Cell Structure and Functions

Question 1

thin barrier that surrounds the cell and separates the cytoplasm from the cell’s environment

Answer 1

The Cell Membrane

Question 2

Functions of the Cytoplasmic Membrane

Answer 2

Permeability barrier, Anchor for many proteins, Energy conservation

Question 3

Prevents leakage and functions as gateway for transport of nutrients

Answer 3

Permeability barrier

Question 4

water transport system

Answer 4

Aquaporins

Question 5

Site of proteins that participate in transport, biogenetics and chemotaxis

Answer 5

Protein Anchor

Question 6

Site of generation and use of proton motive force (transport, motility, and biosynthesis of ATP)

Answer 6

Energy Conservation

Question 7

Shape and rigidity of the cell

Answer 7

Cell Wall

Question 8

C.W. much thicker and consists of primarily single type of molecule

Answer 8

Gram +

Question 9

C.W. chemically complex and consists of at least two layers

Answer 9

Gram -

Question 10

• Polysaccharide: two sugar derivatives,
• N-acetylglucosmaine
• N-acetylmuramic acid

Answer 10

PEPTIDOGLYCAN

Question 11

Break in B-1,4-glycosidic bonds

Answer 11

Lysozymes

Question 12

Glycosidic link between NAM and NAG

Answer 12

PEPTIDOGLYCAN

Question 13

between the amino acids in NAM

Answer 13

Peptide bonds

Question 14

True or False: Thermoplasma has a cell wall

Answer 14

False

Question 15

T or F: Archaea contain tough cytoplasmic membrane because they live in osmotically protected habitats

Answer 15

True

Question 16

T or F: Mycoplasma has sterols, which adds strength and rigidity

Answer 16

True

Question 17

T or F: Gram- bacteria is 90% PDG while Gram+ bacteria is 10% PDG

Answer 17

False

Question 18

T or F: Gram- bacteria has an outer membrane

Answer 18

True

Question 19

T or F: E. coli is a gram+ bacteria

Answer 19

False

Question 20

Keep proteins whose activities occur outside the cytoplasmic membrane from diffusing away from the cell

Answer 20

Outer Membrane

Question 21

• Space located betw. outer surface of cytoplasmic mem.
• Gel like consistency
• May contain hydrolytic enzyme, binding proteins, chemoreceptors

Answer 21

Periplasm

Question 22

• Embedded in outer membrane
• Functions as channels for entrance of solutes

Answer 22

Porins

Question 23

• Composed of altering N-acetylglucosamine
• Glycosidic bonds in B-1,3
• Not all archaea, some has thick polysaccharide like Methanosarcina and Halococcus

Answer 23

Pseudomurin

Question 24

• Most common CW of archaea
• Paracrystaline surface layer, symmetrical patterns
• Found in major lineages of Archaea, and some bacteria
• Withstand osmotic bursting, Ex. Methanocaldococcus jannaschii
• Function as selective sieve, allows of low-molecular weight solutes
• Archaea naturally resistant to lysozymes

Answer 24

S-Layers

Question 25

- Layer that is organized in a tight matrix that excludes small particles like Indian ink - Adheres firmly to CW, some linked to peptidoglycan - Virulent factor, difficult to phagocitize

Answer 25

Capsules

Question 26

- Layer that is easily deformed and do not exclude particles and is more difficult to see - Are loosely attached and can be lost from the cell surface

Answer 26

Slime layer

Question 27

- Enable cells to stick to surfaces, including animal tissues - Can form pellicles, thin sheet of cells on liquid surface

Answer 27

Fimbriae

Question 28

- Similar to fimbriae but longer and only one or few pillion surface of a cell - Facilitate genetic exchange in conjugation - Adhesion to host tissue

Answer 28

Pili

Question 29

- Assist in cell adhesion - Twitching motility (a gliding motility) - Genetic Transfer

Answer 29

Type IV Pili

Question 30

Granules or other inclusions functions as energy reserves, can be seen directly with a microscope

Answer 30

Cell Inclusions

Question 31

- Carbon and energy storage polymer - Synthesized when there is excess of carbon - Many prokaryotes produce PHA

Answer 31

Poly-B-hydroxyalkanoate( PHA)

Question 32

- Polymer of glucose - Storehouse of glucose and carbon energy - Produced when carbon is in excess

Answer 32

Glycogen

Question 33

- Source of phosphate for nucleic and phospholipid biosynthesis, ATP - Phosphate, limiting nutrient in the env. - Reside in periplasm - H2S to SO4^2-

Answer 33

Polyphosphates

Question 34

- can orient themselves using magnetic field - Found in several aquatic organism - Grow at low O2 concentration - Surrounded in thin membrane containing phospholipids, glycoproteins and proteins (not a bilipid layer) - Proteins play a role in precipitating Fe3+ to Fe3+O4

Answer 34

Magnetosomes

Question 35

- Spindle-shaped structures of proteins - Hollow yet rigid, impermeable to liquid and solutes - Cluster of vesicles, gas vacuoles - GvpA, forms the vesicle shell, hydrophobic, rigid - GvpC, strengthen the shell by cross-linking GvpA - For buoyancy - Phototrophic organisms

Answer 35

Gas Vesicles

Question 36

- Produce endospores in a process called sporulation - Differentiated cells, resistant to heat and chemicals, radiation - Vegetative to Endospore (dormant stage) to Vegetative - Bacillus and Clostridium specie

Answer 36

Endospores

Question 37

– activated endospores are conditioned to germinate when placed in presence of nutrients

Answer 37

Activation

Question 38

– rapid process, involves loss of microscopic refractibility, Ability to be stained & Loss resistance to heat

Answer 38

Germination

Question 39

– swelling due to water uptake, Synthesis of RNA, proteins and DNA

Answer 39

Outgrowth

Question 40

- Bind tightly in DNA in the core and protect it from desiccation and dry heat - Also, as carbon and energy source for outgrowth

Answer 40

SASPs, small acid-soluble proteins

Question 41

a thin protein cover

Answer 41

Exosporium

Question 42

composed of layers of spore-specific proteins

Answer 42

Spore coat

Question 43

consists of loosely cross-linked peptidoglycan

Answer 43

Cortex

Question 44

contains core wall, cytoplasm, nucleoid, ribosomes, other cellular essentials

Answer 44

Core

Question 45

- Funct. by rotation to push or pull cell - Long, thin appendages - Flagella are not straight but helical - Composed of flagellin proteins - Powered by proton motive force

Answer 45

Bacterial Flagella

Question 46

- Roughly half the diameter of bacterial flagella - Same rotation with bacterial flagella - Several flagellin protein are known for Archaea and no relationship with proteins in bacteria - swim at speeds 1/10 that of E. coli - Powered by ATP

Answer 46

Archaeal Flagella

Question 47

- Bacteria that do not have flagella, glide - Slower and smoother form - Needs to be in contact with surface to glide - Found in filamentous or rod-shaped cells

Answer 47

Gliding Motility

Question 48

are genetic elements that cannot replicate independently of a living cell

Answer 48

Viruses

Question 49

T or F: Viruses are not cells and thus nonliving

Answer 49

True

Question 50

T or F: Viruses are: - Obligate intracellular parasite - Different form plasmid because viruses have intracellular form - They are important in microbial genetics and genetic engineering

Answer 50

True