Bio 2 1St Exam Review Chapter 26

Front 1

Ancient Earth age?

Back 1

age of 4.5 BY

Front 2

Ancient Earth

Back 2

- early reducing atmosphere including carbon dioxide, water, hydrogen sulfide, methane, no oxygen

Front 3

Oldest Microfossils

Back 3

prokaryotes, emerging ~3.5 bya

Front 4

Good to know about Oldest Microfossils

Back 4

Consider: Eukaryotic cells were not until ~2.1 bya & multicellular organisms not until ~700 mya

Front 5

Miller Urey Experiment

Back 5

included assembling a reducing atmosphere with H2, CH4, NH3, and H2S, placing this atmosphere over liquid water, increasing the temperature of the gases, and providing energy with electrical spark discharges which produced amino acid glycine, hydrogen cyanide, and formaldehyde

Front 6

Good to know about Miller Urey Experiment

Back 6

Consider: If the atmosphere had been an oxidizing one, life may never have arisen because oxygen is corrosive and tends to strip off electrons there by destroying organic compounds...the reducing atmosphere promoted buildup of organic compounds

Front 7

Probable CHemical pathway to origin of life

Back 7

C, H, O, N → CH4 and NH3 → amino acid → proteins

Front 8

Properties of life

Back 8

cellular organization, sensitivity, growth, development, reproduction, regulation, homeostasis, and heredity

Front 9

Good to know about the Properties of Life

Back 9

Consider: The diversity of life is the result of mutation, sexual reproduction, multicellularity, horizontal gene transfer, and endosymbiosis

Front 10

Catalysis

Back 10

can be carried out by enzymes and RNA acting as a ribozyme

Front 11

Bacteria and Archaebacteria Domains

Back 11

contain no eukaryotes

Front 12

Good to know about Bacteria and Archaebacteria Domains

Back 12

Consider: Archea and eukaryotes are more closely related to each other than to bacteria. One characteristic they (archea & Eukarya) share is tRNA methionine

Front 13

Life's Diversity

Back 13

results from sexual reproduction, endosymbiosis, horizontal gene transfer, and mutation

Front 14

Good to know about Life's Diversity

Back 14

Consider: Eukaryotic cells acquired mitochondria (purple and chloroplasts (from cyanobacteria) through endosymbiosis

Front 15

Deep-Sea vent Hypothesis based on

Back 15

formation of prebiotic organic molecules resulting from temperature gradients of the cold ocean water mixing with hot water and hot gaseous substances released from the vents

Front 16

ET hypothesis

Back 16

formation of prebiotic organic molecules resulting from early Earth being bombarded by carbonaceous chondritic meteorites carrying carbon to the early earth

Front 17

POlymerzation of prebiotic organic molecules

Back 17

prebiotic synthesis of polymers not possible in aqueous solutions but will form on clay surface

Front 18

Characteristics of Probionts

Back 18

- internal polymers contained information
-boundary membrane separating internal from external environments
- protobionts capable of self-replication

Front 19

RNA

Back 19

suggested to be first macromolecule found in protobionts

Front 20

good to know about RNA

Back 20

Consider: RNA would have been chemically selected for because it can act as an enzyme (ribozyme) and can self-replicate

Front 21

Liposomes (lipospheres)

Back 21

vesicle surrounded by a lipid layer - may have formed the hollow spheres of phospholipids

Front 22

Coacervates

Back 22

Droplets that form spontaneously from the association of charged polymers; tend to absorb and incorporate substances from environment so semipermeable membrane surrounding first protocell could have been very similar

Front 23

Dna

Back 23

found in nucleus, mitochondria, chloroplasts

Front 24

Radioisotope dating

Back 24

Fossils can be dated using a measured amount of a given isotope as well as the amount of isotope (decay product) produced when the isotope decays

Half-life – length of time required for exactly one-half of original isotope to decay

Front 25

Good to know about Radioisiotope Dating

Back 25

Consider: If you started with 10g of Carbon-14, in 5730 years you would have .5g of Carbon-14 and .5g of Nitrogen-14.

Front 26

Earliest Cells

Back 26

probably anaerobic, heterotrophic, prokaryotic and arose during Archean Eon

Front 27

good to know about Earliest Cells

Back 27

Consider: Protocells would have been present before the development of a true cell but would have had specific characteristics such as a lipid and protein membrane surrounding it and would have contained a biochemical pathway for energy metabolism.

Front 28

Appearance of Hominids

Back 28

Tertiary Period

Front 29

Endosymbiosis

Back 29

prokaryotic cells being engulfed and becoming internal symbionts within an early eukaryotic cell

Front 30

Cambrian Explosion

Back 30

rapid increase in major animal groups' diversity; oxygen levels support larger animals

Front 31

Land PLants

Back 31

appear in fossil record Ordovician Period

Front 32

Reptiles

Back 32

appear during Carboniferous Period

Front 33

Dinosaurs

Back 33

existed from the Triassic to the end of the Cretaceous

Front 34

Mammals

Back 34

arose from mammal-like reptiles in the Triassic but remained small and insignificant while dinosaurs dominated

Front 35

Mass Extinction

Back 35

have occurred about 4 or 5 times in fossil record, due in some cases to catastrophic changes

Front 36

when did (oldest microfossils)Eukaryotic cells first appear?

