chapter 7 cell structure and function. anton van leeuwenhoek father of the microscope - 1600s used...
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Chapter 7
Cell Structure and Function
Anton van Leeuwenhoek
Father of the microscope - 1600’s
used lens technology
fabric quality
telescope same time
1st to see life in a drop of water (“animalcules”)
Robert Hooke
1665
1st to examine plant
tissue
Resembled monastery’s
tiny rooms
“Cells”
Matthias Schleiden
1838 - all plants are made of cells
Theodor Schwann
1839 - All animals are made of cells
Rudolf Virchow
1855 - Cells come from other preexisting cells
The Cell Theory
All living things are composed of cells
Cells are the basic units of structure and function in living things
New cells are produced from existing cells
What do all cells have in common?
Cell membranethin, flexible barrier surrounding the cell (protection)
Cytoplasmfluid within the cell
Genetic Material (DNA/RNA)
Major Groups of Organisms
1. Bacteria
2. Protists (amoeba, algae, seaweed)
3. Fungi
4. Plants
5. Animals
Basic Cell Types
Prokaryotic Cellscell membrane
cytoplasm
genetic material (lack a nucleus)
bacteria Cell membrane
cytoplasm
Genetic Material
Eukaryotic CellsCell membrane
Cytoplasm
Nucleus
Membrane-bound organelles
animals, plants, fungi and protists
Prokaryotic Cell
Cell membrane
Cell membrane
Cytoplasm
Cytoplasm
Nucleus
Organelles
Eukaryotic Cell
Section 7-1
Go to Section:
7-2 A Closer Look at the Cell
Your objective is to…
Describe the main functions of each
cell structure
Cell WallPlants, bacteria (prokaryotes), fungi, algae (protists)
Provides structure and protection
Gas and water exchange
Plants - made of polysaccharide cellulose
Nucleus
Controls cell processes
Contains DNAdeoxyribose nucleic acid
codes for protein and other molecules
ChromatinDNA bound to protein
Chromosomeschromatin condenses during cell division
Nucleolusmake ribosomes
Nuclear Envelope2 layers with pores that allow for the passage of material
Nucleus
The Nucleus
Nucleolus Nuclear envelope
Nuclear pores
Chromatin
Cytoskeleton
Network of protein filaments
(microtubules and microfilaments)
Maintains cell shape
Cell Movement
Intracellular Movementmoves organelles
important during cell division
Tracks for organelle movement
Cell membrane
Endoplasmicreticulum
Microtubule
Microfilament
Ribosomes Mitochondrion
Figure 7-7 Cytoskeleton
Structures for Movement:
Flagella-tail-like structures to propel cell in whipping motion
Cilia- hair-like projections that beat together to move the cell
Transportation
The Organelles
Specialized structures within the cytoplasm of the cell that
perform specific jobs
Ribosomes
Use genetic information to make protein
found free in cytoplasm or on RER
Endoplasmic Reticulum
2 typesRough and Smooth
Cell membrane assembly
Roughcontain ribosomes
certain proteins are modified
Smoothsynthesis of lipids
Endoplasmic Reticulum
Ribosomes
Endoplasmic Endoplasmic ReticulumReticulum
Golgi Apparatus
Receive proteins from RER
Use enzymes to attach carbohydrates and lipids to proteins
Sent to final destination
Lysosomes
Contain enzymes that breakdown large molecules into smaller molecules
Recycle old organelles and debris
Enzyme
Recycling
Vacuoles
Storage units for water, salts, proteins and carbohydrates
Provide support for plants “water”Central water vacuole
Vacuole
ChloroplastsFound in plants and algae (some bacteria)
photosynthesis
2 membranes
Contains DNA
Chloroplast
Mitochondria
Convert food into high-energy compounds (ATP) that the cell uses to power growth, development and movement
ATP = Energy
2 membranes
Contains DNA
Mitochondrion
Animal vs. Plant Cells
Plant Cells have the following (Animal Cells do not):
Cell Wall
Chloroplasts
Central Water Vacuole
Prokaryotes Eukaryotes
Cell membraneRibosomesCell wall
NucleusEndoplasmic reticulumGolgi apparatusLysosomesVacuolesMitochondriaCytoskeleton
Animal Cells Plant Cells
Lysosomes
Cell membraneRibosomesNucleusEndoplasmic reticulumGolgi apparatusVacuolesMitochondriaCytoskeleton
Cell Wall
Chloroplasts
Section 7-2
Venn Diagrams
Go to Section:
