chapter 6 objectives

Question 1

micronutrients vs. macronutrients

Answer 1

macro: required in large quantities for metabolic processes
micro: required in smaller amounts (trace elements); present in enzyme function

Question 2

autotroph

Answer 2

organism that use inorganic CO2 as carbon source

Question 3

heterotroph

Answer 3

organism that must obtain carbon in organic form

Question 4

chemotroph

Answer 4

microbe that gets energy from chemical compounds

Question 5

6 essential nutrients of a bacterial cell

Answer 5

carbon, hydrogen, oxygen, nitrogen, phosphate, sulfur

Question 6

diffusion vs osmosis

Answer 6

diffusion: molecules move in gradient from high concentration to low concentration
osmosis: water diffuses through selectively permeable membrane

Question 7

effects of isotonic condition on cell

Answer 7

rates of diffustion are equal

Question 8

effects of hypotonic condition on cell

Answer 8

water enters cell and in result it swells

Question 9

effects of hypertonic condition on cell

Answer 9

water exits cell and in result shrinks

Question 10

two types of passive transport

Answer 10

simple diffusion: no atp required, molecules move freely across membrane
facilitated diffusion: has binding site protein that moves molecules across membrane

Question 11

one type of active transport

Answer 11

carrier mediated active transport: protein pumps that use ATP to carry molecules across membrane

Question 12

endocytosis

Answer 12

ell encloses a substance in its membrane, forms a vacuole while engulfing a substance

Question 13

phagocytosis

Answer 13

ingest an entire cell/solid matter

Question 14

pinocytosis

Answer 14

ingestion of liquids like oils/molecules in a solution

Question 15

6 enviornmental factors that effect cell growth

Answer 15

1. temperature
2. gases (oxygen/carbon dioxide)
3. pH
4. osmotic pressure
5. radiation and atmospheric pressure
6. other organisms

Question 16

temperature group that contains most pathogens

Answer 16

mesophiles (growth at 25° C to 40° C)

Question 17

5 groups of organisms based on oxygen requirements

Answer 17

aerobes: use oxygen in metabolism (obligate means cannot growth without)
microaerophiles: harmed by normal atmospheric concentrations of oxygen, but still require in small amounts
facultative anaerobes: do not require oxygen but use when present
obligate anaerobes: lack enzyme systems to use oxygen (cannot survive)
aerotolerant anaerobes: do not utilize oxygen but survive to a limited extent

Question 18

capnophillic

Answer 18

organisms that grow best at higher CO2 tension than is normally present in the atmosphere

Question 19

isotonic solution

Answer 19

concentration of solutes/pressures equal inside and outside cell

Question 20

hypotonic solution

Answer 20

concentration of solutes/pressures is greater inside the cell than outside

Question 21

hypertonic solution

Answer 21

concentration of solutes/pressures is greater outside the cell than inside

Question 22

5 types of associations microbes can have with hosts

Answer 22

mutualism: both benefit
commensalism: one benefits, the other neither benefited nor harmed
parasitism: parasite benefits, host harmed
synergism: members cooperate/share nutrients
antagonism: some members are destroyed by others

Question 23

steps of bacterial binary fission

Answer 23

B period: cell increases in mass and size
C period: dna replicates and the two strands separate
D period: synthesis of a septum forms two identical cells

Question 24

doubling time

Answer 24

refers to specific time it takes for a bacterial population to double in time

Question 25

how does doubling time lead to exponential growth

Answer 25

bacterial population is continuously doubling in size

Question 26

4 phases of growth in bacterial growth curve

Answer 26

1. lag phase: slow growth (adjusting to environment)
2. exponential phase: rapid/exponential growth due to optimal conditions (acute infection)
3. stationary phase: growth slows down because of depletion of nutrients (plataeu)
4. death phase: decline in bacterial population (resolution)

Question 27

6 ways we can measure cell growth

Answer 27

1. optical density: measures cloudiness
2. direct cell counting: counts individual cells
3. colony-forming unit counting: plating diluted samples and counting colonies
4. turbidity: measures light scattered by cells
5. biomass: measuring total dry weight of the bacterial cells
6. metabolic activity assays: measuring rate of specific metabolic processes