Figure 6-01

1
Figure 6-01
2
Investigating Cell Structure and Function

• 1. Cell Theory
• 2. Microscopy-
• a. History
• b. Types
• 3. Studying cell organelles
• Cell homogenization
• b. Cell Fractionation

3
LE 6-2
10 m
Human height
1 m
Length of some nerve and muscle cells
Unaided eye
0.1 m
Chicken egg
1 cm
Frog egg
1 mm
Measurements 1 centimeter (cm) 102 meter (m)
0.4 inch 1 millimeter (mm) 103 m 1 micrometer
(µm) 103 mm 106 m 1 nanometer (nm) 103
µm 109 m
100 µm
Most plant and animal cells
Light microscope
10 µm
Nucleus
Most bacteria
Mitochondrion
1 µm
Electron microscope
Smallest bacteria
100 nm
Viruses
Ribosomes
10 nm
Proteins
Lipids
1 nm
Small molecules
Atoms
0.1 nm
4
Table 7.1 Different Types of Light Microscopy A
Comparison
5
LE 6-3a

• Brightfield (unstained
• specimen)

50 µm

• Brightfield (stained
• specimen)

Phase-contrast
6
LE 6-3b
Differential- interference- contrast (Nomarski)
Fluorescence
50 µm
Confocal
50 µm
7
LE 6-4
1 µm
Scanning electron microscopy (SEM)
Cilia
Longitudinal section of cilium
Transmission electron microscopy (TEM)
Cross section of cilium
1 µm
8
LE 6-4a
1 µm
Cilia
Scanning electron microscopy (SEM)
9
LE 6-4b
Longitudinal section of cilium
Cross section of cilium
1 µm
Transmission electron microscopy (TEM)
10
LE 6-9a
ENDOPLASMIC RETICULUM (ER
Nuclear envelope
Flagellum
Rough ER
Smooth ER
NUCLEUS
Nucleolus
Chromatin
Centrosome
Plasma membrane
CYTOSKELETON
Microfilaments
Intermediate filaments
Microtubules
Ribosomes
Microvilli
Golgi apparatus
Peroxisome
Mitochondrion
Lysosome
In animal cells but not plant cells
Lysosomes Centrioles Flagella (in some plant
sperm)
11
Inner Life of A Cell

• http//www.studiodaily.com/main/searchlist/6850.ht
  ml

12
LE 6-5a
Homogenization
Tissue cells
Homogenate
Differential centrifugation
13
LE 6-5b
1000 g (1000 times the force of gravity) 10 min
Supernatant poured into next tube
20,000 g 20 min
80,000 g 60 min
Pellet rich in nuclei and cellular debris
150,000 g 3 hr
Pellet rich in mitochondria (and chloro- plasts
if cells are from a plant)
Pellet rich in microsomes (pieces of
plasma membranes and cells internal membranes)
Pellet rich in ribosomes
14
Cell Structure

• 1. Basic requirements to be a cell
• Cytoplasm
• DNA
• Ribosome
• Cell membrane
• Prokaryotic and eukaryotic cells
• 3. Limitations to cell size
• Lower limits
• Upper limits-SA/volume ratio

15
Prokaryotic and Eukaryotic Cells
16
LE 6-6
Pili
Nucleoid
Ribosomes
Plasma membrane
Cell wall
Bacterial chromosome
Capsule
0.5 µm
Flagella
A typical rod-shaped bacterium
A thin section through the bacterium
Bacillus coagulans (TEM)
17
LE 6-7
Surface area increases while Total volume remains
constant
5
1
1
Total surface area (height x width x number of
sides x number of boxes)
6
150
750
Total volume (height x width x length X number of
boxes)
125
125
1
Surface-to-volume ratio (surface area ? volume)
1.2
6
6
18
An overview of animal cell structure

• Nucleus
• Ribosomes
• Endomembrane System
• RER SER
• Vesicles
• Golgi apparatus
• Vacuoles
• Lysosomes
• 4. Mitochondria
• 5. Cytoskeleton

19
LE 6-9a
ENDOPLASMIC RETICULUM (ER
Nuclear envelope
Flagellum
Rough ER
Smooth ER
NUCLEUS
Nucleolus
Chromatin
Centrosome
Plasma membrane
CYTOSKELETON
Microfilaments
Intermediate filaments
Microtubules
Ribosomes
Microvilli
Golgi apparatus
Peroxisome
Mitochondrion
Lysosome
In animal cells but not plant cells
Lysosomes Centrioles Flagella (in some plant
sperm)
20
LE 6-8
Outside of cell
Carbohydrate side chain
Hydrophilic region
Inside of cell
0.1 µm
Hydrophobic region
Hydrophilic region
Phospholipid
Proteins
Structure of the plasma membrane
TEM of a plasma membrane
21
What is contained in the nucleus of a cell?

