Prokaryotes

Question 1

What are the 3 domains of life

Answer 1

• Bacteria
• Archaea
• Eukarya

Question 2

What are prokaryotes

Answer 2

Prokaryotes: Bacteria and Archaea

• small
• unicellular
• some colonies
• no membranes bound organelles (mitochondria, chloroplast… )

Question 3

What are the 3 main shapes of prokaryotes

Answer 3

cocci = spherical

bacilli = rod-shaped

spirochete = spiral

Question 4

What are some general anatomy features of prokaryotes

Answer 4

Have cell walls + capsules to protect the cell membrane

Fimbriae adhere to other cells

flagella for locomotion

RNA + DNA in single chromosomes and or “rings” called plasmids

Question 5

What are Archaea

Answer 5

• similar in form to bacteria
• associated with extreme environments and habitats
• sisters to eukaryotes

Question 6

Where can you find prokaryotes

Answer 6

Prokaryotes can be found in diverse environments from the Antarctic to hydrothermal vents

Question 7

What are the different types of autotrophs

Answer 7

Autotrophs:
1. Photoautotroph: energy from light, carbon from CO2, HCO3- or other compounds, found in plants, protists, photosynthesizing bacteria, etc

1. Chemoautotroph: energy from inorganic materials like H2S, NH3, Fe2+, carbon from CO2, HCO3-, or others. Found in certain protists

Question 8

What are the different types of heterotroph

Answer 8

1. Photoheterotroph: energy from light, carbon from organic compounds, found in aquatic and salt loving prokaryotes
2. Chemohaterotroph: energy and carbon from organic compounds, found in animals, fungi, many protists, many prokaryotes

Question 9

What are the 3 types of Symbiosis

Answer 9

1. Parisitism

one party benefits at expense of others (includes pathogens)

1. Commensalism

2+ organisms coexisting, neither party is harmed

1. Mutualism

Both parties benefit

Question 10

How many prokaryotes are there

Answer 10

prokaryotes make up around half of earth’s biomass, around 6 x 10^30 cells

Question 11

How do prokaryotes mainly reproduce

Answer 11

They reproduce mainly through binary fission, which is a type of vertical gene transfer

Question 12

what is conjugation

Answer 12

• Conjugation
  
  • One prokaryotes passes genetic material to another through a type of gene bridge

Question 13

What is transformation

Answer 13

• Transformation
  
  • a prokaryote absorbs nucleic acid from the environment

Question 14

what is transduction

Answer 14

• Transduction
  
  • nucleic acid transmitted by viruses

Question 15

What are the three types of primary horizontal gene transfer in prokaryotes

Answer 15

Conjugation,
Transformation,
Transduction.

Question 16

Where are viruses on the tree of life

Answer 16

on our 3 domain tree of life, we have bacteria, eukaryotes containing plants, animals, fungi, and groups of protists, and archaea. But where are viruses?

well Viruses are not considered living, so they are not on the tree of life.

Question 17

How might we define life

Answer 17

We might define life as anything that can or has the following characteristics:

• reproduction or replication
• structural order (cells)
• consumption and conversion of energy
• regulation of internal processes (homeostasis)

Question 18

Why are viruses alive

Answer 18

Viruses meet the first characteristic but aren’t made of cells, don’t consume / convert energy, and don’t demonstrate homeostasis.

Question 19

What might viruses illustrate

Answer 19

They might illustrate possible paths to the origins of life on earth, though since they are dependant on living cells, they are not the same as pre-cell lifelike things

Question 20

What is the structure of a virus

Answer 20

small segment of nucleic acid

covered in a capsid and protein coat

Invade a host cell to replicate its nucleic acid sequence using the cells “machinery”

Question 21

What is the replication cycle of viruses

Answer 21

1. Attaches to a living cell
2. Injects its nucleic acid into the cell
3. the viral DNA or RNA takes over the cell
4. It forces the cell to synthesize viral genomes and proteins (the building blocks of viruses)
5. these components self assemble into new viruses
6. the new viruses burst out of the cells

Question 22

what are prions

Answer 22

a “selfish” protein

they can replicate themselves at the expense of cellular life

Causes diseases like mad cow

no nucleic acid, but they force other proteins to match their form

Question 23

When did earth form and when did life begin

Answer 23

the earth formed around 4.5 billion years ago, but for the first 500 million years it was inhospitable during a time dubbed the Hadeon Eon

Prokaryotes emerged in the Archaen Eon, around 3.7-3.5 billion years ago.

Question 24

what environment did early life start in

Answer 24

At this point the atmosphere contained no ozone and little oxygen, but it did have lots of UV, ammonia, and methane.

Life probably started in a warm ocean soup of carbon, nitrogen, and hydrogen.

Question 25

what affects did prokaryotes have on the earth

Answer 25

Nitrogen fixing prokaryotes converted the unusable atmospheric nitrogen to usable forms, this makes up the base of the ecosystem.

Cyanobacteria and other photosynthesizers caused the 1st mass extinction when they “rapidly” increased the amount of oxygen in the atmosphere

Question 26

what are 6 biotech uses of prokaryotes

Answer 26

Through gene editing technology like Crisper we can do a number of useful things

• make allergy free / better food
• green fuel
• eradication of disease
• bioremediation
• synthesizing materials
• storing data in DNA hard drives

Question 27

what is the LTEE

Answer 27

LTEE (Long Term Evolution Experiment)

began in 1988 and still ongoing

12 populations of E.Coli were set up to feed on a glucose food source

everyday (equating to around 6-7 generations) 1% of each population were transferred to a fresh medium

Several lines evolved an interesting adaptation: the ability to feed on the wast product citrate.