![Page 1: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/1.jpg)
Cell StructureChapter 4
![Page 2: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/2.jpg)
2
Cell Theory
1. All organisms are composed of cells
2. Cells are the smallest living things
3. Cells arise only from pre-existing cells
• All cells today represent a continuous line of descent from the first living cells
![Page 3: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/3.jpg)
3
Cell size is limited
• Most cells are relatively small due reliance on diffusion of substances in and out of cells
• Rate of diffusion affected by– Surface area available– Temperature– Concentration gradient– Distance
![Page 4: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/4.jpg)
4
![Page 5: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/5.jpg)
Surface area-to-volume ratio
• Organism made of many small cells has an advantage over an organism composed of fewer, larger cells
• As a cell’s size increases, its volume increases much more rapidly than its surface area
• Some cells overcome limitation by being long and skinny – like neurons
5
![Page 6: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/6.jpg)
What do all cells do?
• Make more cells/DNA
• Make energy
• Make proteins
• Transport materials into and out of cell
6
![Page 7: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/7.jpg)
What part of the cell does this?
• Make more cells
• Energy • Proteins
• Transport into and out of cells
7
![Page 8: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/8.jpg)
8
Basic structural similarities
1. Nucleoid or nucleus where DNA is located
2. Cytoplasm– Semifluid matrix of enzymes/organelles – Cytosol
3. Ribosomes– Synthesize proteins
4. Plasma membrane– Phospholipid bilayer
![Page 9: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/9.jpg)
9
Prokaryotic Cells
• (Simplest organisms)
• Lack a membrane-bound nucleus– DNA is present in the nucleoid (“cluster”)
• Enzymes
• Do contain ribosomes (not membrane-bound organelles)
• Cell membrane
• Cell wall outside of plasma membrane
![Page 10: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/10.jpg)
10
![Page 11: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/11.jpg)
Two Domains of Prokaryotes
• Two domains of prokaryotes– Archaea
• Extremophiles
– Bacteria• “Bacteria”
11
![Page 12: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/12.jpg)
12
![Page 13: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/13.jpg)
13
![Page 14: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/14.jpg)
Prokaryotic cell walls
• Archaea lack peptidoglycan• Most bacterial cells are encased by a strong cell
wall– composed of peptidoglycan– Cell walls of plants, fungi, and most protists different
• Protect the cell, maintain its shape, and prevent excessive uptake or loss of water
• Susceptibility of bacteria to antibiotics often depends on the structure of their cell walls
14
![Page 15: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/15.jpg)
EUKARYOTIC CELLS
15
![Page 16: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/16.jpg)
What do all cells do?
• Make more cells/DNA
• Make energy
• Make proteins
• Transport materials into and out of cell
16
![Page 17: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/17.jpg)
BUT…
• Now these have specialized membrane-bound organelles!
17
![Page 18: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/18.jpg)
18
Eukaryotic Cells
• Possess a membrane-bound nucleus
• More complex than prokaryotic cells
• Compartmentalization– Achieved through use of membrane-bound
organelles and endomembrane system
• Possess a cytoskeleton for support and to maintain cellular structure
![Page 19: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/19.jpg)
What do all cells do?
• Make more cells/DNA – Nucleus
• Make energy– Mitochondria
• Make proteins – Ribosomes
• Transport materials into and out of cell– SER, RER, Golgi, Cell Membrane
AND other specialized organelles19
![Page 20: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/20.jpg)
20
![Page 21: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/21.jpg)
21
![Page 22: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/22.jpg)
22
Nucleus
• Repository of the genetic information• Most eukaryotic cells possess a single nucleus• Nucleolus – region where ribosomal RNA
synthesis takes place• Nuclear envelope
– 2 phospholipid bilayers– Nuclear pores – control passage in and out
• In eukaryotes, the DNA is divided into multiple linear chromosomes– Chromatin is chromosomes plus protein
![Page 23: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/23.jpg)
23
![Page 24: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/24.jpg)
Ribosomes
• * Ribosomes do NOT have a membrane
• Cell’s protein synthesis machinery
• Found in all cell types in all 3 domains
• Ribosomal RNA (rRNA)-protein complex
• Protein synthesis also requires messenger RNA (mRNA) and transfer RNA (tRNA)
• Ribosomes may be free in cytoplasm or associated with internal membranes
24
![Page 25: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/25.jpg)
25
Endomembrane System
• Series of membranes throughout the cytoplasm
• Divides cell into compartments where different cellular functions occur
• One of the fundamental distinctions between eukaryotes and prokaryotes
![Page 26: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/26.jpg)
26
Endoplasmic reticulum
• Rough endoplasmic reticulum (RER)– Attachment of ribosomes to the membrane gives a
rough appearance– Synthesis of proteins to be secreted, sent to
lysosomes or plasma membrane
• Smooth endoplasmic reticulum (SER)– Relatively few bound ribosomes– Variety of functions – synthesis, store Ca2+ ,
detoxification
• Ratio of RER to SER depends on cell’s function
![Page 27: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/27.jpg)
27
![Page 28: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/28.jpg)
28
Golgi apparatus
• Flattened stacks of interconnected membranes (Golgi bodies)
• Functions in packaging and distribution of molecules synthesized at one location and used at another within the cell or even outside of it
