A tour of the Cell A tour of the Cell Chapter 7 Chapter 7 http://www.youtube.com/watch? http://www.youtube.com/watch? v=o1GQyciJaTA&feature=related v=o1GQyciJaTA&feature=related http://www.ibiblio.org/virtualcell/textbook/ http://www.ibiblio.org/virtualcell/textbook/ chapter3/chapter3.htm chapter3/chapter3.htm http://vcell.ndsu.edu/animations/ http://vcell.ndsu.edu/animations/
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of a substance from where they are more concentrated to where they are less concentrated
DiffusionDiffusion
The random movement of molecules The random movement of molecules from a high concentration to a low from a high concentration to a low concentrationconcentration
If system is left alone the molecules If system is left alone the molecules will eventually spread themselves will eventually spread themselves equally every where – the molecules equally every where – the molecules do not stop moving throughdo not stop moving through
Types of Transport through plasma
membrane Passive transport– Diffusion: some molecules cross the
plasma membrane with no expenditure of energy or help from transport proteins
Osmosis: diffusion of water through a membrane
– Facilitated diffusion: Transport proteins provide a pathway for certain molecules to pass
Active transport
Water moves from high concentration to low concentration
What happens to a red blood cell when it is What happens to a red blood cell when it is placed in water with different placed in water with different concentrations of salt?concentrations of salt?
Results of water Results of water movement on cells – movement on cells – Osmotic PressureOsmotic Pressure
Types of Transport through plasma membrane Passive transport
– Diffusion Osmosis
– Facilitated diffusion Active transport: A transport
protein pumps a solute across a membrane in the opposite direction to the way it travels with diffusion. It requires chemical energy.
Bulk TransportBulk Transport
For larger molecules and solid For larger molecules and solid clumps of material the cell usesclumps of material the cell usesEndocytosis Endocytosis – cell takes in materials – cell takes in materials in by infoldings in the membranein by infoldings in the membrane
Main cell parts and Main cell parts and functionsfunctions
CytoplasmCytoplasm: holds : holds organelles - transport organelles - transport mediummedium
NucleusNucleus: Control : Control center – contains the center – contains the DNA (genetic material)DNA (genetic material)
Ribosomes: make Ribosomes: make proteinsproteins
RibosomeRibosome
RERRER: modify and : modify and transport proteinstransport proteins
SERSER: Production of : Production of lipids (fats)lipids (fats)
Golgi apparatusGolgi apparatus: Process : Process and package proteins and and package proteins and lipidslipids
ChloroplastChloroplast: Where : Where photosynthesis occurs photosynthesis occurs
MitochondriaMitochondria: Release : Release energy usable by the energy usable by the cellcell
LysosomeLysosome: Breaks : Breaks down macromolecules down macromolecules into particles the cell into particles the cell can use can use
HomeostasisHomeostasis ((homeo_homeo_=same=same
_stasis_stasis=standing still)=standing still) Unicellular organisms as well as Unicellular organisms as well as cells in multicellular organisms cells in multicellular organisms must maintain homeostasismust maintain homeostasis, or that , or that is to say, relatively constant is to say, relatively constant physical or chemical conditions.physical or chemical conditions.Unicellular organismsUnicellular organismsMulticellular organismsMulticellular organisms
To maintain HomeostasisTo maintain Homeostasis
Unicellular organismsUnicellular organisms– GrowGrow– Respond to environmentRespond to environment– reproducereproduce
Multicellular organismsMulticellular organisms– Have specialized cells that Have specialized cells that
communicate with each othercommunicate with each other
Examples of Homeostasis in humansExamples of Homeostasis in humans
In multicellular organisms there is In multicellular organisms there is a division of labor among the a division of labor among the specialized cellsspecialized cells