Chp 22

Question 1

The universe began with the Big Bang about how many years ago

Answer 1

13.7 bya

Question 2

H and He were converted to what heavier elements

Answer 2

C, N, O

Question 3

Stars that exploded are called

Answer 3

Supernovas

Question 4

Clouds collapsed to make

Answer 4

New stars and soar systems

Question 5

Solar systems began

Answer 5

4.6 bya

Question 6

Earth is how old

Answer 6

4.55 bya

Question 7

Earth originated from aggregation of

Answer 7

Planetesimals over a period of 100-200 my

Question 8

Earth cooled enough for outer layers to solidify and oceans to form

Answer 8

4 bya

Four cooling

Question 9

Origin in 4 overlapping stages

Answer 9

Nucleotides and AA—>[polymerize] DNA, RNA, and proteins —>[enclosed in] membrane —>[aquired] cellular properties

Question 10

Organic molecules

Answer 10

Little free oxygen gas

Prebiotic soup

Question 11

Reducing atmosphere hypothesis

Answer 11

Atmosphere rich in water vapor, h2, ch4, nh3 and little o2
Miller- urey experiment of 1953
Formed precursors, AA, sugars and nitrogenous bases
Showed says techsis was possible not proven

Question 12

Extraterrestrial hypothesis

Answer 12

Meteorites brought organic carbon to earth; may include amino acids and Nucleic acid bases
Opponents argue that most of this would be destroyed in the intense heating and collision

Question 13

Deep sea vent

Answer 13

Molecules may have formed in the temp gradient between extremely hot vent water and cold ocean water
Supported by experiments (kirt: the only experiments were those that show fe reacts with h2s to form pyrites and give off energy that may cause n2 to form nh3
Communities that derive energy from chemicals in the vent found here

Question 14

Prebiotic synthesis if polymers not possible in aqueous solutions because

Answer 14

Hydrolysis competes

Question 15

Formation of Nucleic acid polymers and polypeptides on what kind of surface

Answer 15

Clay because they can bind organic molecules because of negative charges, and they attract metal ions like Mg+ that can catalyze rxns to produce polymers

Question 16

Their experiments they added monomer building blocks and watched them aggregate

Answer 16

They positioned the nucleotides

Question 17

Aggregate of prebiotically produced molecules and macromolecules that aquired a boundary

Answer 17

Protobiont

Question 18

Boundary that allowed it to maintain an internal chemical environment distinct from that of its surroundings

Answer 18

Lipid bilayer

Question 19

4 characteristics of protobionts

Answer 19

1. Boundary Seperated external environment from internal contents
2. Polymers inside the protobiont contained information
3. Polymers inside the protobiont had enzymatic function
4. Protobiont capable of self replication-not self reproduction but divide to increase in number
   Assumption that metabolic pathways formed w/in that could modify the molecules.

Question 20

Droplets that form spontaneously from the association of charged polymers

Answer 20

Coacervates

Enzymes inside can perform primitive metabolic function

Question 21

Vesicles surrounded by a lipid layer

Answer 21

Liposomes

Question 22

Clay can catalyze for action of ___ that grow and divide

Answer 22

Liposomes

Question 23

Majority of scientists favor ___ as the first macromolecules of protobionts

Answer 23

RNA –simpler

Question 24

3 key RNA functions

Answer 24

1. Ability to store information
2. Capacity for self replication
3. Enzymatic functions-ribozymes

Question 25

DNA and proteins do not have all 3 functions

Answer 25

True

Question 26

Chemical within a mixture of different chemicals has special properties or advantages that cause it to increase in number compared to other chemicals in the mixture

Answer 26

Chemical selection

Question 27

Hypothetical scenario with 2 steps

Answer 27

1. One of the RNA molecules mutates and has enzymatic ability to attach nucleotides together- advan of faster replication 2. Second mutation produces enzymes ability to synthesize nucleotides - no reliance on prebiotic synthesis

Question 28

Information storage

Answer 28

DNA would have relieved RNA of informational role and allowed RNA to do other functions DNA is less likely to suffer mutations or breaks

Question 29

Metabolism and other cellular functions

Answer 29

Proteins have a greater catalytic potential/efficiency Proteins can perform other tasks-cytoskeleton, transport, etc Proteins came into being as RNA can catalyze formation of peptide bonds

Question 30

Preserved remains of past life on earth

Answer 30

Fossils

Question 31

Who study fossils

Answer 31

Paleontologists

Question 32

Many rocks with fossils are

Answer 32

Sedimentary

Question 33

Older rock is deeper and older organisms are ___ in the rock bed

Answer 33

Deeper

Question 34

Fossils can be dated using elemental isotopes in accompanying rock

Answer 34

Radioisotope dating

Question 35

Length if time required for exactly one half of the original isotope to decay measures amount of a given isotope as well as the amount of the decay product usually igneous rock dated

Answer 35

Half life

Question 36

Geological time scale: origin 4.55 bya to present | The four eons are:

Answer 36

Hadean 4.5-3.8 bya - 3.8- first prokaryo Archaean 3.8-2.5 bya- 2.5 first eukaryo Proterozoic 2.5 to 543 mya- Cambrian explosion Phanerozoic- 543 mya to present

Question 37

Changes in living organisms the result of

Answer 37

genetic changes

Question 38

Environment changes:

Answer 38

allow for new types of organisms | responsible for extinctions

Question 39

Major environmental changes

Answer 39

``` climate temp atomosphere (o2 started accum 2.4 bya)- origin of body plans coincide with o2 rise land masses-continental drift occured flood glaciation snowball earth hyopthesis volcanic eruptions meteoric impacts ```

Question 40

Mass extinctions- 5 large mass extinctions

Answer 40

near end of Ordovician, Devonian, Permian, Triassic, and Cretaceous periods boundaries between geoloci time periods are often based on these events

Question 41

rapid extinction of mmany modern species due to human activites is sometimes referred to as the

Answer 41

sixth mass extinction

Question 42

When diverse microbial life (prokaryotic cells) floursihed in primoridal oceans

Answer 42

archaeon eon

Question 43

all life forms prokaryotic during hardly any free oxygen so organisms were anaerobic first cells were heterotrophs; autotropsh evolved as supply of organic molecules dwindled

Answer 43

Archaeon Eon

Question 44

layered structure of calcium carbonate

Answer 44

stromatolites

Question 45

Multiccellular eukary arise 1.5 bya; 2 possible origins indiv form a colony single cell divides and stays stuck together First animals invertebrates-bilateral symmetry facilitates locomtion

Answer 45

proterozoic eon

Question 46

Paleozoic era- cambria, ordovician, silurian, devonian, carboniferous, permian Mesozoic era- triassic and jurassic Cenozoic era- tertiary and quaternary

Answer 46

Phanerozoic Eon- proliferation of multicellular eukaryotic life extensive