Transcript Chapter 17 PowerPoint

Chapter 17
Bacteria and Archaea
Dentist: ©BSIP/Phototake; Biofilm: ©Dennis Kunkel Microscopy, Inc./Phototake
Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.
What Are Prokaryotes?
A prokaryote is a singlecelled organism that lacks
a nucleus and membranebounded organelles.
Section 17.1
Bacteria: ©Kwangshin Kim/Science Source; Archaea: ©Ralph Robinson/Visuals Unlimited
Figure 17.1
What Are Prokaryotes?
Bacteria and archaea are
prokaryotes belonging to
distinct domains.
Section 17.1
Bacteria: ©Kwangshin Kim/Science Source; Archaea: ©Ralph Robinson/Visuals Unlimited
Figure 17.1
What Are Prokaryotes?
DNA sequences and
chemical composition
distinguish these domains.
Section 17.1
Bacteria: ©Kwangshin Kim/Science Source; Archaea: ©Ralph Robinson/Visuals Unlimited
Figure 17.1
What Are Prokaryotes?
The first cells were likely
prokaryotic. They have
thrived for billions of years.
Section 17.1
Bacteria: ©Kwangshin Kim/Science Source; Archaea: ©Ralph Robinson/Visuals Unlimited
Figure 17.1
Clicker Question #1
According to the evolutionary tree below, why might the
term “prokaryote” be controversial among scientists?
A. Prokaryotes are extinct.
B. Prokaryotes consist of a small portion of life’s diversity.
C. Prokaryotes consist of distantly related domains.
D. All of the above are true.
Flower: © Doug Sherman/Geofile/RF
Clicker Question #1
According to the evolutionary tree below, why might the
term “prokaryote” be controversial among scientists?
A. Prokaryotes are extinct.
B. Prokaryotes consist of a small portion of life’s diversity.
C. Prokaryotes consist of distantly related domains.
D. All of the above are true.
Flower: © Doug Sherman/Geofile/RF
17.1 Mastering Concepts
What are two domains that contain
prokaryotes?
Dentist: ©BSIP/Phototake; Biofilm: ©Dennis Kunkel Microscopy, Inc./Phototake
Comparing Bacteria and Archaea
Section 17.2
15.1
Figure 17.2
Comparing Bacteria and Archaea
The nucleoid is the region
where the DNA resides.
Section 17.2
Figure 17.3
Comparing Bacteria and Archaea
Plasmids are circles of DNA
apart from the chromosome.
Section 17.2
Figure 17.3
Comparing Bacteria and Archaea
Ribosomes use mRNA to
synthesize proteins.
Section 17.2
Figure 17.3
Comparing Bacteria and Archaea
A pilus is a hair-like
projection made of protein.
Pili enable cells to adhere to
objects.
Section 17.2
Figure 17.3
Comparing Bacteria and Archaea
A flagellum rotates like a
propeller, allowing
prokaryotes to move.
Section 17.2
Figure 17.3
Comparing Bacteria and Archaea
Flagella are used for taxis,
movement toward or away
from a stimulus.
Section 17.2
Figure 17.3
Comparing Bacteria and Archaea
The glycocalyx is a layer of
proteins or polysaccharides
surrounding the cell wall.
Section 17.2
The glycocalyx functions
include protection and
attachment.
Figure 17.3
Comparing Bacteria and Archaea
The cell wall gives the cell
its shape.
Section 17.2
Figure 17.3
Bacteria Cell Walls Are Multi-layered
Bacteria have two types of cell walls. Gram positive cells have a
thick peptidoglycan (a carbohydrate) layer.
Staining cells distinguishes bacteria based on cell wall type.
Section 17.2
Stained bacteria: ©Jack Bostrack/Visuals Unlimited
Figure 17.5
A Cell Wall Determines Cell Shape
The three most common
shapes are coccus (spherical),
bacillus (rod-shaped), and
spirillum (spiral).
Section 17.2
Coccus: © David M. Phillips/Visuals Unlimited; Bacillus: © SciMAT/Photo Researchers;
Spirillum: © Ed Reschke/Peter Arnold/Photolibrary
Figure 17.4
Endospores Keep Some Bacteria Alive
Some bacteria form thickwalled endospores that
survive harsh conditions.
Clostridium botulinum, the
cause of botulism, is one
example.
