Ch 4

Question 1

1. What are the common characteristics of all living things (single and multicellular)?
2. What are the 2 basic cell types?
3. What types of organisms comprise each cell type?
4. What are the differences between the 2 cell types in the following criteria:
   a. Types of organism
   b. specialization
   c. size
   d. nucleus
   e. organelles
   f. DNA
   g. cell wall
   h. internal membranes
   i. ATP synthesis.

Answer 1

1. All have: Basic shape (spherical, cubical, cylindrical), Internal content (cytoplasm, surrounded by a membrane), DNA (chromosome(s), ribosomes), and metabolic capabilities
2. Eukaryotic and prokaryotic
3. Eukaryote: animals, plants, fungi, and protists.
   Prokaryote: bacteria and archaea
4. a. Type of organism: eukaryote: complex organisms, plants and animals.
   prokaryote: simple organisms bacteria and cyanobacteria

b. Specialization: eukaryote: specialize to carry out functions. Group together to make organs and organisms. Prokaryote: usually exist as single identical cells.
c. Size: eukaryote: animals: 10-30 micrometers across. Plants: 10-100 micrometers. Prokaryotes: 1-10 micrometers across.
d. Nucleus: eukaryotes: contain nucleus. Prokaryotes: lack nucleus.

e. Organells: eukaryotes: yes
prokaryotes: no

f. DNA: eukaryotes: DNA wrapped around histones. Prokaryotes: no histones
g. Cell wall: eukaryotes: present in plant cell, but no muramic acid. Prokaryote: present, contain muramic acid
h. Internal Membranes: Eukaryote: complex. Encases organelles. Prokaryote: very simple or not present at all.
i. ATP Synthesis: Eukaryote: found on inner-membrane of organells, mitochondria and chloroplasts. Prokaryote: localized on cell membrane

Question 2

1. what are the 6 characteristics of life?

Answer 2

1. • Reproduction and heredity of genome
     - growth and development
     - metabolism
     - movement and response to stimuli
     - cell support (storage/protection)
     - transport of nutrients.

Question 3

1. Name the 12 common structures of bacterial cells

Answer 3

1. capsule, cell membrane, cell wall, ribosomes, fimbriae, glycocalyx, actin filaments, chromosomes (DNA), pilus, inclusion bodies, flagellum, and cytoplasmic matrix.

Question 4

1. • 4. Name and describe the 4 types of flagellar arrangements:
2. • 8. Name and describe the 4 flagellar responses:

Answer 4

1. Monotrichous: single flagella at one end.
2. Lophotrichous: small bunches of flagella emerging from same site.
3. Amphitrichous: flagella at both ends of cell
4. Peritrichous: flagella dispersed all over cell’s surface
5. positive and negative chemotaxis: guide bacteria toward or away from chemical stimulus
6. positive and negative phototaxis: guide bacteria toward or away from light stimuli
7. Run: counterclockwise motion that sends bacterium in a straight smooth line.
8. Tumble: clockwise motion that causes bacterium to roll

Question 5

1. What are fimbriae, and what is their function?
2. What are Pili, and where are they found?
3. What is a glycocalyx?
4. What are the 3 functions of the glycocalyx?
5. What is the cell envelope?
6. What are the 2 functions of the cell wall, and what is its primary component?

Answer 5

1. Fine, proteinaceous, hairlike bristles emerging from the cell surface that function in adhesion to surfaces and other cells
2. tubular structure found in G- bacteria for conjugation.
3. Coating of molecules on external surface of cell made of sugars and/or proteins. Slime layer or capsule are the 2 types
4. protection from dehydration and nutrient loss, inhibits phagocytosis, formation of biofilms
5. external covering comprised of cell wall and cell membrane
6. determines cell shape, and prevents lysis by osmotic changes. Made of peptidoglycan.

Question 6

1. What is G+ and what are its characteristics?
2. What is G- and its characteristics?
3. is G+ or G- more permeable to molecules? Which has a more extensive periplasmic space?
4. What is a Gram-stain, and what are the results?
5. Do some bacteria have nontypical cell walls, or no cell wall at all? If so, which ones?

