1. Chapter 15-1 & 15-2 THE BASIC UNIT OF LIFE— THE CELL

2. Characteristics of Life
All living things:
use energy
develop and grow
maintain themselves
can reproduce
are part of evolving populations

3. All living things use energy.
Plants use electromagnetic energy from sunlight.
Animals convert food energy from plants or other animals into chemical energy.
How living things use energy is consistent with the laws of physics.

4. All living things develop and grow, changing over time.
Unicellular organisms go through division and cell change over time
Most multicellular organisms begin as 1 cell and become many cells, often having specialized tissues.

5. Living things also maintain themselves.
They build structures (bones, stems).
They repair damage (immune system).
They maintain an internal environment that is consistent (body temperature, ion balance), this is known as Homeostasis.

6. All living things are capable of reproducing.
Asexual reproduction occurs when an organism reproduces by itself.
Sexual reproduction occurs when organisms produce sperm and eggs that join to form new individuals.
Sexual Reproduction creates Variation.

7. All living things are part of populations that evolve.
Populations do not remain constant.
Populations change over time, across generations.

8. Macromolecules Needed for Life
Proteins (C,H,O,N,& S)
Carbohydrates (C,H,O – 1:2:1)
Lipids (C,H,O, - little O)
Nucleic acids (C,H,O,N,P)

9. Importance of Macromolecules
As stated last semester macromolecules are important to living things because:
They help to construct cell organelles and tissues.
Provide energy for life processes
Used in hair, feather, nails, muscles, and cell movement.
Lubricate and cushion cells, and help to make other chemicals like hormones.
Storage of genetic information.

10. Cell Types
Prokaryotic cells have no nucleus. Prokaryotes are almost always single-celled microscopic organisms.
* Their DNA is found in a single
circular chromosome. They
usually have an outer cell wall.
Many have a 2nd small circular
Chromosome with extracellular
DNA called a plasmid.

11. Cell Types They: contain their DNA inside the nucleus
Eukaryotic cells have a nucleus and may be
single celled or multicellular.
They:
contain their DNA inside
the nucleus
have linear chromosomes
contain organelles
are larger cells than
prokaryotes