1. Cell Structure and Function
Chapter 3
Cell Structure and Function

2. KEY CONCEPT: Cells are the Basic unit of life.
3.1: Cell Theory
KEY CONCEPT: Cells are the Basic unit of life.

3. Many scientists contributed to the cell theory.
1665
Identified and named cells
1674
Observed living cells; could see greater detail due to better lenses
1838
Noted that plants are made of cells
1839
Concluded that all living things are made of cells
1855
Proposed that all cells come from other cells

4. The cell theory grew out of the work of many scientists and improvements in the microscope.
Many scientists contributed to the cell theory.
More was learned about cells as microscopes improved.
The cell theory is a unifying concept of biology.

5. Early studies led to the development of the cell theory.
The Cell Theory has three principles:
All organisms are made of cells.
All existing cells are produced by other living cells.
The cell is the most basic unit of life.

6. All cells share certain characteristics. Cells tend to be microscopic.
Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells.
All cells share certain characteristics.
Cells tend to be microscopic.
All cells are enclosed by a membrane.
cell membrane
Bacterium (colored SEM; magnification 8800x)
cytoplasm

7. Organelle: small part of a cell that carries out
All cells are filled with cytoplasm: jellylike substance that surrounds all organelles
Organelle: small part of a cell that carries out
a specific job in a cell.
Cell membrane
Bacterium (colored SEM; magnification 8800x)
Cytoplasm

8. There are two cell types:
Eukaryotic cells have a nucleus and membrane-bound organelles.
Prokaryotic cells do not have a nucleus and membrane- bound organelles.
nucleus
organelles
cell membrane
cytoplasm

9. KEY CONCEPT Eukaryotic cells share many similarities.
3.2: Cell Organelles
KEY CONCEPT Eukaryotic cells share many similarities.

11. Cells have an internal structure.
The cytoskeleton has many functions.
supports and shapes cell
helps position and transport organelles
provides strength
assists in cell division
aids in cell movement

12. Several organelles are involved in making and processing proteins.
The nucleus stores and protects DNA.
Direct all the activities of the cell

13. The nucleus is enclosed in a double membrane – nuclear envelope.
Has tiny holes (pores).
Pores allow molecules to move between nucleus and cytoplasm.

14. The nucleus contains the nucleolus.
Region where ribosomes are assembled.
Ribosomes are essential for making proteins.

15. The endoplasmic reticulum (ER) is a network of thin, folded membranes that helps in production of proteins and other molecules.

16. There are two types of ER:
rough endoplasmic reticulum:
has ribososmes attached
looks bumpy
- makes and packages proteins
rough ER – (has ribosomes)

17. There are two types of ER:
Smooth endoplasmic reticulum:
no ribosomes attached
makes lipids
makes steroid hormones,
the site of detoxification of organic compounds within liver cells (breaks down drugs & alcohol)
Smooth ER
(no ribosomes)

18. Ribosomes make proteins by linking amino acids.
Found in two areas:
on surface of the rough ER
- make membrane proteins

19. 2. Floating in the cytoplasm
2. Floating in the cytoplasm. - make proteins used in chemical reactions in cytoplasm

20. The Golgi apparatus is a stack of layers of membranes that modifies, packages, and transports proteins.

21. Vesicles are membrane-bound sacs that hold materials.
Carry molecules to where they are needed.

22. Mitochondria supply energy to the cell.
site of cellular respiration: process used to obtain energy from food by organisms
“Powerhouse of the cell”

23. Vacuoles are fluid-filled sacs that store materials such as water, food molecules, ions, and enzymes.
Plant cell have a large central vacuole.

24. Lysosomes contain enzymes to digest material.
Also break down old cell parts

25. Centrioles are tubes found in the centrosomes.
Centrioles help divide DNA
Centrioles form cilia and flagella.

26. Plant cells have cell walls and chloroplasts.
A cell wall provides rigid support.
It surrounds the cell membrane

27. Plant cells have cell walls and chloroplasts.
Chloroplasts convert solar energy to chemical energy.
Carry out photosynthesis

28. 3.3: Cell Membrane

29. The cell membrane has two major functions.
forms a boundary between inside and outside of the cell
controls passage of materials into and out the cell
cell membrane
outside cell
inside cell

30. Cell membranes are mainly composed of two phospholipid layers.
The two layers of phospholipid molecules have protein molecules embedded in them
protein
cholesterol
carbohydrate
chain
protein channel
cell membrane

31. Phospholipid Structure
Two part molecule:
Hydrophilic polar phosphate group head is attracted to water  faces outward towards water
Hydrophobic non-polar fatty acids tails  face inward toward each other—away from water

32. The cell membrane is selectively permeable (semipermeable) .
Some molecules can cross the membrane while others cannot.

33. Biological systems
System: complex organization formed from a combination of simpler parts
Systems have properties based on the arrangement and interaction of their parts
Your body, like that of any organism, is a living system.
Describe all the parts and interactions of your body system when you type on a computer keyboard.

34. The Cellular Basis of Life
Cell is the basic unit of life
All organisms are made of and develop from cells
Single cell organisms  unicellular
Organisms composed of many cells multicellular
Cells are organized by their function
Cells  tissues  organs systems

35. Organize the terms below in a flowchart. (smallest to largest)
cell
organ system
molecule
organ
tissue
organelle
atom
organisms

38. 3.4 Diffusion & Osmosis

39. Passive Transport NO Energy/ATP  High Low
does not require energy input from a cell.
moves from high to low concentration
NO Energy/ATP
High 
Low

40. There are three types of passive transport.
Diffusion: Molecules move from high to low concentration
Facilitated diffusion is diffusion through transport proteins.
Osmosis: the diffusion of water molecules across a semipermeable membrane.

41. 3.5: Active Transport

42. Active Transport  High Low requires energy or ATP
moves a substance from low to high concentration (against its concentration gradient)
Cells use active transport to maintain homeostasis.
Energy/ATP
High 
Low

43. Cells use energy to transport material in vesicles.
Endocytosis is the process of taking material into the cell.
Exocytosis is the process of expelling material from the cell.