1. Organelle Notes

2. What structures are involved in protein production?
3.4 The nucleus and endomembrane system
What structures are involved in protein production?
Nucleus
Ribosomes
Endomembrane system

3. What is the structure and function of the nucleus?
3.4 The nucleus and endomembrane system
What is the structure and function of the nucleus?
Bound by a porous nuclear envelope
Houses DNA and associated proteins called chromatin
Contains nucleoplasm
Nucleolus region(s) that contain ribosomal RNA (rRNA)
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nuclear
envelope
chromatin
nucleolus
rough ER
nuclear
pores
smooth ER
(nuclear pores): Courtesy E.G. Pollock; (ER): © R. Bolender & D. Fawcett/Visuals Unlimited

4. What is the structure and function of ribosomes?
3.4 The nucleus and endomembrane system
What is the structure and function of ribosomes?
Organelles made of RNA and protein
Found bound to the endoplasmic reticulum and free floating in the cell
Site of protein synthesis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
nuclear
envelope
chromatin
nucleolus
rough ER
nuclear
pores
smooth ER
(nuclear pores): Courtesy E.G. Pollock; (ER): © R. Bolender & D. Fawcett/Visuals Unlimited

5. What is the endomembrane system?
3.4 The nucleus and endomembrane system
What is the endomembrane system?
A series of membranes in which molecules are transported in the cell
It consists of the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes and vesicles

6. How does the endomembrane system function and appear?
3.4 The nucleus and endomembrane system
How does the endomembrane system function and appear?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
secretion
plasma
membrane
incoming vesicle
secretory vesicle
enzyme
Golgi apparatus
modifies lipids and proteins
from the ER; sorts and packages
them in vesicles
lysosome
contains digestive enzymes
that break down cell parts or
substances entering by vesicles
protein
transport vesicle
takes proteins to
Golgi apparatus
transport vesicle
takes lipids to
Golgi apparatus
lipid
rough endoplasmic
reticulum
synthesizes proteins and
packages them in vesicles
smooth endoplasmic
reticulum
synthesizes lipids and has
various other functions
Nucleus
ribosome

7. Summary of the parts of the endomembrane system?
3.4 The nucleus and endomembrane system
Summary of the parts of the endomembrane system?
Rough endoplasmic reticulum – studded with ribosomes used to make proteins
Smooth endoplasmic reticulum – lacks ribosomes but aids in making carbohydrates and lipids
Golgi apparatus – flattened stacks that process, package and deliver proteins and lipids from the ER
Lysosomes – membranous vesicles made by the Golgi that contain digestive enzymes
Vesicles – small membranous sacs used for transport

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9. What is the cytoskeleton?
3.5 The cytoskeleton, cell movement, and cell junctions
What is the cytoskeleton?
A series of proteins that maintain cell shape as well as anchors and/or moves organelles in the cell
Made of 3 fibers: large microtubules, thin actin filaments and medium-sized intermediate filaments

10. What are cilia and flagella?
3.5 The cytoskeleton, cell movement, and cell junctions
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
What are cilia and flagella?
Flagellum
microtubules
Both are made of microtubules
Both are used in movement
Cilia are about 20x shorter than flagella
plasma
membrane a.
cilia
sperm
flagellum
secretory cell b.
flagellum c.
(b): © Y. Nikas/Photo Researchers, Inc.; (c): © David M. Phillips/Photo Researchers, Inc.

11. What are cell junctions?
3.5 The cytoskeleton, cell movement, and cell junctions
What are cell junctions?
Junctions between the cells of human tissue that allow them to function in a coordinated manner.
Three main types
Adhesion junctions: mechanically attach adjacent cells (common in skin cells)
Tight junctions: connections between the plasma membrane proteins of neighboring cells produce a zipperlike barrier (common in digestive system and kidney where fluids must be contained to a specific area)
Gap junctions: communication portals between cells. Channel proteins of the plasma membrane fuse, allowing easy movement between adjacent cells.

12. plasma membranes cytoplasmic plaque plasma membranes plasma membranes
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plasma
membranes
cytoplasmic
plaque
plasma
membranes
plasma
membranes
tight junction
proteins
membrane
channels
filaments of
cytoskeleton
intercellular
filaments
intercellular
space
intercellular
space
intercellular
space
a. Adhesion junction
b. Tight junction
c. Gap junction

13. (top): © Dr. Don W. Fawcett/Visuals Unlimited
3.6 Mitochondria and cellular metabolism
What do mitochondria do and what do they look like?
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A highly folded organelle in eukaryotic cells
Produces energy in the form of ATP
They are thought to be derived from an engulfed prokaryotic cell
outer
membrane
200 nm
matrix
intermembrane
space
inner
membrane
cristae
(top): © Dr. Don W. Fawcett/Visuals Unlimited