1. Chapter 7: Cell Structure and Function

2. 7-1: Life is Cellular The Discovery of the Cell
Robert Hooke coins the term “cell” to describe sections of cork that he sees through his microscope in 1665.
Left: Hooke’s cork cells
Right: cork cells by electron microscope

3. 7-1: Life is Cellular
Around the same time Anton van Leeuwenhoek finds “animacules” in pond water.

4. This leads to the Cell Theory:
7-1: Life is Cellular
This leads to the Cell Theory:
All living things are composed of cells.
2. Cells are the basic unit of living things.
3. New cells are produced from existing cells.

5. Cells come in all shapes and sizes
7-1: Life is Cellular
Cells come in all shapes and sizes
a typical cell is 5-50 micrometers in diameter
smallest cells (bacteria) are 0.2 micrometers across
Biggest cells (ex: amoeba) can be 1000 micrometers across – visible with the naked eye
Diatom
Amoeba

6. Check out this interactive to get an idea of the scale of cells…
How big is an e-coli bacteria?
Which is bigger the influenza virus or hepatitis?

7. Prokaryotes and Eukaryotes Greek roots
7-1: Life is Cellular
White Blood Cell attacking Bacteria
Two Broad Categories of Cells
Prokaryotes and
Eukaryotes
Greek roots
“pro-” means first or before
“eu-” means true
“-karyon” means kernel
Both types have cell membranes and DNA
Prokaryotes are much smaller than eukaryotes
Prokaryotes vastly outnumber eukaryotes

8. Prokaryotes No nucleus Bacteria are prokaryotes
7-1: Life is Cellular
Prokaryotes
No nucleus
(DNA is free- floating in the cytoplasm)
Bacteria are
prokaryotes
Streptococcus bacteria

9. Eukaryotes Contains nucleus
7-1: Life is Cellular
Eukaryotes
Contains nucleus
(DNA is contained within the nucleus)
Single-celled organisms and all multicellular organisms
Often perform specific functions
White blood cell among red blood cells

10. 7-2: Eukaryotic Cell Structure
How is a cell like a factory?
Organelles perform specific, repetitive tasks
“Organelles” means little organs
Organelles inside a cell

11. 7-2: Eukaryotic Cell Structure
Muscle cells: Nuclei are stained purple.
Nucleus
Contains DNA (instructions for making proteins)
Control center for cellular activities
Nuclear anatomy
Nuclear envelope (porous)
Chromatin (DNA attached to proteins)
Chromatin becomes chromosomes during cell division

12. 7-2: Eukaryotic Cell Structure
Ribosomes
Made of RNA and proteins
Ribosomes make proteins (important!)
Use amino
acids to make
chains that form
proteins

13. 7-2: Eukaryotic Cell Structure
Endoplasmic Reticulum
Lipid components of cell membrane and proteins that get exported from the cell are made on the endoplasmic reticulum
Two types of ER
Smooth ER – synthesis of membrane lipids and detoxification of drugs
Rough ER
Called “rough” because of ribosomes on surface
proteins bound for export are chemically modified

14. 7-2: Eukaryotic Cell Structure
Golgi Apparatus (AKA Golgi Body)
It’s a stack of membranes (like pancakes)
Final touches on proteins after they leave the endoplasmic reticulum, before they leave the cell
Lysosomes are made by the Golgi apparatus

15. 7-2: Eukaryotic Cell Structure
Protein
Synthesis

16. 7-2: Eukaryotic Cell Structure
Lysosomes
Made by the
Golgi apparatus
Contain
digestive
enzymes –
garbage men
of the cell

17. 7-2: Eukaryotic Cell Structure
Vacuoles
Saclike structures that store materials like water, salts, proteins, and carbohydrates
Prominent feature of plant cells

18. 7-2: Eukaryotic Cell Structure
Mitochondria
Power House of the cell
Energy from glucose is converted into energy that organelles can use
Inherited from your mother

19. 7-2: Eukaryotic Cell Structure
Chloroplasts
Organelles of photosynthesis (found in plants and other photosynthetic organisms)
Contain green pigment, called chlorophyll

20. 7-2: Eukaryotic Cell Structure
Organelle DNA
Mitochondria and Chloroplasts have their own DNA!? American biologist Lynn Margulis has suggested that these organelles are descendants of ancient, independent prokaryotes. The ancestors of modern-day eukaryotes may have developed symbiotic relationships with such prokaryotes millions of years ago.
Mitochondrion
Prokaryote

21. Endosymbiotic theory

22. 7-2: Eukaryotic Cell Structure
Cytoskeleton
A network of protein filaments that help to support eukaryotic cells (also help some cells to move)
Composed primarily
of microfilaments and
microtubules
Microfilaments in red Microtubules in green