Section 17.2
15.1
Clostridium: ©Michael Abbey/Science Source
Figure 17.7
Scientists Classify Prokaryotes Based on
Metabolic Pathways
Prokaryotes obtain carbon and energy in many ways.
Section 17.2
15.1
Scientists Classify Prokaryotes Based on
Metabolic Pathways
Oxygen requirements are also important in classification.
Aerobic habitats house obligate aerobes and facultative
anaerobes; anaerobic habitats are home to obligate and
facultative anaerobes.
Section 17.2
15.1
Figure 17.8
Scientists Classify Prokaryotes Based on
Molecular Data
DNA sequences, such as those
that encode ribosomal RNA, are
important for distinguishing
archaea and bacteria.
Section 17.2
Bacteria: ©Kwangshin Kim/Science Source; Archaea: ©Ralph Robinson/Visuals Unlimited
Figure 17.1
Clicker Question #2
Bacteria, archaea, and eukaryotes all have
ribosomes, but ribosome structure slightly
varies between these groups. What is the
best explanation for this observation?
A. The common ancestor of these three domains
had ribosomes; slight changes have accumulated
since the lineages split.
B. Ribosomes arose independently in all three
groups.
Flower: © Doug Sherman/Geofile/RF
Clicker Question #2
Bacteria, archaea, and eukaryotes all have
ribosomes, but ribosome structure slightly
varies between these groups. What is the
best explanation for this observation?
A. The common ancestor of these three domains
had ribosomes; slight changes have accumulated
since the lineages split.
B. Ribosomes arose independently in all three
groups.
Flower: © Doug Sherman/Geofile/RF
Prokaryotes Transmit DNA Vertically
and Horizontally
Vertical gene transfer
Section 17.2
Horizontal gene transfer
Figure 17.9
Prokaryotes Transmit DNA Vertically
and Horizontally
Vertical gene transfer
Vertical gene transfer is also
called binary fission. It is an
asexual process that
replicates DNA and
distributes it to two cells.
Section 17.2
Prokaryotes Transmit DNA Vertically
and Horizontally
Horizontal gene transfer
In horizontal gene transfer,
a cell receives DNA from a
cell that is not its ancestor.
This occurs in three ways.
Section 17.2
Figure 17.9
Prokaryotes Transmit DNA Vertically
and Horizontally
Horizontal gene transfer: Transformation
Section 17.2
Figure 17.9
Prokaryotes Transmit DNA Vertically
and Horizontally
Horizontal gene transfer: Transduction
Section 17.2
Figure 17.9
Prokaryotes Transmit DNA Vertically
and Horizontally
Horizontal gene transfer: Conjugation
Section 17.2
Figure 17.9
Clicker Question #3
What type of horizontal gene transfer relies
on direct contact between two bacteria?
A. Transduction
B. Transformation
C. Conjugation
D. Binary fission
Flower: © Doug Sherman/Geofile/RF
Clicker Question #3
What type of horizontal gene transfer relies
on direct contact between two bacteria?
A. Transduction
B. Transformation
C. Conjugation
D. Binary fission
Flower: © Doug Sherman/Geofile/RF
17.2 Mastering Concepts
Distinguish between vertical and horizontal
gene transfer.
Dentist: ©BSIP/Phototake; Biofilm: ©Dennis Kunkel Microscopy, Inc./Phototake
The Diversity of Domain Bacteria
Proteobacteria
Proteobacteria (left image)
form one phylum of bacteria;
their metabolic pathways and
habitats are diverse.
Section 17.3
15.1
Bacteria: ©Dr Gopal Murti/Science Source; Anabaena: ©John Walsh/Science Source
Figure 17.10
The Diversity of Domain Bacteria
Proteobacteria
E. coli and Salmonella are
types of proteobacteria.
Section 17.3
Bacteria: ©Dr Gopal Murti/Science Source; Anabaena: ©John Walsh/Science Source
Figure 17.10
The Diversity of Domain Bacteria
Proteobacteria
Cyanobacteria
Cyanobacteria (right image)
form another phylum of
bacteria. These autotrophs
were the first to release
oxygen gas as a byproduct of
photosynthesis.
Section 17.3
Bacteria: ©Dr Gopal Murti/Science Source; Anabaena: ©John Walsh/Science Source
Figure 17.10
The Diversity of Domain Bacteria
Proteobacteria
Cyanobacteria
Other phyla of bacteria
include Spirochaetes,
Firmicutes, actinobacteria,
and Chlamydiae.
