Cell Structure & Function

A Little History• 1600’s – cork cells – Robert Hooke

Anton van Leeuwenhoek-1600’s

• Observed “animalcules”

Anton’s Words

• . . . my work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men. And therewithal, whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof.

Antony van Leeuwenhoek. Letter of June 12, 1716

Matthias Schleiden – 1800’s

• Plant Biologist – started as lawyer

• Father of cell theory

• One of first German

scientists to accept

Darwin’s theory of

Evolution

Theodor Schwann -1800’s

• Medicine – physiology

• Met with Schleiden

• Helped with cell

theory after realizing that nucleus was in both plant and animal cells

Rudolf Virchow – 1800’s

• Studied cell division

• Completed cell theory

Cell Theory

• All living things are made up of cells.

• Cells are the smallest working units of all living things.

• All cells come from preexisting cells through cell division.

Janet Plowe – 1900’s• Showed that the cell membrane is an

actual structure

George Langford - now

• Studied movement of vesicles along the cytoskeleton

• Both myosin tubules and actin filaments

Definition of Cell

A cell is the smallest unit that is capable of performing life

functions.

Examples of Cells

Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

• Sizes of cells (Click)

Two Types of Cells

•Prokaryotic

•Eukaryotic

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

Structures/Organelles

Cell Membrane• Outer membrane of cell that controls movement

in and out of the cell• Double layer

Cell Wall

• Most commonly found in plant cells & bacteria• Supports & protects cells

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

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

Cytoplasm• Gel-like mixture filled with proteins

• Surrounded by cell membrane

Rough Endoplasmic Reticulum

• Moves materials around in cell

• ribosomes embedded in surface

• New proteins are twisted and folded

Smooth Endoplas-

mic Reticulum• No ribosomes• Synthesize lipids• Site for enzyme action• Storage of enzymes

Ribosomes

• Each cell contains thousands

• Make proteins

• Found on ER & floating throughout the cell

Mitochondria

• Produces energy

through chemical

reactions – breaking

down fats &

carbohydrates• Controls level of water

& other materials in cell• Recycles and

decomposes proteins,

fats, and carbohydrates

Golgi Bodies• Protein 'packaging plant'• Move materials within

the cell• Move materials out of the

cell

Cytoskeleton

• Composed of proteins

• Movement of vesicles

• Support for cell

• Cilia, flagellae, cell division

Lysosome• Digestive 'plant' for proteins,

fats, and carbohydrates• Transports undigested

material to cell membrane for removal

• Cell breaks down if lysosome explodes

Peroxisome

• Oxidative enzymes - catalase• Self- replicating• Do not form at Golgi Body• Rid body of toxins such as hydrogen peroxide

Vacuoles – vesicles

• Digestion

• Secretion

• Transport

• Water - vacuole

Vacuoles – in Plants

• Membrane-bound sacs for storage, digestion, and waste removal

• Contains water solution

• Help plants maintain shape

Chloroplast - Plant• Where

photosynthesis takes place

• Contains

chlorophyll• Found in

plants,

protists

Centrosome/Centrioles - Animal• Involved in cell division – formation of spindle

• Microtubule Organizing Center