OBJECTIVES Define the cell cycle. Describe the four phases of the cell cycle. Define the cell cycle. Describe the four phases of the cell cycle.

Cell Growth Cells are limited in their growth. The larger a cell grows the more difficult it is to get things in and out of it. If cells grow too large they would not be able to supply their own needs, and growth would come to a stop. Cells are limited in their growth. The larger a cell grows the more difficult it is to get things in and out of it. If cells grow too large they would not be able to supply their own needs, and growth would come to a stop.

Why is a small cell more efficient than a large cell? It is easier for things like nutrients to get in and out of the cell.

Surface Area to Volume Ratio in Cells Cell Size Volume (length x width x height) Surface Area (number of surfaces X length x width) Surface Area / Volume Ratio 1 cm x 1 cm x 1 cm = 1cm 3 6 x 1 cm x 1cm = 1cm 3 6 cm 2 /1cm 3 = 6/cm 2 cm x 2 cm x 2 cm = 8cm 3 6 x 2 cm x 2cm = 24cm 3 24 cm 2 /8cm 3 = 3/cm

growth DNA replication preparation for cell division

Cell division and cell growth are controlled in multicellular organisms.

Prokaryotic Cell

Binary fission E. coli

Eukaryotic Cell

Amoeba (eukaryotic cell) Binary fission

G 2 - phase

Mitosis

Interphase

Prophase

Metaphase

Anaphase

Telophase

CELL SPECIALIZATION Specific cells are uniquely suited to carry out specific functions

A macrophage, in (yellow), engulfs and consumes a bacterium (green). They help protect the body against infection.

T-lymphocytes are specialized white blood cells that identify and destroy invading organisms such as bacteria and viruses.

Erythrocytes, or red blood cells, are the primary carriers of oxygen to the cells and tissues of the body.

Thrombocytes, or platelets, are the smallest cellular component of blood.

Neurons are the cells by which large groups of cells communicate with each other.

Specialized cells organize into tissues.

Tissue is a group of similar cells that perform similar functions.

Human smooth muscle, also referred to as visceral or involuntary muscle, is composed of slender, spindle-shaped cells.

Skeletal muscle enables the voluntary movement of bones.

Cardiac muscle is a unique muscle tissue found only in the heart.

Organ is a group of tissues that work together to perform a specific function.

LEVELS OF ORGANIZATION CELLS TISSUES ORGANS ORGAN SYSTEMS CELLS TISSUES ORGANS ORGAN SYSTEMS

Smooth muscle tissue Stomach (organ) Organ System

Eukaryotic Cell