1. Cellular Level of Organization FTCE Biology 6-12 Day 1

2. Cell discovery timeline
Hooke: 1660
Cork, used term “cells”
Van Leeuwenhoek:
1673’s
Wee beasties, protists
Schleiden: 1839
Plants made of cells
Schwann: 1839
Animals made of cells

3. Cell theory Rudolf Virchow -1855 The cell theory
1. Cells are the units of structure & function in organisms.
. All cells come from pre-existing cells.
Cells are 1µm to 20µm small. Why is small better?
1000 µm = 1mm
Ex. on pg. 156

4. Microscopes
Magnification: the ratio between the size of the image and the object
Resolution: the smallest degree of separation at which 2 objects appear distinct

5. Resolution (resolving power)
The ability to see clearly between two points.
Limited by the wavelength of the source of illumination
Visible light is used for “light microscopes”
Beam of electrons for EM

6. Two types of microscopes
Light microscope
Visible light to see image
Parfocal
Highest magnification with decent resolution = about 1000x
Can observe living cells
Electron microscope
Electrons bounced off object
Highest magnification with decent resolution = about 1,000,000x
Preparation is severe.

7. Two types of electron microscopes
Transmission electron microscope
(TEM)
2-D image
Scanning electron microscope
(SEM)
3-D image

8. Three Views of Red Blood Cells
Light Microscope
SEM
Scanning Probe Microscope

9. Parts of the microscope
Eyepiece
Arm
Base
Revolving
nosepiece
Stage
Clips
diaphragm

10. Parts of the microscope cont.
Nosepiece
Objective lenses
Low (book calls it scanning)
4x magnification
Medium (book calls it low)
10x magnification
High (book calls it same thing)
40x magnification
Overall mag. 10x (eyepiece) x lens

11. Parts of the microscope cont.
Coarse focus knob
Only when using
low power objective
Fine focus knob
For small
adjustments
diaphragm
Light switch
& cord

12. Two general types of cells
Prokaryote
No true nucleus
No membrane- bound
organelles
Ex. Monera /bacteria
Eukaryotes
True nucleus
Membrane- bound organelles
Ex. Protist cells, fungi cells, plant cells, animal cells

13. Prokaryote structure Cell wall Plasma membrane Cytoplasm Nucleoid
Plasmid
(some) flagellum

15. Bacteria Shapes
Cocci/sphere
Bacilli/rod
Spirilla/spiral

16. (Protists, Fungi, Plant, Animal)
Eurkaryotes
(Protists, Fungi, Plant, Animal)
organelles
plasma membrane
cell wall of cellulose (plants)
nucleus w/nuclear membrane
nucleoli
cytoplasm

17. amoeba

18. Amoeba

19. Paramecium

20. Onion skin

21. Elodea

22. Studying Cells Cytology: Cyto-cell –ology study of
Human body-2 types of cells
1. Sex cells: sperm (male)
oocyte (female)
2. Somatic cells: all other cells

23. Generalized Generalized
Animal Cell Plant Cell

24. Cell organelles

25. Cell Organelles Compartmentalize cell’s activities improve efficiency
protect cell contents from harsh chemicals
Enable cells to:
secrete substances
perform cellular respiration
degrade debris
reproduce

26. Cell Organelles
Cell membrane: lipid bilayer containing phospholipids, steroids, proteins and carbohydrates
F-isolation: keeping proteins inside
protection:
sensitivity: receptors that allow the cell to recognize and respond to specific molecules.

27. Cell membrane (continued)
Structural support: to stabilize (skin)
Transport: control of entrance and exit of materials (ions, glucose, elimination of wastes)

28. cytoplasm: entire contents of the cell, except the nucleus, bounded by the plasma membrane
cytosol: gelatinlike portion of the cytoplasm that bathes the organelles of the cell

29. Organelles of Eukaryotic Cells
Organelles compartmentalize a cell’s activities.
1. Nucleus
surrounded by a double membrane
two phospholipid bilayers (nuclear envelope), perforated with nuclear pores
contains DNA & nucleolus (stores RNA nucleotides)
functions to separate DNA from rest of cell
Nuclear pores are protein channels (importins & exportins) that selectively allow materials to enter & leave nucleus.
DNA & RNA belong to which category of major organic compounds? -> Nucleic acids

30. Nucleus Functions (Continued)
Controls metabolism
Stores and processes genetic information
Controls protein synthesis

31. Nucleolus Dense region in nucleoplasm of nucleus
Site of rRNA synthesis and assembly of ribosomal units

32. Nucleolus

33. Cytoskeleton Network of protein filaments throughout the cytosol
Functions
cell support and shape
Site of some chemical reactions
cell & organelle movement
Continually reorganized

34. Ribosomes Packages of Ribosomal RNA & protein
Free ribosomes are loose in cytosol
make proteins used inside the cell
Membrane-attached ribosomes
attached to endoplasmic reticulum or nuclear membrane
make proteins needed for plasma membrane and/or for export
Inside mitochondria, synthesize mitochondrial proteins

35. Ribosome Large + small subunits made in the nucleolus
assembled in the cytoplasm

36. 2. Endoplasmic reticulum (ER)
interconnected network of membranes extending from nucleus to plasma membrane

37. Rough ER - studded with ribosomes
site of protein production (most will be exported out of the cell)
Free ribosomes in the cytoplasm produce proteins that remain in cell.
Smooth ER - lacks ribosomes
site of lipid production
contains enzymes that detoxify drugs & poisons
Ribosomes are “protein factories” (synthesize proteins). If attached to ER, then they synthesize proteins that usually end up being exported out of the cell [pepsin is a protein (enzyme) produced by stomach cells - functions in digestion of proteins in food]
Ribosomes floating freely in cytoplasm usually produced proteins that stay within the cell (actin, myosin).

