Chapter 3 , part 2
An Introduction to
The Cellular Level of Organization
SECTION 3-3
The Cytoplasm
The fluid (cytosol)
The organelles the cytosol surrounds
The cytoplasm contains:
Nonmembranous organelles are not enclosed by a membrane and always in touch with the cytosol
Cytoskeleton, microvilli, centrioles, cilia, ribosomes, proteasomes
Membranous organelles are surrounded by lipid membranes
Endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria
Organelles
Figure 3.2 The Anatomy of a Representative Cell
Figure 3.2
Microfilaments
Intermediate filaments
Microtubules
Thick filaments

Microvilli increase surface area
Cytoskeleton provides strength and flexibility
Figure 3.5 The Cytoskeleton
Figure 3.5
Direct the movement of chromosomes during cell division
Organize the cytoskeleton
Cytoplasm surrounding the centrioles is the centrosome
Centrioles
Is anchored by a basal body
Beats rhythmically to move fluids across cell surface
Cilia
Figure 3.6 Centrioles and Cilia
Figure 3.6
Are responsible for manufacturing proteins
Are composed of a large and a small ribosomal subunit
Contain ribosomal RNA (rRNA)
Can be free or fixed ribosomes
Ribosomes
Figure 3.7 Ribosomes
Figure 3.7
Remove and break down damaged or abnormal proteins
Require targeted proteins to be tagged with ubiquitin
Proteasomes
Intracellular membranes involved in synthesis, storage, transportation and detoxification
Forms cisternae
Rough ER (RER) contains ribosomes
Forms transport vesicles
Smooth ER (SER)
Involved in lipid synthesis
Endoplasmic reticulum
Figure 3.8 The Endoplasmic Reticulum
Figure 3.8
Forms secretory vesicles
Discharged by exocytosis
Forms new membrane components
Packages lysosomes
Golgi Apparatus
Figure 3.9 The Golgi Apparatus
Figure 3.9
Figure 3.10 Functions of the Golgi Apparatus
Figure 3.10
Lysosomes are
Filled with digestive enzymes
Responsible for autolysis of injured cells
Peroxisomes
Carry enzymes that neutralize toxins
Lysosomes and Peroxisomes
Figure 3.11 Lysosome Functions
Figure 3.11
Continuous movement and recycling of membranes
ER
Vesicles
Golgi apparatus
Cell membrane
Membrane flow
Responsible for ATP production through aerobic respiration
Matrix = fluid contents of mitochondria
Cristae = folds in inner membrane
Mitochondria