honors cells ppt - pkwy.k12.mo.us file• eukaryotic cells have many organelles allowing them to 1....
TRANSCRIPT
Cells
Variation and Function of Cells
• Cell Theory states that:1. All living things are made of cells2. Cells are the basic unit of structure and functio n
in living things3. New cells are produced from existing cellsTwo major types of Cells
Prokaryotic cells are very small and have no membrane bound organelles or a nucleus. All Bacteria are prokaryotes and have circular DNA.
Eukaryotic Cells are more organized and complex than prokaryotes, they have membrane bound organelles, linear chromosomes and tend to be very large in comparison. P169-173
• Prokaryotic Cells come in two major classes (domains)
1. Eubacteria-are very diverse often have a cell wall that contains peptidoglycan
2. Archaebacteria- lack peptidoglycan in cell walls, have different membrane lipids, and have some genes that are more similar to eukaryotes than eubacteria.
Terms for classification:Bacilli=rod shaped Strepto= in rowsCocci= spherical Staphylo=clumpsSpirilla= cork screw shaped p471-474
• Eukaryotic Cells have many organelles allowing them to
1. Grow much larger as they developed organization and distribution abilities
2. Compartmentalize delicate and destructive processes within separate microenvironments.
3. Specialize function of individual cells to work with different functions of other cells (multi-cellular)
Plasma Membrane= the “skin” of a cell, it protects and nourishes the cell while communicating with other cells at the same time.
Fig. 6-9a
ENDOPLASMIC RETICULUM (ER)
Smooth ERRough ERFlagellum
Centrosome
CYTOSKELETON:
Microfilaments
Intermediatefilaments
Microtubules
Microvilli
Peroxisome
MitochondrionLysosome
Golgiapparatus
Ribosomes
Plasma membrane
Nuclearenvelope
Nucleolus
Chromatin
NUCLEUS
Fig. 6-9b
NUCLEUS
Nuclear envelopeNucleolusChromatin
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Ribosomes
Central vacuole
Microfilaments
Intermediate filamentsMicrotubules
CYTO-SKELETON
Chloroplast
PlasmodesmataWall of adjacent cell
Cell wall
Plasma membrane
Peroxisome
Mitochondrion
Golgiapparatus
Fig. 6-30a
Collagen
Fibronectin
Plasma membrane
Proteoglycancomplex
Integrins
CYTOPLASMMicro-filaments
EXTRACELLULAR FLUID
• Lipid Bilayer- the cell membrane is made up of phospholipids that arrange themselves into two parallel layers with the phosphate heads facing the internal cytosol and the external environment and the hydrophobic tails sandwiched in between.
• The membrane then has two outer hydrophilic layers and an inner hydrophobic layer which prevent the entrance of nearly all large molecules and charged or polar molecules
• The membrane has several proteins that pass through it creating channels that only allow a specific ion or molecule to cross the membrane.
Fig. 6-7
TEM of a plasmamembrane
(a)
(b) Structure of the plasma membrane
Outside of cell
Inside ofcell 0.1 µm
Hydrophilicregion
Hydrophobicregion
Hydrophilicregion Phospholipid Proteins
Carbohydrate side chain
Fig. 7-6
RESULTS
Membrane proteins
Mouse cellHuman cell
Hybrid cell
Mixed proteinsafter 1 hour
Fig. 7-7
Fibers ofextracellularmatrix (ECM)
Glyco-protein
Microfilamentsof cytoskeleton
Cholesterol
Peripheralproteins
Integralprotein
CYTOPLASMIC SIDEOF MEMBRANE
GlycolipidEXTRACELLULARSIDE OFMEMBRANE
Carbohydrate
Fig. 6-30
EXTRACELLULAR FLUIDCollagen
Fibronectin
Plasmamembrane
Micro-filaments
CYTOPLASM
Integrins
Proteoglycancomplex
Polysaccharidemolecule
Carbo-hydrates
Coreprotein
Proteoglycanmolecule
Proteoglycan complex
• Trans-membrane proteins have hydrophilic ends and a hydrophobic center which keeps them locked into the cell membrane
• Passive transport is the movement of a solute down its concentration gradient.
• Channel proteins provide a path for solute movement only.
-Aquaporins are one channel protein specific to water
• Carrier proteins change shape when they bind to substrate going from being open to one side to being open to the other
Fig. 7-8
N-terminus
C-terminus
αααα HelixCYTOPLASMICSIDE
EXTRACELLULARSIDE
Fig. 7-15
EXTRACELLULAR FLUID
Channel protein
(a) A channel protein
Solute CYTOPLASM
Solute Carrier protein
(b) A carrier protein
• Active transport is the movement of a solute which requires an input of energy, often because the solute is moving against its concentration gradient.
