1 Cells BS122 Principles of Biology II Daniel W. Ward.
-
Upload
marjorie-mckenzie -
Category
Documents
-
view
215 -
download
1
Transcript of 1 Cells BS122 Principles of Biology II Daniel W. Ward.
1
Cells
BS122 Principles of Biology II
Daniel W. Ward
2
The Cell Theory
Major Components– all living things are composed of cells– the cell is the structural and functional unit of
life– cells come from pre-existing cells– human disease often reflects abnormality at the
cellular level
3
The Cell Theory
Origins– the first two components were put forward by
the German biologists Matthias Schleiden and Theodor Schwann in 1839
– the last two components were put forward by Rudolph Virchow, another German, around 1850
4
Cellular Characteristics
Prokaryotic Cells– General Definition
• single celled
• structurally simple
• lack organelles
5
Cellular Characteristics
Prokaryotic Cells– Structures
• Cell Wall
• Plasmalemma / Cell Membrane
• Flagella
• Deoxyribose Nucleic Acid (DNA)
• Nucleoid
• Ribosome
6
Cellular Characteristics
Prokaryotic Cells– Structures
• Cell Wall– surrounds the cell
– rigid
– composed of peptidoglycans (peptide sugars)
7
Cellular Characteristics
Prokaryotic Cells– Structures
• Plasmalemma / Cell Membrane– located beneath the cell wall
– contains enzymes which speed up certain chemical reactions
– may contain invaginations where cell division might occur
8
Cellular Characteristics
Prokaryotic Cells– Structures
• Flagella– tail-like appendage
– found in some prokaryotes
– anchored to the cell wall and the cell membrane
– functions in locomotion
9
Cellular Characteristics
Prokaryotic Cells– Structures
• Deoxyribose Nucleic Acid (DNA)– genetic material of the cell
– arranges in a single circle
– “naked” because it is not complexed with proteins or surrounded by a membrane
10
Cellular Characteristics
Prokaryotic Cells– Structures
• Nucleoid– nucleus-like structure
– contains the DNA
– may appear fibrous when viewed under the microscope
11
Cellular Characteristics
Prokaryotic Cells– Structures
• Ribosomes– composed of RNA and protein
– allows a cell to utilze DNA to manufacture proteins
» this process is fast in prokaryotes due to the proximity of the DNA, RNA, and ribosomes
12
Cellular Characteristics
Prokaryotic Cells– Generalized
Structure
13
Cellular Characteristics
Prokaryotic Cells– while simple, prokaryotes compose the majority
of living cells on the planet– they also have effects on humans
14
Cellular Characteristics Prokaryotic Cells
– Negative Affects• Syphilis (Treponema pallidum)
• Gonorrhea (Neisseria gonorrhoeae)
• Typhoid Fever (Salmonella typhosa)
• Cholera (Vibrio cholerae)
• Bubonic Plague (Yersinia pestis)
• Toxic Shock Syndrome & Food Poisoning (Staphylococcus aureus)
• Tetanus (Clostridium botulinum)
• Legionnaire’s Disease (Legionella pneumophila)
• Strep Throat & Rheumatic Fever (Streptococcus)
15
Cellular Characteristics
Prokaryotic Cells– Positive Affects
• production of buttermilk, American cheese (Streptococcus lactis)
• production of yogurt (Leuconostoc bulgaricus)
• Production of Swiss chesse (Lactobacillus bulgaricus)
• Production of genetically enginerred drugs (Escherichia coli)
• Production of food grade acetic acid from corn alcohol (Acetobacter suboxydans)
• Conversion of sulfur in crude oil into water soluble compounds (Psedomonas)
• Extraction of oil (Closterium acetobutylicum)
16
Cellular Characteristics
Eukaryotic Cells– General Definition
• a complex cell
• contains organelles which carry out a variety of functions
17
Cellular Characteristics
Eukaryotic Cells– Structures
• Cell Membrane / Plasmalemma
• Cell Wall
• Nucleus
• Nucleolus
• Ribosomes
• Endoplasmic Reticulum
• Golgi Apparatus
• Vacuoles & Vesicles
18
Cellular Characteristics
Eukaryotic Cells– Structures (cont.)
