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Physiology (LEC) > Photosynthesis > Flashcards

Photosynthesis Flashcards

1
Q

The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

A

Photosynthesis

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2
Q

Photosynthesis in plants generally involves the green pigment _______ and generates _________ as a byproduct

A

chlorophyll
oxygen

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3
Q

This process is important for the growth and survival of autotrophic organisms, as well as for providing oxygen to the atmosphere

A

Photosynthesis

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4
Q

PHOTOSYNTHESIS

A

• The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

• Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct

• The process photosynthesis is important for the growth and survival of autotrophic organisms, as well as for providing oxygen to the atmosphere

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5
Q

Photosynthesis: Life from _______

A

Light

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6
Q

Ancient civilizations, such as the Greeks and Egyptians, noted that plants appeared to “eat” air and sunlight.

A

17th Century

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7
Q

(17th century) Ancient civilizations, such as the ______ and ________, noted that plants appeared to “eat” _____ and ______

A

Greeks and Egyptians
air and sunlight.

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8
Q

Jan Baptista Van Helmont conducted experiments and concluded that water was the source of a plant’s increased mass.

A

16th century

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9
Q

In the 16th century, __________ conducted experiments and concluded that ______ was the source of a plant’s increased mass.

A

Jan Baptista Van Helmont
water

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10
Q

-English chemist ________ conducted experiments with a variety of gases, including “__________” (now known as oxygen).

A

Joseph Priestley
dephlogisticated air

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11
Q

He observed that plants exposed to sunlight released a gas that could relight a burning candle, which we now recognize as _________.

A

Joseph Priestley
oxygen

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12
Q

HETEROTROPHS

A

• get their energy from eating “others”
• consumers of other organisms
• consume organic molecules

• consumers
• animals
• fungi
• most bacteria

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13
Q

AUTOTROPHS

A

• get their energy from “self”
• get energy from sunlight
• use light energy to synthesize organic molecules

• producers
• plants
• photosynthetic bacteria (blue-green algae)

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14
Q

This obtains raw materials in plants

A

(Plants structure)
Sunlight
Carbon dioxide
Water
Nutrients

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15
Q

PLANT STRUCTURE
• Obtaining raw materials

◆ sunlight
_______=_______
◆ CO2
_________ = _________
◆ H2O
___________
◆ nutrients
___________

A

◆ sunlight
sunlight = solar collectors
◆ CO2
stomates = gas exchange
◆ H2O
uptake from roots
◆ nutrients
uptake from roots

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16
Q

What does it mean to be a plant?
■Need to…

A

◆ collect light energy
transform it into chemical energy
◆ store light energy
in a stable form to be moved around the plant & also saved for a rainy day
◆ need to get building block atoms from the environment
C,H,O,N,P,S
◆ produce all organic molecules needed for growth
carbohydrates, proteins, lipids, nucleic acids

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17
Q

Plant structure

■ Chloroplasts
◆
◆
◆
◆

■ Chlorophyll & ETC in thylakoid membrane
◆

A

■ Chloroplasts
◆ double membrane
◆ stroma
◆ thylakoid sacs
◆ grana stacks

■ Chlorophyll & ETC in thylakoid membrane
◆ H+ gradient built up within thylakoid sac

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18
Q

They are photosynthetic machines that maximize the absorption of light

A

Leaves

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19
Q

The leaf is sheathed with an ________ and ________. The exposed surfaces of the epidermal cells are coated with a ________.

A

• upper and lower epidermis
• cuticle

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20
Q

The photosynthetic tissues are located between the two epidermal layers and are consequently identified as _________.

(meso, ______; phyll, _____)

A

mesophyll tissues

(meso, middle; phyll, leaf)

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21
Q

The ___________ generally consists of one to three layers of ___________.

