- 1.
- Chapter 4 Cell Structure (Sections 4.1 - 4.7)
2.
- Helpful intestinal bacteria make vitamins that mammals cant,
and they crowd out more dangerous germs
3. Escherichia coliis one of the most common intestinal bacteria
of warm-blooded animals only a few of the hundreds of types (
strains ) are harmful 4.
- E. coliO157:H7 makes a potent toxin that can severely damage
the lining of the human intestine
5. Causes serious illness in people who eat contaminated foods
6.
- 4.2 What, Exactly, Is a Cell?
-
- The smallest unit that has the properties of life
- Cells pictured are individual organisms (protists)
7.
- Traits Common to All Cells
- Although cells differ in size, shape, and function, each starts
out with aplasma membrane ,cytoplasm , and a region of DNA (in
eukaryotic cells, anucleus )
-
- A cells outermost membrane
- 8. Alipid bilayeris the structural foundation of cell
membranes, includingorganellemembranes
9.
-
- Structure that carries out a specialized metabolic function
inside a cell
-
- Semifluid substance enclosed by a cells plasma membrane
-
- Organelle with two membranes that holds a eukaryotic cells
DNA
10.
11.
- Bacteria are single-celled organisms
12. Archaeans are similar to bacteria in overall structure
13.
14.
15.
16.
17.
18.
- Animation: Overview of Cells
19.
- S urface-to-volume ratiolimits cell size
20. If the cell gets too big, inward flow of nutrients and
outward flow of wastes across the membrane will not be fast
enough
-
- A relationship in which the volume of an object increases with
the cube of the diameter, but surface area increases with the
square of the diameter
21.
- The physical relationship between increases in volume and
surface area constrains cell size and shape
22.
- Animation: Surface-to-Volume Ratio
23.
- The cell is the structural and functional unit of all
organisms
-
- Theory that all organisms consist of one or more cells, which
are the basic unit of life
24.
- History of Cell Discovery
- 1665: Antoni van Leeuwenhoekfirst observedmany very small
animalcules
25. Robert Hooke magnified a piece of thinly sliced cork
andnamed the tiny compartments he observed cellae 26. 1820s: Robert
Brown was first to identify a cell nucleus 27. Matthias Schleiden,
hypothesized that a plant cell is an independentliving unit even
when it is part of a plant 28. Schleiden and Theodor Schwann
concluded that the tissues of animals as well as plants are
composed of cells 29.
- Four generalizations constitute thecell theory :
-
- 1. Every living organism consists of one or more cells
- 30. 2. A cell is the smallest unit of life, individually alive
even as part of a multicelled organism
31. 3. All living cells come from division of preexisting cells
32. 4. Cells contain hereditary material, which they pass to their
offspring during division 33.
-
- A cell is the smallest unit of life
- 34. Each has a plasma membrane that separates its interior from
the exterior environment
35. A cells interior contains cytoplasm and DNA 36.
- Most cells are far too small to see with the naked eye
37. We use different types of microscopes and techniques to
reveal cells and their internal and external details 38.
39. Phase-contrast microscopes 40. Fluorescence microscope
41. Transmission electron Microscopes 42. Scanning electron
microscopes 43.
- Compound light microscope
- Transmission electron microscope (TEM)
44.
- prism that directs rays to ocular lens
- path of light rays (bottom to top) to eye
45.
46.
- Animation: How a Light Microscope Works
47.
- Different Views, Same Organism
- CFluorescence micrograph.
- DA transmission electron micrograph reveals fantastically
detailed images of internal structures.
- EA scanning electron micro-graph shows surface details. SEMs
may be artificially colored to highlight specific details.
- A reflected light microscope captures light reflected from
specimens.
- A phase-contrast microscope yields high-contrast images of
trans- parent specimens. Dark areas have taken up dye.
- This image shows fluorescent light emitted by chlorophyll
molecules in the cells.
48.
49.
-
- 1 centimeter (cm) = 1/100 meter, or 0.4 inch
- 50. 1 millimeter (mm) = 1/1000 meter, or 0.04 inch
51. 1 micrometer ( m) = 1/1,000,000 meter, or 0.00004 inch 52. 1
nanometer (nm) = 1/1,000,000,000 meter, or 0.00000004 inch 53. 1
meter = 10 2cm = 10 3mm = 10 6 m = 10 9nm 54.
-
- Most cells are too small to see with the naked eye
- 55. We use different types of microscopes to reveal different
details of their structure
56.
- Animation: How an Electron Microscope Works
57.
- 4.4 Membrane Structureand Function
- A cell membrane functions as a selectively permeable barrier
that separates an internal environment from an external one
58. Membranes of most cells can be described as afluid mosaic of
lipids (mainly phospholipids) and proteins 59. Lipids are organized
as alipid bilayer : a double layer of lipids in which the nonpolar
tails of both layers are sandwiched between the polar heads 60.
