Lecture 6: Prokaryotes and Protists

Question 1

How long have Prokaryotes been around?

Answer 1

alone most of history of life on earth, approximately 2.5 billion years .

• origin of life = 4 billion
• Prokaryotes = 3.5 billion
• Photosynthesis = 2.8 billion
• Eukaryotic cells = 1.5 billion

Question 2

What was the main atmospheric change after prokaryotes?

Answer 2

-photosynthesis

Question 3

Cyanobacteria

Answer 3

first photosynthetic, abundant organisms

-produce Oxygen as waste

Question 4

Two major consequences of Photosynthesis creating Oxygen

Answer 4

• Aerobic (efficient) metabolism
• Accumulation of ozone shield (O3) protected life from UV irradiation (allowed life on land) (human metabolism is reliant on oxygen)

Question 5

Few Eukaryotes can operate _______ oxygen.

Answer 5

without

Question 6

Aerobic

Answer 6

“in the presence of oxygen”

Question 7

Archaea is the ______ group to Eukarya

Answer 7

sister

Question 8

Archaea and bacteria are both __________. but differ more from each other than Archaea and Eukarya.

Answer 8

prokaryotic

Question 9

What are the two Kingdoms in Prokarya?

Answer 9

Kingdom Bacteria

Kingdom Archaea

Question 10

Explain Kingdoms in Eukarya (Old method)

Answer 10

OLD

• Protists
• Plants
• Fungi
• Animals

Question 11

What are the seven Kingdoms in Eukarya (New) method)?

gee whiz/don’t need to know these

Answer 11

NEW

1) Excavato
2) Discicristata
3) Alveolata
4) Stramenopila
5) Rhizaria
6) Plantae
7) Opisthokonta
8) Amoebozoa

Question 12

When was Archaea first sequenced (genome)

Answer 12

1996

Question 13

How are bacteria and Archaea similar and how are they different?

Answer 13

Superficially similar;

Genetically and Morphologically different
IE- bacteria walls contain peptidoglycan whereas Archaea have different substances, polysaccharides or glycoproteins

Question 14

What differences between Archaea and Bacteria led to the three Domain concept?

Answer 14

• differences in RNA sequences
• membrane structure
• others

Question 15

Extremophiles

Answer 15

-many archaea are extremophiles
-Organisms that thrive in extreme conditions
IE - Sulfolobus is an Archaea that thrives at very high temperatures and acidic environments)

Question 16

Which organism is the most numerous and diverse?

Answer 16

Prokaryotes

Question 17

What percent of Prokaryotes were cultured using cell staining?

Answer 17

1%

Now use culture-free DNA sequencing

Question 18

How many species of Prokaryotes live in gut?

Answer 18

about 1000 inside (probably more); thousands on skin too

Question 19

How many prokaryotic cells relative to human cells in gut?

Answer 19

10 times

Question 20

How much of our weight is bacteria?

Answer 20

1 kg

Question 21

Prokaryotes in the Gut

Answer 21

• important for normal gut development
• calibrate immune system
• different communities more or less efficient at extracting calories from food

Question 22

Skin prokaryotes

Answer 22

1) prevent pathogens from invading

2) stimulate skin immunity, protects against skin disease

Question 23

Provide example of Prokaryotes powerful effects

Answer 23

-bacteria that turns males into females

• female minute (stingless) parasitic wasps have bacteria in their cells that are transmitted to the next generation egg cytoplasm
• Males don’t transmit the bacterium
• The bacteria cause all of the wasp offspring to be female and there are no males in this population

Question 24

What do Prokaryotes have that’s different from (most) Protists and animals?

Answer 24

A cell wall.

-Cell walls provide structural support, protection, and prevent water loss or rupture of cell from turgor pressure.

Question 25

Prokaryotic cells are usually much ________ than Eukaryotic cells

Answer 25

smaller. | -They are closer to the size of mitochondria or chloroplast.

Question 26

In a prokaryotic cell, everything is in ______ compartment.