Section 17.3
Bacteria: ©Dr Gopal Murti/Science Source; Anabaena: ©John Walsh/Science Source
Figure 17.10
The Diversity of Domain Archaea
Domain Archaea are often
collectively called
extremophiles, since this
domain was first discovered
in extreme habitats.
Archaea often live in places
that lack oxygen or that are
extremely hot, salty, or
acidic.
But some live in moderate
environments.
Section 17.3
Archaea habitat: ©Ralph Eagle Jr./Science Source; Inset: ©Eye of Science/Science Source
Figure 17.11
The Diversity of Domain Archaea
Archaea are essential in
geochemical cycles on land
and in water.
Scientists are only beginning
to organize Domain Archaea
into phyla.
• Euryarchaeota
• Crenarchaeota
• Korarchaeota
Section 17.3
Archaea habitat: ©Ralph Eagle Jr./Science Source; Inset: ©Eye of Science/Science Source
Figure 17.11
Clicker Question #4
Where (approximately) would you expect to
find Salmonella on the evolutionary tree
below?
D
A
Flower: © Doug Sherman/Geofile/RF
B
C
Clicker Question #4
Where (approximately) would you expect to
find Salmonella on the evolutionary tree
below?
D
A
Flower: © Doug Sherman/Geofile/RF
B
C
Prokaryotes Are Essential to Life
Prokaryotes in root nodules
of some plants carry out
nitrogen fixation, an
essential process in which
atmospheric nitrogen (N2) is
converted to ammonia.
Only a few species of
bacteria and archaea can use
N2. Without nitrogen
fixation, most nitrogen
would be locked in the
atmosphere.
Section 17.4
Rhizobium: ©Dr. John D. Cunningham/Visuals Unlimited; Root nodule cross section: ©Science VU/Visuals Unlimited
Figure 17.12
Prokaryotes Are Essential to Life
Harmless bacteria in our
bodies help crowd out
pathogenic bacteria.
Section 17.4
Figure 17.13
Prokaryotes Are Essential to Life
Salmonella is in
undercooked eggs.
Harmful bacteria might be
ingested or inhaled, or they
enter the body through
wounds or orifices.
Section 17.4
Raw egg: ©Ingram Publishing RF
Prokaryotes Are Essential to Life
When we take antibiotics,
some of our resident microbes
die, sometimes leading to
secondary infections.
Section 17.4
15.1
Pill: ©Rick Gomez/Corbis RF
Prokaryotes Are Essential to Life
Prokaryotes also help make food and drugs. In wastewater
treatment plants, microbes help break down organic matter.
Section 17.4
15.1
Making cheese: ©Joe Munroe/Science Source; Humulin: ©David Wrobel/Visuals Unlimited ; Filter process: ©Jonathan A.
Meyers/Science Source
Figure 17.14
Prokaryotes Are Everywhere
This image shows
a tiny sampling
of the diversity of
prokaryotes
(bacteria, in this
case) found at a
park.
Section 17.4
15.1
Figure 17.17
Clicker Question #5
Are the prokaryotes that typically reside
inside of us useful?
A. No, we would be in better health without
these microbes.
B. Yes, they help crowd out harmful
prokaryotes.
Flower: © Doug Sherman/Geofile/RF
Clicker Question #5
Are the prokaryotes that typically reside
inside of us useful?
A. No, we would be in better health without
these microbes.
B. Yes, they help crowd out harmful
prokaryotes
Flower: © Doug Sherman/Geofile/RF
17.5 Mastering Concepts
In what ways are bacteria and archaea
important to eukaryotic life in general and to
human life in particular?
Dentist: ©BSIP/Phototake; Biofilm: ©Dennis Kunkel Microscopy, Inc./Phototake
Investigating Life: A
Bacterial Genome Solves
Two Mysteries
Scientists used bacterial
DNA to determine the
origins of antibiotic
resistant bacteria (MRSA).
Their results indicate that
antibiotic resistance has
evolved independently
several times.
Section 17.5
Figure 17.15
Investigating Life: A
Bacterial Genome Solves
Two Mysteries
They also determined
that bacteria that cause
toxic shock syndrome
have several separate
origins.
Section 17.5
Figure 17.15
Investigating Life: A
Bacterial Genome Solves
Two Mysteries
Researching bacteria
evolution helps to
prevent the spread of
disease.
Section 17.5
Figure 17.16