1. Cellular Processes and structure
04 Homeostasis
Exchange of energy/matter
Homeostatic mechanisms
Defense against infection

2. Immune system
Holtzclaw:

3. Animals have a variety of chemical defenses against infections
Pathogen - anything that causes disease, typically a "germ“
Invertebrates only have nonspecific (innate) response mechanisms
Insects and other invertebrates
cells recognize peptidoglycan
trigger anti-bacterial cascade response

5. …nonspecific response mechanisms
Phagocytes
recognize, engulf, and digest pathogenic cells
Natural killer cells
detect virus-infected cells and initiate apoptosis

6. Mammals have specific immune responses
In addition to nonspecific immune responses
Two types: cell mediated and humoral

7. … Mammals have specific immune responses
Antigens - proteins found on pathogens that generate an immune response
Antibodies -"tag" antigens by attaching to them
Allow them to be phagocytized

8. Humoral immune response (specific)
Responds to antigens found in the blood and lymph (humors)
B Cells
Type of lymphocyte (white blood cell)
Respond to intact antigens (where?)
Produce antibodies (function?)

9. Cell-mediated immune response (specific)
Responds to antigens fragments which have already infected a cell.
T Cells – also types of lymphocytes
Cytotoxic T cells
Helper T-cells
Memory T Cells

10. Cell-mediated immune response (specific)
T Cells – also types of lymphocytes
Cytotoxic T cells
Also called natural killer cells (function?)
Helper T-cells
Release cytokines (a type of cell signal) that initiates and coordinates the activity of other immune cells (see diagram)
Memory T Cells
Produced during infection
Stay in the system
Secondary immune response

12. Cell-mediated immune response (specific)
MHC – major histocompatibility complex
cell surface proteins
determines histocompatibility (self vs nonself)
Presents protein fragments to leukocytes

16. Plant defenses against pathogens
Barrier defenses
infection triggers chemical responses
adjacent cells are destroyed

17. Plant defenses against pathogens
include molecular recognition systems
Shared between cells
Plants do not have mobile immune cells like mammals
Evolved innate, specific responses
More details later…

18. Cellular Processes and structure
04 Homeostasis
Exchange of energy/matter
Homeostatic mechanisms
Defense against infection