2.6 Prokaryotic and eukaryotic cells

Question 1

Animals, plants, and fungi are all what?

Answer 1

complex multicellular organisms

Question 2

The cells making up animals, plants, and fungi are what type

Answer 2

eukaryotic

Question 3

There is a lot evidence that suggests that eukaryotic cells are what?

Answer 3

eukaryotic cells evolved from less complex prokaryotic cells

Question 4

Less complex prokaryotic cells are present where?

Answer 4

present in great numbers and live in an incredibly diverse range of habitats

Question 5

Prokaryotic cells, unicellular organisms can be classed into two what?

Answer 5

evolutionary domains- Archaea and Bacteria

Question 6

These unicelllular organisms are classed into what two evolutionary domains?

Answer 6

archaea and bacteria

Question 7

Where have the two evolutionary domain, archaea and bacteria evolved from?

Answer 7

an ancient common ancestor

Question 8

What may have been among the earlliest forms of life on earth?

Answer 8

prokaryotic cells

Question 9

When have prokaryotic cells first appeared?

Answer 9

around 3.5 billion years ago when the surface of the Earth was a very hostile environment

Question 10

Scientists believe that prokaryotic cells were adapted to living in extremes of what??

Answer 10

that these early cells were adapted to living in extremes of salinity, pH and temperature

Question 11

Early cells that were adapted to living in extremes of salinity, pH and temperature
that still exist today are called what?

Answer 11

extremophiles

Question 12

Where can extremophiles be found?

Answer 12

in hydrothermal vents and salt lakes- similar environments to those believed to have made up the early Earth

Question 13

What are extremophiles usually the domain of?

Answer 13

Archaea and more recently they have been found in more hospitable environments such as soil and the human digestive system

Question 14

Prokarytic organisms are always what?

Answer 14

unicellular with a relatively simple structure

Question 15

The DNA in prokaryotic organisms are not contained within what?

Answer 15

within a nucleus

: they have few organelles and the organelles they do have or not membrane bound

Question 16

Describe the DNA in both eukaryotes and prokaryotes

Answer 16

the structure of the DNA contained within prokaryotes is fundamentally the same as in eukaryores but packaged differently

Question 17

Describe the DNA in a prokaryote

Answer 17

They generally have only one molecule of DNA, a chromosome, which is supercouiled to make it more compact

Question 18

What shape is the chromosome in prokayotes and why?

Answer 18

supercoiled to make it more compact

Question 19

The genes on the supercoild chromosome of the prokaryote is often what?

Answer 19

often grouped into operons, meaning a number of genes are switched on or off at the same time

Question 20

Which ribosomes are smaller. Prokaryotic or eukaryotic?

Answer 20

prokaryotic

Question 21

The relative size of ribosomes in prokaryotic cells are determined by what?

Answer 21

the rate at which they settle, or form a sediment in solution

Question 22

The larger eukaryotic ribosomes are desginated what?

Answer 22

80s

Question 23

The smaller prokaryotic ribosomes are designated what?

Answer 23

70s

Question 24

Both designated ribosomes are necessary for protein synthesis, although the larger 80s ribomes are involved in what?

Answer 24

the formation of more complex proteins

Question 25

Prokaryotc cells have a cell wall made from what?

Answer 25

peptidoglycan, also known as murein

Question 26

What is peptidoglycan, the thing cell walls are made from in prokaryotic cells/

Answer 26

it is a complex polymer formed from amino acids and sugars

Question 27

The flagella of prokaryotes is what compared to the equivallent structure of eukaryotes and does not have the?

Answer 27

it is thinner and | does not have the 9+2 arrangement

Question 28

In prokaryotic cells, the energy to rotate the filament that forms the flagellum is supplied from the process of what?

Answer 28

chemiosis, not from ATP as in eukaryotic cells

Question 29

In prokaryotic cells, the flagelllum is attached to the cell membrane of a bacterium by and is rotated by what?

Answer 29

a basal body and rotated by a molecular motor

Question 30

In prokaryotic cells, the basal-body attaches the filament comprising the flagellum to what?

Answer 30

the cell-surface membrane of a bacterium

Question 31

In prokaryotic cells, flagellum wise, what does a molecular motor cause

Answer 31

causes the hook to rotate giving the filament a whip like movement, which propels the cell

Question 32

The first eukaryotic cells appeared when?

