Photosynthesis Flashcards
1
Q
chloroplasts
A
- have outer membrane, inner membrane, and inter membrane space
- inter membrane is not important
2
Q
thylakoid membranes
A
- 3rd membrane system
- stack of interconnected discs (stack called granum)
- lamellae connect the granum
3
Q
electromagnetic spectrum
A
- Visible light- between 400-740 nm
- Smaller wavelengths are more energetic
- x rays- smaller- can penetrate through soft tissue
4
Q
chlorophyll
A
- major pigment arranged in a particular way to absorb light
- look green, embedded in membranes
- 2 major types, a and b
- structure: porphyrin ring- with Mg inside, hydrophobic tail (important for anchoring into membrane)
- R group can be methyl or aldehyde (A or B)
5
Q
absorption spectrum (chlorophyll A and B)
A
- A absorbs blue, orange/yellow
- B absorbs blue and orange
NEITHER absorb green–> plants reflect green
6
Q
photosystem
A
- cluster of chlorophyll and proteins found in thylakoids
- Photon of light hits- absorbs energy of light, passed around through complex in a way that directs energy through what is called reaction center
- Putting energy onto electrons and boosted energy levels
7
Q
antenna complex
A
- part of a photosystem, containing an array of chlorophyll molecules and accessory pigments, that receives energy from light and directs the energy to a central reaction center during photosynthesis
8
Q
NADPH
A
- An electron carrier involved in photosynthesis. Light drives electrons from chlorophyll to NADP+, forming NADPH, which provides the high-energy electrons for the reduction of carbon dioxide to sugar in the Calvin cycle
9
Q
Z diagram
A
- A representation of the path of excited electrons through the photosystems, acceptors, and donors
- oxygen comes out (waste)
10
Q
photosystem (1 and 2)
A
- contain chlorophyll
- absorb light energy during the light-dependent reactions
11
Q
Carbon Fixation (Calvin Cycle)
A
- during photosynthesis
- forms sugar and other organic compounds
- Requires ATP
- need CO2, ATP, NADPH
- product:glucose, ADP+, NADP+
- Location: stroma
12
Q
autotroph
A
- an organism that makes its own food
13
Q
light reactions (calvin cycle)
A
- the first of two major stages in photosynthesis (preceding the Calvin cycle)
- occur on the thylakoid membranes or on membranes of certain prokaryotes
- convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process
- light absorbed in PS2–> e- in pigment is boosted in energy level and transferred to acceptor next to PS1–> e- passed to PS1–> PS1 absorbs light and boosts an e- and passes excited e- to protein pump–> electron flows through pump–> electron put on NADP+ e- acceptor to make NADPH (stores reducing power)
14
Q
dark reactions (calvin cycle)
A
- Second step of photosynthesis where chemical energy is used to make sugar (Glucose)
- reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars
15
Q
heterotroph
A
- an organism deriving its nutritional requirements from complex organic substances.
16
Q
cyclic photosphorolation
A
- electrons break this pattern and instead loop back to the first part of the electron transport chain, repeatedly cycling through PSI instead of ending up in NADPH
17
Q
C3 photosynthesis
A
- the most common form of photosynthesis in which atmospheric CO2 is used to form 3-phosphoglycerate, a three-carbon sugar
18
Q
bundle sheath cells
A
- in C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf
19
Q
CAM plants
A
- plants close their stomata during the day, collect CO2 at night, and store the CO2 in the form of acids until it is needed during the day for photosynthesis
- cacti, pineapples, bromeliads
20
Q
C4 cycle/ Hatch Slack Cycle
A
- an alternative form of carbon fixation that some plants use, particularly in hot weather, to increase the concentration of CO2 available for the Calvin cycle reactions
- takes place in the bundle sheath cells, not mesophyll
21
Q
Rubisco
A
- enzyme in C3 plants that first captures CO2 to begin the Calvin cycle
22
Q
Engelmann’s experiment
A
- strip of green algae under light reflected through a prism, creating a visible light spectrum
- Then put oxygen-using bacteria into the mix and they congregated where photosynthesis was most active (violet/blue and red light)
23
Q
Endosymbiont Hypothesis in plants
A
- Believe that chloroplasts have also come from endosymbiotic pathway
- Some ate up photosynthetic bacterium and then had ability to make ATP with mitochondria and glucose with chloroplasts
24
Q
History of O2 in atmosphere
A
- Early earth atmosphere- no or very little O2 in the atmosphere
- Eventually water splitting photosynthesis evolved and O2 released
- After a while- became much more efficient and huge numbers of organisms with photosynthesis–> oxygen levels went up to about 20%
- -> caused many organisms to die out (b/c O2 steals e-, organisms poisoned)
