Review I - Bacterial structures and Function.

Question 1

Know the three basic shapes of bacteria.

Answer 1

bacillus- rod, coccus-round, spirillium-spiral

Question 2

Know the composition, function and any special feature for each of the following possible parts of a bacteria cell: 1. Capsule

Answer 2

function: protects from dehydration and adheres bacteria from each other (aides in establishing infection) Protects from phagocytosis

Question 3

Know the composition, function and any special feature for each of the following possible parts of a bacteria cell: 2. Cell wall – review the 2 basic types of cell walls in bacteria

Answer 3

Peptidoglycan is a complex polysacharide found in the cell wall of most bacteria, Peptidoglycan provides rigidity to help maintain cell shape

**ATYPICAL bacteria: **archaebacteria a cell wall but lack peptidoglycan

**CELL WALL FUNCTION: **determines cell shape due to rigidity, Protection from water pressure changes, holds cell together

Question 4

Know the composition, function and any special feature for each of the following possible parts of a bacteria cell: 3. Cell membrane

Answer 4

**COMPOSITION: **60% protein and 40% lipid, Phospholipid bi-layer embedded with protein

Cell Membrane functions
•Surrounds cytoplasm
•Boundary of cell
•Semi-permeable membrane – selective
•Anchor DNA molecule (not necessary in eukaryotes because DNA protected in nucleus)
•Site of Cell Metabolism or ATP production

Question 5

. Know the composition, function and any special feature for each of the following possible parts of a bacteria cell: 4. Flagellum/flagella

Answer 5

• *•Composition:** Long strands of protein
• *•Function:**1) Used for locomotion 2) Establish infection

Question 6

. Know the composition, function and any special feature for each of the following possible parts of a bacteria cell: 5. Pili/Fimbrae

Answer 6

• Composition: Hollow tubes of Protein
• Rigid structures
• Extend from cell

Pili Functions
•NO role in motility
•Attach bacteria to body tissue
•“Sex” pili allow transfer of DNA between bacteria cells (Conjugation) from donor to recipient only

Question 7

. Know the composition, function and any special feature for each of the following possible parts of a bacteria cell: 6. Cytoplasm

Answer 7

Cytoplasm is a gel-like matrix

Question 8

. Know the composition, function and any special feature for each of the following possible parts of a bacteria cell: 7. Endospores/Spores

Answer 8

• Dormant structures
• Do not grow or reproduce
• Only produced by certain bacteria
• Very resistant to heat, chemicals, UV light

Question 9

. How is the main Chromosome material different from Plasmids?

Answer 9

Chromosomes
•DNA: Deoxyribonucleic acid
•Genetic material of cell
•Single loop
•Double-stranded

Plasmids
•Extra piece of DNA
•Small, circular
•0 – 100 plasmids per cell
•Encodes useful information like antibiotic resistance

Question 10

What is sporulation?

Answer 10

• 1 Bacteria cell ⇒ 1 spore
• 1:1 ratio
• Event initiated by reduced food supply or adverse environmental conditions

Question 11

. What conditions stimulate a bacteria cell to produce spores?

Answer 11

•Event initiated by reduced food supply or adverse environmental conditions

Question 12

Know the complete spore cycle.

Answer 12

sporulation ⇒ 1 spore ⇒germination ⇒1 vegetative cell

Then back to sporulation.

Question 13

Function of ribosomes. Is the function of ribosomes the same in prokaryote and eukaryote cells?

Answer 13

The same.

They are smaller in prokaryote and larger in eukaryote.

Question 14

Main differences between a Gram + vs. Gram - bacteria cell.

Answer 14

Gram positive

• Peptidoglycan layer is 25nm
• Teichoic acid creates links between Peptidoglycan layers

•No outer extra membrane

Gram Negetive

• Peptidoglycan layer is 3nm
• No Teichoic acid because there is only 1 layer of peptidoglycan
• Outer membrane: Lipopoly-saccharide (LPS) bilayer

Question 15

Know flagellar placement.

Answer 15

Monotrichous

Lophotrichous

Anphitrichous

Peritrichous

Question 16

What is the difference between positive and negative chemotaxis?

Answer 16

• Positive chemotaxis: movement toward a favorable environment such as a food source
• Negative Chemotaxis: Move away from a harmful environment such as toxic chemicals

Question 17

What is the importance of pili structures?

Answer 17

Attach bacteria to body tissue

Question 18

What is conjugation? How does conjugation apply to transfer of DNA information between bacteria cells?

Answer 18

DNA transfer via sex pilus from donor to recipient

Allow transfer of DNA ⇒ to recipient only

Increase gentic variation.

Question 19

What is the chemical composition of plasmids?

Answer 19

DNA

Question 20

Do all bacteria have plasmids?

Answer 20

No

there can be 0-100 plasmids per bacteria cell