Answer 6

1. bacterial cell wall characterized by thick peptidoglycan, contain teichoic acid and lipoteichoic acid, and 1 layer of periplasmic space between the cell wall and the cell membrane.
2. A cell wall that has outer and inner cell membranes sandwiching a thin layer of peptidoglycan. It has two periplasmic spaces. Outer layer has lipopolysaccharides that become an endotoxin during infection. Also has porins to let molecules enter and leave cell.
3. G+ is more permeable, G- more periplasmic space.
4. A lab test to aid in diagnosing infection and guiding drug treatment. Differentiates btw G+ and G- bacterial types. G+ retains crystal violet, and G- loses crystal violet and stains red with safranin counterstain.
5. Mycobacteria and Nocardia have atypical cell walls, but are considered G+, and have mycolic acid. Mycoplasma has no cell wall, and is stabilized by sterols. It is pleomorphic.

Question 7

1. Describe the structure of the cell membrane.
2. What is the function of the cell membrane?
3. Is the cell membrane selectively permeable?

Answer 7

1. Known as the fluid mosaic model. Its a phospholipid bilayer with embedded proteins
2. site for energy reactions, nutrient processing, and synthesis. Passage of nutrients into the cell and discharge of wastes
3. yes.

Question 8

1. What is the nucleoid?
2. Describe a bacterial chromosome:
3. Describe a plasmid

Answer 8

1. It is the bacterial cell’s nucleus which contains chromosomes and plasmids.
2. Single, circular, double-stranded DNA molecule that contains all the cell’s genetic information.
3. Free small circular, double-stranded DNA that are not essential to bacterial growth and metabolism. Used in genetic engineering - readily manipulated and transferred from cell to cell

Question 9

1. Bacterial ribosomes are made of 60% ……… and 40% ………… .
2. Consist of ….. subunits

Answer 9

1. Ribosomal RNA, and protein

2. 2 subunits large 50s and small 30s (equals 70s, but who knows why).

Question 10

1. What are inclusions and granules?

2. What is the cytoskeleton?

Answer 10

1. Internal structures of bacterial cells. They are for storage. Can be used when environmental sources are depleted.
2. internal network of protein polymers that give support to the cell and cell wall.

Question 11

1. What are endospores and what types of cells produce them?
2. What are the 2 phases of endospores?
3. What is sporulation?
4. What is germination?
5. How do you kill endospores?

Answer 11

1. Inert, resting, cells produced by some G+ bacteria.
2. Vegetative Cell - metabolically active and growing.
   Endospore- when conditions suck, go into survival mode.
3. Formation of endospores. Not a means of reproduction
4. Return to vegetative growth
5. pressurized steam at 120C for 20-30 minutes.

Question 12

1. • 3. What are the 3 bacterial shapes?
2. What determines bacterial arrangement?
3. Name a few different bacterial arrangements for cocci and bacilli:

Answer 12

1. coccus (spherical)
2. bacillus (rod) (coccobacillus short and plump, and vibrio gently curved)
3. Spirillum (helical, comma, twisted rod) (spirochete, springlike).
4. Arrangement of cells is dependent on pattern of division and how cells remain attached after division:
5. Cocci: Singles, Diplococci (in pairs), Tetrads (groups of four), Irregular clusters, Chains, Cubical packets (sarcina)

Bacilli: Diplobacilli, chains, and palisades

Question 13

1. What is pleomorphism?

Answer 13

1. variation in cell shape and size within a single species. Some species are noted for their pleomorphism

Question 14

1. • 2. What are the 2 domains within Prokaryotes?
2. What are the 3 phylums within domain bacteria?
3. Which domain is primitive and adapted to extreme habitats with odd modes of nutrition?

Answer 14

1. Domain Archaea (although they are more closely related to eukaryotes than bacteria).
2. Domain Bacteria
3. Phylum Proteobacteria (G-), Phylum Firmicutes (mostly G+), and Phylum Actinobacteria (mostly G+)
4. domain archaea