What is Life?

1. What is Life? Bio – logy: The study of Life Organism: Any living thing

2. Key Vocabulary Terms

3. Definitions • Cell: Basic functional and structural unit of all organisms. • Performs specific functions • Provides shape / structure • Unicellular: organisms made up of only one cell. (Uni = one) • Multicellular: organisms made up of more than one cell.(multi = more than one)

4. Definitions (continued) • Differentiation: When the cells of multicellular organisms become different from each other as they multiply and begin to perform specific functions according to their genetic instructions.

5. Definitions (continued) • Autotroph (-ic): An organism that produces its own food. -photosynthetic organisms; AKA: “Producers” Example: plants • Heterotroph (-ic): An organism that must obtain its food from another source. -organisms that can not photosynthesize; AKA: “Consumers” Example: humans

6. Definitions (continued) • Organelle: “Mini” Organs within a cell that carry out specific functions. • Some organelles are “membrane-bound” which means they are surrounded by their own individual membrane. • Examples: nucleus, mitochondria, chloroplasts

7. Definitions (Continued) • Cell Membrane: Outer “covering” of the cell which acts as a “gate-keeper” and determines what may enter and leave the cell. The cell membrane is “semi-permeable” or “selectively permeable” which means it will allow some substances to enter the cell and block other substances from entering.

8. Definitions (continued) • Prokaryote (-ic): -Bacteria cells -Simple cell type -no membrane bound organelles • Eukaryote (-ic): -Term used to describe more complex cell types. -All organisms EXCEPT bacteria are made of Eukaryotic cells, including single celled protists. -This cell type contains many organelles, including the following “membrane-bound” organelles: Nucleus, Mitochondria, and Chloroplasts.

9. Characteristics of Life

10. Characteristics of Life • Cells- • All organisms are made of cells. • Some organisms are unicellular and some are multicellular • There are two types of cells: • Eukaryotic • Prokaryotic *Compare and contrast Eukaryotic and Prokaryotic cells*

11. Characteristics of Life • Reproduction- The process by which organisms produce new organisms. -All living organisms reproduce. Two Types of Reproduction: 1.) Sexual: -Requires two parents (Two cells) -Offspring genetically different from parents 2.) Asexual: -Only one parent (one cell) is involved -Offspring genetically identical to parent or parent cell. (Clones)

12. Characteristics of Life • Growth- Organisms use materials and energy from their environment to increase in size. GROWTH = INCREASE IN SIZE Growth occurs two ways: a) Cell grow in circumference b) Cells multiply/reproduce (divide)

13. Characteristics of Life • Development- Changes that occur during growth, i.e. differentiation. *Contrast Growth and Development* Growth = increase in size Development = changes occuring during growth

14. Characteristics of Life • Response- Organisms respond to their environment (i.e. plants respond to sunlight) • Adaptation- Organisms develop traits that make them better able to survive in their environment. (i.e. Natural Selection)

15. Characteristics of Life • Homeostasis- A stable level of internal conditions. All living organisms strive to establish and maintain homeostasis. (i.e. Blood Pressure and Thermoregulation)

16. Characteristics of Life • Energy Use- Energy: The ability to do work Food = NRG source Primary energy source = Carbohydrates Secondary energy source = Lipids/Fats Tertiary energy source = Proteins

17. Characteristics of Life • Energy Use (cont.)- ANIMALS = HETEROTROPHS: Take in food (NRG), break it down, and build long chains of glucose molecules which are stored in the liver as “GLYCOGEN” PLANTS = AUTOTROPHS Food (NRG) produced as a byproduct of photosynthesis and stored in the plant as long chains of glucose called “STARCH”

18. Characteristics of Life • Energy Use (cont.)- • Photosynthesis: • Process used by plants to convert CO2, water and sunlight to stored NRG (starch)

19. Characteristics of Life • Energy Use (cont.)- The stored forms of NRG, glycogen and starch must be converted to “usable” energy: ANIMALS and PLANTSuse CELLULAR RESPIRATION to convert food (NRG) ingested to a form they can use: ATP- Adenosine triphosphate

20. Characteristics of Life • Energy Use (cont.)- • CELLULAR RESPIRATION: • How food is broken down on a cellular level to produce VIABLE energy. • 3 stages of Cellular Respiration (later) • O2 is required for Cellular Respiration to go to completion

21. Characteristics of Life • Energy Use (cont.)- • Animals:Breathe in O2 which moves from the lungs to the blood stream which carries oxygen to all cells so that cellular respiration can occur. • Products of Cell Respiration: • CO2, H20, and ATP • -Water used in other cell processes, CO2 not needed in large quantities, so exhaled.

22. Characteristics of Life • Energy Use (cont.)- • Plants:Take in CO2 which is used for photosynthesis. Products of Photosynthesis: O2 and glucose (starch) -O2 and glucose in turn used in cellular respiration to form ATP, usable NRG

23. Characteristics of Life • Energy Use (cont.)- • SOOO… • Plants convert CO2 to a usable form for animals and animals produce CO2 for plants as a biproduct of cellular respiration. • *Write a short summary demonstrating your knowledge of • this energy cycle*

24. Characteristics of Life • Energy Use (cont.)- • PLANTS: Energy produced during cellular respiration is used to power photosynthesis • ANIMALS: Energy produced during cellular respiration is “free” energy that can be used to power all of the processes needed to sustain life.