1. Cell Unit Notes Lecture I

2. Cell Biology Standards in Lecture I  1c ~ students know how prokaryotic cells, eukaryotic cells, and viruses differ in complexity and in general structure  1e ~ students know the role of the endoplasmic reticulum and the Golgi apparatus in the secretion of proteins  *1j ~ students know how eukaryotic cells are given shape and internal organization by a cytoskeleton, cell wall, or both

3. The Scientists involved in the Cell Theory  In 1665 Robert Hooke looked at a slice of cork under a microscope The tiny chambers reminded him of the “cells” in a monastery so he called them cells The tiny chambers reminded him of the “cells” in a monastery so he called them cells  In 1674 Anton von Leeuwenhoek made better lenses for the microscope and was able to see cells in greater detail

4. The Scientists involved in the Cell Theory  Matthias SchleidenTheodore Schwann  In 1838 and 1839 Matthias Schleiden and Theodore Schwann observed that all living things are made up of cells Schleiden Schleiden noted that all plants are made up of cells Schwann Schwann stated that all animals are made up of cells  Rudolf Virchow  In 1855 Rudolf Virchow states that all cells come from pre-existing cells

5. The Cell Theory  All living things are composed of cells  Cells are the basic functional units of life  New cells are produced from existing cells

6. Prokaryotes vs. Eukaryotes  Prokaryotes  smaller & simpler  Contain a cell membrane & cytoplasm  Sometimes a cell wall  Also have ribosomes  No nucleus  All bacteria are prokaryotes  DNA is “free – floating”  Eukaryotes  Have a nucleus containing DNA  Most have specialized structures called organelles  All plants, animals, protists, and fungi are eukaryotes  Larger and more complex

7. Cell membrane Cytoplasm Nucleus Organelles Eukaryotic Cell Prokaryote vs. Eukaryote Prokaryotic Cell

8. Prokaryotes & Viruses  Prokaryotes are simple, living organisms that can reproduce on their own  They have diverse ways of obtaining nutrients: Photosynthesis Photosynthesis Chemosynthesis Chemosynthesis Heterotrophic consumers Heterotrophic consumers

9.  Bacteria (prokaryotes) live in every habitat possible and are the most numerous of all living things on our planet  All living things depend upon bacteria – including, especially, humans! Prokaryotes & Viruses

10. 3 Domains of Life on Earth

11.  Archea represent the “ancient bacteria” and they live in extreme environments such as boiling water or extremely salty environments  They are the oldest living organisms on this planet. Evidence suggests that they were present during the early stages of Earth over 3.9 billion years ago Prokaryotes & Viruses

12.  Bacteria have cell membranes and most have a cell wall  Their DNA is one circular molecule  They often have many plasmids Small circular rings of DNA usually containing one gene Small circular rings of DNA usually containing one gene  Pili help bacteria “stick” to things Prokaryotes & Viruses Many bacteria have a flagellum or many flagella to help them move

13.  Viruses are extremely small particles not considered to be “alive”  They act like parasites because they can ONLY reproduce in a host  They consist of a protein coat and contain either DNA or RNA inside Prokaryotes & Viruses

14. Eukaryote Cell Structures  Cell Wall Found in many organisms including plants, algae, fungi, and nearly all prokaryotes Not found in animal cells Not found in animal cells

15. Cell Wall The main function of the cell wall is to provide support and protection for the cell The main function of the cell wall is to provide support and protection for the cell Plant cell walls are made of cellulose

16. The Nucleus  The nucleus is the “control center” of the cell  The nucleus controls most cell processes and contains the hereditary information of DNA  Almost all eukaryotic cells, including plant and animal, contain a nucleus

17. The Nucleus  Nucleolus – small dense region in nucleus where ribosomes are produced   Nuclear envelope – double membrane layer surrounding the nucleus (aka. Nuclear membrane)

18. The Cytoskeleton  A network of protein filaments that help the cell maintain it’s shape  It is also involved in many forms of movement Microfilament Microtubule

19. The Cytoskeleton  Made up of three types of structures : Microtubules – hollow tubes of protein that help maintain cell shape and serve as “tracks” for organelles to travel on Intermediate Filaments – smaller than microtubules – gives a cell its strength Microfilaments – long thin fibers that support cell movement and support

20. Organelles in the Cytoplasm  Ribosomes Organelle that “assembles” proteins Organelle that “assembles” proteins A is made up of 2 parts: A ribosome is made up of 2 parts: a proteina protein rRNA (ribosomal RNA)rRNA (ribosomal RNA) Ribosomes make proteins from the “coded” instructions of the DNA inside the nucleus Ribosomes make proteins from the “coded” instructions of the DNA inside the nucleus Ribosomes

21. Endoplasmic Reticulum  An internal membrane where parts of the cell membrane are made and some proteins are modified  The is where protein synthesis occurs  The Rough Endoplasmic Reticulum is where protein synthesis occurs Ribosomes are on it’s surface making it appear “rough” Ribosomes are on it’s surface making it appear “rough” Rough endoplasmic reticulum

22. Endoplasmic Reticulum  The does not have any ribosomes on it’s surface  The Smooth Endoplasmic Reticulum does not have any ribosomes on it’s surface It contains enzymes that make lipids (fats) It contains enzymes that make lipids (fats) Smooth endoplasmic reticulum

23. Golgi Apparatus  After proteins are assembled and produced by the they move to the where :  After proteins are assembled and produced by the Rough ER they move to the Golgi Complex where : Carbohydrates (sugars) and lipids (fats) are attached to the protein They are then sent to their final destination Golgi apparatus

24. Lysosomes  Small organelles that are filled with digestive and other enzymes They break down lipids (fats), carbohydrates (sugars), and proteins from food particles so it can be used by the rest of the cell They break down lipids (fats), carbohydrates (sugars), and proteins from food particles so it can be used by the rest of the cell Lysosomes also break down “old” organelles that have outlived their function Lysosomes also break down “old” organelles that have outlived their function Basically, they “take out the trash” Basically, they “take out the trash”

25. Vacuoles  Serve as a storage for water, salts, proteins, and “carbs” (plant and animal cells)   In Plants : They usually have one large vacuole filled with water to support structures like leaves and flowers Vacuole

26. Chloroplasts  The producer! They use sunlight to power a familiar process called Photosynthesis They use sunlight to power a familiar process called Photosynthesis The green pigment (color) chlorophyll is what gives leaves their color and is found inside chloroplasts The green pigment (color) chlorophyll is what gives leaves their color and is found inside chloroplasts Chloroplast

27. Mitochondria  The “powerhouse” of the animal and plant cell! Mitochondria use energy from food to make high- energy compounds (ATP) Mitochondria use energy from food to make high- energy compounds (ATP) The cell uses these high- energy compounds for growth, development, and movement The cell uses these high- energy compounds for growth, development, and movement In that way, the mitochondria makes “fuel” for the cell In that way, the mitochondria makes “fuel” for the cell

28. Typical Plant Cell

29. Typical Animal Cell