LESSON-16
PROKARYOTIC CELL
A. Objectives
-
Describe the structure of the bacterial cell, with its chromosome, ribosome and
inclusions; discuss the site equivalent to the chloroplast and mitochondria of
eukaryotes; compare the bacterial flagellum to the eukaryotic kinetochore.
Describe and draw schematically the structure of peptidoglycan; compare concisely
gram—positive and gram—negative bacteria.
List differences between the prokaryotic and eukaryotic cell especially: size, presence
of organelles, organization of genetic material, ribosomes, flagella and cell wall.
Explain the origin of eukaryotes by symbiosis of prokaryotes and find evidence for this
in the comparison of the structure and function of cell organelles and the structure of the
prokaryotic cell.
B.
Lecture outline
1.
THE STRUCTURE OF THE PROKARYOTIC CELL.
Read:
Prokaryotes (SBM p512-517)
Prokaryotes and Eukaryotic cells (SBM p80-810
the protoplast
b. the cell wall: peptidoglycan
c. gram-positive and gram-negative bacteria
d. appendages: flagella, pili or fimbriae
a.
2.
COMPARISON BETWEEN THE PROKARYOTIC AND EUKARYOTIC CELL.
3.
SYMBIOSIS AND THE ORIGIN OF EUKARYOTES.
Read:
Eukaryotic cells descended from prokaryotic cells (SBM p453-454).
C. Study Questions.
1.
What cell organelles are present in both the eukaryotic and prokaryotic cell?
A. nucleus.
B. ribosomes.
C. undulipodia.
D. mitochondria.
E. Golgi complex.
2.
Peptidoglycan of the bacterial cell wall is made up of a polysaccharide backbone and side
chains of
A. amino acids.
B. sugars.
C. phospholipids.
D. lipid polysaccharide.
E. nucleotides.
3.
What macromolecule is typical for bacteria?
A. a closed, circular DNA molecule.
B. membrane phospholipids.
C. 1 ipopolysaccharide.
D. peptidoglycan.
E. NAD.
4.
Cells that have a wall composed of many layers of highly cross-linked peptidoglycan are
A. gram—negative bacteria.
B. animal cells.
C. plant cells.
D. yeasts.
E. gram—positive bacteria.
5.
The number of membranes surrounding a gram—negative bacterium is the same as that of a
A. centriole.
B. lysosome.
C. nucleus.
D. ribosomes.
E. Golgi complex.
6.
What is the major evidence that mitochondria and chloroplasts are derived from bacterial
endosymbionts?
A. Both mitochondria and chloroplasts contain energy.
B. Both organelles can be propagated separately in culture.
C. Mitochondria consume oxygen and chloroplasts produce oxygen.
D. Both organelles are surrounded by two membranes.
E. Both organelles contain a circular DNA molecule.
7.
The mean diameter of a bacterium is
A. 10-3 m.
B. 10-4 m.
C. 10-5 m.
D. 10-6 m.
E. 10-7 m.
8.
The bacterial flagellum contains
A.
B.
C.
D.
E.
9.
flagellin.
tubulin.
cytoplasm.
microtubules.
actin.
Microfilaments are found in
A.
bacteria.
B. animal cells.
C. plant cells.
D. animal and plant cells.
E. bacteria and plant and animal cells.
10. A plasma membrane is part of
A. bacteria.
B. animal cells.
C. plant cells.
D. animal and plant cells.
E. bacteria and plant and animal cells.
11. Chloroplasts are part of
A. bacteria.
B. animal cells.
C. plant cells.
D. animal and plant cells.
E. bacteria and plant and animal cells.
12. Peptidoglycan is present in
A. bacteria.
B. animal cells.
C. plant cells.
D. animal and plant cells.
E. bacteria and plant and animal cells.
13. Glycogen granules are present in
A. bacteria.
B. animal cells.
C. plant cells.
D. animal and plant cells.
E. bacteria and plant and animal cells.
14. The cytoskeletal subunit protein of the undulipodium is
A. vimentin.
B. flagellin.
C. tubuJ.in.
D. actin.
E. cholesterol.
15. The locomotive structure of bacteria is called
A. pillus.
B. cillium.
C. undulipodium.
D. fimbria.
E. flagellum.
16. The volume of a typical bacterium is about ____________ the volume of a typical
eukaryotic cell.
A. equal to
B. a half
C. a tenth
D. a hundredth
E. a thousandth
17. A chain of round bacteria would be called:
A.
B.
C.
D.
E.
spirilla.
diplococci.
bacilli.
streptococci.
streptobacilli.
18. Rod-shaped bacteria are called:
A. streptococci.
B. bacilli.
C. diplococci.
D. vibrio.
E. spirochete.
19. Even though bacteria lack membrane-bound organelles, such as chloroplasts and
mitochondria, they can still perform the functions of these organelles by localizing
certain metabolic enzymes on:
A. the nuclear membranes.
B. the endoplasmic reticulum.
C. the plasma membrane.
D. ribosomes.
E. the cell wall.
20, 21.
Use the figure to answer the
corresponding questions.
20. The structure in the accompanying figure
labeled C is:
A. a ribosome.
B. the plasma membrane.
C. the capsule.
D. the cell wall.
E. the flagellum.
21. What is the function of the structure labeled A in the accompanying figure?
A. to adhere to surfaces or other bacteria
B. to prevent phagocytosis
C.
D.
E.
support and protection in hypotonic conditions
transmission of DNA between bacteria
locomotion
22. Most bacterial cells keep from bursting in a hypotonic environment by:
A. an efficient water pump.
B. a tough cell membrane.
C. pumping large quantities of salts into the cell.
D. a rigid cell wall.
E. a stiff capsule.
23. Gram-positive bacteria would stain __________ in a gram stain because of a thick layer
of __________ in their cell walls.
