Download Protists

Viruses
Is a Virus
?
• All living things are made of cells, are able to
grow and
, and are guided by
information stored in their
•
are segments of nucleic acids
contained in a protein coat. Viruses are not cells.
• Viruses are
disease.
—agents that cause
• Viruses do not grow, do not have homeostasis,
and do not
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Viruses
Viral Structure
• The virus protein coat, or
either RNA or DNA, but not both.
, may contain
• Many viruses have a membrane, or
surrounding the capsid.
,
• The envelope helps the virus enter cells. It consists of
proteins, lipids, and
, which are
proteins with attached carbohydrate molecules that
are derived from the host cell.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Viruses
Viral Reproduction
• Viruses must rely on living cells (
for replication.
• Before a virus can
infect a living cell.
)
, it must first
• An animal virus enters its host cell by
• A bacterial virus, or bacteriophage, punches a hole in
the bacterial cell wall and injects its
into the
cell.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Viruses
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Viruses
Important Viral Diseases – like
(vaccinations can help prevent some)
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Bacterial Structure
• Bacteria differ from
in at least seven ways.
• Bacteria are prokaryotes. Unlike eukaryotes,
prokaryotes lack a cell nucleus.
• Most bacterial cells are about 1 µm in diameter; most
eukaryotic cells are more than
times that size.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Bacterial Structure, continued
• All bacteria are
• Bacterial chromosomes consist of a single
circular piece of
. Eukaryotic chromosomes
are linear pieces of DNA that are associated with
proteins.
• Bacteria reproduce by
, a process
in which one cell pinches into two cells.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Bacterial Structure, continued
• Bacteria have many metabolic abilities that
eukaryotes lack. For example, bacteria perform
several different kinds of
and
aerobic processes, while
are
mostly aerobic organisms.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Bacterial Cell Shapes
• A bacterial cell is usually one of three basic
shapes:
, a rod-shaped cell;
, a round-shaped cell; or
, a spiral
cell.
• Members of the kingdom Eubacteria have a
made of peptidoglycan, a network of polysaccharide
molecules linked together with chains of
• Outside the cell wall and membrane, many
bacteria have a gel-like layer called a
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Bacterial Cell Shapes, continued
• Eubacteria can have two types of cell walls,
distinguished by a dye staining technique called the
•
Positive = purple, negative = pink.
• Gram staining is important in medicine because the
two groups of eubacteria differ in their susceptibility
to different
• Antibiotics are chemicals that interfere with life
processes in
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Important Bacterial Diseases – (
Chapter menu
)
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Bacteria
Importance of Bacteria
Food and
Production
• Many of the foods that we eat, such as pickles,
cheese, sauerkraut, olives, vinegar, and sourdough
bread, are processed by specific kinds of
• Humans are able to use different bacteria to produce
different kinds of chemicals for
uses.
• Genetic engineering companies use genetically
engineered bacteria to produce their many products,
such as drugs for medicine and complex chemicals
for
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Characteristics of Protists
Diversity
Characteristics
• The kingdom
consists of an
unusually diverse assortment of eukaryotes
that exhibit a broad array of characteristics.
• Some protists are photosynthetic (like plants),
some ingest food (like animals), and some absorb
their
• Protists are found almost everywhere there is
water. Many live in lakes and oceans, floating as
plankton or anchored to rocks. There are about
•
protista species
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Characteristics of Protists
Protist – algae
• Classified in
phyla based on color. Some
cause red tide. Some are microscopic, some
large seaweed.
• Diatoms =
Spirogyra =
Volvox =
•
have flagella
& spiral shaped
, green algae
– moves like a little animal, but
has chlorophyll like a plant, has sexual & asexual
reproduction
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Protist Diversity
Structure of Euglena – has chlorophyll,
moves like an
, also eats other things
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Characteristics of Protists
Diversity, continued
What Unites Protists?
• The kingdom Protista contains all
that
cannot be classified as animals, plants, or fungi.
• The major phyla of protists are very different from
one another and, with a few exceptions, are only
distantly
• Historically, scientists have referred to heterotrophic
protists as protozoa and to photosynthetic protists as
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Protozoa
•
•
•
•
•
•
Protozoa means first animals. They are
Some are free living and some
Most are heterotrophic.
The respond using
and eyespots.
Some are classified according to
Some cause malaria, african sleeping sickness,
dysentary (caused by amoeba – protist, moves by
)
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Protist Diversity
Ameboid Movement
• Amoebas, members of the phylum Rhizopoda,
are protists that move by using flexible,
• These extensions are called
from
the Greek words pseudo, meaning “false,”
and podium, meaning “foot.”
• During
movement, a
pseudopodium bulges from the cell surface,
stretches outward, and anchors itself to a nearby
surface.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Protist Diversity
Paramecium (reproduce by
has cilia – eat smaller organisms
Chapter menu
)
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Protists and Health
Diseases Caused by
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Protists and Health
Protists and Humans, continued
Beneficial Protists
• Cattle could not digest the cellulose in the hay and
grass they eat without the aid of
in their digestive tract.
• Protists are also the single largest group of
•
on the planet.
• Many protists are also detritivores, so they help
recycle important chemicals, such as nitrogen,
carbon, and phosphorus, in the
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Kingdom
•
•
•
•
•
•
Single celled or many celled
Not
Many are
(break down dead things)
Reproduce sexually or asexually (some both ways)
Ex.: mushrooms,
Used for making blue cheese, beer, wine, bread,
penicilin
• Some cause diseases like athlete’s foot,
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.