Answer 26

one

Question 27

Eukaryotes (difference from Prokaryote)

Answer 27

- have a nuclear envelope - often (except for plants) no cell wall (allows for movement) - sophisticated cytoskeleton - vesicles for digestion - Organelles

Question 28

nucleus (not on quiz)

Answer 28

stores genetic info

Question 29

chloroplast(not on quiz)

Answer 29

responsible for photosynthesis

Question 30

ribosomes(not on quiz)

Answer 30

site of protein synthesis

Question 31

endoplasmic reticulum(not on quiz)

Answer 31

the highway network for transportation

Question 32

golgi apparatus(not on quiz)

Answer 32

the carbohydrate factory and sorting/packaging facility

Question 33

cytoskeleton(not on quiz)

Answer 33

the scaffolding of the cell

Question 34

mitochondria(not on quiz)

Answer 34

site of cellular respiration (converts energy in sugar to ATP)

Question 35

lysome(not on quiz)

Answer 35

digestion machine

Question 36

prokaryotic cells are structurally more _________ than eukaryotic cells.

Answer 36

simple (because no nuclear membrane-Eukaryotic cells have true nuclei and membrane-bounded organelles)

Question 37

Membrane

Answer 37

the thin layer that forms the outer boundary of a living cell or an internal cell compartment

Question 38

Main functions of Membranes in cells

Answer 38

(1) REGULATE the passage of molecules into and out of cells and organelles (selectively) (2) Divide the cell into numerous COMPARTMENTS, each with its own specialized function (3) act as surfaces that hold ENZYMES (catalysts for reaction) (4) Dynamic and constantly CHANGing with the environment

Question 39

All biological membranes are ______________.

Answer 39

selectively permeable

Question 40

Evidence of Endosymbiosis

Answer 40

Organelles share features with prokaryotes - mitochondria and chloroplast organelles store their own DNA/RNA - genes most closely related to existing bacteria (chloroplasts closely related to cyanobacteria and mitochondria closely related to proteobacteria) - both cyanobacteria and chloroplasts have chlorophyll in their membranes (and other similarities

Question 41

How do prokaryotes reproduce?

Answer 41

asexually by fission

Question 42

How do prokaryotes exchange genetic info?

Answer 42

Conjugation: transfer of DNA via a cytoplasmic bridge Transformation: Take an extracellular DNA spontaneously Transduction: DNA can be transferred by a bacterial virus (a bacteriophage)

Question 43

prokaryotes have a ________ rage of shapes and sizes

Answer 43

fairly narrow

Question 44

all ancestral prokaryotes were ________ and some still are. Some can shift back and forth

Answer 44

anaerobic anaerobic: metabolism in the absence of oxygen aerobic: metabolism that requires oxygen

Question 45

all living organisms need a source of ________ and a source of _________ to survive and grow.

Answer 45

- energy - carbon (human get both from eating)

Question 46

chemolithotrophs

Answer 46

some prokaryotes use simple inorganic molecules like nitrogen or sulfur for energy but CO2 for carbon

Question 47

photoheterotrophs

Answer 47

prokaryotes that use light for energy but need to ingest organic compounds for carbon

Question 48

chemical tricks for prokaryotes vs eukaryotes

Answer 48

- digest cellulose (in plant walls) | - produce amazing toxins like polyketids, many antibiotics

Question 49

prokaryotes play key role in global nutrient cycles

Answer 49

nitrogen fixation: extract N2 out of the air nitrification: ammonia produced from nitrogen fixation is converted into nitrate ions (a form that's better for plants to use denitrification: return nitrogen from waste to atmospheric nitrogen

Question 50

protists defined by what they are not

Answer 50

-not animals, not plants, not fungi - most are unicellular but some are multicellular - many evolved independently in different lineages - some more closely related to plants, some to animals, some to fungi - not a monophyletic group

Question 51

There are 8 major lineages of Eukaryotes. Most are ______ lineages.

Answer 51

protist note: protists are paraphyletic (common ancestor not all descendants)