Its All About Cells Living or Nonliving n

It’s All About Cells!

Living or Nonliving n To be considered a living thing an organism must be able to carry out life functions, such as, acquire energy and water, grow, reproduce, dispose of waste, and survive. n A nonliving thing does not do any of those life functions.

n In 1665, Robert Hooke, an English scientist, experimented with a simple microscope.

Can you see cells? n He observed tiny, orderly, but empty spaces in a thin slice of cork, a type of dead plant material. He called these spaces cells.

CELLS Cells are the BASIC units of ALL LIVING organisms.

The Cell Theory n n n ALL living things are made up of CELLS. The CELL is the BASIC unit of ALL living things. Only LIVING cells can produce LIVING CELLS.

The structure of cells n n n Cells come in many SHAPES and SIZES. Some cells are very SIMPLE in their STRUCTURE. Other cells, however, do contain many SPECIALIZED structures that perform the various functions of cell activity.

TYPES OF CELLS: n PROKARYOTIC OR EUKARYOTIC.

EUKARYOTES n n Eukaryotic cells have an organized nucleus. They usually have organelles that work to make the cell a self-sufficient organism.

Types of Eukaryotic Cells n n Protists Fungi Plants Animals

Protist Cell

Fungi Cell

Plant Cell

Animal Cell

Basic Eukaryote Parts

CELL MEMBRANE n n SURROUNDING each cell is a COVERING called the cell membrane. This is the part of the cell that determines what ENTERS and LEAVES the cell.

CYTOPOLASM n n All cells have a JELLY -LIKE substance called cytoplasm. Many of the ACTIVITIES of a CELL are CARRIED out here.

NUCLEUS n n Near the CENTER of most cells is a structure called the nucleus. It is the “CONTROL CENTER” of the CELL that directs all of the CELL’S activities.

n It is surrounded by a MEMBRANE called the NUCLEAR MEMBRANE or PLASMA MEMBRANE.

Contained in the nucleus are the genetic materials DNA and RNA. n DNA n RNA

DNA stands for DEOXYRIBONUCLEIC ACID.

n These complex organic molecules contain, TRANSPORT, and INTERPRET the instructions for the REPRODUCTION, growth, and DEVELOPMENT of all LIVING organisms.

Throughout the nucleus are structures called CHROMOSOMES. They are ROD- shaped structures that are made of coiled DNA.

All human cells have 46 chromosomes.

ORGANELLES

TINY specialized structures within a CELL that PERFORM cell functions.

Organelles means “LITTLE ORGANS”

VACUOLES n STORAGE areas located in the CYTOPLASM

n Some of these vacuoles store FOOD for future use. Some store CHEMICALS. Others store WASTES until they can be removed from the cell.

n In animal cells they resemble TINY AIR BUBBLES. n In plants they are much larger.

MITOCHONDRIA Structures in the CYTOPLASM that release ENERGY and FOOD.

n These are also called the POWER GENERATORS or the “power house” of the cell.

RIBOSOMES n Structures in the CYTOPLASM where PROTEINS are made.

n They are TINY, round structures that are attached to a LONG, WINDING NETWORK in the cytoplasm called the endoplasmic reticulum.

UNIQUENESS OF PLANT CELLS n n Plant cells contain all the structures that are found in animal cells. But there are several (mainly 3) differences that are unique to plant cells.

Size of Vacuole n Vacuoles in plant cells are very large. n Like the vacuoles in animal cells, the plant cell vacuole also acts as a storage area.

n It’s also filled with a clear fluid that is mostly water, but also contains some sugar, starch, and protein molecules.

CELL WALL n n Plant cells also have a THICK, FIRM, outer boundary called a cell wall. It is a rigid, protective structure that SURROUNDS the plant cell. The cell wall SUPPORTS and PROTECTS the cell. Animal cells DO NOT have a cell wall, just a CELL MEMBRANE.

Ability to Make Its Own Food n In the CYTOPLASM of some plant cells, there are many SMALL, GREEN structures called CHLOROPLASTS.

n n These OVAL-shaped structures in plant cells contain CHLOROPHYLL. Chlorophyll is organic MATERIAL in green plants that ABSORBS sunlight for MAKING FOOD.

Prokaryotic Cells n n Prokaryotic cells do not have an organized nucleus. Their DNA is kind of floating around the cell. It's clumped up, but not inside of a nucleus. Bacterial Cells are an example of prokaryotic cells.

Prokaryotic Cells

Unicellular or Multicelluar n Some living organisms are unicellular (one) or multicellular (many).

Unicellular Organisms n n n The body of the organism is composed of a single cell. A single cell carries out all of the life functions. The cell body is exposed to the environment on all sides. An injury to the cell can cause death to the organism. Life span is short due to the heavy work load.

Unicellular Organisms

Multicellular Organisms n n n The body of the organism is composed of numerous cells. Different cells are specialized to perform different functions. Division of labor may be at the cell, tissue, organ system level. A multicellular body can attain a large size. Injury or death of some cells will not affect the organism.

Multicellular Organisms