Microbiology Part 2 (2.2)

Question 1

What can organisms and biological entities be catergorised as?

Answer 1

Cellular and Acellular

Question 2

By what process are prokaryotes able to replicate asexually?

Answer 2

Binary Fission

Question 3

By what process do single celled eukaryotes replicate asexually?

Answer 3

Mitosis

Question 4

What are the stages of Mitosis?

Answer 4

• Prophase
• Metaphase
• Anaphase
• Telophase

Question 5

By what process can single celled eukaryotes replicate sexually?

Answer 5

Meiosis

Question 6

What are the stages of Meiosis?

Answer 6

• Meiosis 1
• Prophase 1
• Metaphase 1
• Anaphase 1
• Telophase 1
• Meiosis 11

Question 7

What happens in the process of budding yeast reproduction?

Answer 7

• asexual reproduction via budding
• fusion of two haploid cells to form a diploid cell
• formation of haploid spores via meiosis

Question 8

Microbes reproduce rapidly. True or False?

Answer 8

True - makes them excellent models for experimental evolution studies.

Question 9

What are the stages in growth curves? (in a closed system)

Answer 9

• inoculation
• lag phase
• exponential phase
• stationary phase
• decline/death phase

Question 10

How is metabolism carried out in an energy source?

Answer 10

• phototrophs gain energy from sunlight

- chemotrophs gain energy from inorganic and/or organic compounds

Question 11

How is metabolism carried out in electron sources?

Answer 11

• organotrophs gain electrons from organic compounds

- lithotrophs gain electrons from inorganic compounds

Question 12

How is metabolism carried out in a carbon source?

Answer 12

• autotrophs use CO2 to make carbon compounds (primary producers)
• heterotrophs use organic compounds from their environment

Question 13

What is a niche?

Answer 13

set of environmental conditions where a species of microbe can replicate.

Question 14

What are some conditions that determine where a microbe can live?

Answer 14

• nutrient availability
• oxygen concentration
• temperature
• pH
• light intensity
• radiation
• solute concentration (osmolarity & water activity)

Question 15

What is a entailed in a free-living lifestyle?

Answer 15

• it inhabits every type of environment on Earth

- wide range of metabolic capabilities

Question 16

With a symbiotic lifestyle, what happens in a pathogenic environment?

Answer 16

• interaction with host organism

- host is damaged

Question 17

With a symbiotic lifestyle, what happens in a mutuallistic environment?

Answer 17

• interaction with host organism

- where both partners benefit

Question 18

With a symbiotic lifestyle, what happens in a commensal environment?

Answer 18

• interaction with host organism
• one partner benefits
• other is unaffected

Question 19

What is bacteria?

Answer 19

a single-celled prokaryote

Question 20

How does bacteria reproduce?

Answer 20

Asexually by binary fission.

Question 21

What lifestyles does bacteria have?

Answer 21

• free-living
• commensal
• mutualistic
• pathogenic

Question 22

What can be found in a bacteria?

Answer 22

• no nucleus
• 1 circular chromosome (dsDNA)
• one or more plasmids

Question 23

What shapes do bacteria usually take on?

Answer 23

• spherical
• rods
• spirals

Question 24

What is usually found in the cell wall of bacteria?

Answer 24

Peptidoglycan - (gram stains help to identify 2 main groups)

Question 25

How can you identify a gram positive bacterium?

Answer 25

- peptidoglycan traps crystal violet (iodine stain - purple) - cells are not decolourised by ethanol wash - purple stain masks safranin counters

Question 26

How can you identify a gram negative bacterium?

Answer 26

- crystal violet (iodine stain) = washed away by ethanol wash - cell = stained red/pink with safranin counterstain

Question 27

What does a capsule help bacteria do? (produced by some species of bacteria)

Answer 27

- attach to surfaces | - evade the immune response

Question 28

What do fimbriae help bacteria do?

Answer 28

- being thread-like appendages | - helps to attach to surfaces/ other cells

Question 29

What is flagellum?

Answer 29

- tail-like appendage that bacteria use to swim through liquid - rotational movement propels bacteria towards nutrients/ away from toxicants via chemotaxis

Question 30

What is biofilm?

Answer 30

- aggregation of bacteria that are attached to each other/ and or a surface - embedded in an extracellular polymeric substance

Question 31

What is a sex-pilus?

Answer 31

- thread - like appendage that bacteria use to exchange plasmids (bacterial conjugation)

Question 32

What does Photorhabdus luminescens (bacterium) form?

Answer 32

- forms a mutualistic relationship with nematodes - with EPN (entomopathogenic nematode) - infect insect larvae - cause lethal septicaemia - dead insect larvae glow in the dark

Question 33

What are archaea and how do they reproduce?

Answer 33

- single- celled prokaryotes - perform asexual reproduction - lack peptidoglycan in cell wall - unique cell membrane lipids - 1 circular chromosome - no nucleus - 1 or more plasmids

Question 34

What are the forms of archaea?

Answer 34

- spherical - rods - spirals - rectangles - squares - lemon - shaped

Question 35

What the lifestyles of archaea?

Answer 35

- free-living (many are extremophiles) | - commensals

Question 36

What are fungi and how do they reproduce?

Answer 36

- single - celled & multicellular eukaryotes - asexual/sexual reproduction - chitin in cell wall - multiple linear chromosomes within the nucleus

Question 37

What are the forms of fungi?

Answer 37

- yeasts | - moulds

Question 38

What are the lifestyles of fungi?

Answer 38

- decomposers - mutualistic - pathogenic

Question 39

Give one common mould that acts as a decomposer of food.

Answer 39

Penicillium

Question 40

What are protists and how do they reproduce?

Answer 40

- single - celled & multiceullar eukaryotes - e.g. slime molds, algae, amoebae - by asexual/ sexual reproduction - multiple linear chromosomes with nucleus

Question 41

What forms do protists exist in?

Answer 41

- unicellular (most) | - multicellular

Question 42

What are the lifestyles of protists?

Answer 42

- free- living - pathogenic - mutualistic