A

• upper photosynthetic tissue
• palisade mesophyll cells

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22
Q

_________ are elongated, cylindrical cells with the long axis perpendicular to the surface of the leaf.

A

Palisade cells

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23
Q

Below is the ________, so named because of the prominent air spaces between the cells.

A

spongy mesophyll

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24
Q

•The energy for photosynthesis comes from the ______.
•Sunlight has both ______ and _______.
•Particles are called _______–are the smallest unit of light.

A

• sun
• wave and particle nature
• photons

25
Q

The light emitted from the sun contains photons in a wide spectrum of wavelengths, called the __________

A

electromagnetic spectrum

26
Q

Photosynthetic organisms use only a short portion of the electromagnetic spectrum called ________.

A

visible light

27
Q

Contains pigment that facilitate the capture of wavelength from light in the visible light range.

A

Photosynthetic organisms

28
Q

Photosynthetic organisms contains ________ that facilitate the capture of ________ from light in the _________.

A

pigment
wavelength
visible light range

29
Q

•The color of the pigment comes from the ________ of __________.

•Plants appear green because they reflect __________ wavelengths of light.

•__________ wavelengths are absorbed and provide the energy needed that is used for photosynthesis.

A

wavelengths
light reflected

yellow and green

Red and blue

30
Q

Chloroplast are green because they absorb ___________ in red & blue and reflect green back out

A

light wavelengths

31
Q

Photosynthesis performs work only with __________

◆ ____________ - the dominant pigment- absorbs best in ____& _____ wavelengths & least in ______

◆ other pigments with different structures have different absorption spectra

A

• absorbed wavelengths of light
• chlorophyll a
• red & blue wavelengths & least in green

32
Q

• Carbon dioxide and water are converted into ______ and _______, driven by the energy of sunlight captured by chlorophyll and other pigments.
• This process is essential for the production of _______ and ________ that sustain life on Earth.

A

• glucose and oxygen
• energy and organic compounds

33
Q

CHEMICAL FORMULA (Photosynthesis)

6CO2 + 6H2O

A

C6 H12 O6 + 6O2

34
Q

This molecules are taken in from the surrounding environment.

A

Carbon dioxide (6CO2)

35
Q

This is absorbed by chlorophyll and other pigments in the chloroplasts.​

A

Water 6H2O

36
Q

• It is the primary product of photosynthesis and serves as an energy-rich molecule for the cell.
• It is a simple sugar

A

Glucose (C6 H12 O6)

37
Q

________ is released as a byproduct of photosynthesis and is released into the atmosphere.

A

Oxygen (6O2)

38
Q

The reactions that synthesize glucose occurs in the _______

A

stroma

39
Q

The light dependent reactions occurs in the ________.

A

thylakoids

40
Q

Convert solar energy to chemical energy (NADPH & ATP)

A

Light reactions

41
Q

Uses chemical energy (NADPH & ATP) to reduce CO2 to C6 H12 O6 (sugars)

A

Calvin cycle

42
Q

Collects chlorophyll molecules

A

Photosystems

43
Q

Act as light gathering “anthena complex”

A

2 photosystems of thylakoid membrane (Photosystems l & ll)

44
Q

• Chlorophyll a
• P680 = absorbs 680 nm wavelength red light

A

Photosystem ll

45
Q

• Chlorophyll b
• P700 = absorbs 700nm wavelength red light

A

Photosystem l

46
Q

The key to the photosynthetic electron transport chain is the presence of two large, multimolecular, pigment-protein complexes known as _________ and ________

A

photosystem I (PSI) and photosystem II (PSII).

47
Q

Photosystems l and ll operate in series linked by a third multiprotein aggregate called the _________.

A

cytochrome complex

48
Q

The effect of the chain is to extract low-energy electrons from water and, using light energy trapped by chlorophyll, raise the energy level of those electrons to produce a strong reductant _______.

A

NADPH

49
Q

Fractionation studies have revealed that PSI and PSII each contain several different proteins together with a collection of _________ and __________ that absorb photons.

