1. ORGANELLES OF THE CYTOPLASM

2. Cytoplasm Located between plasma membrane and nucleus Cytosol
Water with solutes (protein, salts, sugars, etc.)
Cytoplasmic organelles
Metabolic machinery of cell

3. Cytoplasmic Organelles
Membranous
Mitochondria
Peroxisomes
Lysosomes
Endoplasmic reticulum
Golgi apparatus
Nonmembranous
Cytoskeleton
Centrioles
Ribosomes
(Harvard cell)
(real time protein synthesis)
(dna replication)

4. Mitochondria Double-membrane structure with shelflike cristae
Provide most of cell’s ATP via aerobic cellular respiration
Contain their own DNA and RNA

5. Outer mitochondrial membrane Ribosome Mitochondrial DNA Inner
Cristae
Matrix
(c)
Enzymes
(b)
Figure 3.17

6. Ribosomes Site of protein synthesis
Free ribosomes synthesize soluble proteins
Membrane-bound ribosomes synthesize proteins destined for membranes or secretion

7. Endoplasmic Reticulum (ER)
System of Interconnected tubes and parallel membranes enclosing cisternae
Continuous with nuclear membrane
Two varieties:
Rough ER
Smooth ER

8. (a) Diagrammatic view of smooth and rough ER
Smooth ER
Nuclear
envelope
Rough ER
Ribosomes
(a) Diagrammatic view of smooth and rough ER
Figure 3.18a

9. Rough ER External surface studded with ribosomes
Manufactures all secreted proteins
Synthesizes membrane integral proteins and phospholipids

10. Smooth ER Its enzymes catalyze reactions involved with:
In the liver-Lipid metabolism, cholesterol synthesis, synthesis of lipid components of lipoproteins
In testes: Synthesis of steroid-based hormones (testes)
In skeletal & cardiac muscle—storage & release of calcium

11. Golgi Apparatus Stacked and flattened membranous sacs
Modifies, concentrates, and packages proteins and lipids
Proteins exit via secretory vesicles

12. destined for exocytosis Secretion by exocytosis Extracellular fluid
Protein-
containing
vesicles pinch
off rough ER
and migrate to
fuse with
membranes of
Golgi
apparatus. 1
Rough ER ER
membrane
Phagosome
Plasma
mem-
brane
Proteins in
cisterna
Pathway C:
Lysosome containing
acid hydrolase
enzymes
Proteins are
modified within
the Golgi
compartments. 2
Vesicle becomes
lysosome
Proteins are
then packaged
within different
vesicle types,
depending on
their ultimate
destination. 3
Secretory
vesicle
Golgi
apparatus
Pathway B:
Vesicle membrane
to be incorporated
into plasma
membrane
Pathway A:
Vesicle contents
destined for exocytosis
Secretion by
exocytosis
Extracellular fluid
Figure 3.20

13. Lysosomes
Spherical membranous organelles containing digestive enzymes (acid hydrolases)
Can degrade/breakdown:
Ingested bacteria, viruses, and toxins
Nonfunctional organelles
Break down and release glycogen
Break down bone to release Ca2+

14. Nucleus Nuclear envelope Smooth ER Rough ER Vesicle Golgi apparatus
Plasma
membrane
Transport
vesicle
Lysosome
Figure 3.22

15. Peroxisomes Membranous sacs containing powerful oxidases and catalases
Detoxify harmful or toxic substances
Neutralize dangerous free radicals

16. Cytoskeleton Elaborate series of rods throughout cytosol
Microtubules -hollow tubes, mostly radiating from a centrosome; determine overall shape of cell and distribution of organelles
Microfilaments -actin strands attached to cytoplasmic side of plasma membrane; Involved in cell motility, change in shape, endocytosis and exocytosis
Intermediate filaments-Tough, insoluble ropelike protein fibers ;Resist pulling forces on the cell and attach to desmosomes

