Exam 1 SG questions - Part 2

Question 1

Describe the major structural features of the eukaryotes.

Answer 1

• Cell walls contain cellulose
• plasma membrane contains sterols such as cholesterol for structural support
• have glycocalyces, but they aren’t as organized as prokaryotes
• 2 types of appendages: flagella that move in whip like motion and cilia
• Contains organells: Nucleus, SER, RER, ribosomes, Golgi Apperatus, Mitochondria

Question 2

Identify the distinguishing structural features of the prokaryotes.

Answer 2

No nucleus, always has a cell wall, can have fimbrae/pili, flagella that rotate

Question 2

Describe a prokaryotic capsule

Answer 2

• Considered a glycocalyx
• protects cell from phagocytosis and drying out
• osmosis barrier
• nutrient reservoir
• virulence factor

Question 3

Describe a prokaryotic slime layer

Answer 3

• Associated with biofilms
• used for attachment
• Glycocalyx

Question 4

What are prokaryotic glycocalyces?

Answer 4

• gelatinous sticky substance surrounding outside of the cell
• composed of polysaccharides, polypeptides, or both
• 2 types: capsule or slime layer

Question 5

What are fimbrae?

Answer 5

• Hollow tubes that protrude from some bacteria
• composed of protein
• used for attachment

Question 6

What are pili?

Answer 6

• tubules composed of pilin
• longer in length than fimbrae but shorter than flagella
• typically 1-2 per bacteria cell
• mediate the transfer of DNA from 1 cell to another
• ONLY A GRAM NEGATIVE MECHANISM

Question 7

Identify the three morphological shapes of bacteria and their tendencies of gram specificity.

Answer 7

1. Coccus: circular, gram positive or negative
2. Bacilli: rod, gram positive or negative
3. Spirili: only gram negative because they need LPS to be flexible
4. Strepto: chain
5. Diplo: pair
6. Tetra/micro: in 4
7. Staph: clusters like grapes

Question 8

Compare and contrast the structures and functions of Gram-positive and Gram-negative cell walls.

Answer 8

• Gram positive: LARGE peptidoglycan layer (sugar chains of NAG and NAM), teichoic acid (used as anchor/screw).
• Gram negative: LPS (lipopolysaccharides = fats and sugars), SMALL peptidoglycan layer, no teichoic acid.

Question 9

What are a few differences Eukaryotes have in cell walls that prokaryotes don’t?

Answer 9

1. Contain cholesterol
2. CHO/protein act as endcap cell indicator/marker

Question 10

Compare and contrast the following: simple diffusion, osmosis, facilitated diffusion, active transport, and phagocytosis.

Answer 10

• Simple Diffusion: doesn’t require energy, moves across concentration gradient.
• Facilitated Diffusion: doesn’t require energy, moves across concentration gradient using a carrier (inside a little pocket/car to pass hydrophobic)
• Osmosis: diffusion of water
• Active Transport: against the concentration gradient, requires energy
• Endocytosis/Phagocytosis: substance engulfed by cell membrane/eats absorbs bacteria