cell and holds the organelles in position. Microtubules are about 24 nanometers in diameter, somewhat thicker than microfilaments or intermediate fibres. Microtubules are hollow and composed largely of the protein tubulin. Microtubules help to position, anchor, and move organelles. They are also important in cellular reproduction and in the movements of cells. Microtubules are important components of both cilia and flagella, and of centrioles.
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Cilia and flagella Main function Movement
Usually found in animal or Protist cells
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Plant cells Special features include: Cell wall Chloroplasts
Large single vacuole No centrioles
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Animal cells Special features include: No cell wall No chloroplasts
Vacuoles usually small and numerous Centrioles
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What type of cell am I?
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What type of cell am I? plant animal plant Prokaryotic Prokaryotic
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What type of cell am I?
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What type of cell am I? animal plant plant animal
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Label the cells
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Label the cells Cell wall chloroplast mitochondrion lysosome
Smooth endoplasmic reticulum Golgi body centrioles vacuole vacuole Cell membrane Cell membrane nucleus nucleus nucleolus nucleolus Nuclear membrane Nuclear membrane Chromatin/DNA Chromatin/DNA Smooth endoplasmic reticulum Rough endoplasmic reticulum Rough endoplasmic reticulum ribosomes cytoplasm cytoplasm
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Identify the organelles
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Identify the organelles
mitochondrion Rough endoplasmic reticulum Nuclear membrane Nuclear pore nucleolus nucleus nucleolus chloroplast cytoplasm nucleus vacuole Cell wall vacuole chloroplast Cell wall nucleolus
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Identify the function of these
cell membrane cell wall cytoplasm nucleus nucleolus nuclear membrane mitochondria Golgi body Controls entry and exit of substances Provides structure and support Provides a medium for reactions & site for organelles Control centre – contains the genetic blueprint (genes) for coding proteins, hence controls all cell activities Site of RNA production & storage Keeps DNA within nucleus Site of aerobic respiration – energy production Packaging for secretion
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Identify the function of these
endoplasmic reticulum ribosomes lysosomes centrioles cilia/flagella chloroplasts vacuole contractile vacuole Transport system, site for reactions to occur Site of protein synthesis. Some are found free in the cytoplasm Most are found attached to the endoplasmic reticulum Storage of wastes Most contain enzymes that break down substances Forms spindle during cell division Movement Site of photosynthesis Storage of food and water In plants provides strength and structure to cell Pumps out excess water, hence maintaining water balance in the cell
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