Ch. Two

Question 1

Proteins

Answer 1

• organis molecules that contain C, H, O, N, and S
• essential in cell structure and function
• enzymes are proteins that speed chemical reactions
• amino acids (~20)
• disruption of the secondary (helix or pleated sheets), tertiary (3D), and quaternary (2 or more 3D) structure is called denaturation

Question 2

Peptide Bonds

Answer 2

• between amino acids are formed by dehydration synthesis

Question 3

Nucleic Acids

Answer 3

• consist of nucelotides
• nucleotides consist of a: pentose sugar, phosphate group and nitrogen-containing (purine (A&G) or pyrimidine (T&C&U)) base
• 2 kinds: DNA and RNA

Question 4

ATP

Answer 4

• adenosine triphosphate
• has ribose, adenine, and 3 phosphate groups
  adenosine-P-P-P

Question 5

Spiral Shape

Answer 5

• vibrio ex. vibrio cholerae (causes cholera)
• spirillum: have flagella
• spirochete: have endoflagella or axial filaments, very flexible and coiled; ex. Treponema pallidum (causes syphilis)

Question 6

Baccillus

Answer 6

• rod/staff
• single baccillus: ex. Bacillus anthracis
• diplobacilli
• streptobacilli

Question 7

Coccus

Answer 7

• diplococci
• streptococci: ex. Streptococcus pyogenes (causes strep throat)
• staphylococcus: ex. Staphylococcus aureus (causes skin infections, TSS)

Question 8

Coccobacillus

Answer 8

• intermediate between baccillus and coccus

Question 9

Pleomorphic

Answer 9

• variable in size and shape

- can alter shape

Question 10

Protein’s four level of organization

Answer 10

1. primary: unique sequence of amino acids linked together to form a polypeptide chain
   - genetically determined and can have profound metabolic effects
2. secondary: twisting or folding of chain
   - helix or pleated sheets
   - between hydrogen bonds
3. tertiary: 3D
4. quaternary: 2 or more polypeptide chains operating as a single functional unit

Question 11

Glycocalyx (capsule)

Answer 11

• secreted to cell surface
• outside cell wall
• made up of polysaccarides, polypeptides, or both
• slimy/gelatinous
• functions:
  increase disease-causing ability (streptococcus pneumoniae)
  evade phagocytosis
  attach to a host cell (Streptococcus mutans- causes tooth decay)

Question 12

Flagella

Answer 12

1. monotrichous
2. amphitrichous: at both poles of cell
3. lophotrichous: many coming from one pole
4. peritrichous: distributed over entire cell

3 basic parts:

• filament: flagellin
• hook: protein
• basal body: anchors the flagellum to the cell wall and plasma membrane

motility: runs (1 direction for a long time) and interrupted ny random change in directions called tumbles

Question 13

Axial Filament

Answer 13

• found in spirochetes
• corkscrew movement
• endoflagella

Question 14

Fimbria(e)

Answer 14

• vary from few to several hundred
• used for attachment
• shorter, thinner, and straighter than flagella
  ex. Nisseris gonorrhoeae

Question 15

Pili

Answer 15

• 1-2 per cell
• involved in motility and DNA transfer
  ex. Escherichia coli

Question 16

Peptidoglycan (murein)

Answer 16

• made up of proteins and glucose
  GLUCOSE:
• monosaccarides: N-acetylglucosamine (NAG) and N-acetylmuramic (NAM)
  PROTEINS:
• polypeptides (number varies)
• tetrapeptide (# is 4 amino acids attached to NAM backbone)

Question 17

Gram-positive Cell Wall

Answer 17

• many layers of peptidoglycan
• Teichoic acids: consists of alcohol (ribitol or glycerol) and phosphate
• 2 types:
  lipoteichoic acid: spans PG layer and linked to plasma membrane
  wall teichoic acid: linked to PG layer
• function: because of neg charge from phosphate they attract cations & antigen specificity which makes them identifiable

Question 18

Gram-negative Cell Wall

Answer 18

• one or two layers of PG
• outer membrane consists of:
• phospholipid molecules: forms bilayer
• Lipoprotein: acts as an anchor
• porinprotein: form channels and permeability
• Lipopolysaccharide: recognizes bacteria and consists of:
  Lipid A (endotoxin), and polysaccharide (antigen and distinguish species)
• Periplasm

Question 19

Infection of Gram-negative

Answer 19

• fever, nausea, vomiting, diarrhea, miscarriage, and shock

Question 20

Atypical Cell Walla

Answer 20

1. Mycobacterium tuberculosis (TB) and Mycobacterium leprae (leprosy)
   - mycolic acid: acid-fast walls
2. Mycoplasma
   - no cell walls and smallest bacteria
   - have sterols which protect from rupturing
3. Archaea
   - lack walls or false PG

Question 21

Damage to Cell Wall

Answer 21

1. lysozyme are preset in mucous, saliva, tears and breast milk
   - action: destroy PG (glycan)
   - Gram-positive: cell wall destroyed called protoplast= death
   - gram-negative: some outer membrane remains called spheroplast= death
2. antibiotic: penicillin inhibits peptide bridges in PG
   - by interfering with formation of the peptide cross-bridges of PG
   - more effective on gram-positive because of outer cell wall in gram-negative and have fewer peptide cross-bridges

Question 22

Plasma Membrane

Answer 22

• phospholipid bilayer
• peripheral proteins: function as enzymes that catalyze chemical reactions, “scaffold” for support, and mediators of changes in membrane shape
• integral proteins: penetrate membrane completely and are called transmembrane proteins; have pore for substances to enter and exit
• selective permeability: allow passage of some molecules
• large molecules cannot pass, and small molecules can pass, ions can pass slowly, and substances that dissolve in lipids

Question 23

Movement of Materials Across Membrane

Answer 23

• simple diffusion: movement of a solute from an area of high concentration to an area of low concentration
• facilitated diffusion: solute combines with a transporter protein in the membrane
• osmosis: movement of water across selectively permeable membrane from high to low concentration

Question 24

Cytoplasm

Answer 24

• substance inside the plasma membrane
• in prokaryotes, nuceloid, and particles called ribosomes
• no cytoskeleton

Question 25

The Nucleoid

Answer 25

- contains bacterial chromosome - thread of double-stranded DNA - not surrounded by nuclear envelope and no histones

Question 26

Ribosomes

Answer 26

- same as eukaryotes except smaller | - 70 S vs 80S

Question 27

Endospores

Answer 27

- are resting cells - become active when nutrient or water is unavailable (survive extreme heat, lack of water and exposure to toxins) - gram-positive: Bacillusanthracis - gram-positive: Clostridium tetani, Clostridium perfringens (causes gangrene), Clostridium botiulinum, Clostridium difficile (causes colitis) - gram-negative: Coxielia burnetti (Q fever)