1. LIFE, ORGANELLES, CELL MEMBRANE, CELLULAR TRANSPORT
Cells
LIFE, ORGANELLES, CELL MEMBRANE, CELLULAR TRANSPORT

2. Part 1 What is Life?
The prefix “bio” means life and the suffix “ology” means the study of. The word biology means the study of life.

3. 1. What do biologists do?
Imagine being the first person to look through a magnifying lens and see cells. Or being the person who discovered dinosaurs had feathers. Will we defeat cancer? Will we find life on other planets or moons?

4. 1. What do biologists do?
A. Biologists study the diversity of life. Jane Goodall spent years living among and studying chimpanzees, learning about their growth, daily travels, how they gather food, and their social complexities.

5. 1. What do biologists do?
B. Biologists research genetics. Mary-Claire King studied the genetics of chimpanzees and humans. She learned that our DNA is 99% identical.

6. 1. What do biologists do?
C. Biologists research the spread and treatment of diseases. They study how the body fights viruses, and how viruses are spread. Biologists are working on vaccines that prevent the spread of HIV. They are studying ways to prevent obesity, high cholesterol, and Alzheimer’s disease.

7. 1. What do biologists do?
D. Biologists help drive innovations in technology. Prosthetic limbs have come a long way, many of which are bionic. Charles Drew discovered a way to remove blood plasma from blood cells, saving millions of lives through his now safe transfusions.

8. 1. What do biologists do?
E. Biologists work to improve agriculture. Imagine everyone in the world being fed, no more hunger. Biologists work to modify plants for maximum output and health benefits.

9. 1. What do biologists do?
F. Biologists help preserve the environment. They help keep areas from being developed, protecting certain species. Lee Ann Martinez helps rural communities in Africa build compostable toilets, as very little water is available for standard toilets. The compost is then used a soil fertilizer.

10. 2. Characteristics of Life
There are 8 defining characteristics that biologists agree describe all living things.
A. Made of one or more cells. Many organisms are just one cell, or unicellular, like bacteria. Humans and most plants are multicellular.

11. 2. Characteristics of Life
B. Displays organization. Unicellular organisms have highly organized and functional organelles. Multicellular organisms organize in a predictable way are they become more complex, forming tissues and organs.

12. 2. Characteristics of Life
C. Grow and develop. Living organisms grow from the single cell they all begin as. Even unicellular organisms grow larger during their lifespan. They also develop during the natural stages of the life cycle.

13. 2. Characteristics of Life
D. Reproduce. Although an individual may not reproduce, but as a group, the entire species produces offspring.

14. 2. Characteristics of Life
E. Responds to Stimuli. Living organisms respond to their environment. Plants grow towards light. Sharks are attracted to the smell of blood. What do you do when you’re really cold?

15. 2. Characteristics of Life
F. Requires Energy. All living things either make or produce the energy needed for their life functions. Autotrophs harvest energy from the sun (photosynthesis) or from thermal vents at the bottom of the ocean (chemosynthesis). Heterotrophs must acquire their food by eating other organisms.

16. 2. Characteristics of Life
G. Maintain homeostasis. All living organisms regulate their internal system to stay normal. Keeping a steady temperature, water amount, salinity, pH, etc. is all part of maintaining homeostasis.

17. 2. Characteristics of Life
H. Adaptations and Evolve. This does not refer to the changes a single organism may have over its lifetime. Instead, this refers to the small genetic changes that lead an entire species to have an advantage for survival.

18. 3. The gray area: Are Viruses Alive?
A. They have some of the characteristics of living things, but not all.

19. 3. The gray area: Are Viruses Alive?
B. The fight for life: A virus is a strand of DNA or RNA coated in a layer of protein. They can reproduce by infecting a host cell and forcing the cell to become a virus-making factory. They evolve, which is why you can catch a cold even though you’ve already had a cold before.

20. 3. The gray area: Are Viruses Alive?
C. Non-living: They do not have cell walls, so cannot maintain homeostasis. They are already full-sized when they are made, so they do not grow or develop. They do not acquire or use energy or respond to stimuli. So what are they?