Nutrition of microbes

Question 1

explain microbe nutrition requirements

Answer 1

microorgnisms require about 10 elements in large quantities to construct carbs, proteins, lipids and nucleic acids and other elements are needed in small amounts and are part of enzymes and cofactors

Question 2

what are nutrients

Answer 2

substances in the environment used by organisms for catabolism and anabolism

Question 3

what are macronutrients

Answer 3

required n large amounts- e.g carbon, oxygen, hydrogen, ntrogen, sulfur and calcium

Question 4

what are micronutrients

Answer 4

required in very small amounts- e.g iron, copper, molybdenium and zinc and these are trace elements and are essential for the activity of certain enzymes, usually as cofactors

Question 5

what is also needed for growth

Answer 5

contaniments in water, glassware and regular growth components are adequate for growth

Question 6

what are growth factors

Answer 6

amino acids= protein synthesis
purines and pyrimidines= nucleic acid synthesis
vitamins= forming part enzyme cofactors and only very small amounts are needed for growth

Question 7

heterptrophs

Answer 7

CHO- organic carbon

Question 8

autotrophs

Answer 8

CO2

Question 9

Microorganisms have extraordinary….

Answer 9

flexability

Question 10

omnivores

Answer 10

use over 100 carbon compounds

Question 11

fastidious

Answer 11

catabolise only a few carbon compounds

Question 12

phototrophs

Answer 12

use light as an energy source

Question 13

chemothrophs

Answer 13

obtain energy from oxidation of chemical compounds

Question 14

lithotrophs

Answer 14

use reduced inorganic substances as their electron source- energy

Question 15

organotrophs

Answer 15

extract electrons from organic compounds

Question 16

photoautotrophs

Answer 16

use light energy, inorganic hydrogen and CO2 carbon source as sources of energy and found in algae and purple and green bacteria

Question 17

photoheterotrophs

Answer 17

uses light energy and organic carbon source and sources of energy and found in green sulfur bacteria and purple nonsulfur bacteria

Question 18

chemoautotrophs

Answer 18

chemical energy source and CO2 carbon source as sources of energy and found in sulfur-oxidising bacteria and hydrogen bacteria

Question 19

chemoheterotrophs

Answer 19

chemcial energy source and organic carbon source as sources of energy and found in most bacteria, fungi and protozoa

Question 20

what can nutrients frequently not pass

Answer 20

the selectively permeable plasma membrane through passive diffusion

Question 21

what are nutrients carried through (the mechanisms)

Answer 21

passive transport (simple difusion), facilitated difusion, active transport and group translocation

Question 22

what is passive diffusion

Answer 22

molecules move from a region of higher concentraiton to one of lower concentration due to thermal agitation-no energy used and no carieer protein used

Question 23

what is facilitated diffusion

Answer 23

difusion process is aided by a carier and involves careier proteins, permeases and higher con to a lower con
no energy input

Question 24

what are permeases

Answer 24

they are embedded in the plasma membrane and are carier proteins that increases the rate of diffusion across selectively permeabke membranes

Question 25

what is active transport

Answer 25

transport of solute molecules from low concentrations to high concentration and involves permeases and energy ATP

Question 26

explain protein gradients

Answer 26

symport- linked transport of 2 substances in the same direction
antiport- linked transport of 2 substances in the opposite direction
uniport- one substance enters

Question 27

what is group translocation

Answer 27

a process in which a molecule is transported into the cell while being chemically altered- e.g PTS transports sugars to prokaryotic cells while phosphorlating them using PEP

Question 28

Explain siderophores

Answer 28

low molecular weight and iron chelating compounds able to complex with ferric iron and supply it to the cell. microbes secrete siderosphores when little iron is avaliable

Question 29

what are the types of media

Answer 29

culture, synthetic or defined, complex, solid, selective and differential

Question 30

what is culture media

Answer 30

a solid or liquid preparation used to grow, transport and store microbes. Used in the isolation and identification, the testing of antibiotic sensitives and water and food analysis

Question 31

what is synthetic media

Answer 31

media in which all componenets are knwown

Question 32

what is a complex media

Answer 32

some ingrediants of unknown chemical ocmposition like peptones, meat and yeast extract. Peptones are protein hydrolysates

Question 33

what is the solid media

Answer 33

includes agar and 40-42 degrees harden and 80-90 degrees melt. most microbes cannot degrade it. Silica gel is used for autotrophic bacteria and is a drying agent used to absorb moisture and condensationfrom the surrounding environment

Question 34

what is the selective media

Answer 34

favours the growth of particular microorganisms and have componenets that inhibit the growth of unwanted bacteria and have components that promote the growth of favoured bacteria

Question 35

what is differentail media

Answer 35

can distinguish between different groups of bacteria e.g MacConkey agar

Question 36

what is the thermal death time for most organisms

Answer 36

15 mins