A. green; peptidoglycan
B. purple; peptidoglycan
C. green; cellulose
D. purple; polysaccharides
E. red; polysaccharides
24. The walls of bacteria contain peptidoglycan, which is:
A. lipids crosslinked with sugars.
B. sugars crosslinked with proteins.
C. a protein.
D. a lipid.
E. a polysaccharide.
25. Penicillin works most effectively against gram-positive bacteria because:
A. penicillin affects cell membranes.
B. they have a thick peptidoglycan cell wall, and penicillin affects the synthesis of
peptidoglycans.
C. they have special protein channels that allow penicillin to enter the cell and halt the
cell cycle.
D. they are smaller than gram-negative bacteria and, thus, easily take up penicillin by
diffusion.
E. they contain prophages that negatively interact with penicillin.
26. Some bacteria avoid being phagocytized by a host’s immune system by means of:
A. efficient use of their flagella.
B. ameboid motion.
C. their capsule.
D.
E.
changing their cell wall structure.
eliminating the use of a membrane.
27. Small hairlike structures on the surface of bacteria are called:
A. capsids.
B. pili.
C. chromatids.
D. plasmids.
E. virons.
28. Pili are involved in adhesion of bacterial cells to a substrate or host, or in transmission of
__________ between bacteria.
A. ribosomes
B. cytoplasm
C. vectors
D. RNA
E. DNA
29. Bacteria:
A. are incapable of locomotion.
B. move by means of pili
C. move by means of cilia.
D. move by means of a rotating flagella.
E. move by means of a whiplike flagella.
30. Small circles of DNA called ______________ exist in addition to the bacterial
chromosome.
A. capsids
B. plasmids
C. chromatids
D. pili
E. centromeres
31. Plasmids of bacteria often have genes involved in:
A. reproduction.
B. motility.
C. viral resistance.
D. antibiotic resistance.
E. photosynthesis.
32. Prokaryotes have their genetic information stored in:
A. several small, circular pieces of DNA.
B.
C.
D.
E.
a single, small, circular piece of DNA.
a large, linear piece of DNA.
several small, linear pieces of DNA.
a large, circular piece of DNA.
33. The most common mode of reproduction in bacteria is:
A. binary fission.
B. transformation.
C. transduction.
D. conjugation.
E. mitosis.
34. _______________ is a form of genetic exchange in bacteria that involves contact
between two cells.
A. Transformation
B. Transduction
C. Conjugation
D. Binary fission
E. Budding
35. Which of the following statements concerning an F factor is FALSE?
A. It is found in recipient cells, not donor cells.
B. It is a DNA sequence.
C. It is found in F+ cells.
D. The F stands for fertility.
E. It is involved with forming sex pili.
36. _____________ are dormant structures formed by bacteria in response to adverse
environmental conditions.
A. Capsids
B. Endospores
C. Exotoxins
D. Endotoxins
E. Heterocysts
37. Which of the following statements concerning biofilms is FALSE?
A. They are formed by bacteria living in a watery environment.
B. They enable bacteria to attach to solid surfaces.
C. They are usually less than 2 μm thick.
D. An example is dental plaque.
E. They may develop on surgical implants.
38. Most bacteria are:
A. photoheterotrophs.
B. chemoheterotrophs.
C.
D.
E.
autotrophs.
heterotrophs.
chemoautotrophs.
39. A bacterium that gains nourishment from dead organisms is referred to as:
A. an autotroph.
B. a parasite.
C. a saprotroph.
D. a chemoautotroph.
E. a pathogen.
40. A(n) ___________________ bacterium would not be able to survive in the presence of
oxygen.
A. facultative aerobic
B. facultative anaerobic
C. facultative autotrophic
D. obligate aerobic
E. obligate anaerobic
41. Bacterial flagella
A. Are homologous with eukaryotic flagella
B. Exhibit a rotary motion
C. Consist of a basal body and nine pairs of microtubules
D. Are important in transduction
E. Are characteristics of gram-positive bacteria
42. In conjugation
A. Two bacterial cells of different mating types come together, and genetic material is
transferred from one to another
B. A bacterial cell develops a bulge that enlarges and eventually separates from the
mother cell
C. Fragments of DNA released by a broken cell are taken in by another bacterial cell
D. A phage carries bacterial genes from one bacterial cell to another
E. Walls develop in the cell, which then divide into six new cells
43. Endospores
A. Are formed by some viruses
B. Are extremely durable cells
C. Are comparable to the reproductive spores of fungi and plants
D. Cause fever and other symptoms of the host
E. Are extremely vulnerable to infection by phages
44. The majority of heterotrophic bacteria are
A. Free living chemoheterotrophs
B. Photoautotrophs
C. Chemoautotrophs
D.
E.
Facultative anaerobes
Obligate anaerobes
45. Which of the following do not belong to domain Archaea?
A. Prokaryotes that produce methane from carbon dioxide and hydrogen
B. Thermophiles
C. Halophiles
D. Bacteriophages
E. Prokaryotes with cell walls that lack peptidoglycan
46. Bacteria that thrive in puncture wounds are likely to be
A. Chemoautotrophs
B. Photoautotrophs
C. Chemoautotrophs
D. Endospores
E. Obligate anaerobes
47. Bacteria that are C-autotrophs
A. Do not require atmospheric oxygen for cellular respiration
B. Manufacture their own organic materials from simple raw materials
C. Must obtain organic compounds from other organisms
D. Get their nourishment from dead organisms
E. Produce endospores when oxygen levels are too low for active growth
48. Peptidoglycan is a macromolecule of the cell wall of
a. Viroids.
b. Archaea
c. Bacteria
d. Eukarya
e. Plants.