Chemical level: a molecule in the membrane that encloses a cell

Cellular level: a cell in the stomach lining

Tissue level: layers of tissue in the stomach wall

Organ level: the stomach

Body system level: the digestive system

Organism level: the whole body

2

• The cell is the basic structural, functional and biological unit of life.

• Cells are the smallest living unit; the building blocks of life.

3

First to View CellsFirst to View Cells• In 1665, Robert

Hooke used a microscope to examine a thin slice of cork (dead plant cell walls)

• What he saw looked like small boxes

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Anton van Leeuwenhoek

• In 1673, Leeuwenhoek (a Dutch microscope maker), was first to view organism (living things)

• Father of Microbiology

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Beginning of the Cell Beginning of the Cell TheoryTheory

• In 1838, a German botanist named Matthias Schleiden concluded that all plants were made of cells

•Schleiden is a cofounder of the cell theorycopyright cmassengale

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Beginning of the Cell Beginning of the Cell TheoryTheory

• In 1839, a German zoologist named Theodore Schwann concluded that all animals were made of cells

•Schwann also cofounded the cell theory

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Beginning of the Cell Beginning of the Cell TheoryTheory

• In 1855, a German medical doctor named Rudolph Virchow observed, under the microscope, cells dividing

• He reasoned that all cells come from other pre-existing cells by cell division

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Discoveries Discoveries SinceSince the the

Cell TheoryCell Theory

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ENDOSYMBIOTIC THEORYENDOSYMBIOTIC THEORY• In 1981, American biologist,

Lynn Margulis, provided evidence that some organelles within cells were at one time free living cells themselves

• Supporting evidence included organelles with their own DNA

• Chloroplast and Mitochondria

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10copyright cmassengale

1.All life forms are made from one or more cells.

2.Cells only arise from pre-existing cells. 3.The cell is the smallest form of life.

Proposed in 1838 by Schleiden, Schwann and Virchow

• NO NUCLEUS or Membrane Bound NO NUCLEUS or Membrane Bound OrganellesOrganelles• Small, simple, single celledSmall, simple, single celled• A prokaryotic cell is enclosed by a plasma membrane and is usually encased in a rigid cell wall

–The cell wall may be covered by a sticky capsule

–Inside a prokaryotic cell are its DNA, ribosomes and cytoplasm

• Grow & reproduceGrow & reproduce•Example: E. coli (bacterial cells)Example: E. coli (bacterial cells)

•HAVE A NUCLEUS & MEMBRANE-BOUND ORGANELLES

•Grow & reproduce

•Some live as single cells

•Examples: Plants, animals, fungi, protists

•Unicellular organisms are made up of only 1 cell

•All prokaryotes and some protists•Multicellular organisms are made up of more than one cell. Cells are often specialized.

– plants, animals, fungi and some protists

Plasma membrane

Figure 4.5A

Golgiapparatus

Ribosomes

NucleusSmooth endoplasmicreticulum

Roughendoplasmicreticulum

Mitochondrion

Not in most plant cells

Cytoskeleton

Flagellum

Lysosome

Centriole

Peroxisome

Microtubule

Intermediatefilament

Microfilament

Figure 4.5B

Nucleus

Golgiapparatus

Not inanimal

cells

Centralvacuole

Chloroplast

Cell wall

Mitochondrion

Peroxisome

Plasma membrane

Roughendoplasmicreticulum

Ribosomes

Smoothendoplasmicreticulum

Cytoskeleton

Microtubule

Intermediatefilament

Microfilament

• Organelle = “little organ”• Organelles are structures that have

specific jobs within the cell.

FOUND ONLY IN EUKARYOTIC CELLS

Function: The jelly-like fluid that fills a cell is called cytoplasm. It is made up of mostly water and salt. Cytoplasm is present within the cell membrane of all cell types and contains all organelles and cell parts.

