Prokaryotes

Question 1

Prokaryotes?

Answer 1

No nucleus, or other membrane bound organelles, unicellular

Eg, bacteria and archaea

Question 2

Why can’t you use biological species concept to classify bacteria and archaea, what can you use?

Answer 2

Because they are Asexual, you can use morphology, aggression, nutrition, habitats, genetic components and gram staining to classify these domains

Question 3

Describe the 3 morphology shapes

Answer 3

1. Cocci - spherical form
2. Bacilli - rod form
3. Spirilla- spiral form

Question 4

Describe aggregation and colonies?

Answer 4

Way to classify archer and bacteria, although prokaryotes are unicellular, bacteria and archaea can still form, colonies bc each cell offers different functions

1. Diplo- pairs of cells
2. Strepto - chain form
3. Staphylo - clusters form

Eg Diplococci, streptobaccil

Question 5

Compare nutrition (A v B)

Answer 5

Some archea and bacteria and autotrophs and heterotrophs, others use inorganic compounds such as hydrogen, Sulphide and iron for nutrions

Question 6

Comparing nutrition: what is archaea’s unique process, describe it

Answer 6

Archaea has a unique anaerobic metabolic process called methanogenesis, methane is a byproduct if this, and thus lives in the digestive tract of cows/cattle

Question 7

Comparing nutrition:What is the most common type of photosynthetic bacteria?

Answer 7

Cyanobacteria
Phototrophic archaea exists as well however it does not generate oxygen

Question 8

What does anaerobic and aerobic mean? What are the different types of anaerobics?

Answer 8

Anaerobic- organisms that can live in the absence of oxygen.
- obligate anaerobe: only can live in environments w/o oxygen
- facultative anaerobe: will use oxygen if available but can still live and produce energy without

Aerobic- organisms that require oxygen to produce energy

Question 9

Comparing habitats: which environments can archea and bacteria both live in, separately?

Answer 9

• A/B can both live in aerobic and anaerobic environments
• A can live in more extreme environments making it an extremophile
  -B lives in less extreme environments making it a mesophile

Question 10

What are the types of extremophiles, describe them. (Archaea)

Answer 10

-Thermophile - survives in extreme temperatures up to 100c, lives in hot springs.

• Acidophiles - survive in acidic environments such as volcanic craters, can survive in places where pH is under 3. Eg( picrophilus)

-halophiles - lives in high concentrations of salt, when salinity exceeds 20% only halophiles can survive,salt lakes. Eg, Halococcus

Question 11

Why are extremophiles important?

Answer 11

• important for biotechnology
• Archaea contains enzymes of special use to humans due to its with-stance to extreme conditions, used for DNA research by bio technologists

Question 12

What are the 2 forms of reproduction for bacteria and archaea?

Answer 12

Binary fission (asexual)
Conjugation (sexual)

Question 13

Explain binary fission and conjugation

Answer 13

• Binary fission: Asexual, a cell makes a copy of original chromosome, when cell reaches ideal size, it elongates which separates the 2 chromosomes, it then builds a separation wall called a septum, cell splits into 2 smaller twin cells.
• this is quick however, all offsprings are genetically identical making it more susceptible to threats

-Conjugation: sexual reproduction, involves 2 cells, exchange genetic material.
Donor cell attaches to recipient cell by conjugation pilus, both cells come into contact and attach, one strand of a plasmid (double stranded circular DNA), transfers into recipient cell, both cells synthesize creating complementary stands ensuring each plasmid is double stranded, then bacteria detaches

• no offspring is created, just dna exchanged, increases biodiversity (more combos)
• conjugation Lao allows to build antibiotic resistance

Question 14

What are endospores?

Answer 14

A dormant BACTERIA cell which is able to survive for long periods in extreme conditions.

They have hard walls so they can protect and store genetic material. They are formed when environmental conditions threaten an organism, and they revert back to an active bacterium when conditions regulate.

Question 15

Compare bacteria and archaeas cell walls/membrane

Answer 15

-Bacteria cell wall: made of peptidoglycan (proteins and sugars)
Bacteria membrane: lipid bilayer

-Archea cell wall: polysaccharides (sugars)
Archaea membrane: lipid bilayer or monolayer

Question 16

What’s gram staining? Explain it

Answer 16

Technique that divides groups of bacteria based on cell wall thickness.

Gram pos - purple
Gram neg - pink

Gram neg stains pink bc the 2 membranes make it more difficult for colour to pass through and absorb as much.
Gram pos stains purple bc it only has 1 membrane making it easier to pass though and hold colour, protein is thick so stores colour

Question 17

Are gram pos or gram neg more susceptible to antibiotics? Why?

Answer 17

Gram pos has a higher susceptibility to antibiotics (less resistance) as it has a single membrane, making it easier to pass antibiotics thro.

Gram neg has lower susceptibility as it has 2 membranes, harder to pass thro

Question 18

How can we kill bacteria?

Answer 18

Antiseptics: antibacterial chemicals
Antibiotics:poison bacteria with chemicals made by other bacteria/fungi
Human defenses: skin, mucus, lymphocytes

Question 19

What are the functions of bacteria in our gut? (probiotic bacteria)

Answer 19

1. Break down food we cannot digest, straches, fibers, sugars
2. Produce important nutrients like vitamin B12, K
3. Regulate the immune system
4. Protect immune system from harmful bacterias

Question 20

3 differences btw prokaryotes and eukaryotes

Answer 20

-pro have no nucleus, unicellular, smaller
- Eu, habe nucleus, multi cellular, and way large