Prokaryotic and Eukaryotic Cell Structure And a Little Taxonomy too!
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Transcript of Prokaryotic and Eukaryotic Cell Structure And a Little Taxonomy too!
Prokaryotic and Eukaryotic Prokaryotic and Eukaryotic Cell StructureCell Structure
And a Little Taxonomy too!
TaxonomyTaxonomy
The science of classification of living organisms.– So we can identify and understand relationships
between organisms.
Linnaean SystemLinnaean System First developed by Carolus Linnaeus (1707-1778).
– Method of classifying things in a hierarchical structure from most general to most similar.
– Binomial System (2 names) Domain
– Kingdom (most general)– Phylum or Division – Class – Order – Family– Genus– Species
Ex. Eschericia coli
or E. coli
Classification Classification
Domains constitute a level of classification above the kingdom.
Domains are further subdivided into kingdoms etc.
The 3 DomainsThe 3 Domains
1. Archaea 2. Bacteria 3. Eukarya - animals
- plants
- algae
- protozoa
- fungi
Prokaryotes Eukaryotes
5 Kingdoms 5 Kingdoms
Based on similar morphology, geographic distribution, and if multicellular, the ability to interbreed.
Bacteria
Bergey SystemBergey System
Another system for classifying Prokaryotes.Still use kingdom, division or phylum,
class, order, family, genus, species.Classification based on similar
morphological and biochemical characteristics.
Eukaryotic and Prokaryotic CellsEukaryotic and Prokaryotic Cells
How are they different and
how are they the same?
What Is a Cell?What Is a Cell?
It is the fundamental unit of all living matter.
Has all characteristics of life.Can live independently of other cells.
All Cells Have the Following:All Cells Have the Following: Enzymes
– A protein that speeds up a chemical reaction. DNA – deoxyribonucleic acid
– A large molecule that stores genetic information. RNA – ribonucleic acid
– A large molecule involved in protein synthesis. ATP – adenosine triphosphate
– The main energy currency of a cell. Amino Acids
– Proteins are composed of basically the same 20 amino acids.
Eukaryotic Cell StructureEukaryotic Cell StructurePossess membrane-bound organelles.10-30µm in diameter.Eukaryote = “true nucleus”
– Their DNA is enclosed by a double membrane.
Eukaryotic Cell StructureEukaryotic Cell StructureCell Membrane
– Phospholipid (fatty chain with a phosphate) bi-layer with different types of proteins interspersed.
– Separates inside of cell from external environment.
– It has selective permeability. Only certain things can get in and out.
– Other organelle membranes are similar in structure.
Cell MembraneCell Membrane
Eukaryotic Cell StructureEukaryotic Cell Structure Nucleus
– Controls the functions of the cell (“the control center).
– Nuclear membrane – surrounds nucleus.– Nucleoplasm – gelatinous matrix.– Chromosomes – linear DNA molecules and
proteins.– Gene – specific DNA segment on the
chromosome that contains the information for making a gene product, usually a protein.
– Nucleolus – where rRNA is made and is used to make a structure called ribosomes.
Eukaryotic Cell StructureEukaryotic Cell Structure
Cytoplasm– A semi-fluid, gelatinous, nutrient matrix.– Contains storage granules and cell organelles.– Most of cell’s metabolism occurs.– Often called the cytosol.
Eukaryotic Cell StructureEukaryotic Cell StructureEndoplasmic Reticulum (ER)
– An irregular maze of spaces enclosed by a membrane.
– “Assembly Line”– Rough ER
Contains ribosomes Involved in making proteins
– Smooth ER Does not contain ribosomes Involved in lipid metabolism (fat storage)
Eukaryotic Cell StructureEukaryotic Cell Structure
Ribosomes– Are important in protein synthesis.– Are found in the Rough ER.
Eukaryotic Cell StructureEukaryotic Cell Structure
Eukaryotic Cell StructureEukaryotic Cell Structure
Golgi Complex– “packaging plant.”– Stacks of flattened, membranous sacs.– Completes and packages newly formed proteins
and lipids.– Packages them so that they are ready for
storage within the cell or outside of the cell.