• DNA
• Chromosomes
• Genes
• R-rna
• All of the above

22
LE 6-10
Nucleus
Nucleus
1 µm
Nucleolus
Chromatin
Nuclear envelope Inner membrane
Outer membrane
Nuclear pore
Pore complex
Rough ER
Surface of nuclear envelope
Ribosome
1 µm
0.25 µm
Close-up of nuclear envelope
Pore complexes (TEM)
Nuclear lamina (TEM)
23
What is the function of ribosomes?

• Protein synthesis
• DNA synthesis
• Intracellular digestion
• Transport of proteins outside of the cell

24
LE 6-11
Ribosomes
ER
Cytosol
Endoplasmic reticulum (ER)
Free ribosomes
Bound ribosomes
Large subunit
Small subunit
0.5 µm
TEM showing ER and ribosomes
Diagram of a ribosome
25
There is a difference in the make-up of
cytoplasmic eukaryotic ribosomes and prokaryotic
ribosomes

• True
• False

26
Proteins that are secreted from a cell are
produced by

• Membrane-bound ribosomes
• Free ribosomes

27
Secreted proteins are carried away from the ER by

• The golgi apparatus
• Lysosomes
• Mitochondria
• vesicles

28
LE 6-12
Smooth ER
Nuclear envelope
Rough ER
ER lumen
Cisternae
Ribosomes
Transitional ER
Transport vesicle
200 nm
Smooth ER
Rough ER
29
If a secreted protein needs to be chemically
modified after it leaves the ER in a vesicle, it
will go to

• A lysosome
• Mitochondria
• A storage vacuole
• The Golgi apparatus

30
LE 6-16-3
Nucleus
Rough ER
Smooth ER
Nuclear envelope
cis Golgi
Transport vesicle
Plasma membrane
trans Golgi
31
Vesicles from either the ER or the Golgi that
contain proteins involved in intracellular
digestion fuse to form this cell organelle

• Storage vacuole
• Mitochondria
• Lysosome

32
Lysosomes are involved in destroying worn out
cell organelles

• True
• False

33
Up to 5 optional points

• You have 3 minutes to write a short answer to
  this question
• Why is it important that the pH of a lysosome is
  acidic compared to the cytoplasm of the cell?

34
LE 6-14a
1 µm
Nucleus
Lysosome
Lysosome contains active hydrolytic enzymes
Hydrolytic enzymes digest food particles
Food vacuole fuses with lysosome
Digestive enzymes
Plasma membrane
Lysosome
Digestion
Food vacuole
Phagocytosis lysosome digesting food
35
LE 6-14b
Lysosome containing two damaged organelles
1 µm
Mitochondrion fragment
Peroxisome fragment
Hydrolytic enzymes digest organelle components
Lysosome fuses with vesicle containing damaged
organelle
Lysosome
Digestion
Vesicle containing damaged mitochondrion
Autophagy lysosome breaking down damaged
organelle
36
Malfunctions within a lysosome can cause diseases.

• True
• False

37
Vacuoles

• Can be formed by endocytosis
• May store substances the cell will need later
• Can be formed by vesicles joining together
• Can be filled with water
• All of the above

38
LE 7-14
50 µm
Filling vacuole
50 µm
Contracting vacuole
39
This cell organelle has a structure adapted for
making ATP during cellular respiration.

• Lysosome
• Nucleus
• Vacuole
• Golgi apparatus
• mitochondria

40
LE 6-17
Mitochondrion
Intermembrane space
Outer membrane
Free ribosomes in the mitochondrial matrix
Inner membrane
Cristae
Matrix
Mitochondrial DNA
100 nm
41
The Cytoskeleton

• Made up of 3 elements
• a. Microtubules
• b. Microfilaments
• c. Intermediate filaments
• 2. Functions-diverse including maintaining cells
  shape motility contraction and organelle
  movement

42
LE 6-20
Microtubule
Microfilaments
0.25 µm
43
Table 6-1a
44
LE 6-22
Centrosome
Microtubule
Centrioles
0.25 µm
Longitudinal section of one centriole
Microtubules
Cross section of the other centriole
45
Cilia and Flagella

• Cell Movement

46
LE 6-23a
Direction of swimming
Motion of flagella
5 µm
47
LE 6-23b
Direction of organisms movement
Direction of active stroke
Direction of recovery stroke
Motion of cilia
15 µm
48
This cell organelle contains 2 compartments
separated by a membrane, which is necessary for
chemiosmosis to occur

• Golgi apparatus
• Mitochondria
• RER
• Lysosome
• vacuole

49
Which of the following statements is/are true?

• The cytoskeleton is composed of protein
• The cytoskeleton is involved in the segregation
  of chromosomes during mitosis
• The cytoskeleton can reorganize by
  polymerizing/depolymerizing
• A and B
• B and C
• All of the above