Answer 32

about 1.5 billion years ago

Question 33

Eukaryotic cells are more _____ than prokaryotic cells

Answer 33

complex

Question 34

Where is the DNA present in eukaryotic cells and what do they exist as?

Answer 34

present within a nucleus and exists as multiple chromosomes

Question 35

Describe the chromosomes in eukaryotic cells

Answer 35

DNA exists as multiple chromosomes: supercoiled i) each one wraps around a number of proteins called histones, forming a complex for efficient packaging. ii) this complex is called chromatin and chromatin coils and condenses to form chromosomes

Question 36

Eukaryotic genes are generally what?

Answer 36

switched on and off individually

Question 37

Eukaryotic cells have membrane bound organelles. What does this include?

Answer 37

mitochondria and chloroplasts

Question 38

Organisms from the plant, animal, fungi, and protoctista kingdoms are all composed of what?

Answer 38

eukaryotic cells, many are multicellular

Question 39

What is the theory of endosymbiosis

Answer 39

- evolution of eukaryotic cells - mitochondria and chloroplasts, and possibly other eukaryotic organelles, were formerly free-living bacteria, that is prokaryotes - these prokaryotes were taken inside another cell as an endosymbiont (an organism that lives within the body or cells of another organism)

Question 40

Outline the difference in prokaryotes and eukaryotes with nucleus

Answer 40

prokaryoes- not present | eukaryotes- present

Question 41

Outline the difference in prokaryotes and eukaryotes with DNA

Answer 41

prokaryotes- dna is naked, circular and usually no introns (not in chromosomes) eukaryotes- DNA is bound to proteins, linear and usueally has introns

Question 42

Outline the difference in prokaryotes and eukaryotes with DNA organisation

Answer 42

prokaryotes- fold and condense dna | eukaryotes- associate with proteins called histones

Question 43

Outline the difference in prokaryotes and eukaryotes with extra chromosomal DNA

Answer 43

prokaryotes- circular DNA called plasmids | eukaryotes- only present in certain organelles such as chloroplasts and mitochondria

Question 44

Outline the difference in prokaryotes and eukaryotes with organelles

Answer 44

prokaryotes- non-membrane bound | eukaryotes- membrane bound and non-membrane bound

Question 45

Outline the difference in prokaryotes and eukaryotes with cell wall

Answer 45

prokaryotes- peptidoglycan | eukaryotes- chitin in fungi, cellulose in plants, not present in animals

Question 46

Outline the difference in prokaryotes and eukaryotes with ribosomes

Answer 46

prokaryotes- smaller, 70s | eukaryotes- larger 80s

Question 47

Outline the difference in prokaryotes and eukaryotes with cytoskeleton

Answer 47

prokaryotes- present | eukaryotes- present, more complex

Question 48

Outline the difference in prokaryotes and eukaryotes with reproduction

Answer 48

prokaryotic- binary fission, does not have nucleus, asexual | eukaryotic- asexual or sexual

Question 49

Outline the difference in prokaryotes and eukaryotes with cell type

Answer 49

prokaryotic- unicellular | eukaryotic- unicellular and multicellular

Question 50

Outline the difference in prokaryotes and eukaryotes with cell-surface membrane

Answer 50

prokaryote- present | eukaryote- present

Question 51

list three structural differences between prokaryotic cells and eukaryotic cells

Answer 51

1. dna is free floating 2. no membrane bound organelles 3. prokaryotic has cell wall from peptidoglycan 4. prokaryotic has no nucleus 5. smaller ribosomes 6. extra chromosomal DNA

Question 52

Suggest why the lack of membrane-bound organelles does not stop prokaryotic cells making proteins

Answer 52

- Prokaryotic cells have ribosomes, which are needed for protein synthesis - ribosomes are not membrane bound

Question 53

Some antibiotics kill bacteria by disrupting the formation of peptidoglycan molecules. Explain why these antibiotics kill bacteria and why they do not have any effect on eukaryotic cells

Answer 53

Eukaryotic cells do not have cell walls, neither a cell wall formed of peptidolgycan molecules -antibiotics do not damage any other cell components for example nucleus, ribosomes and mitochondria