INTRODUCTION TO CELLS

Life is cellular

Robert Hooke

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

In 1665 he is the first person to use the term “cells” after looking at cork under a simple microscope.

Anton van Leeuwenhoek 1632-1723

In 1673 he perfects the simple microscope and is the first to observe living cells and microorganisms.

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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)

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

Cell differentiation

Cells in organisms are specialized to perform different tasks. Cells are basic units of structure and function of living things.

Cell TypesPROKARYOTE No nucleus No membrane-bound

organelles 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 nucleus Many organelles Larger ribosomes Cells can be between

2 - 1,000 μm in size Evolved 1.5 billion

years ago Includes Protista,

Fungi, Plantae and Animalia Kingdoms

Cell Type: ProkaryotesProkaryotes, which includes all bacteria,

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

Typical bacteria cell

Shapes of bacteria

Cell Types: EukaryotesEukaryotic cells

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

Which Cell?Prokaryotic 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 2-1000μmvery small 1-10 μm

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¤ Genetic material

cytoplasmribosomesnuclear materialcell membrane

cytoplasm

nucleus

cell membrane

chloroplast

central vacuole

mitochondria

cell wall

ribosomes

Parts of Plant Cellscytoplasm: 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

golgi body

Endoplasmic reticulum

Parts of Animal Cells

cell membrane

mitochondria

ribosome

Golgi apparatus

nucleus

cytoplasm

Endoplasmic reticulum

lysosome

Golgi apparatus: modifies, sorts and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell

Endoplasmic reticulum: site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell

lysosome: digests biomolecules into smaller molecules that can be used by the rest of the cell; also involved in breaking down organelles that have outlived their usefulness

Cell Membrane

Mitochondria

Chloroplast

Endoplasmic Reticulum

Nucleus

Lysosome

Golgi Body

Central Vacuole

Ribosome

Cell Wall

Comparison

Animal Plant

How small are cells?