INTRODUCTION TO CELLS

Robert Hooke

naturalist, philosopher, inventor, architect....(July 18, 1635 - March 3, 1703)

He was the first person to use the term “cells”.

Anton van Leeuwenhoek 1632-1723

perfected the simple microscope

He discovered bacteria in 1674 and four years later, he discovers protozoa.

Matthias Schleiden

all plants are made of cells

Cell Theory

Cell Theory

Theodore Schwann

all animals are made of cells

Rudolf Virchow

all cells came from pre-existing cells

Cell Theory

Cell Theory

• all living things are made up of cells• cells are the basic units of structure and function in

an organism• new cells are produced from existing cells

Matthias Schleiden

concluded that all plants are made of

cells (1838)

Theodore Schwann

concluded that all animals are made

of cells (1839)

Rudolf Virchowconcluded that all cells came from pre-existing cells

(1855)

Cell Specialization

Cells in organisms are specialized to perform different tasks.

Photos from Biology, Prentice Hall

Multicellular organisms are arranged from simple to complex according to their level of cellular grouping.

cell tissue

organ organ system

organism

The Levels of Organization

Simple Complex

Level Function Example

What is the benefit of being made of all of these cells?

Nervous System

Brain

Nervous Tissue

Neuron

Levels of Organization

Organ system

Organ

Tissues

Cells

Different organs function together

Different tissues function together

Similar cells function together

Cells can perform special jobs

Cell TypesPROKARYOTE No membrane-bound

organelles (nucleus) Small ribosomes Most cells are 1 -10

μm in size Evolved 3.5 billion

years ago Found only in

Archaebacteria and Eubacteria Kingdoms

EUKARYOTE Has membrane-

bound organelles (nucleus)

Larger ribosomes Cells can be between

2 - 1,000 μm in size Evolved 1.5 billion

years ago Includes Protista,

Fungi, Plantae and Animalia KingdomsA unit of length equal to one

thousandth (10-3) of a millimeter

Cell Type: ProkaryotesProkaryotes, which includes all bacteria,

are the simplest cellular organisms. They have genetic material but no nucleus.

Typical bacteria cell

Cell Types: EukaryotesEukaryotic cells

contain a membrane-bound nucleus and numerous membrane -enclosed organelles (e.g., mitochondria, lysosomes, Golgi apparatus) not found in prokaryotes.

Examples of Eukaryotes

Different Types of CellsProkaryotic Eukaryotic

no nucleus

protists, fungi, plants, animals

only in bacteria

small

small ribosomeslarger ribosomes

very small

organellesno organelles

nucleusno nucleus

small ribosomes

organellesno organelles

nucleus

protists, fungi, plants, animals

only in bacteria

small 2-1000umvery small 1-10um

larger ribosomes

What Are the Parts of Cells

Both prokaryotic and eukaryotic cells have some things in common.

All cells have¤ cell membrane ¤ cytoplasm¤ ribosomes¤ nuclear material

cytoplasmribosomesnuclear materialcell membrane

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel Lipid bilayer

Carbohydratechains

Section 7-3

Figure 7-12 The Structure of the Cell Membrane

PHOSPHOLIPID BILAYER

Prokaryotes Eukaryotes

Cell membraneContain DNA

NucleusEndoplasmic reticulum

Golgi apparatusLysosomesVacuoles

MitochondriaCytoskeleton

Animal Cells Plant Cells

Centrioles

Cell membraneRibosomes

NucleusEndoplasmic reticulum

Golgi apparatusLysosomesVacuoles

MitochondriaCytoskeleton

Cell WallChloroplasts

Section 7-2

Venn Diagrams

Animal Cell

Centrioles

NucleolusNucleus

Nuclearenvelope

Rough endoplasmic reticulum

Golgi apparatus

Smooth endoplasmicreticulum

Mitochondrion

CellMembrane

Ribosome(free)

Ribosome(attached)

Section 7-2

Figure 7-5 Plant and Animal Cells

Plant Cell

Nuclearenvelope

Ribosome(attached)

Ribosome(free)

Smooth endoplasmicreticulum

Nucleus

Rough endoplasmic reticulum

Nucleolus

Golgi apparatus

Mitochondrion

Cell wall

CellMembrane

Chloroplast

Vacuole

Section 7-2

Figure 7-5 Plant and Animal Cells

cytoplasm

nucleus

cell membrane

chloroplast

vacuole

mitochondria

cell wall

ribosomes

Parts of a plant cellcytoplasm: semi-liquid material that fills the cell

(p. 175)

nucleus: controls most cell processes, contains hereditary information (DNA)

chloroplast: capture energy from sunlight and convert it into chemical energy (food), (photosynthesis occurs here)

vacuole: sac-like structure that stores water, salts, foods, etc

ribosomes: manufacture proteinsmitochondria: convert chemical energy stored in food into ATP (cellular respiration occurs here)

cell membrane: regulates what enters and leaves the cell, protection and support

cell wall: outer layer in plant cells, support and protection

endoplasmicreticulum

golgi complex

endoplasmic reticulum:transportation system throughout the cell

Golgi complex: packages proteins

cytoplasm

nucleus

cell membrane

chloroplast

vacuole

mitochondria

cell wall

ribosomes

(p. 175)

Plant Cell

endoplasmicreticulum

golgi complex

Cell Membrane

Mitochondria

Chloroplast

Endoplasmic Reticulum

Nucleus

Lysosome

Golgi Body

Vacuole

Ribosome

Cell Wall

Cell Organelles

Animal Plant

Cell Video Q’s

How did they grow the little girl’s skin?Can an organism live with only one cell?Why did Hooke call the objects he viewed with

microscope cells?If all plants are made of cells, why do you

think they vary in size and appearance?