• H+ pumps or Na/K pumps both build a charge on one side of the membrane and keep adding to that charge. They must use ATP or other energy to do this.
• Cotransport is tricky because the cotransportprotein itself uses no energy but it relies on a gradient that does. A solute that would not normally move across the membrane is allowed to because it is accompanied by a molecule that is moving down its concentration gradient.
2
EXTRACELLULAR
FLUID[Na+] high[K+] low
[Na+] low [K+] high
Na+
Na+
Na+
Na+
Na+
Na+
CYTOPLASM
ATP
ADPP
Na+
Na+
Na+
P
3
K+
K+
6
K+
K+
5 4
K+
K+
PP
1
Fig. 7-16-7
Fig. 7-19
Proton pump
–
–
–
–
–
–
+
+
+
+
+
+
ATP
H+
H+
H+
H+
H+
H+
H+
H+
Diffusionof H+
Sucrose-H +
cotransporter
Sucrose
Sucrose
• Endocytosis- taking large materials into a cell• Exocytosis- kicking large materials out of a cell• Phagocytosis is endocytosis that takes in a
large amount of solid material from the outside environment.(cell eating)
• Pinocytosis is endocytosis that take in a large amount of liquid from the environment surrounding the cell.
• Because water is passively transported, the addition of hypotonic water to a cells environment will cause the cell to swell.
• The addition of hypertonic solution to a cells surrounding will cause the cell to shrink.
Fig. 6-14a
Nucleus 1 µm
Lysosome
Lysosome
Digestive enzymes
Plasma membrane
Food vacuole
Digestion
(a) Phagocytosis
Fig. 6-14b
Vesicle containingtwo damaged organelles
Mitochondrion fragment
Peroxisomefragment
Peroxisome
Lysosome
DigestionMitochondrionVesicle
(b) Autophagy
1 µm
Fig. 7-13
Hypotonic solution
(a) Animalcell
(b) Plantcell
H2O
Lysed
H2O
Turgid (normal)
H2O
H2O
H2O
H2O
Normal
Isotonic solution
Flaccid
H2O
H2O
Shriveled
Plasmolyzed
Hypertonic solution
• In a plant, swelling from the hypotonic environment provides support.
• “Saline” solution used to clean wounds and contacts means “Salt” but it is isotonic in concentration to tears and body fluid to protect cells.
• Prokaryotic cells are limited in their structure. They have ribosomes, circular DNA, rely on the exterior membrane to complete any membrane related function and rely on diffusion for transport.
• Eukaryotes are incredibly complex in comparison with several unique organelles that maximize their efficiency.
• Plants have a few unique organelles and structures
• Cell Wall- in plants these are made up of Cellulose and lignin creating a rigid outer shell that is made even stronger when the plant has a hypotonic environment.
• Chloroplast- the light converting plastid (membrane sac) it absorbs light energy and converts it to chemical energy.
• Plastids- several different membrane sacs that hold various pigments, metabolites, etc.
• Central Vacuole- a huge vacuole found in the center of the cell that tends to hold water and keeps the organelles nearer the edge of the cell
Fig. 6-9b
NUCLEUS
Nuclear envelopeNucleolusChromatin
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Ribosomes
Central vacuole
Microfilaments
Intermediate filamentsMicrotubules
CYTO-SKELETON
Chloroplast
PlasmodesmataWall of adjacent cell
Cell wall
Plasma membrane
Peroxisome
Mitochondrion
Golgiapparatus
• All Eukaryotes have the following organelles and structures.
Nucleus• Nuclear envelope- a membrane that contains the DNA
and the proteins necessary to organize and maintain the DNA
• Chromatin-DNA and Protein that is found unwound in a cell between divisions.
• Chromosomes-condensed form of chromatin these are linear and found during mitosis.
• Nucleolus- area of the nucleus thought to be used to assemble ribosomes.
Cytosol• Ribosomes- RNA and protein complex that work
together to read mRNA and build a protein from its code.
Fig. 6-10
NucleolusNucleus
Rough ER
Nuclear lamina (TEM)
Close-up of nuclear envelope
1 µm
1 µm
0.25 µm
Ribosome
Pore complex
Nuclear pore
Outer membraneInner membraneNuclear envelope:
Chromatin
Surface ofnuclear envelope
Pore complexes (TEM)
• Organelles are small membrane bound, specially designed and tasked parts of cells
• Endoplasmic Reticulum- network of membrane found in the cell along side the nucleus, makes lipid and protein components of the membrane and materials for export from the cell.
