Topic 1.5: The Origin of Cells Flashcards Preview

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Flashcards in Topic 1.5: The Origin of Cells Deck (21):
1

Define abiogenesis

The theory that living cells arose from non-living matter

2

What is The theory that living cells arose from non-living matter?

abiogenesis

3

What is the first step of abiogenesis?

There was non-living synthesis of simple organic molecules (from primordial inorganic molecules)

4

After There was non-living synthesis of simple organic molecules (from primordial inorganic molecules) what is the next step of abiogenesis?

These simple organic molecules became assembled into more complex polymers

5

After These simple organic molecules became assembled into more complex polymers what is the next step of abiogenesis?

Certain polymers formed the capacity to self-replicate (enabling inheritance)

6

After Certain polymers formed the capacity to self-replicate (enabling inheritance) what is the next step of abiogenesis?

These molecules became packaged into membranes with an internal chemistry different from their surroundings (protobionts)

7

What was the first step of the Miller-Urey Experiment?

Water was boiled to vapour to reflect the high temperatures common to Earth’s original conditions

8

After Water was boiled to vapour to reflect the high temperatures common to Earth’s original conditions what was the next step of the miller-urey experiment?

The vapour was mixed with a variety of gases (including H2, CH4, NH3) to create a reducing atmosphere (no oxygen)

9

After The vapour was mixed with a variety of gases (including H2, CH4, NH3) to create a reducing atmosphere (no oxygen) what was the next step of the miller-urey experiment?

This mixture was then exposed to an electrical discharge (simulating the effects of lightning as an energy source for reactions)

10

After This mixture was then exposed to an electrical discharge (simulating the effects of lightning as an energy source for reactions) what was the next step of the miller-urey experiment?

The mixture was then allowed to cool (concentrating components) and left for a period of ~1 week

11

After The mixture was then allowed to cool (concentrating components) and left for a period of ~1 week what was the next step of the miller-urey experiment?

After this time, the condensed mixture was analysed and found to contain traces of simple organic molecules

12

Define biogenesis

the idea that cells can only be formed by the division of pre-existing cells

13

Define endosymbiont

a cell which lives inside another cell with mutual benefit

14

Explain endosymbiotic theory

Eukaryotic cells are believed to have evolved from early prokaryotes that were engulfed by phagocytosis

The engulfed prokaryotic cell remained undigested as it contributed new functionality to the engulfing cell (e.g. photosynthesis)

Over generations, the engulfed cell lost some of its independent utility and became a supplemental organelle

15

What are two organelles that are evidence for endosymbiosis?

mitochondria and chloroplasts

16

What are the five pieces of evidence for endosybiosis?

Membranes (double membrane bound)

Antibiotics (susceptibility)

Division (mode of replication)

DNA (presence and structural composition)

Ribosomes (size)

17

What is the first step of the RNA world hypothesis?

RNA forms from inorganic sources

18

After RNA forms from inorganic sources what is the next step of the RNA world hypothesis?

RNA self-replicates (via ribozymes)

19

After RNA self-replicates (via ribozymes) what is the next step of the RNA world hypothesis?

RNA catalyses protein synthesis

20

After RNA catalyses protein synthesis what is the next step of the RNA world hypothesis?

Membrane formation changes internal chemistry allowing new functionality

21

After Membrane formation changes internal chemistry allowing new functionality what is the next step of the RNA world hypothesis?

RNA codes both DNA and protein

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