Cell Structure & Function

http://koning.ecsu.ctstateu.edu/cell/cell.html

Cell Theory an explanation of the relationship between cells and living things

• All living things are composed of cells.

• Cells are the basic units of structure and function in living things

• All cells are produced from other cells.

Definition of Cell

The basic unit of structure and function in living things

Cells form the parts of an

organism and carry out all of an organism’s processes, or

functions

Seeing Cells

•  The invention of the microscope made it possible for people to discover and learn about cells

•  Robert Hooke was one of the first people to observe cells using a compound microscope he built in 1663. He looked at a thin slice of cork.

•  He thought they looked like tiny rectangular rooms and called the empty spaces cells, which is a word meaning “small rooms”

Examples of Cells Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

Cells

•  Different body tissues and organs are made of different kinds of cells. – Nerve cells make up nerves, brain cells make

up the brain, muscle cells make up muscles

» Muscle Cell

» Red and White Blood Cells

Making New Cells

•  Cells are repeatedly dividing resulting in more cells and growth and repair in multicellular organisms

•  This process is called mitosis.

Cells Sustain Life

•  Many basic functions of organisms occur in cells – Cells take in nutrients and energy to perform

work •  Every cell is covered by a membrane that

controls what can enter and leave the cell •  Within the cell are specialized parts for the

transport of materials, energy capture and release, protein building, waste disposal, information feedback and movement

Living Systems •  Living systems at all levels of organization demonstrate

the complementary nature of structure and function –  The level of organization within organisms includes

cells, tissues, organs, organ systems and whole organisms

–  Whether the organism is single-celled or multicellular, all of its parts function as a whole to perform the tasks necessary for the survival of the organism

–  Organisms have diverse body plans, symmetry and internal structures that contribute to their being able to survive in their environments

Prokaryotic

•  Do not have structures surrounded by membranes

•  Few internal structures

•  One-celled organisms, Bacteria

http://library.thinkquest.org/C004535/prokaryotic_cells.html

Eukaryotic •  Contain organelles surrounded by membranes •  Most living organisms

Plant Animal

http://library.thinkquest.org/C004535/eukaryotic_cells.html

“Typical” Animal Cell

http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

http://waynesword.palomar.edu/images/plant3.gif

“Typical” Plant Cell

Cell Parts Organelles –

a tiny structure that carries out a specific

function within the cell

Surrounding the Cell

Cell Membrane

•  Outer membrane of cell that controls movement in and out of the cell

•  Double layer

http://library.thinkquest.org/12413/structures.html

Cell Wall •  Most commonly found

in plant cells & bacteria

•  Supports & protects cells

http://library.thinkquest.org/12413/structures.html

Inside the Cell

Nucleus

•  Directs cell activities •  Separated from cytoplasm by nuclear

membrane •  Contains genetic material - DNA

Nuclear Membrane •  Surrounds nucleus •  Made of two layers •  Openings allow

material to enter and leave nucleus

http://library.thinkquest.org/12413/structures.html

Chromosomes •  In nucleus •  Made of DNA •  Contain instructions

for traits & characteristics

http://library.thinkquest.org/12413/structures.html

Nucleolus •  Inside nucleus •  Contains RNA to build

proteins

http://library.thinkquest.org/12413/structures.html

Cytoplasm

•  Gel-like mixture •  Surrounded by cell membrane •  Contains hereditary material

Endoplasmic Reticulum •  Moves materials around

in cell •  Smooth type: lacks

ribosomes •  Rough type (pictured):

ribosomes embedded in surface

http://library.thinkquest.org/12413/structures.html

Ribosomes •  Each cell contains

thousands •  Make proteins •  Found on ER &

floating throughout the cell

http://library.thinkquest.org/12413/structures.html

Mitochondria •  Produces energy through

chemical reactions – breaking down fats & carbohydrates

•  Controls level of water and other materials in cell

•  Recycles and decomposes proteins, fats, and carbohydrates

http://library.thinkquest.org/12413/structures.html

Golgi Bodies •  Protein 'packaging

plant' •  Move materials within

the cell •  Move materials out of

the cell

http://library.thinkquest.org/12413/structures.html

Lysosome •  Digestive 'plant' for

proteins, fats, and carbohydrates

•  Transports undigested material to cell membrane for removal

•  Cell breaks down if lysosome explodes

http://library.thinkquest.org/12413/structures.html

Vacuoles •  Membrane-bound

sacs for storage, digestion, and waste removal

•  Contains water solution

•  LARGE vacuoles help plants maintain shape

http://library.thinkquest.org/12413/structures.html

Chloroplast •  Usually found in plant

cells •  Contains green

chlorophyll •  Where

photosynthesis takes place

http://library.thinkquest.org/12413/structures.html