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“Cells” & How Organisms Transport Materials

(Harcourt Science Textbook, Unit 2, Lesson 1, pages 142-149)

5th Grade Standard Covered: Life Science 2.a → ”Students know many multicellularorganisms have specialized structures to support the transport of materials.”

The First Microscopes

The first microscopes were invented in the 1600s.

Robert Hooke, in 1665, recorded his observations of cork cells and gave them the name “cells” (they reminded him of tiny rooms).

It took almost 200 years after this for scientists to figure out that all plants and animals are also made of cells.

CellsThe cell is the basic unit of structureand function of all living things.

All living things are made up of one or more cells (a great analogy is a structure built only of LEGOS, which come in many shapes, sizes and colors)

Some simple organisms are made up of just one cell (i.e.: amoeba)

Humans are made up of 50-100 trillion cells

Most cells are microscopic - you need a microscope to see them (a single drop of blood holds millions of red blood cells)

This human body structure, built out of LEGO

S, is an exam

ple of how all living things are made up of cells.

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This Volvo, constructed out of LEGOS that come in many shapes, sizes and colors, is a great analogy for multicellular organisms

Cells

• Each kind of cell has a special function for the body (i.e: red blood cells, nerve cells, muscle cells).

• Most cells have the same needs for survival that you do. They:

• take in food, release energy from food, get rid of body waste, make new cells for growth and repair, and often communicate and work with other cells.

Common Organelles (Cell Parts)

All cells have some of the same organelles.

Each cell contains smaller “specialized”structures called organelles that “support the transport of materials” in and out of the cell.

Some of the more common organelles found in the cells of most organisms are:

Nucleus

• Function: Directs a cell’s activities and stores genetic information

• Analogy: The brain or boss of the cell

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Chromosomes

• Function: A threadlike structure that contains genetic information about the characteristics of that organism.

• Analogy: Computer software or memory chip/hard drive in computers

Cell Membrane

• Function: Holds the cell together and decides what comes in or exits and what stays out

• Analogy: Like the skin in humans or a security guard of a building

Cytoplasm

• Function: a jelly-like substance that protects the organelles and helps the cell stay healthy

• Analogy: bubble wrap or styrofoam beans in a package

Mitochondria

• Function: The powerhouse of a cell. It releases energy from nutrients for the cell to use

• Analogy: Battery inside a flashlight or a protein shake for humans

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Vesicle (animal cell)

Vacuole (plant cell)

• Function: Stores nutrients, water and waste for the cell

• Analogy: A refrigerator or trash can in a house

Cell Wall (plant cell only)

• Function: This hard outer layer that is around the cell membrane supports and protects a plant cell and helps it stand up.

• Analogy: A fence outside of a house or what the rib cage does to your heart and lungs

Chloroplast (plant cell only)

• Function: Makes food for the cell

• Analogy: Your very own personal chef (i.e.: Mom or sometimes Dad)

What are the Differences

between Plant & Animal Cells?

• Plant cells differ from animal cells in that they also have a cell wall and chloroplasts.

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Cells showing other organellesfound in animal and plant cells

How Do Cells Get What They Need?

Cells obtain the materials they need by passive transport or active transport, through the cell membrane.

Active transport requires energy from the cell.

Passive transport does not require any energy from the cell.

4 Levels of Organization in Living Things

• Cells usually do not do their jobs alone. Instead, they join together with other cells of the same kind to perform a specific function.

• Cells with similar functions form tissue.(i.e: cartilage, tendons in humans, bark of a tree in plants)

Cells ► Tissue

• Tissues that function together make up an organ.(i.e: heart and lungs in humans, roots and leaves in plants).

Tissues ► Organ

• Organs working together form an organ system. (A human has 10 major organ systems)

Organs ►Organ System

• Because they are organized in tissues, organs, and organ systems, cells can do larger jobs for the organism than they can do alone.

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4 Types of Tissue in Your Body

• Connective Tissue – The tissue found in bones, cartilage, tendons and blood.

• Muscle Tissue – A tissue made up of cells that contract when they get a signal from the brain, in order to help your body move.

• Epithelial Tissue – A tissue that makes up the body covering of an animal (i.e.: skin) and lines the walls of most organs and blood vessels.

• Nervous Tissue – The signals from your brain travel through nervous tissue. The brain and spinal cord, as well as the places where sight, hearing, taste, smells and touch begin, are all nervous tissue.

Silly phrase to remember the 4 types of Tissue: “Clothed MEN”

How do Organisms Transport Materials?• Multicellular organisms have specialized tissues,

organs, and organ systems that transport materials to, and remove wastes from, all cells in the organism.

Q: How are materials transported in many animals?• The circulatory system carries needed materials

(i.e.: oxygen, water, and nutrients) to the body’s cells. It also carries away waste materials created in each cell (i.e.: carbon dioxide and ammonia) for eventual removal from the body.

Q: How are materials transported in plants?• From the roots, water and nutrients move upward

through a system of tubes. Other tubes carry sugar made in the leaves to all parts of the plant.