Week 3

Question 1

What are the three domains of life?

Answer 1

Bacteria, Archea (Prokaryotes) and Eukarya

Question 2

What are the 5 similarities of all organisms?

Answer 2

• All use glycolisis (common set of metabolic pathways)
• All use DNA as genetic material
• All use almost the same genetic code to programme protein synthesis
• All use similar molecular machinery for gene expression
• All have plasma membranes and ribosomes

Question 3

What are the differences between prokaryotes and eukaryotes?

Answer 3

Prokaryotes don’t have:
-Cytoskeleton
-Membrane bound nucleus and organelles
Prokaryotes divide by binary fission.

Question 4

Eukarya are more similar to___?

Answer 4

Archea

Question 5

Describe the three types of morphology of bacteria:

Answer 5

• Circular shape (cocci)
• Rod shape (Bacilli)
• Helical shape

Question 6

Why bacteria have restricted types of shape?

Answer 6

Because of the presence of peptidoglycan in their cell walls

Question 7

What are the two types of gram stained bacteria?

Answer 7

Gram Negative and Gram Positive

Question 8

Describe gram negative:

Answer 8

Their cell walls have 3 components

• 2 plasma membranes (distinct from one another)
• Peptidoglycan layer sandwiched between.

Question 9

Describe gram positive:

Answer 9

Their cell walls have 2 components:

• Cell wall made of peptidoglycan which provide rigidity
• Plasma membrane

Question 10

Describe the four types of archea morphology:

Answer 10

• spherical
• rod
• square
• triangular

Question 11

What is the main difference between archea and bacteria?

Answer 11

Archea lack of peptidoglycan wall

Question 12

What are anaerobes?

Answer 12

They are organisms that don’t use oxygen as an electron acceptor for cellular respiration.

Question 13

What are the two types of anaerobes?

Answer 13

Obbligate and facultative

Question 14

Describe obbligated anaerobes

Answer 14

They can’t tolerate oxygen at all.

Question 15

Describe facultative anaerobes

Answer 15

They’ve developed a way of dealing with oxygen toxicity. They can switch between aerobic and anaerobic respiration.

Question 16

What are denitrifiers?

Answer 16

Organisms that use NO3 as an electron acceptor under anaerobic conditions. They release N2 in the atmosphere.

Question 17

What are nitrifiers?

Answer 17

Organisms that are chemolitotrophs that oxide ammonia to nitrates.

Question 18

What are nitrogen fixers?

Answer 18

Organisms that convert N2 into ammonia.

Question 19

What is Lateral Gene Transfer?

Answer 19

Under stress conditions bacteria tend to congregate together and become pourous to DNA and their share plasmids. So basically DNA can move laterally from one species to another and this is because you can’t base the taxonomy of procariotes on DNA.

Question 20

What do you use to track the philogeny of prokaryotes?

Answer 20

rRNA because it isn’t shared between bacteria.

Question 21

What are the properties of prokaryotes?

Answer 21

1- They’re unicellular
2- Don’t divide by mitosis
3-The organization of the genetic material differ
4- Prokaryotes don’t have organelles enclosed in a membrane

Question 22

Describe the features of eukaryotes:

Answer 22

• They have a cytoskeleton
• They divide by mitosis
• They have membrane-bound nucleus and organelles

Question 23

What are protists?

Answer 23

All eukaryotes except animals, plants and fungi

Question 24

Describe the peculiarity of eukaryotic cell:

Answer 24

Flexible Cell Surface
Infolded membrane
Nuclear envelope
Digestive vacuoles
Mithocondria
Chloroplasts

Question 25

What’s primary endosymbiosis?

Answer 25

The engulfment of a cyanobacterium from an eukaryote (2 membrane)

Question 26

What’s secondary endosymbiosis?

Answer 26

The engulfoment of a cyanobacterium-containing eukaryote by another eukaryote (3 membrane)