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Bio 120 > Chapter 3 > Flashcards

Chapter 3 Flashcards

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Biology 101 flashcards
1
Q

What are the 3 parts to the cell theory?

A

1) All living things are composed of one or more cells
2) Cells are the smallest units of living things
3) New cells only come from pre-existing cells by division

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2
Q

How old is the earth?

A

4.55 billion years old

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3
Q

When is it thought that life has begun on earth?

A

between 4 and 3.5 billion years ago

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4
Q

Bacteria existed for over _________ years before eukaryotes came along

A

1.5 billion years

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5
Q

As the Earth formed and cooled, the atmosphere was much different than today.. How?

A

There was no oxygen

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6
Q

What was the early atmosphere made up of? (4)

A

1) NH3 (amonia)
2) CO2 (Carbon dioxide)
3) CH4 (methane)
4) H2O (water)

**Observe, no molecular oxygen**

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7
Q

In the 1920s Aleksander Oparin and John Haldane suggested that …

A

In the 1920s Aleksander Oparin and John Haldane suggested that the chemicals in the early atmosphere could react to produce simple organic compounds

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8
Q

Who started the Reducing Atmosphere Hypothesis? And what was it?

A

Oparin and Haldane

The key was the ‘reducing environment and lack of a protective ozone layer

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9
Q

What was the Miller-Urey Experiment in 1953?

A

They tried to mimic the early atmosphere (early earth) to determine if organic compounds could be produced

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10
Q

What did the Miller- Urey Experiment produce?

A

Produced simple and complex organic molecules

1) Cyanide (HCN)
2) Formaldehyde (H2CO)
3) Amino acids
4) Sugars

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11
Q

How did the Miller-Urey experiment work?

A

They put the compounds of the early atmosphere (CH4, NH3, H2O, H2) which went through a condenser (water in and out) which formed water containing organic compounds… then boiled what and got organic molecules (HCN,H2CO, amino acids, sugars)

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12
Q

What was the conclusion of the Miller- Urey experiment?

A

The conclusionn was that simple organic molecules could form under the conditions of the primitave Earth

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13
Q

Do the results of the Miller-Urey Experiment prove that organic molecules came about this way?

A

No, but it did demonstrate that chemical evolution could occur and that it could be tested in the lab under controlled conditions

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14
Q

_______ provide many ofthe same characteristics as early earth atmosphere plus high pressure

A

Hydrothermal (deep sea) Vents

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15
Q

The high temperatures and pressures of Deep-sea vents can also promote the production of _______

A

Complex organic molecules

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16
Q

It is thought that the diverse _______ emitted by the vent, the gradient of _______ and the immense ______ could result in organic compounds being produced

A

It is thought that the diverse chemicals emitted by the vent, the gradient of temperatureand the immense pressure could result in organic compounds being produced

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17
Q

Comets and Meteors often contain ______ compounds and may have contributed to the _____ present on Earth

A

Comets and Meteors often contain carbon compounds and may have contributed to the carbon present on Earth

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18
Q

Simple biomolecules:

How did they become more complex?

A

Initial ideas suggest that clays may have acted as a polymerization catalyst

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19
Q

Polymers of atleast ________ are required for a simple genetic system

A

Polymers of atleast 30-60 units are required for a simple genetic system

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20
Q

Clay particles tend to be _____ charged and thus attract _________ ions which will interact with _______ charged organic molecules

A

Clay particles tend to be negatively charged and thus attract positive ions which will interact with negatively charged organic molecules

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21
Q

Clays could give rise to _______________

A

Clays could give rise to stable nucleic acid polymers

22
Q

Protibionts:

Next a compartment was needed… what could have formed a primitive cell membrane?

A

Amphipathic molecules (lipids or even proteins)

Which are made up of hydrophobic (inside-hate water) and hydrophilic (outside- like water) ends

23
Q

What did Dr. Jack Szostak’s lab at Harvard University study?

A

They looked at in vitro vesicle formation and RNA synthesis

*In vitro = “in glass”- outside and organism*

24
Q

Protobionts?

It is also suggested that particles of _____ and ______ may have attracted water to form compartments, essentially providing a_________

A

It is also suggested that particles of protein and carbohydrate may have attracted water to form compartments, essentially providing a surface for reactions

25
Q

In experiments these simple compartments supplied with modern enzymes, took in _______ and made _______

A

In experiments these simple compartments supplied with modern enzymes, took in glucose-phosphate and made starch

26
Q

What is the track of the enzymes in a protobiont?

