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Biology🧪🌱💦 > Lecture 12 > Flashcards

Lecture 12 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are the key words for the 4 main stages required for the Origin of Life?

A
  • abiotic synthesis
  • polymers
  • protobionts
  • self-replicating -> inheritance
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2
Q

How did life originate in the very past?

A

Life originated under very different conditions than those experienced today

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3
Q

How was the air?

A

The atmosphere of early earth may have been a “reducing” atmosphere:
– thick with water vapor, nitrogen, and its oxides, carbon dioxide, methane, ammonia, hydrogen, and hydrogen sulfide.

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4
Q

In this context, what does “reducing” mean?

A

the addition of electrons (usually in the form of a hydrogen) -> allows the formation of organic compounds from simple molecules

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5
Q

4 requirements are necessary for the creation of organic chemicals from simple molecules:

A

a) no free oxygen
b) source of energy
c) chemicals
d) TIME!!

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6
Q

Name a couple of sources of energy:

A

volcanism, thunderstorms, lighting, and UV
radiation

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7
Q

How old is the Earth

A
  • earth is approximately 4.6 billion years old
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8
Q

State the main difference between the atmosphere composition 4.6 billion years ago and today

A

before: 80% CO2, 10% N2, 10% H2O
now: 78% N2, 21% O2
(so no more CO2)

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9
Q

simple organic molecules* formed from WHICH simpler raw materials (4):

A
  • amino acids, sugars, lipids, nucleotide bases
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10
Q
A
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10
Q

How did we make polymers?

A

made by dripping solutions of monomers onto
hot sand, clay, or rock

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11
Q

What are the 2 properties of life:

A

replication & metabolism

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12
Q

What are protobionts?

A

(similar to cells, but not cells): aggregates of abiotically produced molecules

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13
Q

Approximately how many years since the packaging of these molecules into Protobionts?

A

≈3.8BYA

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14
Q

What is called the maintenance of an internal chemical environment different from its surroundings?

A

Homeostasis

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15
Q

What is The origin of self-replicating
molecules leading to inheritance involved?

A

RNA (ribozymes that can make copies of RNA)

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16
Q

Which one evolved later DNA or RNA?

A

DNA

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17
Q

RNA could catalyze what?

A

protein formation

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18
Q

Were the first cells pro or eukaryotes?

A

prokaryotes

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19
Q

What is the oldest fossils?

A

stromatolites

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20
Q

How old are they?

A

3.5-billion-year-old

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21
Q

Did life originate before or after that? (think about it)

A

If bacterial communities existed 3.5 billion years ago, life originated much earlier

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22
Q

Perhaps, how many BYA?

A

perhaps 3.7-3.8 BYA

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23
Q

Protobionts were replaced by what?

A

by organisms that could feed on the available organic molecules found in their environment

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24
Q

What do we call these types of organisms?

A

heterotrophs (using organic molecules in
their environment to sustain themselves)

25
Q

Since there was no O2 back then, what type of nutritional aspect would they be considered?

A

obligate anaerobes (dies in the presence of O2)

26
Q

Therefore, what does it mean if it’s a heterotroph + anaerobic? (more specifically)

A

a Chemoheterotroph

27
Q

The limited supply of natural organic molecules led to what?

A

led to the evolution of organisms that could produce all their needed compounds from molecules in their environment occurred

28
Q

If there are no natural organic molecules, organisms evolve to become more independent, what type of organisms do they become?

A

Autotrophs: producing all required compounds for life

29
Q

Name one type of autotroph:

A

photoautotroph like cyanobacteria

30
Q

Most atmospheric oxygen is biological
origin, from WHAT process?

A

photosynthesis!!

31
Q

So, basically, photosynthesis is responsible for the initial appearance of O2 about how many years ago? (cyanobacteria -> photo -> O2)

A

2.7 BYA

32
Q

What are the characteristics of the Oxygen Revolution

A

oxygen accumulated gradually bw 2.7 and 2.2 BYA + it shot up to 10% of current values around 2.4 BYA TO 2 bya.

33
Q

It was thought to coincide with the origin of what? (2)

A

of eukaryotes and endosymbionts (mitochondria + chloroplasts)

34
Q

The autotrophs (that make their own food) allowed the emergence of WHAT?

A

of more heterotrophs

35
Q

How comes there are more heterotrophs?

A

Since autotrophs produced molecules, heterotrophs live on these molecules

36
Q

Eukaryotes arose from prokaryotes estimated how many BY?

A

2.1 BYA

37
Q

How old is the fossil?

A

1.7 BYA

38
Q

How did eukaryotes arise from prokaryotes

A

from symbioses and genetic exchanges between prokaryotes

39
Q

Name the formation of the organelles in order:

A
  • formation of nuclear mem + endoplasmic reticulum
  • mitochondria
40
Q

What 2 organelles are derived from prokaryotes?

A

mitochondria + chloroplasts

41
Q

How did mitochondria & chloroplasts come about?

A

living within larger cells & became mutually beneficial
- they got ingested (but not digested)
- reproduced along with host cell

42
Q

Then the formation of the mitochondria, what came after?

A

Formation of Chloroplasts

43
Q

TRUE OR FALSE: all eukaryotic cells have mitochondria

A

TRUE

44
Q

TRUE OR FALSE: all eukaryotes have chloroplasts

A

FALSE

45
Q

TRUE OR FALSE: Mitochondria thought to evolve
before chloroplasts

A

TRUEEE

46
Q

Mitochondria & chloroplasts are about the size of what?

A

of bacteria

47
Q

do Mitochondria & chloroplasts have a single or double membrane?

A

double membrane

48
Q

what is the shape of Mitochondria & chloroplasts’s DNA?

A

circular DNA

49
Q

Do Mitochondria & chloroplasts have ribosomes?

A

YES, they have their own ribosomes and protein synthesis machinery

50
Q

What is Biodiversity?

A

Biodiversity is a broad concept which does not have one set definition

51
Q

We can look at it from 3 different perspectives: (name all 3)

A
  • Genetic Diversity
  • Ecosystem Diversity
  • Species Diversity
52
Q

What is Genetic Diversity?

A

the total genetic info contained w/in all individuals of a species
(individuals of a species are genetically different from one another)

53
Q

Why do we say that Genetic diversity is dynamic?

A

b/c it can change with natural selection, immigration, emigration, etc.
-> changes in the allele distributions within a population or species

54
Q

What is an Ecosystem Diversity?

A

the total variety of ecosystems in an area

55
Q

Why do we say that Ecosystem diversity is dynamic?

A

b/c it changes in climate can form new ecosystems or modify old ones

56
Q

What is Species Diversity?

A

the total variety of species within a region
(most commonly used definition + can be easily measured: # of species living in an area)

57
Q

Why do we say that Species Diversity is dynamic?

A

Can increase with speciation (new species) or decrease with extinction

58
Q

How does biodiversity affect us? (say the train of ideas)

A

ecosystem -> autotrophs -> organic nutrients -> heterotrophs -> inorganic nutrients (its mutual)
other consumers (humans) get O2 and release CO2 (help with the inorganic nutrients too)

59
Q

Why is “diversity” important?

A

It is important to have different groups of organisms interacting together

60
Q

If there are many species and plants, is it more stable or less stable?

A

MORE STABLE
(plots of land containing more plant species were more productive and stable than plots
with fewer plant species)

61
Q

Just to make sure everything is clear, what is the sequence of events that lead to origin of
eukaryotes?

A

protocells -> heterotrophic prokaryotes -> autotrophic -> prokaryotes -> endosymbiotic theory -> eukaryotes

Biology🧪🌱💦 (21 decks)

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