Honors Cells PPT - pkwy.k12.mo.us file• Eukaryotic Cells have many organelles allowing them to 1. Grow much larger as they developed organization and distribution abilities 2. Compartmentalize

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.