1. Ch 4 Campbell Biology in Focus HHS AP Biology Eggers
Cellular Organelles
Ch 4 Campbell Biology in Focus
HHS AP Biology
Eggers

2. The Jobs of Cells Three main jobs: Make energy Make proteins
Need energy for all cellular activities
Need to clean up the waste produced while making energy
Make proteins
Proteins do the work in cells – enzymes, structure, transport, etc. – so we need LOTS of them
Make more cells
For growth and development
To replace old, damaged or diseased cells

3. Eukaryotic cells have internal compartments called organelles that make doing all of this work much more efficient
Nucleus
Ribosomes
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Chloroplasts
Peroxisomes
Cytoskeleton: microtubules, centrosomes and centrioles, cilia and flagella, microfilaments, intermediate filaments

4. Nucleus
Bound by the nuclear envelope which is a double membrane composed of two lipid bilayers
Connecting the interior of the nucleus to the cytoplasm are large pores which house a protein pore complex which regulates entry and exit of proteins, RNA and other large molecules.
Contains most of the genes in the cell, which are located on units called chromosomes.
Chromosomes are a combination of both DNA and organizing proteins all wound up together – this is called chromatin.
Within the nucleus, you can see a dense region called the nucleolus, where ribosomal RNA is synthesized.

6. Ribosomes
Located in both the cytosol and also attached to the rough endoplasmic reticulum
Composed of ribosomal RNA (rRNA) and protein
Their job is to synthesize proteins
Free ribosomes synthesize the proteins that will function within the cytosol while the bound ribosomes found on the rough ER synthesize integral membrane proteins and proteins for secretion

8. Endomembrane system
Includes the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, the lysosomes, vacuoles and vesicles, and the cell’s exterior plasma membrane

9. Smooth and rough endoplasmic reticulum (ER)
Smooth ER – synthesis of lipids, carbohydrate metabolism, drug & poison detoxification, and storage of calcium ions (liver cells are packed with smooth ER).
Rough ER – is rough in appearance because it is studded with ribosomes. The rough ER produces glycoproteins for secretion and membrane-bound proteins.
Proteins bound for secretion or destined to reside in the cell’s plasma membrane bud off from the rough ER in transport vesicles.

12. Golgi apparatus/Golgi bodies
Transport vesicles from the ER often travel first to the Golgi.
In the Golgi apparatus, proteins are modified and stored prior to secretion
The flattened stacks of Golgi are called cisternae & are not physically connected.
The side of the stacks facing the nucleus and ER is referred to as the cis face – this side receives vesicles.
The side of the stack facing the plasma membrane is the trans face – this is where the vesicles exit the Golgi.
The Golgi also synthesizes macromolecules such as the polysaccharide pectin in plant cells.

14. Animated tutorial at:

15. Lysosomes Are membranous sacs of hydrolytic enzymes
Carry out intracellular digestion
Eg phagocytosis. A nutrient or food particle is engulfed, forming a membranous food vacuole. The lysosome fuses with the vacuole, releasing its contents. The hydrolytic enzymes break down the material within the vacuole and the more simple molecules pass into the cytosol for use by the cell.
Lysosomes are also involved in autophagy

18. Digit formation, programmed cell death, and lysosomes…

19. Vacuoles Large vesicle derived from the ER & Golgi
Performs selective transport of solutes
Food vacuole formed by phagocytosis
Contractile vacuole found in protists - pumps excess water out of the cell
Central vacuole in mature plant cells - stores critical ions and helps the cell to increase in size without the energy expenditure necessary to produce additional cytoplasm

20. Central vacuole in a plant cell
Contractile vacuole in a paramecium
Central vacuole in a plant cell
Food vacuole in an amoeba

21. Mitochondria & chloroplasts
These organelles provide the usable fuel that keeps cellular processes running = glucose & ATP
Mitochondria perform cellular respiration, which converts pyruvate, derived from glucose, into ATP. ALL eukaryotic cells have mitochondria.
Chloroplasts, found in photosynthetic organisms, capture the sun’s energy and use this to produce glucose from CO2 and H2O in the process of photosynthesis.

22. Endosymbiont theory
Mitochondria and chloroplasts are structurally different from cell organelles derived from the endomembrane system – they are enclosed by a double membrane and chloroplasts have additional membrane-enclosed structures within them
They contain ribosomes and their own DNA, which they use to synthesize proteins specific to their function.

23. Mitochondria

24. Plastids in plants Contain pigments for photosynthesis
Chloroplasts
Chromoplasts
Storage = Leucoplasts
Amyloplast = starch
Elaioplast = lipids
Proteinoplast = proteins

25. Chloroplasts

26. BOTH animal calls and plant cells have mitochondria to make ATP!!
All cells need ATP in order to survive so all eukaryotic cells have mitochondria
BOTH animal calls and plant cells have mitochondria to make ATP!!

27. Peroxisomes
Specialized metabolic compartment surrounded by a single layered plasma membrane
It contains enzymes that detoxify poisons by removing H+ from them and transferring the hydrogen to O2, producing hydrogen peroxide (H2O2)
H2O2 is also toxic, but peroxisomes contain an enzyme called catalase that converts hydrogen peroxide to water

28. The cytoskeleton
The cytoplasm of cells contains a highly organized network of fibers called the cytoskeleton
Give mechanical support & maintains cell shape
Anchors organelles and cytosolic enzymes
Allows for cell motility

29. Microtubules
Microtubules – hollow rods composed of protein subunits called tubulin
Motor proteins use ATP to move along microtubules
In animal cells, the centrosome, near the nucleus, is the microtubule organizing center which gives rise to the microtubule scaffold.

30. Microfilaments Solid rods composed of actin molecules
Helps support the cell’s shape
In muscles, it is actin filaments and another protein called myosin which allow for muscle fiber contraction.

33. Motor proteins (kinesin & dynein) transport organelles along microtubules

34. Cilia & flagella
1. axoneme, 2. cell membrane, 3. intraflagellar transport, 4. basal body, 5. cross section of flagellum, 6. triplets of microtubules in the basal body

35. Cell Fractionation – technique to separate and isolate organelles by size using differential centrifugation

36. Extracellular Matrix

37. Cell Junctions – Animal Cells
Tight junctions – bound by proteins, forms a continuous seal that prevents leakage across epithelial cells
Desmosomes – like rivets, creating strong attachments between cells – in muscles
Gap junctions – like plant plasmodesmata, connect cytoplasm to neighboring cytoplasm

38. Plant plasmodesmata
Plasmodesmata – membrane-lined channels that connect adjacent plant cells.
Allow for the passage of large molecules

39. Cell Videos
Inner Life of a Cell:
Plant cells:
Animal cells:

40. Diseases of cellular components --