17. Strands made of spherical protein subunits called actins
(a) Microfilaments
Strands made of spherical
protein subunits called actins
Actin subunit
Microfilaments form the blue network
surrounding the pink nucleus in this
photo.
Figure 3.23a

18. (b) Intermediate filaments
Tough, insoluble protein fibers
constructed like woven ropes
Fibrous subunits
Intermediate filaments form the purple
batlike network in this photo.
Figure 3.23b

19. Hollow tubes of spherical protein subunits called tubulins
(c) Microtubules
Hollow tubes of spherical protein
subunits called tubulins
Tubulin subunits
Microtubules appear as gold networks
surrounding the cells’ pink nuclei in
this photo.
Figure 3.23c

20. Centrioles
Involved in: cell division
Found within the centrosome

21. Centrosome matrix
Centrioles
(a)
Microtubules
Figure 3.25a

22. Cellular Extensions Flagella
Whiplike, motile extensions on surfaces of certain cells
propel whole cells (tail of sperm)
Cilia move substances across cell surfaces

23. Figure 3.26 Outer microtubule doublet Dynein arms The doublets
also have
attached motor
proteins, the
dynein arms.
Central
microtubule
Cross-linking
proteins inside
outer doublets
The outer
microtubule
doublets and
the two central
microtubules
are held
together by
cross-linking
proteins and
radial spokes.
Radial spoke
TEM
A cross section through the
cilium shows the “9 + 2”
arrangement of microtubules.
Microtubules
Cross-linking
proteins inside
outer doublets
Radial spoke
Plasma
membrane
Plasma
membrane
Cilium
Triplet
Basal body
TEM
TEM
A longitudinal section of a
cilium shows microtubules
running the length of the
structure.
A cross section through the
basal body. The nine outer
doublets of a cilium extend into
a basal body where each doublet
joins another microtubule to
form a ring of nine triplets.
Basal body
(centriole)
Figure 3.26

24. Figure 3.27 Power, or propulsive, stroke Recovery stroke, when
cilium is returning to its
initial position 1 2 3 4 5 6 7
(a) Phases of ciliary motion.
Layer of mucus
Cell surface
(b) Traveling wave created by the activity of many cilia acting together propels mucus across cell surfaces.
Figure 3.27

25. Cellular Extensions Microvilli
Fingerlike extensions of plasma membrane
Increase surface area for absorption

26. Microvillus
Actin
filaments
Terminal
web
Figure 3.28

27. Nucleus
Genetic library with blueprints for nearly all cellular proteins
Responds to signals and dictates kinds and amounts of proteins to be synthesized
Surrounded by nuclear envelope (perforated for exit of material)
Contains threadlike strands of DNA (30%), histone proteins (60%), and RNA (10%) called chromatin
Also contains nucleoli : dark-staining spherical bodies involved in ribosome assembly

28. Chromatin (condensed)
Nuclear pores
Nuclear envelope
Nucleus
Chromatin (condensed)
Nucleolus
Cisternae of rough ER
(a)
Figure 3.29a

29. Surface of nuclear envelope.
Fracture
line of outer
membrane
Nuclear
pores
Nucleus
Nuclear lamina. The netlike
lamina composed of inter-
mediate filaments formed by
lamins lines the inner surface
of the nuclear envelope.
Nuclear pore complexes.
Each pore is ringed by
protein particles.
(b)
Figure 3.29b

30. 1 2 3 4 5 DNA double helix (2-nm diameter) Histones Chromatin
(“beads on a
string”) structure
with nucleosomes 2
Linker DNA
Nucleosome (10-nm diameter; eight
histone proteins wrapped by two
winds of the DNA double helix)
(a)
Tight helical fiber
(30-nm diameter) 3
Looped domain
structure (300-nm
diameter) 4
Chromatid
(700-nm diameter) 5
Metaphase
chromosome
(at midpoint
of cell division)
(b)
Figure 3.30