1. Cells and Their Functions
Chapter 3
Cells and Their Functions

2. The Role of Cells Cytology is the study of cells
Basic unit of all life
Have all characteristics of life
Can live independently of other cells

3. Microscopes Single lens Compound light Transmission electron
Scanning electron

4. Checkpoint 3-1: The cell is the basic unit of life
Checkpoint 3-1: The cell is the basic unit of life. What characteristics of life does it show?
Checkpoint 3-2: Name three types of microscopes.

5. Cell Structure
All cells share certain characteristics.

6. A generalized animal cell, sectional view.
ZOOMING IN • What is attached to the ER to make it look rough? What is the liquid part of the cytoplasm called?

7. Plasma Membrane Encloses cell contents
Participates in cellular activities
Bilayer structure
Phospholipids
Cholesterol
Proteins

8. The plasma membrane.
ZOOMING IN • How many layers make up the main substance of the plasma membrane?

9. Checkpoint 3-3: The outer limit of the cell is a complex membrane
Checkpoint 3-3: The outer limit of the cell is a complex membrane. What is the main substance of this membrane and what are the three types of materials found within the membrane?

10. The Nucleus
Largest organelle in a cell
Chromosomes
Nucleolus

11. Checkpoint 3-4: What are cell organelles?
Checkpoint 3-5: Why is the nucleus called the control center of the cell?

12. The Cytoplasm Material that fills the cell from the nuclear membrane
to the plasma membrane
Endoplasmic reticulum
Ribosomes
Mitochondria
Golgi apparatus
Lysosomes
Peroxisomes
Vesicles
Centrioles

13. Surface Organelles
Structures projecting from the cell surface used for
motion
Cilia
Flagellum

14. Cellular Diversity
Individual cells vary widely
Size
Shape
Function

15. Checkpoint 3-6: What are the two types of organelles used for movement, and what do they look like?

16. Protein Synthesis
Cellular substances that direct the production of proteins
Chromosomes
Genes

17. Nucleic Acids—DNA and RNA
DNA and RNA have similar structures
Four nucleotides
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T) or uracil (U)
Sugar
Ribose or deoxyribose
Phosphate
Nitrogen base

18. DNA
DNA in a cell occurs mainly in chromosomes
Genes are subdivisions of chromosome
Genes code for the building of amino acids

19. Structure of DNA.
ZOOMING IN • Two of the DNA nucleotides (A and G) are larger in size than the other two (T and C). How do the nucleotides pair up with regard to size?

20. Checkpoint 3-7: What are the building blocks of nucleic acids?
Checkpoint 3-8: What category of compounds does DNA code for in the cell?

21. The Role of RNA
Protein synthesis
Transcription
Messenger RNA (mRNA)
Translation
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

22. Transcription.

23. Translation.

24. Checkpoint 3-9: What three types of RNA are active in protein synthesis?

25. Cell Division
Meiosis
Sex cells
Mitosis
Somatic cells

26. Checkpoint 3-10: What must happen to the DNA in a cell before mitosis can occur? During what stage in the life of a cell does this occur?

27. Stages of Mitosis
Prophase
Metaphase
Anaphase
Telophase

28. The stages of mitosis.
ZOOMING IN • If the original cell shown has 46 chromosomes, how many chromosomes will each new daughter cell have?

29. Checkpoint 3-11: What are the four stages of mitosis?

30. Movement of Substances Across the Plasma Membrane
Travel across the membrane is based on several
factors:
Molecular size
Solubility
Electrical charge

31. Movement That Does Not Require Cellular Energy
Passive transport
Diffusion
Osmosis
Filtration
Facilitated diffusion

32. Movement That Requires Cellular Energy
Active transport
Bulk transport or vesicular transport
Endocytosis
Phagocytosis
Pinocytosis
Exocytosis

33. Checkpoint 3-12: Substances are constantly moving into and out of cells through the plasma membrane. What types of movement do not require cellular energy and what types of movement do require cellular energy?

34. How Osmosis Affects Cells
Fluid solutions
Isotonic
Hypotonic
Hypertonic

35. Checkpoint 3-13: The concentration of fluids in and around the cell is important in homeostasis. What term describes a fluid that is the same concentration as the fluid within the cell (intracellular fluid)? What type of fluid is less concentrated? More concentrated?

36. Cell Aging As cells multiply, changes occur that may lead to
their damage or death
Free radical injury
Enzyme injury
Gene alteration or mutation
Slowing cell activity
Apoptosis

37. Cells and Cancer Certain mutations may cause changes in cells
Uncontrolled reproduction of cells
Cells spread (metastasize), producing cancer
Cancer cells form tumors, crowding out normal cells

38. Cancer Risk Factors Certain forces increase the chances of developing
Heredity
Chemicals
Ionizing radiation
Physical irritation
Diet
Viruses