Lesson 1

water plants


  • Explore what makes up living things.
  • Describe the characteristics of an organism.
  • Compare the parts of plant cells and animal cells.
  • Compare one-celled organisms.
  • Describe how cells in a many celled organism work in groups.


oxygen, organism, cell, tissue, organ, organ system

Questions for Study

  • How are all living things alike?
  • Why do you think animal cells do not have chlorophyll in them?
  • What are some of the differences between plan and animal cells?
  • Why must plants make their own food?
  • What makes a microorganism plant like?
  • Is a virus living or nonliving? Why?
  • How can we observe that a dog is alive?
  • What are the basic needs of all living things?




Cells are the building blocks of living things. Most living things have basic needs which are food, water, a place to live and oxygen. Most living things such as plants will use the oxygen to turn food into energy. An organism is a living thing that carries out five basic life functions of its own.
[toggler title=”Four Basic Needs”]

  • source of energy
  • water
  • gasses for respiration
  • an environment that allows it to survive

[toggler title=”Five Basic Life Functions”]

  • respond/react to their environment
  • use energy obtained through eating or making food
  • get rid of waste
  • grow and develop
  • reproduce

Plant cells are shaped like a box and contain chlorophyll. The chlorophyll is a green material. When the chlorophyll is struck by sunlight, it makes food for the plant. The plant cell consists of a cell wall, mitochondrion, and chloroplast. Animal cells are rounded and have a fluid shape. An animal cell consists of a nucleus, chromosomes, vacuole, cell membrane, and cytoplasm.

Microorganisms are small organisms that can be seen with a microscope. Protists are one-celled microorganisms that live in a pond. Bacteria are one-celled organisms. They have a cell wall but no nucleus. They live in many different environments. Fungi are many-celled organisms. Bread and mushroom are fungi.

A human is made up of billions of cells working together. You are made up of blood cells, bone cells, skin cells, and many others. Cells work together in groups called tissues. Organs are groups of tissues that perform a certain function. Organs that work together to carry out a specific life function is an organ system.

A virus is not a living thing because it lacks a nucleus or other cell parts. It cannot make or use food. It does not grow or change. A virus can replicate within a living cell.


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