-
- Structural foundation of cell membranes; double layer of lipids
arranged tail-to-tail
-
- Model of a cell membrane as a two-dimensional fluid of mixed
composition
61.
62.
- At its most basic, a cell is a lipid bilayer bubble filled with
fluid
63.
- Proteins associated with a membrane carry out most membrane
functions
64. All membranes havetransport proteins 65. Plasma membranes
also havereceptor proteins ,adhesion proteins ,enzymes,
andrecognition proteins 66.
-
- Protein that passively or actively assists specific ions or
molecules across a membrane
-
- Membrane protein that helps cells stick together in
tissues
-
- Binds to a particular substance outside of the cell
-
- Tags a cell as belonging to self (ones own body)
67.
68.
- Recognition and Receptor Proteins
69.
70.
- EThis transport protein, an ATP synthase, makes ATP when
hydrogen ions flow through its interior.
- BRecognition proteins such as this MHC molecule tag a cell as
belonging to ones own body.
- CReceptor proteins such as this B cell receptor bind substances
outside the cell. B cell receptors help the body eliminate toxins
and infectious agents such as bacteria.
- DTransport proteins bind to molecules on one side of the
membrane, and release them on the other side. This one transports
glucose.
71.
- Animation: Cell Membranes
72.
- Archaeans do not build phospholipids with fatty acids instead,
the tails of archaean phospholipids form covalent bonds with one
another
73. Archaean membranes are far more rigid than those of bacteria
or eukaryotes 74.
-
- All cell membranes consist mainly of a lipid bilayer and
different types of proteins
- 75. The proteins carry out various tasks, including control
over which substances cross the membrane
76.
- Animation: Lipid Bilayer Organization
77.
- Animation: Fluid Mosaic Model
78.
- 4.5 Bacteria and Archaeans
- Single-celled bacteria and archaeans are the smallest and most
diverse forms of life:
-
- The cytoplasm containsribosomesandplasmids
- 79. A single, circular chromosome is located in anucleoid
80. Many have acell wall ,flagella orpili 81.
-
- Organelle of protein synthesis
-
- Small circle of DNA in some bacteria and archaeans
-
- Region of cytoplasm where the DNA is concentrated inside a
bacterium or archaean
82.
-
- Long, slender cellular structure used for motility
-
- A protein filament that projects from the surface of some
bacterial cells sex pilus
-
- Semi-rigid but permeable structure that surrounds the plasma
membrane of some cells
83.
84.
85.
- Body Plan of Bacteriaand Archaeans
86.
87.
- Animation: Typical Prokaryotic Cell
88.
- The cell wall of most archaeans consists of proteins
89. The wall of most bacteria consists of a polymer of peptides
and polysaccharides 90. Sticky polysaccharides form a slime layer,
or capsule, around the wall of many types of bacteria 91.
- Biofilmsare shared living arrangements among bacteria and other
microbial organisms
-
- Community of different types of microorganisms living within a
shared mass of slime
- 92. May include bacteria, algae, fungi, protists, and
archaeans
93.
- A biofilm organizes itself into neighborhoods, each with a
distinct microenvironment that stems from its location within the
biofilm and species that inhabit it
94.
-
- Archaeans and bacteria have few internal membrane-enclosed
compartments
- 95. In general, they are the smallest and structurally the
simplest cells, but they are also the most numerous
96.
- 4.6 Introducing Eukaryotic Cells
- All protists, fungi, plants, and animals are eukaryotes
- Eukaryotic cells start out life with membrane-enclosed
organelles, including a nucleus
97. Most eukaryotic cells contain an endomembrane system (ER,
vesicles, and Golgi bodies), mitochondria, and a cytoskeleton
98.
- Components of Eukaryotic Cells
99.
100.
101.
- The nucleus contains the cells genetic material (DNA)
102. In the nucleus, ribosome subunits are assembled in dense
regions callednucleoli
- The nucleus has a double-membranednuclear
envelopesurroundingnucleoplasm
103.
-
- In a cell nucleus, a dense, irregularly shaped region where
ribosomal subunits are assembled
-
- A double membrane that constitutes the outer boundary of the
nucleus
-
- Viscous fluid enclosed by the nuclear envelope
104.
- The nuclear membrane controls passage of certain molecules
between the nucleus and the cytoplasm
105. Receptors and transporters stud both sides of the nuclear
envelope; other proteins form nuclear pores 106. The outer bilayer
of the double membrane is continuous with the membrane of the ER
107.
108.
- nuclear envelope (two lipid bilayers)
109.
- Animation: Nuclear Envelope