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Why Go Multicellular > Week 5 > Flashcards

Week 5 Flashcards

1
Q

What is Photosynthesis?

A

An anabolic process by which the energy of sunlight is harvested and used to convert CO2 into more comples molecules

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2
Q

Photosynthesis is endoergonic or esoergonic?

A

Endoergonic (It requires energy from the sun)

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3
Q

A compound that lose an electron become:

A

Oxydized

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4
Q

A compound that gain an electron become:

A

Reduced

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5
Q

Where does Photosynthesis take place?

A

Inside Thylakoids which are located inside the chloroplasts

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6
Q

What happen during Light reactions?

A

Light reactions convert energy from the sun into chemical energy in the form of ATP and the reduced electron carrier NADPH

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7
Q

What happen during light-independent reactions?

A

Don’t use light directly, instead they use ATP, NADPH and CO2 to produce carbohydrates

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8
Q

What are pigments?

A

Molecules that absorb wavelenghts in the visible spectrum

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9
Q

What does chlorophyll drives?

A

Chlorophyll drives the production of ATP and NADPH

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10
Q

What are ATP and NADPH used for in the Calvin Cycle?

A

They’re used to fix CO2 and produce sugar

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11
Q

When a photon meets a molecule it can interact in 3 ways:

A
  • Scattered
  • Transmitted
  • Absorbed
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12
Q

What happen when a photon is absorbed?

A

Absorption transfers the energy from the photon to the molecule and the molecule become excited

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13
Q

Why are the plants green?

A

When a photon of a particular wavelenght it a plant it will be absorbed but green photons are reflected

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14
Q

List the different types of Photosynthetic pigments:

A
  • Chlorophyll a
  • Chlorophyll b
  • Accessory pigments
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15
Q

What’s the role of accessory pigments?

A

Absorb different light spectrum and transfer their energy to chlorophyll

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16
Q

What can happen when a pigment absorb a photon?

A

The energy can be:

  • Released as heat/light
  • Transferred to another molecule
  • Used to drive a chemical reaction
17
Q

What’s the structure of chlorophyll?

A

It has got a magnesium ion that coordinates the flat structure and a long carbon tail which attach it to a protein structure

18
Q

What do photosystems do?

A

They harvest photon to excite chlorophyll which will pass the nergy to another chlorophyll molecule until it reaches the reaction center.

19
Q

What happen when the energy is passed to a reaction center in the photosystem?

A

The last excited chlorophyll will pass its electron to an electron acceptor

20
Q

Describe the features of Photosystem II

A

It’s primary donor is P680, a photon reaches the chlorophyll, it will absorb its energy an pass it to P680 (The reaction center).

21
Q

How does the reaction center get an electron back?

A

By oxydizing water

22
Q

Describe the features of Photosystem I

A

It’s primary donor is P700, which mean that it’s activated by less energy. It will cause the electron to move up and consequently 2 electron will reach NADP+ reductase

23
Q

What’s NADP+ reductase

A

It’s an enzyme that will cause the reduction of NADP+ to NADPH

24
Q

What’s the name of the process that link the 2 photosystem?

A

The Z scheme

25
Q

Describe the cyclic electron transport

A

In this electron transport the electron goes back into the same photosystem causing production of ATP.

26
Q

What’s chemiosmotic production of ATP?

A

It’s a process that occurs as the electron is passed down the transport chain it causes protons (H+) to be bumped in the lumen (against osmotic gradient so it requires energy). At the end all these electron pass through a special molecul called ATP synthase which produce ATP as protons pass through it.

27
Q

Why is the production of ATP called chemi-osmotic?

A

Because it involves two gradients: One of ion/charges and one of concentration.

28
Q

What are the 3 phases of Calvin Cycle?

A

Carbon fixation
Reduction and sugar production
Regeneration of the CO2 acceptor

29
Q

What’s the role of riboluse bisphospate?

A

It’s a five carbon acceptor

30
Q

When did photosynthesis first appeared?

A

2.7 billion years ago

31
Q

What was used for photosynthesis instead of water?

A

Hydrogne Sulfide (H2S)

32
Q

How may photosynthesis have evolved?

A

The depending on sulfide limited the process so photosynthetic organisms started using H2O which required a stronger oxidizing agent. Therefore it required the evolution of photsystem II.

33
Q

What are the advantages of multicellularity?

A
  • Avoidance of predation
  • Overgrowth of unicellular competitors
  • Expanded feeding opportunities
  • Creation of protected internal environments
  • Novel metabolic opportunities
  • Enhanced motility and dispersal
34
Q

What’s avoidance of predation:

A

Unicellular organisms have only engulfment as a way of predation, but as the prey become bigger it become difficult to eat it. However become bigger it’s a problem so by combining with other cell you overcome the problem and you can enlarge.

35
Q

What’s overgrowth of unicellular competitors?

A

When you’re an individual you’ll grow at your own rate but when you’re multicellular you can make some cell specialize in growing faster so you outcompte unicellular organisms.

36
Q

What are the 3 criteria of multicellular organisms and not the colonies?

A
  • Their cells must be held together by a multicellular matrix
  • Their cells must be able to comunicate with eacht other and respond to signals in a coordinated way
  • They must have to include different type of cells, each specialise in a particular role.
37
Q

What are the basic requirements for a multicellular organism?

A
  • Cell adhesion
  • Cell signaling and coordination
  • Programmed cell death (apoptosis)
  • Capacity for cellular differentiation
38
Q

In which two ways could the first multicellular organism have arisen?

A

1) Clonal development by division of a single cell

2) Aggregation of individual cells

Why Go Multicellular (9 decks)

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