1. Microscopes and Cells

2. Microscopes
Light microscope (LM) works by passing light through the specimen. Specimen must be thin.
- Magnification - the increase in apparent size of the object.
- Resolution – a measure of the clarity of the image.
We use these in lab
Know all parts and functions

3. Stereo Light Microscope
Used when 3 dimensional imaging is needed.

4. Microscopes cont.
Electron Microscope (EM) instead of light it uses a beam of electrons.
- 2 types of EM:
- Scanning electron microscopes (SEM)
used to study surfaces
- Transmission electron microscope (TEM)
used to study internal details
- can’t be used to study living specimens

5. SEM- left TEM-right

8. Microscopes

11. Cell Theory
Microscopes advances led to the “cell theory” – All living things are composed of cells and all cells come from other cells.

12. Two types of Cells Prokaryotes
- no internal membranes therefore no nucleus and not many organelles
- Domains Bacteria and Archaea μm
Eukaryotes
- have internal membranes therefore a distinct nucleus and many organelles.

13. Similarities Both Prokaryotes and Eukaryotes have:
- plasma membrane – surrounds the cell
- ribosomes – tiny structures that make proteins
- DNA – passes on hereditary information

14. Prokaryotes

15. Eukaryotes

17. Eukaryote Cell Structure
Plasma membrane – surrounds cell
- made of phospholipid bilayer
- is selectively permeable
- carbohydrates & proteins protrude from surface & have many functions:
- cell to cell recognition
- transport proteins
- signal receptors

20. Nucleus & Ribosomes Genetic control of cell
Nucleus – genetic control center, contains:
- chromatin which is DNA and proteins that help keep it spiraled. This is the genetic code.
- Nucleolus – makes ribosomes
Nuclear envelope – surrounds nucleus
- is a semi-permeable double membrane

21. Ribosomes Protein synthesis Made in nucleus, do their work in cytosol
Can be attached to endoplasmic reticulum
Can be attached to outside of nucleus
Can be suspended in cytosol
DNA directs protein production
DNA-> RNA-> Protein
Nucleus-> cytoplasm-> ribosome

23. Endomembrane system
Internal network made up of endoplasmic reticulum, Golgi apparatus and vesicles.
Two types of endoplasmic reticulum
- smooth
- rough

24. Rough ER Has ribosomes on outside of membrane
Makes more membrane throughout cell
Proteins from ribosomes inserted into ER for transport to other organelles
Transport vesicles-sacs made of membrane bud off ER

25. Smooth ER Lacks ribosomes Contains enzymes
Synthesize lipids including steroids
Detoxify drugs
HOMEWORK: HOW DOES THE LIVER DETOXIFY DRUGS FROM THE BLOOD?

26. GOLGI APPARATUS
Receives, refines, stores and distributes chemical products of cell
One side receiving end, one side ships
Pathway of a protein: ribosome, ER, vesicle, golgi, vesicle, cell membrane

30. lysosomes Develop from vesicles that bud off golgi
Contain enzymes in acid env
Not found in most plant cells
In simple cells, fuse with food vacuoles to add enzymes-digest
Help destroy harmful bacteria- WBC ingest bacteria into vacuoles, enzymes cause lyses

31. Lysosomal storage diseases
Person missing an enzyme of lysosome
Abnormal lysosome engorges with indigestible substances, interferes with other cell functions
Usually fatal
Tay Sachs- nerve cells & brain

32. Vacuoles & vesicles
Vacuoles- large sacs of membrane that bud from ER, Golgi, or plasma membrane
Storage- water, food, waste
Small-vesicle
Central vacuole in plants-store
water, chemicals, poisons
Can act as lysosome for plant

33. Mitochondria-converting energy
Cell respiration-converts chemical energy in food to ATP energy of cell
Structure:
Outer membrane
Matrix contains thick fluid in the space
Inner membrane folds- cristae

35. chloroplast
Perform photosynthesis- converts light energy (sun) into chemical energy (food)
Only in plant cells
Structure:
Outer membrane
Inner membrane organized into stacks called grana
Space between grana called stroma

36. cytoplasm Area between nucleus and cell membrane-2 parts
Cytosol- liquid part
Cytoskeleton-several fibers-protein
Microtubules-straight hollow tubes-shape, support
Intermediate-ropelike for cell shape
Microfilaments- thin, solid- movement

37. centrioles Made of microtubules- Guide movement of chromosomes
Cell division- animal cells-paired
Cilia & flagella- microtubules
Movement- cells-protists
Cilia-shorter, animal & human respiratory cells
Flagella-longer- human sperm, protists

38. Cell walls Found in plants, bacteria, algae, fungi
Found outside cell membrane
Made of cellulose, ligninn pectin

46. Materials entering and exiting cells
membrane function

47. What materials? Enter: - water needed for hydrolysis
- amino acids to build protein
- carb’s like glucose for cellular respiration to make energy
- oxygen for cellular respiration in mitochondria
- cellular respiration equation
C6H12O6 + O2  CO2 + H2 O + Energy
(glucose)

48. Materials cont. Exit: - CO2 - from cellular resp.
- proteins – produced here needed elsewhere
- waste – whatever the cell doesn’t want

49. How materials enter & exit
Most mol’s are liquid when they enter & exit
- solution - ie. salt water
- solute – the dissolved substance (salt)
- solvent – the dissolver (water)

50. Passive transport
Diffusion – mol’s move from area of high concentration to area of low concentration
Molecules move until equilibrium is reached – when conc.is the same on both sides
Molecules always try to reach equilibrium

52. Passive transport cont.
Osmosis – diffusion of water through a selectively permeable membrane

54. What happens to cells in certain environments?
Inside cell:
90% water
10% sugar
Outside cell:
70% water
30% sugar
Cell loses water
The solutions will now be at equilibrium and are called isotonic to each other

55. Terms:
- hypertonic – the solution with the greater amount of solute (sugar)
- hypotonic – the solution with the lesser amount of solute
- isotonic – both solutions have the same conc.

56. Animal Cells
Can swell from gaining water – cytolysis, this leads to cell bursting (lyse)
Can shrink from losing water – crenate
Animals must regulate this to survive. This is called osmoregulation
Animation: Hemolysis and Crenation

57. Plant cells
When cell loses water the cell membrane shrinks but cell wall doesn’t
- called plasmolysis
- cell is flaccid like wilted celery
When cell gains water the cell membrane pushes on the cell wall from inside this is called turgor pressure
- would result in crisp celery

60. Passive transport review
Materials move across cell membrane without using energy from cell
- diffusion & osmosis

61. Passive cont. Facilitated diffusion - helper diffusion
- no energy required
- for somewhat large molecules
- carrier proteins transport molecules
- concentration gradient must exist
- still moving from crowded to less crowded with the concentration gradient

62. Active transport Uses energy from cell
Moves against the gradient – from low to high concentration
2 types of active transport:
- molecular pumps
- movement for large particles

63. Molecular pumps
Pumps mol’s across memb that would not normally go across the memb.
Na+ K + pump
sodium pump animation

65. Movement for large particles
Endocytosis – into cell
- infolding of membrane forms pocket that pinches off & forms a vesicle
- 2 kinds:
phagocytosis – solids (eating)
pinocytosis – liquids (drinking)
Exocytosis – going out
- opposite of endocytosis
exocytosis animation