Back 36

2.1 bya

Front 37

when did (oldest microfossils) multicellular organisms first appear?

Back 37

not unitl 700 mya

Front 38

what did the early reducing atmosphere comprise of?

Back 38

CO2, H2O, hydrogen sulfide, methane, NO OXYGEN!

Front 39

(miller urey experiment)
what negative effects could have occured If there was O2 present within the early reducing atmosphere.

Back 39

O2 is corrosive and tends to strip off electrons there by distroying organic compounds.
(the reducing atmosphere promoted buildup of organic compounds)

Front 40

The diversity of life results from:

Back 40

mutation,
sexual reproduction,
multicellularity,
horizontal gene transfer
Endosymbiosis

Front 41

Where did Eukaryotic cells aquire mitochondria?

Back 41

(purple and chloroplast) from cyanobacteria through endosymbiosis.

Front 42

polymerzation of prebiotic organic molecules will form on __________ but not possible in __________.

Back 42

clay surfaces

aqueous solutions

Front 43

Why would RNA be chemically selected for?

Back 43

beacuse it can act as an enzyme (ribozyme) and can self replicate.

Front 44

when did the earliest cells arise

Back 44

during the Archean Eon

Front 45

The earliest forms of life on earth are found in rocks
A. 1 million years old.
B. 4 million years old.
C. 1 billion years old.
D. 3.5 billion years old.
E. 4.6 billion years old.

Back 45

D. 3.5 billion years old.

Front 46

The term "reducing atmosphere" for the early earth means that the atmosphere
A. was much thinner around the surface of the earth than now.
B. contained only two or three kinds of gases.
C. contained little or no free oxygen.
D. contained little or no free nitrogen.
E. contained little or no carbon dioxide.

Back 46

C. contained little or no free oxygen.

Front 47

The organic soup in which the first cell is believed to have arisen probably contained
A. isolated atoms.
B. bubbling hot gases only.
C. algae and other microscopic organisms.
D. amino and organic acids.
E. nucleic acids and proteins.

Back 47

D. amino and organic acids.

Front 48

The eventual development of oxygen in the atmosphere meant that
A. most environments were no longer suitable for anaerobic prokaryotes.
B. most environments were no longer suitable for aerobic prokaryotes.
C. photosynthetic cyanobacteria declined in number.
D. a large portion of the history of life was devoted to eukaryotic evolution.
E. oxygen was needed in order for evolution to occur.

Back 48

A. most environments were no longer suitable for anaerobic prokaryotes.

Front 49

Which of the following is the correct order, from simple to complex, showing the origin of life?
A. proteins --> CH4 and NH3 --> amino acids --> C, H, O, N
B. C, H, O, N --> CH4 and NH3 --> amino acid --> proteins
C. C, H, O, N --> amino acids --> proteins --> CH4 and NH3
D. amino acids --> proteins --> C, H, O, N --> CH4 and NH3
E. CH4 and NH3 --> proteins --> C, H, O, N --> amino acids

Back 49

B. C, H, O, N --> CH4 and NH3 --> amino acid --> proteins

Front 50

A complex protein-rich cell shelters and supports the DNA genetic code, and the code is the blueprint for the cell proteins; thus is set the "chicken-or-the-egg" dilemma of which came first. This is probably solved by the discovery that
A. RNAs called ribozymes had enzyme functions and could have served as both genetic matter and enzymes.
B. reverse transcriptase can convert RNA back into DNA.
C. all DNA and protein can be distributed evenly inside and outside the nucleus.
D. some proteins are simply assemblages of guanine, cytosine, thymine, and adenine.
E. viruses can give rise to all of the cell molecules.

Back 50

B. reverse transcriptase can convert RNA back into DNA.

Front 51

Which statement is NOT true about a protocell?

A. It would have contained DNA as its genetic material.
B. It would have been present before the development of a true cell.
C. It would have had a lipid and protein membrane surrounding it.
D. It would have contained a biochemical pathway for energy metabolism.
E. It might have been like a coacervate droplet in which a semipermeable boundary allows some materials to be absorbed from the surrounding environment.

Back 51

A. It would have contained DNA as its genetic material.

Front 52

Which term does NOT apply to the first protocell?
A. fermentation
B. autotrophic
C. membrane-bound
D. single-celled
E. self-replicating

Back 52

B. autotrophic

Front 53

The first eukaryotic cells probably arose about _____ billion years ago.
A. 2.1
B. 2.5
C. 3.5
D. 4.5
E. 5.5

Back 53

A. 2.1

Front 54

The position of mammals in evolution is best described as
A. they dominate life in the sea.
B. they were among the first animals to live on land and their variety outstrips all living things known.
C. they arose from mammal-like reptiles in the Triassic but remained small and insignificant while dinosaurs dominated the land.
D. mammals gave rise to birds.
E. mammals have been present since plants and other organisms first appeared on land.

Back 54

C. they arose from mammal-like reptiles in the Triassic but remained small and insignificant while dinosaurs dominated the land.