Transcript CELLS POWERPOINT

Notes on Cells
Life is Cellular
I. History of Cell Theory
A. Microscopes
1. 1500s: merchants invented lenses to assess
cloth quality
2. Early 1600s: Hans & Zaccharias Janssen invent
the first crude microscope
3. 1665: Robert Hooke used a light microscope to
look at thin slices of cork
a. saw tiny compartments
b. Name them “cells”
4. Late 1600s: Anton van Leeuwenhoek
a. developed high quality lenses and first
light microscope
b. observed tiny structures in pond water
[bacteria]
c. “Animalcules”
B. Cell Theory
1. 1830s: Matthias Schleiden & Theodor Schwann
observed many organisms
a. Schleiden- plants are made of cells
b. Schwann- animals are made of cells
2. Rudolph Virchow: studied cell division, bone
marrow, and leukemia
a. Concluded all cells come from other cells
3. Cell Theory
• All living things are composed of cells
• Cells are basic units of structure and
function in living things
• New cells come from existing cells
II. Cell Types
• Two categories:
– Eukaryotes- have nucleus
– Prokaryotes- do not have nucleus
A. Prokaryotes
1. No nucleus
2. No membrane-bound organelles
3. Simple, first to evolve, smaller in size
4. Examples: all bacteria
B. Eukaryotes
1. Have nucleus
2. Membrane-bound organelles [mitochondria,
chloroplasts, nucleus]
3. Complex, evolved after prokaryotes, larger in
size
4. Examples: Animals, Plants, Fungi, Protists
III. Boundaries of the Cell
• Typical cells are 5-50 μm
A. Plasma or Cell membrane
–thin, flexible barrier around cell
B. Cell wall
–strong layer around cell membrane
(plants)
–serve to give support and structure
IV. CELL ORGANELLES
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Nucleus
Nuclear envelope =
nuclear membrane
Chromatin
Chromosomes
Nucleolus
Ribosomes
Cytoplasm
Endoplasmic Reticulum
(ER)
Smooth ER
Rough ER
Golgi (Body or Apparatus)
• Vacuoles
• Lysosomes
• Mitochondria
• Plastids
• Chloroplasts
• Leucoplasts
• Chromoplasts
• Cytoplasm
• Microtubules
• Microfilaments
• Cilia
• Flagella
• Centrioles
• Cytoskeleton
Basic Cell Structures
• Nucleus
– large structure containing cell’s genetic
material and controls cell’s activities
• Cytoplasm
– material inside cell
membrane but not
including the nucleus
Nucleolus
• Small, dense region inside nucleus
– Assembles ribosomes that make proteins
• Nuclear Membrane
– Double-membrane layer
– Many pores
Cytoskeleton
• Microtubules
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hollow tubes; “tracks” that organelles use to move
Important in cell division; separate chromosomes
Cilia
Flagella
• Microfilaments
– Give movement & support
– Tough, flexible framework
– Motor proteins move organelles
Ribosomes
• Made of RNA in nucleolus
• Assemble proteins
• “Workers”
• Endoplasmic Reticulum, “conveyor belt”
– Makes cell membrane components
– Modifies proteins
– rough and smooth
• Rough ER
– involved in synthesis of proteins
– Gets appearance by ribsomes
• Smooth ER
– does not have ribosomes on surface
– Makes lipids for cell membranes
Golgi Apparatus
• “Quality control”
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Stack of membranes
Proteins made by RER move here
Enzymes modify carbohydrates and lipids to proteins
Brings to the cell surface to be secreted
Lysosomes
• “Janitors”
• Small, filled with enzymes
• Break down lipids, carbohydrates, and proteins into particles the cell
uses
• Break down old organelles
Vacuoles
• “Storage”
• Store H2O, salts, proteins, carbs
• Support structures, like leaves and flowers
• Plants often have a central, large vacuole
• Smaller vacuoles called “vesicles”
Chloroplasts
• “Solar panels”
• Found in plants
• photosynthesis
• Two envelope
membranes
Mitochondria
• “Power house”
• Release energy from stored food
• Use energy to make high-energy
compounds
• 2 envelope membranes
• DNA
• Inherited from mom!
• Found in all eukaryotic cells
Cell as a factory
• Plasma membrane- “shipping/receiving
department”
• Cytoskeleton- “walls, roof, and beams”
• Nucleus- “the control center, CEO”
• Ribosome- “workers”
• Golgi Apparatus- “Quality control”
• Mitochondria and chloroplasts- “power sources”
• Lysosomes- “janitors”
V. Differences between Plant & Animal Cells
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Plants have/animals don’t:
B. Animals have/plants don’t:
VI. Cellular Organization
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Unicellular- “one cell”
1. more complex as one cell than a single cell of
a multicellular organism
2. performs all functions that a multicellular
organism does
B. Multicellular- “many cells”
1. Cell specialization
2. Interdependent on other cells
C. 5 Levels of Organization
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Cells
Tissues
Organs
Organ systems
Organism