• Rough ER looks grainy because it has ribosomes embedded in its membrane. Produces membrane bound proteins and proteins for export.
• Smooth ER is the side of the ER away from the nucleus this is the ER responsible for lipid synthesis and detoxification often refines or modifies products from rough ER
Fig. 6-12
Smooth ER
Rough ER Nuclear envelope
Transitional ER
Rough ERSmooth ERTransport vesicle
RibosomesCisternaeER lumen
200 nm
• Golgi Apparatus- Acts as a processing center for products from the ER. May modify some chemicals, while just sorting and packaging others for storage or release.
• Lysosomes are membrane bags of hydrolytic enzymes. They allow cells to keep these dangerous chemicals separate from the rest of the cell’s chemicals and concentrated. Lysosomes bind with food vacuoles to start the digestions of materials that have been consumed.
• Vacuoles-mainly just mean membrane bag and is used to refer to contractile vacuoles that pump out extra water, food vacuoles, and central vacuoles.
Fig. 6-13
cis face(“receiving” side of Golgi apparatus) Cisternae
trans face(“shipping” side of Golgi apparatus)
TEM of Golgi apparatus
0.1 µm
• Mitochondria-the “power house” of the cell. This is the organelle that takes glucose or other chemical energy sources and converts them into ATP. Mitochondria have their own circular DNA, a lot of membrane folds, and their own ribosomes.
• Chloroplasts are the organelles that house chlorophyll allowing them to capture sunlight and convert the energy it carries into the chemical energy (glucose). These also have their own circular DNA, large amounts of internal membrane, and their own ribosomes.
Fig. 6-17
Free ribosomesin the mitochondrial matrix
Intermembrane spaceOuter membrane
Inner membraneCristae
Matrix
0.1 µm
Fig. 9-19
Glucose
Glycolysis
Pyruvate
CYTOSOL
No O2 present:Fermentation
O2 present:Aerobic cellularrespiration
MITOCHONDRION
Acetyl CoAEthanolor
lactateCitricacidcycle
Fig. 9-2
Lightenergy
ECOSYSTEM
Photosynthesisin chloroplasts
CO2 + H2O
Cellular respirationin mitochondria
Organicmolecules+ O2
ATP powers most cellular work
Heatenergy
ATP
Fig. 10-3b
1 µm
Thylakoidspace
Chloroplast
GranumIntermembranespace
Innermembrane
Outermembrane
Stroma
Thylakoid
Fig. 10-7
Reflectedlight
Absorbedlight
Light
Chloroplast
Transmittedlight
Granum
• Cytoskeleton is the structural framework found inside of cells.
• Microfilaments are the smallest form of cytoskeleton fibers and are made of actinThese resist tension very well. These are the fibers that are pulled on in muscles to create a contraction.
• Microtubules are the largest form of cytoskeleton fibers made of tubulin and they resist compression very well. These provide support to a cell against being crushed and act as a rail along which vacuoles and lysosomescan be transported. They are also the basis for the movement of cilia and flagella
Fig. 6-20
Microtubule
Microfilaments0.25 µm
Table 6-1b
Actin subunit
10 µm
7 nm
Table 6-1a
10 µm
Column of tubulin dimers
Tubulin dimerαααα ββββ
25 nm
Fig. 6-21
VesicleATP
Receptor for motor protein
Microtubuleof cytoskeleton
Motor protein (ATP powered)
(a)
Microtubule Vesicles
(b)
0.25 µm
• Centrioles in animal cells are made of microtubules that are in the same arrangement as they are in the base of flagella. Centriolesact as microtubule organizing centers for the act of mitosis and meiosis.
• Intermediated filaments are made of any one of several proteins and they are in between in size and tend to perform a wide range of functions depending on the protein they are made of.
Fig. 6-22Centrosome
Microtubule
Centrioles
0.25 µm
Longitudinal section of one centriole
Microtubules Cross sectionof the other centriole
Fig. 6-22Centrosome
Microtubule
Centrioles
0.25 µm
Longitudinal section of one centriole
Microtubules Cross sectionof the other centriole
• Endosymbiotic Hypothesis- Idea that explained that Mitochondria and some plastids had come into existence as a result of a small bacteria entering a larger cell then developing a close mutualistic relationship with that new cell. Supporting evidence is the DNA, ribosomes, and unique proteins found in these plastids and mitochondria
• Endomembrane System Evolution- is the idea that the endomembrane system of eukaryotes resulted from a primitive ancestor that developed membrane folds to increase surface area. Over time, that folding pattern became more and more complex in its form and function leading to the ER and Golgi’s development.