• Lysosomes
• Mitochodria
• Chloroplasts
• Microtubules
• Actin Filaments
• Centrioles
• Cilia & Flagella
19
Cellular Characteristics
Eukaryotic Cells– Structures
• Cell Membrane / Plasmalemma– surrounds the cell
– composed of a phospholipid bilayer
20
Cellular Characteristics
Eukaryotic Cells– Structures
• Cell Wall– found only in plants
– rigid
– composed mainly of cellulose
– usually comprised of 2 layers
» primary and secondary walls
» pectin in-between
21
Cellular Characteristics
Eukaryotic Cells– Structures
• Nucleus– only one per cell
– contains chromosomes and nucleoli
– involved in cellular reproduction and regulation of protein synthesis
22
Cellular Characteristics
Eukaryotic Cells– Structures
• Nucleolus– an area of concentrated chromatin, RNA, and protein
– involved in the formation of ribosomes
– may be more than one per cell
23
Cellular Characteristics
Eukaryotic Cells– Structures
• Ribosomes– composed into 2 units of protein and RNA
– involved in protein synthesis
24
Cellular Characteristics
Eukaryotic Cells– Structures
• Endoplasmic Reticulum– flat membranous channels and tubular canals
– two types
» Smooth
lacks ribosomes
involved in a variety of functions
» Rough
studded with ribosomes
involved in protein synthesis
25
Cellular Characteristics
Eukaryotic Cells– Structures
• Golgi Apparatus– a stack of membranous saccules
– involved in the processing, packaging, and secretion of proteins
26
Cellular Characteristics
Eukaryotic Cells– Structures
• Vacuoles and Vesicles– membranous sacs
– involved in the storage of substances
27
Cellular Characteristics
Eukaryotic Cells– Structures
• Lysosomes– vesicles that contain digestive enzymes
– involved in intracellular digestion
28
Cellular Characteristics
Eukaryotic Cells– Structures
• Mitochondria– the energy converting organelle
– involved in aerobic cellular respiration
29
Cellular Characteristics
Eukaryotic Cells– Structures
• Chloroplasts– found only in plants
– involved in photosynthesis
30
Cellular Characteristics
Eukaryotic Cells– Structures
• Microtubules– part of the cytoskeleton (tubulin molecules)
– involved in determining cell shape and cell movement
31
Cellular Characteristics
Eukaryotic Cells– Structures
• Actin Filaments– part of the cytoskeleton (actin molecules)
– involved in determining cell shape and the contractile process
32
Cellular Characteristics
Eukaryotic Cells– Structures
• Centrioles– found only in animals
– composed of microtubules in a 9 + 0 arrangement
– involved in microtubule organization
– forms the basal bodies
33
Cellular Characteristics
Eukaryotic Cells– Structures
• Cilia and Flagella– composed of microtubules in a 9 + 2 pattern
– involved in cellular movement
34
Prokaryotic vs. Eukaryotic Cells
Structure Prok. Animal Plantcell size 1-10 um 10-100um 10-100 um
oxygen required by some by all by all
DNA form simple circle coiled linear strands, complex
DNA location in cytoplasm in nucleus in nucleus
DNA length short long long
cellular org. single, some single, most multicellular
colonial with differentiation
cell membrane yes yes yes
cell wall yes (not no yes
cellulose)
nuclear mem. no yes yes
35
Prokaryotic vs. Eukaryotic Cells
Structure Prok. Animal Plantnucleolus no yes yes
mitochondria no yes yes
chloroplasts no no yes
E.R. no yes yes
ribosomes yes (small) yes yes
vacuoles some yes (small) yes (large)
Golgi apparatus no yes yes
lysosome no always often
cytoskeleton no yes yes
centrioles no yes no
cilia/flagella sometimes often some male gametes
36
Cellular Characteristics Animal Cell
– Generalized Structure
37
Cellular Characteristics Plant Cell
– Generalized Structure
38
Endosymbiotic Theory
prokaryotic cells entered eukaryotic cells and eventually evolved into mitochondria and chloroplasts
39
Endosymbiotic Theory
Evidence for the theory– mitochondria and chloroplasts contain limited
amounts of genetic material– both are capable of self-reproduction– their ribosomes resemble those of bacteria– both are membrane bound
• outer formed from engulfing a vesicle
• inner formed from the original prokaryote