Eukaryotic Cell StructureEukaryotic Cell Structure Lysosomes
– “garbage disposal system”– 1 µm diameter– Contain lysozyme and other enzymes that break down
foreign material.– Particles may enter cell by phagocytosis.– Also involved in programmed cell death called autolysis or
apoptosis. Peroxisomes
– Membrane-bound vesicles that generate and break down hydrogen peroxide (a dangerous and highly reactive chemical).
– Used to break down lipids (fats) and destroy toxic molecules.
Eukaryotic Cell StructureEukaryotic Cell Structure
Mitochondria – “the power plant of the cell”– 0.5 – 1 µm in diameter, 7 µm in length– Where ATP (adenosine triphosphate) is
formed. ATP is the energy currency of the cell.
– ATP is formed during a reaction called cellular respiration.
– ATP is formed from our food sources.
Eukaryotic Cell StructureEukaryotic Cell Structure
Eukaryotic Cell StructureEukaryotic Cell Structure
Plastids– Site of photosynthesis.– Contain photosynthetic pigments.
Photosynthesis – converting light energy into a source of chemical energy for organism.
– Chloroplasts – type of plastid that contains chlorophyll.
Chlorophyll – a green photosynthetic pigment.
Eukaryotic Cell StructureEukaryotic Cell Structure- Plant Cell- Plant Cell
micro.magnet.fsu.edu/cells/plants/plantmodel.html
Eukaryotic Cell StructureEukaryotic Cell Structure
Cell Wall– External structure that provides rigidity, shape,
and protection.– May be composed of cellulose, pectin, lignin,
chitin, and some mineral salts.– Usually simpler than prokaryotic cells.
Eukaryotic Cell StructureEukaryotic Cell Structure
Cells stained green (DNA) and red (keratin)
www.newworldencyclopedia.org/entry/Cell_(biology
Illustration by Robert Hooke (c.1665)
askabiologist.asu.edu/.../rhooke.html
Plant Cells
Cell WallsCell Walls
Cell Walls
Present
•Plants
•Algae
•Fungi
•Most Bacteria
Absent
•Animals
•Protozoa
•Mycoplasma species (type of bacteria)
Eukaryotic Cell StructureEukaryotic Cell Structure
Flagella– An organelle of movement.– Long, thin structure that moves like a whip to propel organism
through liquid environment. – Can be found in some species of protozoa, spermatozoa, and
algae. Cilia
– Organelle of locomotion.– Usually short, hair-like structures that beat in coordinated,
rhythmic movement.– Can be found in some species of protozoa and types of cells
that line respiratory tract.
Eukaryotic Cell StructureEukaryotic Cell Structure
Euglena – sp. Protozoa. Notice the flagella.www.biologie.uni-erlangen.de/.../fotonm3_eng.htm
Paramecium – sp. Protozoa. Notice the cilia.microbewiki.kenyon.edu/index.php/Paramecium
Prokaryotic Cell StructureProkaryotic Cell Structure
More simple than eukaryotic cells.Can perform all functions necessary for life.Prokaryotes comprise all bacteria and
archaeans.Do NOT contain membrane-bound
organelles.Typical E. coli cell is about 1 µm wide and
2-3 µm long.
Prokaryotic Cell StructureProkaryotic Cell Structure
Bacterial Cell Wall – Provides rigidity, strength, and protection.– More complex than eukaryote cell walls.– Composed of peptidoglycan (polymer of sugars and amino
acids)– Gram-positive bacteria
Thick layer of peptidoglycan with some other molecules.
– Gram-negative bacteria Thinner layer of peptidoglycan with an outer membrane composed of
lipid macromolecules.
– Genus Mycoplasma do not have cell walls.– Archaens have cell walls but not composed of peptidoglycan.
Prokaryotic Cell StructureProkaryotic Cell Structure
Cell Membrane– Similar to eukaryotic cells.– Contains proteins and phospholipids.– Selectively permeable.– It is very flexible and thin.
Prokaryotic Cell StructureProkaryotic Cell Structure Glycocalyx
– Thick, slimy, gelatinous material produced by the cell membrane and secreted outside the cell wall.
