UNIT 2 ORIGINS OF LIFE

Question 1

What are the 7 characteristics that all forms of life share?

Answer 1

• They have a display order (cell being the fundamental unit of life)
• Harness and utilize energy
• Reproduce
• Respond to stimuli
• Do homeostasis
• Grow and develop
• They evolve

Question 2

What are the 3 main ideas of the cell theory?

Answer 2

• All organisms are composed of one or more cell
• Cell is the smallest unit that has the property of life
• Cells are from growth and division of preexisting cells only.

Question 3

What was the type of atmosphere in early atmosphere?

Answer 3

Reduced atmosphere

Question 4

What is a reduced atmosphere?

Answer 4

Lack of oxygen or other oxidizing gases, leads to the production of complex organic molecules.

Question 5

Early atmosphere constitutants?

Answer 5

Large amount of water, hydrogen sulphide, carbon dioxide, ammonia and methane.

Question 6

What is an oxidizing atmosphere?

Answer 6

02 rich atmosphere that oxidizes surface compounds.

Question 7

What is the atmosphere we have today?

Answer 7

Oxidizing atmosphere

Question 8

Miller-Urey experiement?

Answer 8

Confirmed the reducing atmosphere created building blocks for the creation of life.

Question 9

How did the mille-Urey experiment worked?

Answer 9

They placed the components of a reducing atmosphere in a closed environment and exposed them to an energy source. After a week they found lots of organic compounds in water.

Question 10

What are protobionts?

Answer 10

The first cell. Are abiotic.

Question 11

What is the Oparin-Haldane hypothesis?

Answer 11

Earth was a reducing atmosphere having a lot of electrons that can easily be donated.

Question 12

What are ribozymes and what do they do?

Answer 12

They are a group of RNA molecules that can catalyze reactions on the precursor RNA molecule that leads to their own synthesis.

Question 13

What did RNA served for in primordial earth.

Answer 13

Both the information and the catalyst

Question 14

First energy releasing reaction in primitive cells?

Answer 14

Oxydation-reduction reactions.

Question 15

Exemple of an oxidation-reduction reaction.

Answer 15

We oxidize food molecules to release energy and reduce other molecules like those needed for protein synthesis.

Question 16

What is panspermia?

Answer 16

The hypothesis that simple forms of life are present in space and could have seeded early earth.

Question 17

Panspermia points?

Answer 17

• too little of a window to create life between the cooling of earth and first evidence of life.
• The presence of extremophiles

Question 18

Prokaryotes are 2 organisms?

Answer 18

Archea and bacteria

Question 19

What are the properties of prokaryotes?

Answer 19

They have a plasma membrane and a cytoplast consisting of cytosol. Organelles, electron transport chain, chromosomes and DNA in nucleoid.

Question 20

Are prokaryotes 10 times smaller than eukaryotes?

Answer 20

Yep

Question 21

Prokaryotes have a high metabolic flexibility meaning that:

Answer 21

They can use a variety of substances as a source of energy and carbon source and they synthesize almost all their organic molecules from raw inorganic materials.

Question 22

The evidence of atmospheric increase in CO2 about 2.5 million years ago is shown by what?

Answer 22

Banded iron.

Question 23

How is banded iron formed?

Answer 23

In the sediments of lakes and oceans as dissolved oxygen reacted to dissolved iron which formed rust.

Question 24

What causes our atmosphere to have CO2 now?

Answer 24

Cyanobacteria. Could harness electrons from water and by doing so was forming CO2 that was released. With time the CO2 accumulated in the atmosphere.

Question 25

What is oxygenic photosynthesis?

Answer 25

Photosynthesis that relies on oxydation of water and releases CO2.

Question 26

Ho does eukaryotes distinguish from prokaryotes?

Answer 26

They have a nuclear enveloppe, cytoplasm has membrane bound compartiments with specialized functions (mitochondria, chloroplasts, endoplasmic reticulum, Golgi complex) they also have motor proteins to move cells.

Question 27

What is an endomembrane system?

Answer 27

Collection of internal membrane sacs that divides the cell into functional compartments called organelles.

Question 28

The endomembrane system is derived from the plasma membrane how?

Answer 28

Pockets of plasma membrane extended inwards and surrounded the nuclear region, forming the nucleus. The remaining of those membranes formed ER and the Golgi complex.

Question 29

What is the endoplasmic reticulum?

Answer 29

interconnected network of channels and vesicles.

Question 30

What is lumen

Answer 30

the space inside a vesicle

Question 31

Rough ER.

Answer 31

Contains many ribosomes on it's outer surface.

Question 32

Smooth ER.

Answer 32

Doesn't contain any ribosome on its surface.

Question 33

Where is the Golgi complex located?

Answer 33

Between the rough ER and the plasma membrane.

Question 34

What is the theory of endosymbiosis?

Answer 34

That mitochondria and choloroplasts evoked from ingested prokaryotes.

Question 35

Evidences of the theory of endosymbiosis?

Answer 35

- Morphology, mitochondria ressembles aerobic prokaryotes while chloroplasts resemble cyanobacteria. - Reproduction, Only derived from preexisting. - They both have DNA - Generates ATP from electron transport chains.

Question 36

Cytoskeleton

Answer 36

system of protein, fibers and tubes that extend through the cytoplasm

Question 37

Function of cytoskeleton?

Answer 37

reinforces the plasma membrane and helps the cell stay in shape and maintain their internal organization. Also gives mechanical support to carry division and movement.

Question 38

3 structural elements of cytoskeleton?

Answer 38

-microtubules, -Intermediate fillamanents -microfillaments All interlinked.

Question 39

Plant cytoskeleton contains only

Answer 39

microtubules and microfillamanet

Question 40

Structure of motor protein

Answer 40

one end is attached to the cell, the other end walks along a microtubule or microfilament and then releases. It Neds ATP.

Question 41

Cytoplasmic streaming

Answer 41

Active flowing motion of cytoplasm

Question 42

What is a flagella?

Answer 42

La queu. Helps in movement of the cell.

Question 43

Flagella in prokaryotes

Answer 43

Made of a protein called flagellin

Question 44

Flagella in eukaryotes

Answer 44

Constitute of microtubules.

Question 45

Analogous structures

Answer 45

same functions but not the same evolution history

Question 46

Homologous structures

Answer 46

same evolutionary history

Question 47

Why eukaryotic cells are larger than prokaryotes?

Answer 47

The size of the cell is determined by the surface being able to supply it's volume with necessary metabolic requirement. They have a large area of internal membrane structures.

Question 48

Multicellular eukaryotes

Answer 48

Cells are not identical in structure and function, they help each other to benefit the entire organism.

Question 49

Cell colony

Answer 49

group of cells that are only one type

Question 50

How long did it take for eukaryotes to develop from prokaryotes ?

Answer 50

1.3 billion years.

Question 51

Approximate age of planet?

Answer 51

4.6 billion years

Question 52

What is RNA

Answer 52

Ribonucleic acid. translate the genetic code to proteins from DNA with the help of ribosomes.

Question 53

What is DNA

Answer 53

The molecule that contains the genetic code of an organism.