Characteristics of Life

1. Characteristics of Life

2. Living things are made up of cells • All living things made up of one or more cells • How do we define ‘cell’? • Cells have structures that enable them to carry out life processes • What are some examples of life processes? • Some living things are only one cell • Unicellular • Example: • Some living things are made up of many cells • Multicellular • Example:

4. Living things take in nutrients • All living things take in nutrients • Nutrients: substances that we need but cannot make for ourselves • How do we obtain nutrients?

5. Living things Use Energy • Energy is required for life processes • Producers use the food they make as a source of energy • Consumers get energy from the food they eat • Energy in the food released through cellular respiratoin • What do we do with energy that we obtain?

6. Living things produce waste that must be removed • Waste= a byproduct of the life processes we carry out • Can become harmful if not removed from body system • Different methods of waste removal: • Unicellular: may pass across the outer membrane of a cell or through a vesicle • Multicelluar: structures/systems that collect and remove waste from body: • What system do humans use? What are the specific structures within the system?

7. Living things respond to stimuli • Stimulus: anything that causes a living thing to react (respond) • Internal stimuli: things that occur inside of the body • Examples: stomach growling=indicates hunger=respond by eating • Other examples? • External stimuli: things that occur outside of body • Example: pet dog’s ears perk up in response to noise at the door • Multicelluar organisms respond to stimuli through specific sense organs/sytem • Named?

8. Living things grow • All living things grow by: • increasing in size • Number of their cells • both • Unicellular: grow by increasing the cell size to a certain point • Multicellular: grow by increasing the number of cells in their body

9. Living things reproduce • Reproduce: produce more of own kind (species) • Different ways of reproduction • Many unicellular organisms: dividing cells • Each cell: daughter cell= identical copy of parent cell • Other organisms mate • Offspring are not identical to the parents

11. Where do living things come from? • Living things come from other living things: • The Cell Theory: • All living things are made up of one or more cells • Ex. • All new cells come from pre-existing cells • Ex. • The cell is the basic unit of life. • Ex.

12. Viruses: Living or Not? • Virus: strand of genetic material surrounded by a layer of protein that can infect and reproduce host cell

13. Structure: • Protein coat can vary in size shape

14. How Viruses Work • Viruse DO NOT: • Contain cell parts • Take in nutrients • Use energy • Produce wastes • Reproduce on their own

15. Prior to infecting host, virus does NOT carry any life function • Can exist dormant hours/days/months before reaching host • Once virus reaches host = viruses REPRODUCE

16. Viral Diseases • HIV/AIDS:Human immunodeficiency virus • Can lead to acquired immunodeficiency syndrome, or AIDS, if not treated. • Body can’t get rid of HIV completely, even with treatment. • Destroy cells of immune system that the body can’t fight off infections and disease. • AIDS is the most severe phase of HIV infection. People with AIDS have such badly damaged immune systems that they get an increasing number of severe illnesses

17. Viral Diseases • Influenza (flu) • Contagious respiratory illness caused by influenza viruses • infect the nose, throat, lungs. • Can cause mild to severe illness, even death

18. Is a virus living or non living?