UNIT 1 - Ch5-CELL STRUCTURE & FUNCTION

P. 87-102

TYPES OF CELLS Cells come in a variety of shapes and sizes

that suit their diverse functions.

OBJECTIVES1. Explain the relationship between cell shape

and function.

2. Identify the factor that limits cell size.

3. Describe the three basic parts of a cell.

4. Compare prokaryotic cells and eukaryotic cells.

5. Compare plant and animal cells

6. Know the organelles and their functions

CELL DIVERSITY

Not all cells are alike. Even cells within the same organism show Enormous Diversity in Size, Shape, and Internal Organization. Your Body contains at least 200 Different Cell Types.

CELL SHAPE Most Cells have a Specific Shape. THE SHAPE OF A CELL DEPENDS ON

IT'S FUNCTION. Cells of the Nervous System that carry

information from your toes to your brain are long and threadlike.

Blood Cells are shaped like round disk that can squeeze through tiny blood vessels.

CELL SIZE

A few types of cells are large enough to be seen by the unaided eye. Eg. The Female Egg

Most cells are visible only with a microscope.

MOST CELLS ARE SMALL FOR TWO REASONS:#1-Cells are limited in size by the RATIO of their

Surface Area to Volume. A SMALL CELL HAS MORE SURFACE AREA THAN A

LARGE CELL FOR A GIVEN VOLUME OF CYTOPLASM. This is important because the nutrients, oxygen, and other

materials a cell requires must enter through it surface. (figure 4-5)

#2 -THE CELL'S NUCLEUS (THE BRAIN) CAN ONLY CONTROL A CERTAIN AMOUNT OF LIVING, ACTIVE CYTOPLASM.

COMPARING CELLS All cells share common features, such as a

plasma membrane, cytoplasm, ribosomes, and genetic material (DNA).

But there is a high level of diversity among cells, there are significant differences between prokaryotes and eukaryotes. In addition plant cells have features that are not found in animal cells, although both plant and animal cells are eukaryotic cells.

EUKARYOTIC vs PROKARYOTIC CELLS1. Prokaryotes differ from eukaryotes in that

prokaryotes Lack a Nucleus and Lack Membrane-Bound Organelles.

2. In place of a nucleus, prokaryotes have a region called a Nucleoid in which their genetic material is concentrated.

3. Prokaryotes lack an internal membrane system.

UNICELLULAR ORGANISMS such as bacteria and their relatives are Prokaryotes.

All other organisms are Eukaryotes; plants, fish,

mammals, insects and humans.

The difference between Prokaryotes and Eukaryotes is such an important distinction that Prokaryotes are placed in Two Domains Separate from Eukaryotes - Domains Bacteria and Archaea.

PLANT VS ANIMAL CELLS1. Three unique features distinguish plant cells

from animal cells:

(a) Plant cells have cell walls.

(b) Plant cells contain a large central vacuole.

3) Plant cells contain a variety of Plastids which are not found in animal cells

4) BOTH ARE EUKARYOTIC CELLS

UNIQUE FEATURES OF PLANT CELLS To understand why plant cells have different

structures Not found in animal cells, consider how a plant's lifestyle differs from and animal's. • Plants make there own carbon-containing

molecules (food) directly from carbon dioxide in the environment in a process called Photosynthesis, they convert carbon dioxide, water and energy from the sun into sugars - Autotrophs.

CELL WALL - see fig 5-6

A Cell Wall DOES NOT REPLACE the Cell Membrane; it lies Outside the Cell Membrane.

The Rigidity of Cell Walls Helps SUPPORT and PROTECT the Plant.

Cell Walls of Plants contain POLYSACCHARIDE (long chains) CELLULOSE a complex carbohydrate.

CELLS ORGANELLES You are responsible to know all of the cells

organelles. You must be able to name, identify, and

know the functions of them all Read p. 89-98 and complete the structure

function graph provided THIS IS REVIEW FROM LAST YEAR You will have a quiz on these next class!