1. Cell Organelles
Use this presentation in conjunction with the Cell Organelle note-taking worksheet.

2. Cell Organelles
Organelle (“little organ”) = a small structure in the cell that performs a specific function.
Membrane-bound organelles are found only in eukaryotic cells

3. Cytoplasm Everything in a cell except the nucleus is cytoplasm
Clear, gelatin-like, watery substance surrounding the organelles.
Maintains the shape and consistency of the cell.
Allows for chemical reactions necessary in metabolism

4. Cell Membrane Boundary of the cell
Made of a phospholipid bilayer, with protein molecules scattered all over
Regulates what comes in and out of the cell, provides for some protection of the cell and its organelles
Emphasize word parts here:
phospho= phosphate head; lipid= fatty acid tail
bi= 2

5. Nucleus
Control center of the cell – has the information needed to oversee the chemical reactions in cells (what is the counterpart in a factory?)
Contains DNA (either as chromosomes or chromatin), nucleolus and nuclear envelope
Surrounded by a double membrane called nuclear envelope
Usually the easiest structure to see under a microscope
Usually one per cell, but some cells have many nuclei
Cells with more than one nucleus include muscle cells and liver cells, largely because of the massive volume of cytoplasm and number of organelles that need controlling. 5

6. Nuclear Envelope Boundary of the nucleus
“Envelope” – because it a a double-membrane
Made of a phospholipid bilayer (like the cell membrane)
Regulates what comes in and out of the nucleus, has nuclear pores that allow a large molecule like RNA to move in and out of the nucleus.
Emphasize word parts here:
phospho= phosphate head; lipid= fatty acid tail
bi= 2

7. Chromosome/ Chromatin
Eukaryotic DNA has 2 forms:
Chromatin- DNA that is loosely coiled around a protein. When the cell in NOT dividing, DNA is in this form but cannot be seen in most light microscopes.
Chromosome- chromatin is condensed into chromosomes when the cell divides (mitosis/ meiosis). Humans have 23 pairs of chromosomes which contain all of your DNA. These are visible in a light microscope.
Has the genetic code that directs what proteins get made

8. Nucleolus A large, dense area in the nucleus
Site of ribosome production
nucleolus

9. Ribosome Site of protein synthesis (also known as translation)
Found attached to rough ER or floating free in cytoplasm
Not membrane-bound
Produced in a part of the nucleus called the nucleolus

10. Endoplasmic Reticulum
A.k.a. “E.R.” (endo means inside + cytoplasmic + reticulum means network = network of membranes inside the cytoplasm)
Connected to nuclear envelope
Rough ER: studded with ribosomes; it chemically modifies proteins
Smooth ER: no ribosomes; it makes lipids

11. Golgi Apparatus Looks like a stack of plates; membrane- bound
Stores, transports, and packages proteins
Molecules transported to and from the Golgi by means of vesicles
AKA Golgi Complex

12. Which organelles do lysosomes work with?
Garbage disposal of the cell
Membrane-bound
Contain digestive enzymes that break down big molecules and damaged organelles
Which organelles do lysosomes work with?

13. What type of microscope may have been used to take this picture?
Vacuoles
Large central vacuole usually in plant cells
Many smaller vacuoles in animal cells
Storage container for water, food, enzymes, wastes, pigments, etc.
Membrane-bound
The image is 2D, so it must have been a light microscope or TEM. If the cell is very tiny, then a TEM was used. Otherwise, a strong light microscope could have captured this image.
What type of microscope may have been used to take this picture?

14. Mitochondria
“Powerhouse of the cell” – found in BOTH plant and animal cells
Cellular respiration occurs here to release energy (ATP) for the cell to use
Has 2 membranes – outer and inner membranes (the latter is highly folded that increases surface area for cellular respiration
Has its own circular DNA and ribosomes (wonder why?)

15. Chloroplast Found only in plant cells and plant-like protists
Site of photosynthesis
Bounded by a double membrane – third membrane is “photosynthetic” - contains the green pigment chlorophyll
Contains its own DNA and ribosomes (why?)
Chloroplasts absorb light, which is the starts the process of photosynthesis.

16. Cytoskeleton Acts as skeleton and muscle
Provides shape and structure
Helps move organelles around the cell, or move the cell itself
Made of three types of filaments
Only in eukaryotes
Actin, also found in muscle cells, mainly help maintain cell shape in their cytoskeletal role. Microtubules mostly move organelles around the cell. Intermediate filaments also provide structural support.

17. Centrioles
During cell division – help assemble the spindle apparatus that moves chromosomes
Usually found only in animal cells
Made of microtubules arranged in a special way
Microtubules are also part of the cytoskeleton.

18. Cilia and Flagella
Made of microtubules arranged in a special way (similar to centrioles)
Extensions of (some) eukaryotic cells that have no cell wall
For movement
Cilia in throat cells
Cilia in Paramecium
Cilia in sperm cells

19. Cell Wall Found in plant, fungus, and bacterial cells
Rigid, protective barrier
Located outside of the cell membrane
Made of cellulose (fiber) in plant cells 19

20. Quick Review Which organelle is the control center of the cell?
Which organelle is responsible for converting food energy into usable energy and is present in ALL eukaryotic cells?
Which organelles are not found in animal cells?
Which organelle helps plant cells make food?
What does E.R. stand for?
Which organelles have something to do with making and packaging proteins?
Why are almost all organelles membrane-bound?

21. Identify the organelles