Inside the Cell: Ch.4

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Why do cells need to be small?
Efficiency: Things need to get in and out quickly.
Large Surface Area to Volume Ratio
Cells need a large surface area relative to a small volume.
What are the four common bio-molecules?
Carbohydrates, Lipids, Proteins, Nucleic Acids
All living cells have:
Cell membrane, Ribosomes, Cytoplasm, and Genetic Material
What is special about ribosomes?
They are not membrane bound.
Prokaryotic Cells
Unicellular, Single loop of DNA, no membrane bound organelles, absorb food. Ex: Bacteria
Eukaryotic Cells
Can be both unicellular and multicellular, have chromosomes, have membrane bound organelles, variable ways of getting food. Ex: animal cell
What is the plasma membrane?
Marks boundary between outside and inside of cell. Regulates passage in and out of cell. Phospholipid Bilayer with embedded proteins. Fluid-Mosaic Model: structure of the membrane.
How are organelles a major difference between prokaryotic and eukaryotic cells?
Eukaryotic cells have organelles.
What is an organelle?
A membrane-bound compartment in a cell where a specialized function occurs. Provides organization and improves efficiency in the cell.
Prokaryotic Cells include members from which domains?
Bacteria and Archae
What are four structures found in all prokaryotes?
Cell Wall, Pili, Flagellum, Plasma Membrane, Cytoplasm, Ribosomes, DNA.
Cell Wall
Protects and gives shape to the cell.
Pili
Hair-like projections that help cells attach to other surfaces.
Flagellum
Whip-like projections that aid in cellular movement.
Plasma Membrane
Encloses cell contents.
Cytoplasm
Jelly-like fluid inside the cell.
Ribosomes
Granular bodies in the cytoplasm that convert genetic information into protein structure.
DNA
One or more circular loops containing genetic information.
What are the four kingdoms of Eukaryota?
Plants, Animals, Fungi, Protista
What are three structures/organelles that are absent in animal cells?
Chloroplasts, Cell Wall, and Central Vacuole.
Nucleus
Acts as the genetic control center of the cell, directs cellular activity, and stores hereditary information.
Nucleolus
Center of the nucleus, where ribosomes are assembled.
Chromatin
Thin fibers of DNA which carry all hereditary information.
Cell Wall
Provides the cell with structural strength, gives the cell water resistance, and provides some protection form insects and other animals.
Vacuole
Stores nutrients, retains and degrades waste products. Accumulates poisonous materials. Contains pigments enabling plants to attract birds and insects that help the plant reproduce. Provides physical support.
Ribosomes
Protein making machines.
Mitochondria
Acts as all purpose energy converter, harvests energy to be used for cellular functions.
Endomembrane System
Produces and modifies molecules to be exported to other parts of the organism. Breaks down toxic chemicals and cellular by-products.
What are the steps of the endomembrane system?
1) Transport Vesicle buds from the smooth or rough ER.
2) Transport Vesicle fuses with Golgi Apparatus dumping contents inside.
3) Golgi Apparatus modifies the molecules as they move through its chambers.
4) Modified molecule bud off from the Golgi as a transport vesicle
5) Vesicles fuses with the plasma membrane, dumping contents outside the cell for delivery elsewhere in the organism.
Rough ER
Modifies proteins that will be shipped elsewhere in the organism.
Why is it called the rough ER?
It has ribosomes attached to its surface.
Smooth ER
Synthesizes lipids such as fatty acids, phospholipids, and steriods. Detoxifies molecules such as alcohol, drugs, and metablolic waste products.
Why is it called the smooth ER?
It doesn't have ribosomes on its surface.
What is tolerance?
Liver cells are packed with smooth ER because the liver detoxifies molecules.
Cytoskeleton
Acts as the inner scaffolding of the cell. Provides shape and support. Controls intercellular traffic flow. Enables movement.
Golgi Apparatus
Processes and packages proteins, lipids, and other molecules for export to other parts of the organism.
Lysosome
Act as floating garbage disposals for the cells digesting and recycling cellular waste products consumed material.
Chloroplast
Site of photosynthesis.
What are the three cell connections in animals?
1) Tight Junctions: Water tight cells that anchor other cells and prevent fluid flow.
2) Desmosomes: Proteins that fasten cells together like velcro.
3) Gap Junctions: Pores surrounded by special proteins that form open channels between cells.
What is the theory of endosymbiosis?
At some point certain bacteria (which have DNA and a cell membrane) were engulfed by a larger cell.
Evidence: Mitochondria and Chloroplasts have their own DNA and a double membrane around them.