Prokaryotic vs Eukaryotic Cells

Honors Biology

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LEVELS OF ORGANIZATION

Nonliving Levels:

1. ATOM (element)

2. MOLECULE (compounds like

carbohydrates & proteins)

3. ORGANELLES (nucleus, ER, Golgi …)

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LEVELS OF ORGANIZATION

Living Levels:

1. CELL (makes up ALL organisms)

2. TISSUE (cells working together

3. ORGAN (heart, brain, stomach …)

4. ORGAN SYSTEMS (respiratory, circulatory …)

5. ORGANISM

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Cell Theory

1. All living things are made of cells2. Cells are the basic unit of life3. All existing cells are produced by

other living cells.

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Nerve cells in the retina by Santiago Ramon

FIRST TO VIEW CELLS

• In 1665, Robert Hooke used a microscope to examine a thin slice of cork (dead plant cells)

• What he saw looked like small boxes

FIRST TO VIEW CELLS

• Hooke is responsible for naming cells• Hooke called them

“CELLS” because they looked like the small rooms that monks lived in called Cells

Important People

• 1) Robert Hooke – discovered cells by looking at cork (dead plant cells)

• 2) Anton von Leeuwenhoek – made the first simple microscope, first to view organism (LIVING THINGS)

• 3) Matthias Schleiden – German botanist; concluded that all plants are made up of cells (cofounder of cell theory)

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Important People

• 4) Theodor Schwann – German zoologist; concluded that all animals are made up of cells (cofounder of cell theory)

• 5) Rudolf Virchow – German physician; he reasoned that all cells come from other pre-existing cells by cell division

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CELLS!• Smallest unit of life in all living things• Two basic types:

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Prokaryotic – • Simple• Smaller• No membrane-

bound organelles• No nucleus • MAY have a cell

wall • Ex: Bacteria

Eukaryotic – • More complex• Membrane- bound

organelles• Ex: Plants, Animals,

and Fungi

CELL TYPES• Three Basic types of cells include:

Animal Cell(Eukaryote)

Plant Cell(Eukaryote)

Bacterial Cell (Prokaryote)

**SMALLEST

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CELL SIZE

Typical cells range from 5 – 50 micrometers (microns) in diametercopyright cmassengale

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How Big is a Micron ( µ ) ?

1 cm = 10,000 microns 1” = 25,000 microns

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NUMBER OF CELLSAlthough ALL living things are made of cells,

organisms may be:• Unicellular – composed of one cell

• Multicellular- composed of many cells that may organize into tissues, etc.

MULTICELLULAR ORGANISMS

• Cells in multicellular organisms often specialize (take on different shapes & functions)

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Specialized Animal Cells

Muscle cells Red blood cells

Cheek cells

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ATOMS MOLECULES ORGANELLES

Nonliving Levels

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CELLS – life starts here TISSUES – Similar cells working together

Living Levels

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ORGANSORGAN SYSTEMS ORGANISM

Different tissuesworking together

Different organsworking together

More Living Levels

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ALL CELLS…

Contain 4 basic cell structures:

• Cell Membrane• Cytoplasm• Ribosomes• DNA

• **not an organelle

PROKARYOTES – THE FIRST CELLS

• Simplest and smallest type of cell– Includes bacteria

• NO nucleus • NO/FEW organelles• 1 Single, circular chromosome• Think: “Pro” athlete plays with 1 ball

PROKARYOTES• Nucleoid region (center)

contains the DNA (NO nulceus)

• Surrounded by cell membrane & cell wall (made of peptidoglycan)

• Contain ribosomes in their cytoplasm to make proteins

• Flagella for movement

Prokaryotes• Prokaryotes: (pro- means before, and -karyote means nucleus)

– First type of cells to evolve – Very small (size of mitochondria)– Unicellular– Two Types: • 1)Archaea • 2) Eubacteria

– Cell Division/Reproduction: Asexual via Binary Fission

Prokaryote ShapeThree Shapes:1) Bacillus (rod shaped)2) Cocci (spherical)3) Spirilla (spiral)

Prokaryote Cell StructureComponents:

• cell membrane• cell wall• ribosomes• flagella• nucleoid region (NO

NUCLEUS)• cytoplasm• capsule• pili• NO membrane-bound

organelles

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Functions• Capsule - Found in some bacterial cells, this additional

outer covering protects the cell, and helps the cell adhere to surfaces and nutrients.

• Cell Wall - Outer covering of most cells that protects the bacterial cell and gives it shape.

• Cytoplasm - A gel-like substance composed mainly of water that also contains enzymes, salts, cell components, and various organic molecules.

• Cell Membrane or Plasma Membrane - Surrounds the cell's cytoplasm and regulates the flow of substances in and out of the cell.

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Function cont’d

• Pili - Hair-like structures on the surface of the cell that attach to other bacterial cells.

• Flagella - Long, whip-like protrusion that aids in cellular locomotion.

• Ribosomes - Cell structures responsible for protein production.

• Nucleiod Region - Area of the cytoplasm that contains the single bacterial DNA molecule.

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EUKARYOTES• All eukaryotic cells

HAVE:• a Nucleus• membrane-bound

organelles

• These cell types includes:• protists• fungi• plants• animals

• More complex type of cells

Eukaryotic Cells

• Divided into compartments• Unicellular or Multicellular • Organelles → structures that have a specific

function in the cell (including the nucleus)• Cytoplasm → region between nucleus and

plasma membrane that surrounds organelles– Filled with cytosol (watery-jelly part) and organelles– Contains centrioles, which help with cell division

reproduction

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Organelles• Organelles are individual structures that

have specific functions. Together, these organelles carry out the necessary jobs in order for that cell to survive. Many other things are organized in this way as well.

• Very small (Microscopic)• Perform various functions for a cell• Found in the cytoplasm• May or may not be membrane-bound

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Types of Eukaryotes• Unicellular (Protozoa)– Protists

• Paramecium, amoebae– Fungi

• Yeast

• Multicellular (Metazoa)– Fungi– Plants– Animals

• Reproduction for ALL eukaryotes may be asexual or sexual

Features in Common between Eukaryote & Prokayrote

• Both eukaryote and prokaryote cells have these features in common: 1) Surrounded by a plasma/cell membrane• This determines what enters and leaves the cell• It is thin and flexible and does not provide much

structural support• Ex: school doors

2) Have RIBOSOMES • MAKES proteins by linking amino acids (protein synthesis)

3) Have DNA or RNA as genetic material

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TWO MAIN TYPES OF EUKARYOTIC CELLS

Plant CellAnimal Cell