50
LE 6-24a
Microtubules
Plasma membrane
Basal body
0.5 µm
51
LE 6-24b
Outer microtubule doublet
Plasma membrane
0.1 µm
Dynein arms
Central microtubule
Cross-linking proteins inside outer doublets
Radial spoke
0.5 µm
52
LE 6-25b
Cross-linking proteins inside outer doublets
ATP
Anchorage in cell
Effect of cross-linking proteins
Wavelike motion
53
Organelle Movement

• Position of organelles not fixed in the cell

54
LE 6-21a
Vesicle
ATP
Receptor for motor protein
Motor protein (ATP powered)
Microtubule of cytoskeleton
55
LE 6-21b
Microtubule
Vesicles
0.25 µm
56
Table 6-1c
57
LE 6-26
Microvillus
Plasma membrane
Microfilaments (actin filaments)
Intermediate filaments
0.25 µm
58
Table 6-1b
59
LE 6-27a
Muscle cell
Actin filament
Myosin filament
Myosin arm
Myosin motors in muscle cell contraction
60
LE 6-27b
Cortex (outer cytoplasm) gel with actin network
Inner cytoplasm sol with actin subunits
Extending pseudopodium
Amoeboid movement
61
LE 6-27c
Nonmoving cytoplasm (gel)
Chloroplast
Streaming cytoplasm (sol)
Vacuole
Parallel actin filaments
Cell wall
Cytoplasmic streaming in plant cells
62
Dyneine walking is a key event in this cellular
process

• Chemiosmosis
• Amoeboid movement
• Cytokenesis
• Motility using flagella
• All of the above

63
Plant Cell Structure

• 1. All of the same organelles and structures that
  are in animals plus
• Cell wall
• Large central vacuole
• Chloroplasts

64
LE 6-9b
Nuclear envelope
Rough endoplasmic reticulum
NUCLEUS
Nucleolus
Chromatin
Smooth endoplasmic reticulum
Centrosome
Ribosomes (small brown dots)
Central vacuole
Golgi apparatus
Microfilaments
Intermediate filaments
CYTOSKELETON
Microtubules
Mitochondrion
Peroxisome
Chloroplast
Plasma membrane
Cell wall
Plasmodesmata
Wall of adjacent cell
In plant cells but not animal cells
Chloroplasts Central vacuole and tonoplast Cell
wall Plasmodesmata
65
LE 6-28
Central vacuole of cell
Plasma membrane
Secondary cell wall
Primary cell wall
Central vacuole of cell
Middle lamella
1 µm
Central vacuole
Cytosol
Plasma membrane
Plant cell walls
Plasmodesmata
66
LE 6-15
Central vacuole
Cytosol
Tonoplast
Central vacuole
Nucleus
Cell wall
Chloroplast
5 µm
67
LE 6-18
Chloroplast
Ribosomes
Stroma
Chloroplast DNA
Inner and outer membranes
Granum
1 µm
Thylakoid
68
LE 6-19
Chloroplast
Peroxisome
Mitochondrion
1 µm
69
This cell organelle contains 2 compartments
separated by a membrane, which is necessary for
chemiosmosis to occur

• Golgi apparatus
• Mitochondria
• RER
• Chloroplast
• 2 and 4

70
Because plant cells have a large central water
vacuole, they must also have

• Chloroplasts
• Lysosomes
• Mitochondria
• A cell wall
• RER

71
Plays a role in cytoplasmic streaming, amoeboid
movement, and muscle contraction

• Microfilaments
• Intermediate filaments
• Microtubules
• Dyneine walking
• All of the above

72
These in class clicker questions are helpful

• Strongly Agree
• Agree
• Neutral
• Disagree
• Strongly Disagree

73
Cell Surrface Molecules/Connections

• Cell surface molecules (glycocalyx)
• Cell Connections-Plants
• Plasmodesmata
• 3. Cell connections-Animals
• Tight junctions
• Desmosomes
• Gap junctions

74
LE 6-29a
Proteoglycan complex
EXTRACELLULAR FLUID
Collagen fiber
Fibronectin
Plasma membrane
CYTOPLASM
Integrin
Micro- filaments
75
LE 6-30
Cell walls
Interior of cell
Interior of cell
Plasmodesmata
Plasma membranes
0.5 µm
76
LE 6-31
Tight junction
Tight junctions prevent fluid from moving across
a layer of cells
0.5 µm
Tight junction
Intermediate filaments
Desmosome
1 µm
Gap junctions
Space between cells
Plasma membranes of adjacent cells
Gap junction
Extracellular matrix
0.1 µm
77
LE 6-32
5 µm