• Cis and trans faces
• Vesicles transport molecules to destination
![Page 29: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/29.jpg)
29
![Page 30: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/30.jpg)
30
![Page 31: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/31.jpg)
31
Lysosomes
• Membrane-bounded digestive vesicles
• Arise from Golgi apparatus
• Enzymes catalyze breakdown of macromolecules
• Destroy cells or foreign matter that the cell has engulfed by phagocytosis
• Involved in apoptosis (cell death)
![Page 32: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/32.jpg)
32
![Page 33: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/33.jpg)
Peroxisomes
• Variety of enzyme-bearing, membrane-enclosed vesicles
• Peroxisomes– Contain enzymes
involved in the oxidation of fatty acids
– H2O2 produced as by-product – rendered harmless by catalase
33
![Page 34: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/34.jpg)
34
Vacuoles
• Membrane-bounded structures in plants• Various functions depending on the cell
type
• There are different types of vacuoles:– Central vacuole in plant cells– Contractile vacuole of some protists– Storage vacuoles
![Page 35: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/35.jpg)
35
![Page 36: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/36.jpg)
36
Mitochondria
• Found in all types of eukaryotic cells• Bound by membranes
– Outer membrane– Intermembrane space– Inner membrane has cristae– Matrix
• On the surface of the inner membrane, and also embedded within it, are proteins that carry out oxidative metabolism
• Have their own DNA
![Page 37: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/37.jpg)
37
![Page 38: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/38.jpg)
38
Chloroplasts
• Organelles present in cells of plants and some other eukaryotes
• Contain chlorophyll for photosynthesis
• Surrounded by 2 membranes
• Thylakoids are membranous sacs within the inner membrane– Grana are stacks of thylakoids
• Have their own DNA
![Page 39: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/39.jpg)
39
![Page 40: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/40.jpg)
40
Endosymbiosis
• Proposes that some of today’s eukaryotic organelles evolved by a symbiosis arising between two cells that were each free-living
• One cell, a prokaryote, was engulfed by and became part of another cell, which was the precursor of modern eukaryotes
• Mitochondria and chloroplasts
![Page 41: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/41.jpg)
41
![Page 42: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/42.jpg)
42
Cytoskeleton
• Network of protein fibers found in all eukaryotic cells– Supports the shape of the cell – Keeps organelles in fixed locations
• Dynamic system – constantly forming and disassembling
![Page 43: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/43.jpg)
43
3 types of fibers
• Microfilaments (actin filaments)– Two protein chains loosely twined together– Movements like contraction, crawling, “pinching”
• Microtubules– Largest of the cytoskeletal elements– Dimers of α- and β-tubulin subunits– Facilitate movement of cell and materials within cell
• Intermediate filaments– Between the size of actin filaments and microtubules– Very stable – usually not broken down
![Page 44: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/44.jpg)
44
![Page 45: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/45.jpg)
Centrosomes
• Region surrounding centrioles in almost all animal cells
• Microtubule-organizing center– Can nucleate the assembly of microtubules
• Animal cells and most protists have centrioles – pair of organelles
• Plants and fungi lack centrioles
45
![Page 46: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/46.jpg)
• Eukaryotic cell walls– Plants, fungi, and
many protists– Different from
prokaryote– Plants and protists
– cellulose– Fungi – chitin– Plants – primary
and secondary cell walls
46
![Page 47: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/47.jpg)
47
Extracellular matrix (ECM)
• Animal cells lack cell walls
• Secrete an elaborate mixture of glycoproteins into the space around them
• Collagen may be abundant
• Form a protective layer over the cell surface
• Integrins link ECM to cell’s cytoskeleton– Influence cell behavior
![Page 48: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/48.jpg)
48
![Page 49: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/49.jpg)
49
![Page 50: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/50.jpg)
Cell-to-cell interactions
• Surface proteins give cells identity– Cells make contact, “read” each other, and
react– Glycolipids – most tissue-specific cell surface
markers– MHC proteins – recognition of “self” and
“nonself” cells by the immune system
50
![Page 51: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/51.jpg)
Cell connections
• 3 categories based on function
1.Tight junction– Connect the plasma membranes of adjacent cells in a
sheet – no leakage
2.Anchoring junction– Mechanically attaches cytoskeletons of neighboring
cells (desmosomes)
3.Communicating junction– Chemical or electrical signal passes directly from one
cell to an adjacent one (gap junction, plasmodesmata)
51
![Page 52: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/52.jpg)
52
![Page 53: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/53.jpg)
Cell Movement
Prokaryotes and Eukaryotes can BOTH have flagella and cilia…
53
Prokaryotes Eukaryotes
Smaller and Simpler Larger and more complex
Protein flagellin Tubulin (9+ 2 microtubule arrangement)
Rotary Motion Bending movement
Proton driven ATP driven
![Page 54: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/54.jpg)
Prokaryotic Flagella
54
![Page 55: Cell Structure Chapter 4. 2 Cell Theory 1.All organisms are composed of cells 2.Cells are the smallest living things 3.Cells arise only from pre-existing](https://reader030.vdocument.in/reader030/viewer/2022032606/56649eb35503460f94bba1d6/html5/thumbnails/55.jpg)
Eukaryotic Flagella
55