A

chlorophyll and carotenoid molecules

50
Q

The bulk of the chlorophyll in the photosystem functions as ________.

A

antenna chlorophyll

51
Q

The association of chlorophyll with specific proteins forms a number of different _______________

A

chlorophyll-protein (CP) complexes

52
Q

Photosystems (process)

• The photosystems of the thylakoid consist of _________ and ______ - the molecules that absorb the photons of light.

• Within the pigment molecules, the absorbed ______ excites ________ to a higher state.

• Photosystems will channel the excitation energy gathered by the pigment molecules to a reaction _________ which will then pass the electrons to a series of proteins located at the thylakoid membrane.

-Photons of light strike Photosystems I and II simultaneously.

A

• accessory pigment molecule and chlorophyll

• light energy
• electrons

• centerchlorophyll molecule

53
Q

PHOTOSYSTEM ll

• The core antenna for photosystem II consists of two chlorophyll-proteins (CP) known as ______ and _____.

• These two CP complexes each contain _____ to _____ of chlorophyll a.

• The ______________ absorb light but do not participate directly in photochemical reaction

A

• CP43 and CP47

• 20 to 25 molecules

• core antenna chlorophyll a

54
Q

REACTION CENTER CHLOROPHYLL

• The reaction center chlorophyll plus associated proteins are directly involved in _____________.
• It is an ________—it is the longest-wavelength, thus the lowest-energy-absorbing chlorophyll in the complex.
• Because the _____________ is the site of the primary photochemical redox reaction, it is here that light energy is actually converted to chemical energy.
• The reaction center chlorophyll a of PSI and PSII are designated as ______ and ______, respectively. These designations identify the reaction center chlorophyll a, or pigment (P), with an absorbance maximum at either 700 nm (PSI) or 680 nm (PSII).

A

• lightdriven redox reactions

• energy sink

• reaction center chlorophyll a

• P700 and P680

55
Q

PHOTOSYSTEM II OXIDIZES WATER TO PRODUCE OXYGEN

• Electron transport actually begins with the arrival of _______ at the photosystem II reaction center chlorophyll, P680, which is located near the ________ of the reaction center.

  • _______ is required to change the redox potential of P680 from +0.8 eV to about −0.4 eV for P680, the excited form of P680. As a consequence of this initial endergonic excitation process, P680 can rapidly (within picoseconds, 10−12 s) transfer electrons exergonically to _______ (Pheo).
A

• excitation energy
• lumenalside

• excitation energy
• pheophytin

56
Q

PHOTOSYSTEMII OXIDIZES WATER TO PRODUCE OXYGEN

• Since this initial oxidation of P680 is light dependent, this is called a ___________, which results in the formation of P680+ and Pheo−, a charge separation. This charge separation effectively stores light energy as redox potential energy and represents the actual conversion of light energy to chemical energy.

• The role of the reaction proteins, D1 and D2, is to bind and to orient specific redox carriers of the PSII reaction center in such a way as to decrease the probability of charge recombination between P680+ and Pheo−.

A

• photooxidation event

57
Q

Z-SCHEME FOR PHOTOSYNTHETIC ETC

• The redox components are arranged according to their approximate __________. The vertical direction indicates a change in ______’’ .

• The horizontal direction indicates electron flow. The net effect of the process is to use the energy of light to generate a strong reductant, reduced ferredoxin (fd) from the low-energy electrons of water.

• The downhill transfer of electrons between P680* and P700 represents a negative free energy change. Some of this energy is used to establish a proton gradient, which in turn drives ________. Indicated redox potentials are only approximate

A

• midpoint redox potentials.
• energy level

• ATP synthesis

58
Q

_____________ absorb in- coming photons and transfer the excitation energy to the reaction center where the photochemical oxida- tion-reduction reactions occur.

A

Antenna chlorophyll molecules

Physiology (LEC) (5 decks)

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