The Prokaryotes

Question 1

Archaebacteria Characteristics

Answer 1

Contained in the Archaea domain

Anaerobic cells found almost everywhere

Question 2

What are the 3 groups of Archaebacteria

Answer 2

Thermophiles: love heat, found in hot acidic waters and around ocean vents or sulphur springs
Halophiles: love high salt concentration
Methanogens: take in CO2 and hydrogen gas and release methane, found in swamps, sewage and intestines of animals

Question 3

Eubacteria Characteristics

Answer 3

Only kingdom in the bacteria domain

Smallest and Most abundant thing on earth

Question 4

Slime Capsule (Bacteria Cell)

Answer 4

sticky gelatinous layer that surrounds some bacteria

Question 5

Cell Wall (Bacteria Cell)

Answer 5

Contains peptidoglycan (unique to bacteria domain)

Question 6

Circular DNA (Bacteria Cell

Answer 6

single chromosome arranged as a giant ring of DNA

Question 7

Plasmids (Bacteria Cell)

Answer 7

smaller rings of DNA that contain only a few genes

Question 8

Pili

Answer 8

Short hair like stuctures that help bacteria attach to things and exhange DNA

Question 9

Flagella

Answer 9

Long corkscrew shaped tails found in swimming bacteria to assist with movement

Question 10

What are the 3 shapes of bacteria

Answer 10

Cocci: spherical
Baccili: straight rod shaped
Spirilla: Spiral shaped

Question 11

2 Ways of getting nutrients in bacteria.

Answer 11

Autotrophs: can make their own food through sunlight or chemical reactions
Heterotrophs: rely on other organisms (many feed on dead organisms or waste material)

Question 12

2 Types of Respiration Requirements

Answer 12

Aerobic: need oxygen to live
Anaerobic: grow best in oxygen rich environments but can survive without oxygen

Question 13

Describe Binary Fission

Answer 13

DNA replicates
Cell elongates
Cell divides into 2

Question 14

Types of Genetic Variation in Bacteria

Answer 14

Mutations result from mistakes in copying, harmful chemicals, UV and radiation
Conjugation: donor cell forms a sex pilus and transfers a copied set of DNA
Transformation: bacteria can take and use free DNA left in the environment
Transduction: Viruses can infect bacteria and transfer genes from one cell to another

Question 15

Endospore

Answer 15

Inactive state where bacteria DNA is enclosed in minimal cytoplasm and a thick cell wall called an endosphere
Bacteria remain in this state until favourable conditions return

Question 16

Explain Bacterias Role in the Nitrogen Cycle

Answer 16

Nitrogen-fixing bacteria converts nitrogen into ammonium
Nitrifying bacteria carry out nitrification (ammonium is turned into nitrites then nitrates) so plants can absorb it from the soil (plants are at the bottom of the food chain so everything gets nitrogen through plants/animals that ate plants)
Waste from organisms gets broken down by decomposing bactreia, ammonifying bacteria makes nitrogenous waste into ammonium
Deniftrifyting bacteria turn unused nitrates into atmospheric nitrogen

Question 17

Explain Bacterias Role in the Carbon Cycle

Answer 17

Decomposing bacteria break down waste and decaying organic material and release CO2
Decaying matter would accumulate otherwise and ther would be less CO2

Question 18

Explain Bacterias role in Oxygen Production

Answer 18

Cyanobacteria are considered to be earths first oxygen producing organisms, they carry out photosynthesis

Question 19

Explain Bacterias role in the Human Body

Answer 19

About a 10:1 ratio
Most harmless or helpful
Aid in digestion

Question 20

What are Pathogenic Bacteria?

Answer 20

Disease causing bacteria
Use up nutrients in the body to spread and multiply throughout the body
Body sends white blood cells to eliminate harmful organisms

Question 21

What are the types of Toxins produced by pathogenic bacteria?

Answer 21

Endotoxins: chemical substances found in the cell wall of Gram negative bacteria, released during binary fission, rarely cause death
Exotoxins: Highly toxic, released by some gram-positive and some gram-negative bacteria. May act locally or target specific sites

Question 22

What is the difference between Gram-negative and Gram-positive bacteria?

Answer 22

Gram-negative have a thin layer of peptidoglycan and absorb the red counterstain
Gram-positive have a thick layer of peptidoglycan and absorb the purple stain

Question 23

How do antibiotics work?

Answer 23

Chemicals selectively kill or stop the growth of bacteria cells without harming the body (target cell structures or processes found only in bacteria

Question 24

Explain the issue with the overuse of antibiotics.

Answer 24

Overuse leads to killing the bacteria which are affected by the antibiotics and leaving the bacteria that are resistant
This leads to the resistance being passed on to offspring and eventually only bacteria with resistance will remain