Transcript The scientist is not a person who gives the right answers, he`s one

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Covers Chapter 4
Structure and Function of
the Cell
Pages 68 - 91
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* Scientists have studied the cells of over 2 million
different species
* But, scientists estimate there are over 40 million species
on Earth!
*After studying so many species, scientists observed
that although cell size, shape and function is very
diverse, all cells have some
similarities.
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*All cells are surrounded by a protective layer
*Known as a cell membrane
*Def. – thin layer that forms the outer boundary of the cell
*Protects cell by being selectively permeable
*Def. – only allows certain substances into the cell
*All cells contain cytoplasm
*Cytoplasm – anything that is inside the cell (except
nucleus), includes cytosol
*Cytosol – gelatin-like fluid inside the cell
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*All cells contain genetic material (DNA)
*How DNA is stored is how scientists classify the type of cell
* Prokaryotic cell – DNA not contained
* Eukaryotic cell – DNA contained in a nucleus
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*All cells contain internal cellular structures known as
organelles
*The kinds of organelles they contain is how scientists
classify the type of cell
*Prokaryotic cells do not contain organelles that are
surrounded by a membrane
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Prokaryote
Genetic
Information
(DNA)
Eukaryote
• Clumped, not
contained in an
organelle
• Single chromosome
• DNA stored in nucleus
• Chromosomes usually
come in pairs
Nucleus
• No nucleus
• Has a nucleoid region
• Has a nucleus
Organelles
• Only has organelles
WITHOUT membranes
• Contains organelles with
and without membranes
• Membrane is same
material as cell
membrane
Examples
• Bacteria
• Protist, Fungus, Plant,
Animals
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* Covers Chapter 18, Classification
*Pages 336 – 353
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* Every year, scientists discover thousands
of new species.
* By examining the organisms’ cells, structure,
habitat, feeding patterns, etc., the organisms
are grouped into different categories
* TAXONOMY – science of grouping
organisms according to their
characteristics and evolutionary
history
*Early Taxonomy
*Classified organisms according to where they lived, internal
structures, external structures
*Organisms were given common names
*Could incorrectly describe the organism
*Same organism could have different name around the world
* Today, we use many techniques and information to classify organisms.
Some examples:
*Morphology
*Def. – study of internal and external structures
*Examples: type of cell, type of organelles, type and
arrangement of tissues and organs, etc.
*Phylogeny
*Def. – evolutionary history of a species, tries to group
similar species together
*Fossil record
*Provides clues about the evolution of the species
*Embryo development
*Protein structure
*DNA sequence
*Number of chromosomes
*Once species are classified, scientist can use the information
to study relationships between similar species
*Phylogenetic Tree
*Also known as evolutionary tree
*Def. – “Family Tree” showing evolutionary
relationship between various species
*Changes as new information is discovered
*Cladogram
*Diagram showing the order that new features evolved in
various species
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*Based on the classification and naming system
devised in the 1700s by Carolus Linnaeus (1707 – 1778)
*Levels of Classification – Each category gets more specific
*Domain
*Kingdom
*Phylum
*Class
*Order
*Family
*Genus
*Species
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* Binomial nomenclature – Scientific naming system
* Linnaeus’ classification gave every organism a scientific name
* The scientific name has 2 parts
1. Genus
2. species identifier
* Genus name is always capitalized
* species name is never capitalized
* Homo sapiens
* Scientific name must be either:
* Underlined : Homo sapiens
OR
Italicized: Homo sapiens
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* 3 Domains
* Domain Archaea
* Kingdom Archaebacteria
* Domain Bacteria
* Kingdom Eubacteria
* Domain Eukarya
* Includes all eukaryotic
organisms
* Kingdom Protista
* Kingdom Fungi
* Kingdom Plantae
* Kingdom Animalia
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