A

Glucose-1 phosphate -> (enters the protobiont as Glucose-1 phosphate)

*In the compartment*

Glucose-1 phosphate-> Starch
(Using the enzyme Glycogen phosphorylase)

Starch -> Maltose
(Using the enzyme Amylase)

Maltose -> (leaves the protobiont as Maltose)

27
Q

To become a living cell, these particles (compartments) needed to become ________

A

self-replicating

28
Q

One theory suggests that RNA molecules inside of a primitive compartment may have randomly achieved the ability to enhance the rate of______________

A

One theory suggests that RNA molecules inside of a primitive compartment may have randomly achieved the ability to enhance the rate of adding one RNA nucleotide onto another

*Clay particles inside a protocell may have helped accelerate this process*

29
Q

_____ provides an RNA molecule with the enzymatic ability to synthesize new RNA molecules from pre-existing RNA molecules

A

Mutation

30
Q

What is the chemical selection of a mutation?

A

The amount of this mutant RNA with enzymatic function increases because it can self replicate

31
Q

______ provides an RNA molecule with the enzymatic ability to synthesize ribonucleotides

A

A second mutation

32
Q

What happens at the chemical selection of a second mutation?

A

After many generations the protobionts have 2 enzymatic functions - self replication and ribonucleotide synthesis

33
Q

What is one catalytic RNA molecules possible sequence of events?

A

Catalytic RNA - learning to catalyze the synthesis of proteins from amino acids

34
Q

Catalytic RNA molecules:

Later, ____ may have replaced ____ as the information storage molecule because it is more stable

A

Later, DNA may have replaced RNA as the information storage molecule because it is more stable

35
Q

Once the ________ could speed up their own production, it was probably only a matter of time (LOTS of time) until simple bacteria evolved

A

Primitative particles

36
Q

Do the first cells look like the cells today?

A

Do nothing and look nothing like a cell today

37
Q

What are Stromatolites?

A

They are mineral deposits left by Cyanobacteria

Some are over 3 billion years old

*Shark Bay, Australia*

38
Q

Define Endosymbiotic Theory

A

It is based on a number of observations scientists proposed that chloroplasts and mitochondria originated as bacteria

39
Q

What are the five parts of the Endosymbiotic Theory?

A

1) Morphology (development of Eukaryotes)
2) Reproduction
3) DNA - sequence and organization
4) Transcription and Translation
5) Metabolism

40
Q

What type of life was on the early earth?

A

Life was anaerobic (no oxygen)

41
Q

T or F:

As O2 levels increased it stressed some bacteria, while others adapted to use O2

A

True

42
Q

_______ bacteria would die in the presence of oxygen, if they lived in _______________ they would be protected

A

Anaerobic bacteria would die in the presence of oxygen, if they lived in close contact with areobic bacteria they would be protected

43
Q

… Eventually the membrane of the anaerobic bacteria might __________

A

Eventually the membrane of the anaerobic bacteria might encapsulate the aerobic bacteria

44
Q

Original prokaryotic host cell:

Is thought to have resulted in the formation of _______

The ____ and __________ formed perhaps to help protect the ‘host’

A

Is thought to have resulted in the formation of mitochondria

The ER and Nuclear Envelope formed perhaps to help protect the ‘host’

45
Q

In a second step primitive _______ may have associated with some of the new eukaryotic cells with the end result being the formation of ______

A

In a second step primitive cyanobacteria may have associated with some of the new eukaryotic cells with the end result being the formation of chloroplasts

46
Q

See slide 42

A
47
Q

We can also see the transfer of genetic information between the ________ and the ______

A

Endosymbionts and the nucleus

*We see this same process between bacteria*

48
Q

What can be immuned to bacteria ?

A

Penicillium

49
Q

What are the 3 benefits of Endosymbiosis?

A

1) Compartmentalization of metabolism
2) Many acient cells were sensitive to oxygen; “mitochondria” use oxygen
3) Chloroplasts provided a continuous source of energy

50
Q

What is the difference between reducing atmosphere and an oxidizing atmosphere?

A

Reducing - no oxygen and doesnt break down

Oxidizing - has oxygen and complex things break down

51
Q

What pieces of evidence do scientists think support the endosymbiotic theory of organelle development?

A

There are two organismes that share resources and living space

Mitochondria have their own DNA

52
Q

What was an outcome of horizontal gene transfer?

a) Import of proteins into mitochondria
b) Increase in size of the chloroplast genome
c) Genes localized to the mitochondria were relocated to the nucleus
d) Decrease in the number of proteins in the chloroplast

A

a or c

Bio 120 (12 decks)

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