1. Chapter 4 Preview Section 1 Exchange with the Environment
The Cell in Action
Preview
Section 1 Exchange with the Environment
Section 2 Cell Energy
Section 3 The Cell Cycle
Concept Mapping

2. Section 1 Exchange with the Environment
Chapter 4
Bellringer
Which of the following best describes a living cell:
a) building block
b) a living organism
c) a complex factory
d) all of the above
Write a paragraph in your science journal defending your choice.

3. Chapter 4 Objectives Explain the process of diffusion.
Section 1 Exchange with the Environment
Chapter 4
Objectives
Explain the process of diffusion.
Describe how osmosis occurs.
Compare passive transport with active transport.
Explain how large particles get into and out of cells.

4. Chapter 4 What Is Diffusion?
Section 1 Exchange with the Environment
Chapter 4
What Is Diffusion?
Diffusion is the movement of particles from regions of higher concentration to regions of lower concentration.
Does Not Require Energy
Diffusion of Water The diffusion of water through cell membranes is called osmosis.

5. What Is Diffusion?, continued
Section 1 Exchange with the Environment
Chapter 4
What Is Diffusion?, continued
The Cell and Osmosis Osmosis is important to cell functions.
Semipermeable membrane- only some substances can pass through
Plasma surrounds red blood cells and is made up of water, salts, sugars, and other particles. Osmosis keeps the concentration of these particles in balance.
When a wilted plant is watered, osmosis makes the plant firm again.

6. Moving Small Particles
Section 1 Exchange with the Environment
Chapter 4
Moving Small Particles
Active Transport A process of transporting particles that requires the cell to use energy is called active transport. (Low to High Concentration) require energy
Passive Transport The movement of particles across a cell membrane without the use of energy by the cell is called passive transport. (High to Low Concentration) does not require energy

7. Section 1 Exchange with the Environment
Chapter 4

8. Diffusion and Osmosis
Channels: Passageways in the cell membrane that allow particles through.

9. Moving Large Particles
Section 1 Exchange with the Environment
Chapter 4
Moving Large Particles
Endocytosis The active-transport process by which a cell surrounds a large particle and encloses the particle in a vesicle to bring the particle into the cell is called endocytosis.
Exocytosis The process in which a cell releases a particle by enclosing the particle in a vesicle that then moves to the cell surface and fuses with the cell membrane is called exocytosis.
Both require energy therefore are considered active transport.

10. Moving Large Particles
Section 1 Exchange with the Environment
Chapter 4
Moving Large Particles
Vesicle- a sac that forms from pieces of the cell membrane.
Carry the particles

11. Section 1 Exchange with the Environment
Chapter 4

12. Section 2 Cell Energy
Chapter 4
Bellringer
Make a list of all the different types of cells that you can think of and the jobs they do. Then make a list of all the reasons that a cell needs energy.
Write your answers in your science journal.

13. Chapter 4 Objectives Describe photosynthesis and cellular respiration.
Section 2 Cell Energy
Chapter 4
Objectives
Describe photosynthesis and cellular respiration.
Compare cellular respiration with fermentation.

14. Chapter 4 From Sun to Cell
Section 2 Cell Energy
Chapter 4
From Sun to Cell
Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to make food.
Chlorophyll Plant cells have molecules that absorb light energy. These molecules are called pigments. Chlorophyll, the main pigment used in photosynthesis, gives plants their green color.

15. From Sun to Cell, continued
Section 2 Cell Energy
Chapter 4
From Sun to Cell, continued

16. Getting Energy from Food
Section 2 Cell Energy
Chapter 4
Getting Energy from Food
Cellular Respiration During cellular respiration, food (such as glucose) is broken down into carbon dioxide and water, and energy is released.

17. Getting Energy from Food, continued
Section 2 Cell Energy
Chapter 4
Getting Energy from Food, continued
Connection Between Photosynthesis and Respiration During photosynthesis, cells take in carbon dioxide and release oxygen. During cellular respiration, cells use oxygen to break down glucose and release energy and carbon dioxide.
Fermentation When muscles can’t get the oxygen for cellular respiration, they use fermentation to get energy. Fermentation is the breakdown of food without the use of oxygen.

18. Section 2 Cell Energy
Chapter 4

19. Chapter 4
Section 3 The Cell Cycle
Bellringer
Biology is the only science in which multiplication means the same thing as division—at least with regards to cells.
Explain what is meant by this statement in your science journal.

20. Chapter 4 Objectives Explain how cells produce more cells.
Section 3 The Cell Cycle
Objectives
Explain how cells produce more cells.
Describe the process of mitosis.
Explain how cell division differs in animals and plants.

21. Chapter 4 The Life of a Cell
Section 3 The Cell Cycle
The Life of a Cell
The cell cycle begins when the cell is formed and ends when the cell divides and forms new cells.
Before a cell divides, it must make a copy of its DNA which is organized into structures called chromosomes.

22. The Life of a Cell, continued
Chapter 4
Section 3 The Cell Cycle
The Life of a Cell, continued
Making More Prokaryotic Cells Cell division in bacteria is called binary fission, which means “splitting into two parts.”
Bacteria have a single circular DNA molecule (chromosome). Binary fission results in two cells that each contain one copy of the circle of DNA.

23. The Life of a Cell, continued
Chapter 4
Section 3 The Cell Cycle
The Life of a Cell, continued
Eukaryotic Cells and Their DNA The chromosomes of eukaryotic cells contain more DNA than those of prokaryotic cells.
In a eukaryotic cell, chromosomes are found in the nucleus and are made of DNA and protein.
Pairs of similar chromosomes are called homologous chromosomes.
Copyright © by Holt, Rinehart and Winston. All rights reserved.

24. The Life of a Cell, continued
Chapter 4
Section 3 The Cell Cycle
The Life of a Cell, continued
Making More Eukaryotic Cells The cell cycle has three stages:
Interphase: The cell grows and copies its chromosomes.
Mitosis: The chromatids separate.
Cytokinesis: The cell splits into two identical cells.

25. Mitosis and the Cell Cycle
Chapter 4
Section 3 The Cell Cycle
Mitosis and the Cell Cycle
Mitosis has four phases:
Prophase – chromosomes condense and form chromosomes
Metaphase – Chromatids line up in the middle of the cell
Anaphase – Chromatids move towards opposite ends of the cell
Telophase – New nuclear membrane forms

26. Chapter 4 Mitosis Section 3 The Cell Cycle
Click below to watch the Visual Concept.
Visual Concept

27. Mitosis and the Cell Cycle, continued
Chapter 4
Section 3 The Cell Cycle
Mitosis and the Cell Cycle, continued
Cytokinesis is the division of cytoplasm.
In animal cells and other eukaryotes that do not have cell walls, division of the cytoplasm begins at the cell membrane.
In plant cells and in other eukaryotes with cell walls, a cell plate forms and the cell splits into two cells.

28. Section 3 The Cell Cycle
Chapter 4

29. Chapter 4 Concept Mapping
The Cell in Action
Concept Mapping
Use the terms below to complete the concept map on the next slide.
ATP
photosynthesis
oxygen
water
consumers
lactic acid
producers
respiration
energy

30. Chapter 4
The Cell in Action

31. Chapter 4
The Cell in Action