FOUND IN ALL CELLS

Function: provide support and protection for the cell; found outside of the cell membrane; allows water, oxygen, carbon dioxide and other things to pass through

Made of Cellulose in Plants, Chitin in Fungi, Peptidoglycan in Bacteria

FOUND ONLY IN PLANT, FUNGI AND BACTERIA CELLS

Description: Semipermeable Phospholipid Bilayer with proteins embedded in it. Each phospholipid contains a polar (hydrophilic) head and a non-polar (hydrophobic tail.Function: Provides a barrier between the inside of the cell and the external environment. Maintains homeostasis.

Found in ALL Cells

Description: Double-membrane layer

Function: Selectively allows material to pass into and out of the nucleus via the pores

Location: Surrounds the nucleus

Found in all EUKARYOTIC CELLS

Function: controls most cell processes and contains hereditary info of DNA; has chromatin which forms chromosomes during mitosis

Location: near the center of the cell; surrounded by nuclear envelopeFound in all EUKARYOTIC cells

Function: Location where ribosomes are made

Location: WITHIN the nucleus.

Found in all EUKARYOTIC cells

Description: DNA is spread out and apprears as chromatin in non-dividing cells.Location: WITHIN the nucleus.

Description: DNA is condensed and wrapped around proteins forming as chromosomes in dividing cells. Location: WITHIN the nucleus.

TYPES:Free – are floating around in the cytoplasm

Bound – are attached to rough endoplasmic reticulum

Function: Protein Synthesis

Found in ALL cells

Function: use energy from food to make high-energy particles (ATP) for the cell to use; site of cellular respiration

Location: in the cytoplasm of the cell

Nickname: PowerhouseFound in all EUKARYOTIC Cells

Description: Double membrane structure containing stacks of photosynthetic membranes which contain the green pigment chlorophyll.

Function: Use energy from sunlight to make energy-rich food molecules in a process known as photosynthesis.Found ONLY in PLANT Cells

Description: Folded membrane studded with ribosomes that extends from the nuclear envelope

Function: Protein synthesis can occur ON the ribosomes and then the proteins are modified on the inside of the rough ER.

Found in all EUKARYOTIC Cells

Description: Folded membrane that extends from the rough ER or stands alone in the cytoplasm

Function: Contains collections of enzymes for specialized tasks, including assembly of lipids.

Found in all EUKARYOTIC Cells

Description: Folded membranes that are stacked and form an assembly line for final modification of proteins

Function: Using enzymes, it attaches carbohydrates & lipids to proteins. From the Golgi, proteins are sent to their final destination in vesicles.

Found in all EUKARYOTIC Cells

Function: Contain enzymes used to breakdown lipids, carbohydrates, and proteins.

Lysosomal Enzymes can: - Digest food- Destroy bacteria- Recycle damaged organelles- Function in embryonic development in

animals

Found in Animal Cells Only!

Function: Location for storage of water, salts, proteins & carbohydrates. In plant cells there is usually a single, large, central vacuole that stores liquid.

Found in EUKARYOTIC Cells

Larger in Plant Cells than in Animal Cells

Function: helps the cell maintain its shape; also involved in movement inside the cell

Location: network of protein filaments that goes throughout the cell

Components: Microtubules & Microfilaments

Found in ALL Cells

Function: responsible for protecting the cell against hydrogen peroxide•Contains enzymes (catalase) which act in the production and decomposition of hydrogen peroxide•Involved in energy metabolism

Found in ALL Eukaryotic Cells

Function: used for movement of the cell or for movement of small particles across the cell surface.•Cilia are shorter and more numerous on cells•Flagella are longer and fewer on cells

Found in Animal Cells and Prokaryotic Cells

Structure: paired structures near the nucleus; made of a bundle of microtubulesFunction: appear during cell division and help to pull chromosome pairs apart to opposite ends of the cell.

Found only in Animal Cells

Factors that affect cell size:•Surface area•Volume of a cell•Volume increases faster than the surface area

•When the surface area is no longer great enough to get rid of all the wastes and to get in enough food and water, then the cell must divide.•Therefore, the cells of an organism are close in size.