38. stacks of membrane-enclosed sacs
3. Golgi apparatus
stacks of membrane-enclosed sacs
Golgi apparatus often referred to as a shipping/processing center because it receives materials from ER, processes them & then ships them out.

39. Golgi apparatus functions:
Forms membranes/vesicles (renews/modifies cell membrane)
links simple carbohydrates together to form starch
links simple carbohydrates to proteins (glycoprotein) or lipids (glycolipid)
completes folding of proteins
temporarily stores secretions
Storage, alteration and packaging of secretory products and lysosomal enzymes.

40. Organelle interaction in a mammary gland cell.
Organelles in certain mammary gland cells interact to produce milk that nourishes developing young. Human milk is a mixture of immune system cells, proteins, lipids, carbohydrates & water.
1. Milk protein gene is transcribed into language of mRNA.
2. mRNA exits nucleus through nuclear pore.
3. mRNA binds to ribosome that becomes associated with rough ER. Ribosome translates information on mRNA into milk protein.
4. Enzymes in smooth ER manufacture milk lipids.
5. Milk proteins & lipids are packaged into vesicles for transport to the golgi apparatus.
6. Milk proteins are processed in golgi apparatus & packaged for external export.
7. Vesicles containing packaged proteins & lipids fuse with the cell membrane & release their contents.

41. 4. Mitochondria double-membrane outer is smooth
inner is highly folded (cristae)
#/cell varies with energy demands of that cell (bone cedll have few, muscle cell has thousands)
contain DNA (some mitochondrial genes, rest in nuclear DNA)
Contains some ribosomes for own protein synthesis
inherited only from female parent
site of cellular respiration (production of ATP)
Takes in short carbon chains and oxygen to generate carbon dioxide and ATP
#/cell - A typical liver cell has about 1,700 mitochondria; cells with high energy requirements, such as muscle cells, may have many thousands.

42. Chloroplast: photosynthesis
Plant cells also have...
Cell wall: made of cellulose, provides rigidity and allows for turgor pressure
Vacuole: contains water and digestive enzymes, stores nutrients and wastes
Chloroplast: photosynthesis

43. Chloroplasts #/plant cell varies (few-hundreds)
contain DNA (some chloroplastic genes, rest in nuclear DNA)
found in plants & protists
function photosynthesis
Thylakoid membranes are embedded with enzymes & light-harvesting proteins, which convert sunlight to chemical energy.
Granum = a stack of thylokoids.

44. 6. Lysosomes (suicide sacs)
apoptosis
programmed cell death
vesicles containing > 40 types of digestive enzymes
Called a suicide sacs because if large numbers of them rupture within the cell, they can digest the entire cell.
Recycling - lysosome fuses with vesicle containing old organelles. Enzymes digest the organelles & recycle the products.
Break down cellular byproducts so that they do not accumulate within the cell. If an enzyme is missing results in a lysosomal storage disease such as Tay-Sachs.
Tay-Sachs disease results from a missing lysosomal enzyme that normally breaks down lipids in cells surrounding nerve cells. Without the enzyme, cells of the nervous system gradually drown in lipid. Symptoms are usually noted at about 6 months of age. Children who have inherited Tay-Sachs disease soon lose their vision & hearing & later are paralyzed. All affected children die before they are 4 years old.
NOTE: WBCs & liver cells have large #s of lysosomes; plant cells do NOT have lysosomes (central vacuole functions as a lysosome).
function to recycle damaged organelles, break down cellular byproducts, destroy cell & kill invading microbes

45. Centrioles Found near nucleus Involved in cell divison
Structurally similar to cilia and flagella

46. Cilia and Flagella Differences cilia flagella short and multiple
longer and single

47. Movement of Cilia and Flagella
Move material over cell surface
Respiratory tree & oviduct
Flagella
single flagella wiggles in a wavelike pattern
propels sperm forward

48. The Endosymbiont Theory
Lynn Margulis – eary 1960’s
Proposes that chloroplasts and mitochondria evolved from once free-living bacteria engulfed by larger prokaryotes, but not digested.
Based on fact that mitochondria & chloroplasts resemble certain bacteria (size, shape, membrane structure,have own DNA and ribosomes)

49. Multicellular Organization
Each cell must do their own basic activities (protein synthesis, cellular respiration, cell division, etc.)
Also show a division of labor or specialization and cooperation- contribute to the well being of other cells/tissues/organs etc.
Some form of intercellular communication
Either chemical (hormone) or electrical (nervous)

50. Levels of Organization
Subatomic
Atom
Molecule
Macromolecule
Organelle
Cell
Tissue
Organs
System
Organism
Population
Community
Ecosystem
Biosphere

51. Levels of Structural Organization
Chemical Level
Subatomic, atomic and molecular level
Cellular level
smallest living unit
Tissue level
group of cells that work together on one task

52. Levels of Structural Organization
Organ level
groups of 2 or more tissue types into a recognizable structure with a specific function.
Organ system
collection of related organs with a common function
sometimes an organ is part of more than one system
Organism level
one living individual

53. Levels of Structural Organization
Population
Group of same specie in a given area
Community
All specie in a given area
Ecosystem
Biotic and abiotic in a given area
Biosphere
All ecosystems combined