Research!
• Look up each antibiotic from our lab and describe what it does to bacteria.
• As a group, draw a picture that you think best represents how each antibiotic works.
Cells!
– The cell is the lowest level of structure that can perform all activities required for life.
• Cell Theory:– All living organisms are composed of cells.– All cells come from other cells.
We can distinguish two major types of cells:ProkaryoticEukaryotic
Photo source: Wikipedia
The prokaryotic cell is simple, small, and contains no organelles.
The eukaryotic cell is larger and more complex and contains organelles.
Prokaryotic and Eukaryotic Cells:
(DNA)
(DNA)
Cytosol
Cytosol
A prokaryotic cell
Two typical kindsof eukaryotic cells:- Animal cells- Plant cells
Prokaryotic and Eukaryotic Cells: What do all cells have in common?
(DNA)
(DNA)
Cytosol
Cytosol
Plasma membraneCytosolRibosomesChromosomesmade of DNA A prokaryotic cell
Prokaryotic and Eukaryotic Cells: What is their most significant difference?
Eukaryotic cells havemembrane-bound organellesthat performspecialized functions
Prokaryotic cellsdo not
Look more closely at cellular structures and their functions
• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System
– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles
• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella
Plasma Membrane– The plasma membrane separates the living
cell from its nonliving surroundings.
- Regulates trafficinto and out of the cell
- Allows cell to interact with environment
Membrane Function– A closer look at our membranes
Hydrophobic region
Hydrophilicregion
Cell Surfaces
– Most cells secrete materials for coats of one kind or another that are external to (outside of) the plasma membrane.
– Animal cells have an extracellular matrix and cell junctions,
• Which helps hold cells together in tissues and protects and supports them (not shown).
Cell Surfaces
Try giving your skin a good pull. If your skin is made out of cells,how do they all stick together? Extracellular matrix and junctions!
– Plant cells and bacterial cells have cell walls,• Which help protect the cells, maintain their shape, and keep
the cells from absorbing too much water.
Cell Surfaces
Plant Cell Walls: Cellulose
Bacterial Cell Walls: Peptidoglycan
Osmosis and the Cell Wall
Solute in = solute outWater travels equally
Solute in > solute out Water travels in
Solute in < solute out Water travels out
Structure Meets Function in a Cell
• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System
– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles
• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella
The Nucleus:Genetic Control of the Cell
– The nucleus is the manager of the cell.• Genes on the DNA in the nucleus store information
necessary to produce proteins.
Prokaryotes do not have nuclei. Their genes (on DNA) are in the nucleoid region
Structure and Function of the Nucleus– The nucleus is bordered by a double membrane
called the nuclear envelope.• It contains chromatin and a nucleolus.
Chromatin: long strands of DNA and associated proteins. The DNA stores the genetic information (genes).
Nucleolus: assembles ribosomes
Ribosomes: Protein Synthesis– Ribosomes are responsible for protein synthesis.
How DNA Controls the Cell– DNA controls the cell by transferring its coded
information into RNA.• The information in the RNA is used to make proteins.
Eukaryotic cell
Prokaryotic cell
Structure Meets Function in a Cell
• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System
– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles
• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella
The Endomembrane System: Manufacturing, Distributing, and Storing Cellular Products
Not found in bacterial cells!
Structure Meets Function in a Cell
• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System
– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles
• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella
Energy Conversion:Chloroplasts & Mitochondria
– Cells require a constant energy supply to do all the work of life.
Not found in bacterial cells!
Chloroplasts– Chloroplasts are the sites of
photosynthesis, the conversion of light energy to chemical energy.
All little green circles are chloroplasts
Cell walls
Mitochondria– Mitochondria are the sites of cellular
respiration, which involves the production of ATP from food molecules.
Structure Meets Function in a Cell
• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System
– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles
• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella
The Cytoskeleton:Cell Shape and Movement
– The cytoskeleton consists of a network of fibers.
Also, recently found in bacterial cells!
Cytoskeleton– Mechanical support to
maintain cell shape
– Can change cell shape to allow movement
Structure Meets Function in a Cell
• Plasma Membrane and Cell Surface• Nucleus and Ribosomes• Endomembrane System
– Endoplasmic Reticulum (ER)– Golgi Body– Lysosomes– Vacuoles
• Energy Conversion: Chloroplasts and Mitochondria• Cytoskeleton• Cilia and Flagella
Cilia and Flagella– Cilia and flagella are motile appendages.
Not found on most plant cells!
– Flagella propel the cell in a whiplike motion.
– Cilia move in a coordinated back-and-forth motion.