Animal vs. Plant Cells
Plant Cell
Nuclearenvelope
Ribosome(attached)
Ribosome(free)
Smooth endoplasmicreticulum
Nucleus
Rough endoplasmic reticulum
Nucleolus
Golgi apparatus
Mitochondrion
Cell wall
CellMembrane
Chloroplast
Vacuole
Figure 7-5 Plant and Animal Cells
Animal Cell
Centrioles
NucleolusNucleus
Nuclearenvelope
Rough endoplasmic reticulum
Golgi apparatus
Smooth endoplasmicreticulum
Mitochondrion
CellMembrane
Ribosome(free)
Ribosome(attached)
Figure 7-5 Plant and Animal Cells
7-3 The Cell Membrane
Objectives:
Describe the structure of the cell membrane
Describe how substances move through the cell
Cell Membrane Structure: Lipids, Proteins, Carbohydrates
• Lipid bilayer
• Functions:
1. Regulates entry and exit of materials
2. Protection and support
• Carbohydrate chains act as identification cards
Fluids
ICF = Intracellular Fluid (inside cell/cytoplasm)
ECF = Extracellular Fluid (outside cell)
Always dissolved particles in both of these fluids
Dissolved particles = solutes
Concentration of solutes can varyHigh = more solute
Low = less solute
Outsideof cell
Insideof cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel Lipid bilayer
Carbohydratechains
Figure 7-15 The Structure of the Cell Membrane
Diffusion
Movement of materials from a high concentration to a lower concentration until equilibrium is reached
requires no energy = passive
What materials diffuse across a cell membrane?
Permeability
Ability of membrane to allow substances to penetrate/pass throughLevels of permeability:
Permeable- any solutes can pass throughSemi-permeable/Selectively Permeable- certain solutes are selected to pass throughImpermeable- nothing is able to pass through
All cell membranes are selective = picky/choosyImpermeability is not an optioncell would die! Why???
Osmosis
Diffusion of water across a selectively permeable membrane
Types of Solutionshypertonic - higher concentration of dissolved particles (solute)
hypotonic - lower concentration of dissolved particles (solute)
isotonic - identical concentration
Osmosis occurs b/c the solute is unable to pass through the membrane. Water can always pass through the membrane.
Hydrophobic
•Lipid Tails
•Nonpolar
Hydrophilic
•Lipid Heads
•Polar
Continues until the concentrations are equal
Solutions outside of the cell…..
Problems in Organisms (Maintaining Homeostasis)
Plantsturgor pressure
rigid vs. wilting
Antibiotic effects on bacteria
Single Celled Organismscontractile vacuole
homeostasis
Animals cells bathed in isotonic fluids “blood”
Facilitated Diffusion• specific protein channels for specific substances that cannot diffuse on their own
•glucose channel
Facilitated Diffusion
Protein channel
Glucose molecules
Active Transport
movement of materials from lower concentration to higher concentration
requires energy = ATP
Molecule to be carried
Active Transport
Molecule tobe carried
Moleculebeing carried
Energy
Figure 7-20 Active Transport-going against concentration gradient (low to high). Natural is from high to low (diffusion and facilitated diffusion).
Phagocytosis
Large particles taken into cell
Extension of cytoplasm engulfs large particles outside cell
Pocket folds into cell with contents and breaks loose from cell membrane forming vacuole inside cell (in cytoplasm).
Other examples of
active transport
Unicellular Organisms
A single cell is the entire organism
Includes all prokaryotes and some eukaryotes
Examples include: algae, yeasts, bacteria
Multicellular Organisms
Cells are interdependent (like a team)
Cell specialization- separate roles for each type of cell (ex. Blood cell, nerve cell, muscle cell)
Cells are specialized to perform particular functions within organism
Levels of Organization
Individual cellstissuesorgansorgan systemsorganism
Tissue- group of similar cells that perform particular functionOrgan- groups of tissues working togetherOrgan Systems- group of organs working together to perform specific function (11 major systems in human body)
Muscle cell
Smooth muscle tissueStomach
Digestive system
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