1. Eukaryotic Cell Structures
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2. In some respects, the eukaryotic cell is like a factory
It contains several tiny specialized structures called organelles
Biologists divide the cell into 2 parts: the cytoplasm and the nucleus

3. The cytoplasm is the portion of the cell outside the nucleus
It contains the organelles and is where some cellular processes take place

4. Nucleus
Contains nearly all of the cell’s DNA and instructions for making proteins & other molecules
It is surrounded by a nuclear envelope, which is made up of 2 membranes
Contains 1000’s of tiny pores which allow material (RNA & proteins) to move into and out of nucleus

5. Nucleus contains chromatin, which is DNA bound to proteins
Condenses to form chromosomes during cell division
May also contain a nucleolus, which is where ribosomes are made

7. Ribosomes Site where proteins are assembled Composed of RNA & proteins
Found in the cytoplasm or on other organelles
Produce proteins based on coded instructions from the nucleus

8. Endoplasmic Reticulum (ER)
It is an internal membrane system that synthesizes and exports materials
Site where lipid components of the cell membrane are assembled
Exports proteins and other material for the cell

9. There are 2 types of ER: smooth and rough
Rough ER is involved in protein synthesis
Contains ribosomes on its surface
Proteins leave ribosomes and enter ER to be modified
Smooth ER lacks ribosomes
Contains enzymes the synthesize lipid membranes & detoxify drugs
Large amounts are found in liver

11. Golgi Apparatus Named after Italian scientist Camillo Golgi
Accepts proteins modified in the rough ER
Function is to modify, sort, and package proteins & other materials from the ER

13. Lysosomes
Small organelles filled with enzymes that act like “clean-up crew” in the cell
Functions to digest, or breakdown lipids, carbohydrates, and proteins into small molecules
Breaks down old & worn out organelles

15. Vacuoles
Saclike structure that stores cellular materials like water, salts, proteins and carbs
Plants contain a large vacuole filled with water, which enables plants to support the weight of flowers and leaves

16. Single-celled organisms contain a contractile vacuole,
Used to pump out excess water from cell
Helps to maintain homeostasis

18. Mitochondria & Chloroplasts
Mitochondria are found in plant & animal cells
Functions as the cell’s “powerhouse” by converting energy stored in glucose to the cellular energy ATP
Composed of 2 membranes: inner & outer
The inner membrane is folded to increase surface area

19. Chloroplasts are found in plant cells and in a few other organisms
Contains chlorophyll, which is used to capture the energy during photosynthesis
Also composed of 2 membranes

21. Organelle DNA Chloroplasts and mitochondria contain their own DNA
Biologist Lynn Margulis believes they are descendents from prokaryotic cells
Developed from symbiotic relationships

22. Cytoskeleton Functions as support structure for cell
Consists of a network of protein filaments that help the cell maintain its shape
Two types of protein filaments: microfilaments and microtubules

23. Microtubules are hollow structures made of tubulin
Microfilaments are made of actin and their assembly and disassembly allow cytoplasmic movement
Microtubules are hollow structures made of tubulin
They are important in cell reproduction because they form the mitotic spindle which separates chromosomes

24. They are also responsible for the formation of cilia and flagella, which allow some cells to move
Centrioles are also made of tubulin and help to organize cell division