Bacteria

1
Bacteria

• Section 191
• This section describes two groups of prokaryotes
  and explains how they differ. It also explains
  what factors are used to identify prokaryotes.

2
Introduction

• What are prokaryotes?
• They are single-celled organisms that lack a
  nucleus.

3
Introduction

• Is the following sentence true or false?
• Prokaryotes are much smaller that most Eukaryote
  cells.
• true

4
Classifying Prokaryotes

• What are the two different groups of prokaryotes?
  
• Eubacteria
• Archaebacteria

5
Classifying Prokaryotes

• Which is the larger of the two kingdoms of
  prokaryotes?
• Eubacteria

6
Classifying Prokaryotes

• Where do eubacteria live?
• They live almost everywhereincluding in water,
  on land, and on and within the human body .

7
Classifying Prokaryotes

• What protects a prokaryotic cell from injury?
• The cell wall protects it.

8
Classifying Prokaryotes

• Circle the letter of what is within the cell wall
  of a prokaryote.
• cell membrane

9
Classifying Prokaryotes

• What is peptidoglycan?
• It is a carbohydrate in the cell walls of
  eubacteria.

10
Classifying Prokaryotes

• Some eubacteria have a second_____ outside the
  cell membrane.
• membrane

11
Classifying Prokaryotes

• Circle the letter of each sentence that is true
  about archaebacteria.
• Their membrane lipids are different from those of
  eubacteria.
• They lack peptidoglycan.
• They look very similar to eubacteria.

12
Classifying Prokaryotes

• What is significant about the DNA sequences of
  key archaebacterial genes?
• They are more like those of eukaryotes than those
  of eubacteria.

13
Classifying Prokaryotes

• How are archaebacteria related to eukaryotes?
• Scientist reason that archaebacteria may be the
  ancestors of eukaryotes.

14
Chapter 19, Bacteria and Viruses

• What are methanogens, and where do they live?
• They are prokaryotes that produce methane gas.
  They live in oxygen-free environments, such as
  thick mud and the digestive tracts of animals.

15
Identifying Prokaryotes

• Complete the illustration of a typical prokaryote
  by labeling the parts.

16
Identifying Prokaryotes

• What are four characteristics used to identify
  prokaryotes?
• Their shape
• The chemical nature of their cell walls
• The way they move
• The way they obtain energy

17
Identifying Prokaryotes

• What are each of the differently shaped
  prokaryotes called?
• The rod-shaped are called
• bacilli
• The spherical-shaped are called cocci
• The corkscrew shaped are called spirilla

18
Identifying Prokaryotes

• A method of telling two different types of
  eubacteria apart by using dyes is called_____.
• Gram staining

19
Identifying Prokaryotes

• What colors are Gram-positive and Gram-negative
  bacteria under the microscope when treated with
  gram stain____?
• Gram-positive bacteria appear violet, and
  Gram-negative bacteria appear red.

20
Identifying Prokaryotes

• What are flagella?
• They are whiplike structures used for movement.

21
Identifying Prokaryotes

• Is the following sentence true or false? Some
  prokaryotes do not move at all.
• true

22
Metabolic Diversity
Complete the table about prokaryotes classified
by the way they obtain energy.
23
Metabolic Diversity

• Members of which group of photoautotrophs contain
  a bluish pigment and chlorophyll a?
• Cyanobacteria

24
Metabolic Diversity

• How do the chemoautotrophs that live near
  hydrothermal vents on the ocean floor obtain
  energy?
• They obtain energy from hydrogen sulfide gas that
  flows from the vents.

25
Complete the table about prokaryotes classified
by the way they release energy.
26
Metabolic Diversity

• Facultative anaerobes can switch between cellular
  respiration and____.
• fermentation

27
Growth and Reproduction

• What occurs in the process of binary fission?
• It is a type of asexual reproduction in which a
  prokaryote grows to nearly double its size,
  replicates its DNA, and divides in half,
  producing two identical daughter cells.

28
Growth and Reproduction

• What happens during conjugation?
• A hollow bridge forms between two cells, and
  genes move from one cell to the other.

29
Growth and Reproduction

• Is the following sentence true or false?
• Most prokaryotes reproduce by conjugation.
• false

30
Bacteria and Viruses

• What is an endospore?
• It is a type of spore that is formed when a
  bacterium produces a thick internal wall that
  encloses its DNA and a portion of its cytoplasm.

31
Importance of Bacteria

• How do decomposers help the ecosystem recycle
  nutrients when a tree dies?
• Armies of bacteria attack and digest the dead
  tissue. The bacteria break down dead matter into
  simpler materials, which are released into the
  soil.

32
Importance of Bacteria

• What would happen to plants and animals if
  decomposers did not recycle nutrients?
• Plants would drain the soil of minerals and die,
  and animals that depend on plants for food would
  starve.

33
Importance of Bacteria

• Why do plants and animals need nitrogen?
• They need nitrogen to make amino acids, which are
  the building blocks of proteins.

34
Importance of Bacteria

• How does nitrogen fixation help plants?
• Plants use the nitrogen to build amino acids.

35
Importance of Bacteria

• What kind of relationship do many plants have
  with nitrogen-fixing bacteria?
• They have symbiotic relationships.

36
Importance of Bacteria

• How can bacteria be used to clean up an oil
  spill?
• One type of bacterium can digest petroleum.

37
Importance of Bacteria

• What have biotechnology companies begun to
  realize about bacteria adapted to extreme
  environments? ______
• Those bacteria may be a rich source of
  heat-stable enzymes, which can be used in
  medicine, food production, and industrial
  chemistry.