– Some bacteria have it.– 2 types of glycocalyx
1. Slime Layer– Is not highly organized or firmly attached to cell wall.
– Allows bacteria to glide or slide along surfaces. 2. Capsule
– Highly organized and firmly attached to cell wall.
– Chemical composition allows scientists to determine different types of bacteria.
– Prevent bacteria from being phagocytized by phagocytic white blood cells.
– Can attach bacteria to a wide array of surfaces.
Prokaryotic Cell StructureProkaryotic Cell Structure
diverge.hunter.cuny.edu/~weigang/Lecture-syll.
Prokaryotic Cell StructureProkaryotic Cell StructureProkaryotic Chromosome
– Single, long, supercoiled, circular DNA molecule.
– Embedded in cytoplasm.– Found in nuclear region of cell.– Does not have a nuclear membrane.– Contains all the information for carrying out
life processes.– Plasmids may also be found in prokaryotic
cells.
Prokaryotic Cell StructureProkaryotic Cell Structure
Plasmid– Small, circular molecule of double-stranded
DNA.– Not part of the chromosome.
Called extrachromosomal DNA.
– Found in the cytoplasm.– May contain 10-100s genes.– Number varies per cell.
Prokaryotic Cell StructureProkaryotic Cell Structure
Cytoplasm – Semiliquid interior of cells.– Consists of water, enzymes, dissolved oxygen
(in some bacteria), waste products, nutrients, proteins, carbohydrates, and lipids.
– Everything necessary for its metabolic functions.
Prokaryotic Cell StructureProkaryotic Cell Structure
Cytoplasmic Particles– Ribosomes are found in the cytoplasm.– They are important in protein synthesis.– Some substances are stored in cytoplasmic
granules. Such as starch, lipids, sulfur, or iron. The type of substance stored depends on the species
of organism.
Prokaryotic Cell StructureProkaryotic Cell Structure
diverge.hunter.cuny.edu/~weigang/Lecture-syll.
Prokaryotic Cell StructureProkaryotic Cell Structure
Flagella– A mechanism for
movement for some bacteria.
– Bacteria can be classified and identified by the arrangement of their flagella.
– Nonflagellated bacteria are usually considered to be nonmotile.
Although there are exceptions.
Pseudomonas fluorescens – aerobic soil bacteria.www.scienceclarified.com/As-Bi/Bacteria.html
Prokaryotic Cell StructureProkaryotic Cell Structure
Pili (Fimbriae)– Not associated with motility.– Thin, rigid, hair-like structure.– Arise in cytoplasm and extend through the plasma
membrane, cell wall, and capsule (if present).– 2 types of pili
1. Adhesins - allows bacteria to adhere to surfaces. 2. Sex pilus
– Allows for the transfer of genetic material through a process called conjugation.
– One bacteria attaches its sex pilus to another cell and transfers its genetic material to the other cell usually in the form of a plasmid.
Prokaryotic Cell StructureProkaryotic Cell Structure
Adhesin bacterial cell with pili (fimbriae) ultr23.vub.ac.be/.../fimbrialadhesion.html
Bacterial conjugation with sex pilus. www.cbs.dtu.dk/.../roanoke/genetics980309.html
Prokaryotic Cell StructureProkaryotic Cell Structure
Spores (Endospores)– Bacterial spores called endospores.– Usually found in 2 genera: Bacillus and Clostridium.– Form through the process sporulation.
A copy of the chromosome and some cytoplasm is enclosed in a thick protein coat.
– This occurs when moisture and nutrients are low.– Endospores are resistant to heat, cold, drying, and most
chemicals.– If adequate conditions are present, the endospore can
become an active bacteria.
EndosporeEndospore
Clostridium difficil forming an endospore.
Associated with antibiotic related diarrhea caused by toxins produced
Red structure is endospore forming. www.chem.wayne.edu/feiggroup/research.htm
Prokaryotic Cell Reproduction Prokaryotic Cell Reproduction
Binary Fission– One parent cell splits to become 2 daughter
cells.– This process produces a clone of the parent cell.– During this process, its chromosome is
replicated in a process called DNA replication.– Generation time
The time it takes one parent cell to become 2 identical daughter cells.
Binary FissionBinary Fission
www.uic.edu/.../bios100/lecturesf04am/lect06.htm
The EndThe End