Bacteria/Archaea (Ch.22)

Question 1

Characteristics of gut bacteria

Answer 1

1. help digest your food
2. synthesize vitamin K
3. produce antimicrobial factors protect you from pathogens
   (involved in your odds of developing metabolic diseases, becoming obese and may be even involved in your mental health)

Question 2

What roles do bacteria and other prokaryotes in the environment?

Answer 2

1. recycling nutrients
2. breaking down compounds no other organisms can
3. others carry out reactions important in food production, in industry and in bioremediation of polluted sites

Question 3

Metagenomics

Answer 3

enables us to investigate the diversity of prokaryotic organisms in a wide range of environments

Question 4

In what types of environments do archaea like to live in?

Answer 4

Extreme environments (ie. hot springs)

Question 5

What are some internal structures of prokaryotes?

Answer 5

1. genome is constructed of singular circular DNA molecule
2. small DNA outside of the nucleoid are called plasmids and contain genes for the non-essential but beneficial functions)

Question 6

Horizontal Gene Transfer

Answer 6

allow antibiotic resistance and other traits to spread quickly in bacteria population (also allows bacteria to take up DNA from their environment)

Question 7

Archaea protein synthesis is a combo of _____?

Answer 7

Eurkaryotic processes, prokaryotic processes and unique features

Question 8

How do antibiotics stop infections?

Answer 8

they target the ribosome’s activity (do not interfere with archaea protein synthesis)

Question 9

What are some characteristics of prokaryotic cell walls?

Answer 9

• have a cell wall that lies outside their plasma membrane that protects them from hypotonic conditions or from detergents (disrupt their membrane)
• the primary component of the cell wall is PEPTIDOGLYCAN

Question 10

peptidoglycan

Answer 10

peptide cross-linkages between the chains give it strength and rigidity

Question 11

How does penicillin work?

Answer 11

prevents the formation of these cross-linkages, resulting in a weak cell wall that is easily ruptured killing the cell

Question 12

Gram-Positive

Answer 12

After the procedure, if the cell remains purple it is gram-positive. This means that the cell is composed of a thick layer of peptidoglycan (more sensitive to penicillin)

Question 13

Gram-Negative

Answer 13

After the procedure, if the cell doesn’t remain purple (turns pink) it is gram-negative. This means that it has a think peptidoglycan layer just outside the plasma membrane and outer external to the peptidoglycan layer
- outer membrane protects the cell from harmful substances in the environment (ie. less sensitive penicillin)

Question 14

Capsule

Answer 14

• the cell wall of prokaryotes is surrounded by a layer of polysaccharides
• it is sticky and plays an important role in protecting cells in different environments
• protected to some extent from desiccation, extreme temperatures, bacterial viruses and harmful molecules
• The presence or absence of a capsule differentiates between whether it’ll be infective or non-infective

Question 15

autotrophs

Answer 15

synthesize organic molecules using inorganic carbon

Question 16

heterotrophs

Answer 16

obtain carbon from organic molecules

Question 17

chemoautotrophs

Answer 17

(lithotrophs) obtain energy by oxidizing inorganic substances such as H, Fe, S, NH4 and use CO2 as a carbon source

Question 18

phototrophs

Answer 18

obtain energy from light

Question 19

photoheterotrophs

Answer 19

uses light as an energy source and obtain carbon from organic molecules rather than CO2

Question 20

aerobes

Answer 20

prokaryotic organisms that use oxygen as a final electron acceptor

Question 21

obligate aerobes

Answer 21

cannot survive without oxygen

Question 22

anaerobic respiration

Answer 22

use metals as a final electron acceptor. Involves inorganic molecules such as nitrate or sulphate (only prokaryotes)

Question 23

obligate anaerobes

Answer 23

poisoned by oxygen and survive by fermentation or anaerobic respiration

Question 24

Facultative anaerobes

Answer 24

uses O2 when it’s present, but under anaerobic conditions, they live by fermentation or anaerobic respiration