BACTERIA & PROTISTS HAVE CHARACTERISTICS

OF LIVING THINGS, WHILE VIRUSES ARE NOT ALIVE

SINGLE –CELLED ORGANISMS AND VIRUSES

SINGLE-CELLED ORGANISMS & VIRUSES

• SINGLE-CELLED ORGANISMS HAVE ALL THE CHARACTERISTICS OF LIVING THINGS

• BACTERIA ARE SINGLE-CELLED ORGANISMS WITHOUT NUCLEI

• VIRUSES ARE NOT ALIVE BUT AFFECT LIVING THINGS

• PROTISTS ARE A DIVERSE GROUP OF ORGANISMS

SINGLE-CELLED ORGANISM

• Living things come in many shapes & sizes

• Living things share common characteristics

• Living things need energy, materials, & living space

• Viruses are not alive

Living things come in many shapes & sizes

• One of the largest living organisms is the honey mushroom fungus living mostly underground (about 3 miles or over 1600 football fields)

• Any living thing is called an organism• Microorganisms are very small organisms, and

made of just one cell. (need microscope to see)• Scientists divide the organisms they identify into

groups called KINGDOMS.

Common Characteristics • ORGANIZATION: cells are the basic unit of all living

things. Cells are able to get energy from and sense their environment and move.

• GROWTH: living things increase in size. All living things need energy & materials to build or repair its structures.

• REPRODUCTION: reproduce to form other organisms like themselves. Binary fission = material from 1 cell, splits in 2. Some single celled organisms use this to reproduce.

• RESPONSE: respond to changes in environment (light, temperature, touch, etc. lets them find food or do other tasks needed for survival).

NEEDS

• Living things need ENERGY, MATERIALS & LIVING SPACE

• FOOD: supplies you with energy (to move, grow & develop). Animals break down food to usable forms, plants transform sunlight to usable energy.

• WATER: most activities of living things take place in water (all of cell’s reactions)

• AIR: CO2 & O2 (oxygen) are some things in air that most organisms use to capture & release energy through. Some organism (in hydrothermal vents) use other chemicals to capture & release energy.

VIRUSES ARE NOT ALIVE

• VIRUS has genetic material enclosed in a protein shell.

• Viruses have many of the characteristics of living things but not as complex as a cell and not considered a living thing.

• Animal cells have structures that let them get materials or energy from environment, while viruses do not. They do not grow once formed.

• Viruses can’t reproduce on own, but must “take over” a cell to use it to make more viruses.