Download Chapter 7 - Cell Structure

Cell Structure
Chapter 7
1
2
•
•
•
Cell Theory
All organisms are
composed of one or
more cells.
Cells are the smallest
living units of all
living organisms.
Cells come from preexisting cells.
3
Prokaryote vs Eukaryote Cell
Prokaryote – no nucleus
- single loop of DNA
- few organelles
- bacteria
Eukaryote – enclosed nucleus
- DNA in chromosomes
- many organelles
4
- plants, animals
•
Cell Size
Most cells are relatively small because as
size increases, volume increases much
more rapidly. (surface area:volume)
– longer diffusion time, less efficient
5
Visualizing Cells
•
Resolution - minimum distance two points
can be apart and still be distinguished as two
separate points
– Compound microscopes - magnify in
stages using multiple lenses
– Transmission electron microscope electrons transmitted through specimen
– Scanning electron microscope - electrons
beamed onto surface of the specimen
6
Visualizing Cells
7
8
9
Cell Organelles
•
•
Cytoplasm – a jelly-like substance that
supports the organelles inside
cell membrane encloses the cell contents
– phospholipid bilayer with
embedded proteins
Phospholipid
Membrane
proteins
10
Nucleus
•
•
•
Contains genetic material
(DNA)
Directs activities of the cell
– Nucleolus - region of RNA
synthesis (needed for
making proteins in the cell)
Surface of nucleus bound by
two nuclear membrane
– Nuclear pores – protein
gatekeepers
– Usually proteins go in and
RNA goes out
11
Nucleus
12
Chromosomes
There is
approximately
0.7 kg (1 ½ lbs)
of DNA in your
body!
•
•
•
•
DNA of eukaryotes is densely packed into chromosomes.
Each chromosome contains approximately 1 metre of
DNA (if stretched out)
There are 46 chromosomes in EVERY cell of your body!
The DNA from all of your cells in your body stretched end
to end would go from the Earth to the Sun 100 times!
13
Endoplasmic reticulum
•
•
•
Serves as system of channels from the nucleus
Rough ER is “rough” because of ribosomes
attached (sites of protein synthesis)
Smooth ER – lack ribosomes – contain embedded
enzymes which speed up the synthesis of
carbohydrate and lipid molecules
14
15
Rough endoplasmic
reticulum with ribosomes
Electron micrograph of
smooth endoplasmic
reticulum
16
Golgi Apparatus
–
collection of Golgi bodies
 collect, package, and distribute molecules
synthesized at one location in the cell and
utilized at another location
17
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Golgi apparatus
Proteins
Transport
vesicle
Protein
The golgi
apparatus
sorts and
repackages
molecules into
vesicles that
then travel to
the cell
membrane to
be expelled
18
19
Lysosomes
-
-
membrane-bound vesicles containing digestive
enzymes – from Golgi apparatus
The enzymes break down food particles and destroy
old, worn-out cell parts
20
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Cytoplasm
Endoplasmic
reticulum
Phagocytosis
Food
vesicle
Golgi
apparatus
Lysosomes
Plasma
membrane
Extracellular
fluid
Digestion of
phagocytized
food particles
or cells
Transport
vesicle
Old or damaged
organelle
Breakdown
of old
organelle
21
Ribosomes
–
–
site of protein
synthesis
assembled in
nucleolus of cell
22
23
Mitochondria
-
contain 2 membranes (exterior and interior membranes)
mitochondria convert glucose to usable energy for the
cell (ATP)
24
Mitochondria
25
Mitochondria
mitochondria line
the flagellum
of this cell
A. "Powerhouse of the cell" - cellular metabolism
B. Structure- outer and inner membranes – lots of surface
are for maximum efficiency
26
Chloroplasts
- Chloroplasts are
larger and more
complex than
mitochondria
- they are ONLY found
in plant cells
- they have special
pigment molecules
called
CHLOROPHYLL that
absorb sunlight and
convert it into
GLUCOSE
27
Cytoskeleton
Network of protein fibers
supporting cell shape and
anchoring organelles
– Actin filaments
Microtubules
 cell movement
– Microtubules
Intermediate
filaments
 Hollow tubes
 Facilitate cell movement
– Intermediate filaments
 Stable - don’t break down
Actin
28
Cytoskeleton
29
Plant Cells
•
Central vacuole
–
–
•
often found in the
center of a plant, and
serves as a storage
facility for water and
other materials
It also provides some
support for the cell
because it is filled with
water
Cell wall
- made of cellulose (long
chains of glucose
molecules)
30
Plant Cell
Small green chloroplasts can be seen inside each plant cell
31
Plant cell
32
Animal Cells
•
Animal cells lack cell walls
- these cells use a variety of proteins to provide support,
strength, and resilience
33
Animal cells
•
The centriole
- is found only in
animal cells
- it is located
outside the
nucleus and
plays a role in
cell division
34
The centriole is cylindrical
and attaches spindle fibres to
help pull chromosomes apart
during cell division
Electron micrograph of
2 centrioles inside a cell
35
36
CELLS
•
Watch the following video clip and try to
identify the organelles inside the cell!
37
38
The Harvard Cell
•
http://multimedia.mcb.harvard.edu/
39
What type of cell is this?
cork cells
40
pollen grains
41
bone cells – growth plate
42
onion cells
43
human red blood cells
44
bacteria
45
brain cells
46
Neuromuscular junction –
where nerve cells connect with muscle cells
47
moss cells
48
Sperm and egg - conception
49
blood clot
50
Hair cells in inner ear
51
rods and cones – cells of retina
52
tooth plaque – bacteria + food particles
53
basal cell carcinoma – skin cancer
54
brain cells
55
normal red blood cell ---------- sickled red blood cell
56
common cold virus
57
human immunodeficiency virus (HIV)
58
H1N1 virus (swine flu)
59