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Biology Exam Review > Photosynthesis > Flashcards

Photosynthesis Flashcards

1
Q

Define heterotroph and autotroph.

A

heterotroph~ consume food to obtain nutrients

autotroph~produced own food

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2
Q

What is a chloroplast? Describe the structures.

A

-smooth outer membrane, inside consists of organized internal membranes
thykaloid= disc shaped vesicle
grana= stack of thykaloids
lamellae=membrane extension contains pigment
stroma=fluid filled space

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3
Q

What is light?

A
  • electromagnetic E
  • travels in photons
  • different wavelengths = different E
  • can be transmitted, absorbed, reflected
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4
Q

What happens once light absorbed?

A
  • transmitted/reflected does not affect object
  • absorbed e- will jump to high E level and release absorbed e- when travel back to ground state
  • Ein =Eout
  • released in poorer quality
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5
Q

What is a pigment?

A

-molecule that absorbs specific wavelengths and reflects others

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6
Q

What is chlorophyll?

A
  • pigment in chloroplast, oxidizing agent for photosynthesis
  • max absorption at red/blue, reflect green
  • photosynthesis can occur throughout visible spectrum
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7
Q

What are 3 accessory pigments?

A
  • xanthophyll (refects yellow)
  • cartenoids (reflect orange)
  • anthocyanin (reflects red)
  • absorb blue/green/violet light, can absorb wavelengths that can be transmitted to chlorophyll & emitted as lower E
  • lower E forms than transferred to chlorophyll
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8
Q

What are the 2 major series rxns?

A
  • LDR: ETC

- LIR: Calvin Cycle

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9
Q

What are photosystems?

A
  • photosynthetic unit composed of photosystems, more efficient when both working
  • PSII (P680): absorbs light >680nm
  • PSI (P700): max absorption at 700nm
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10
Q

What is non-cyclic phosphorylation?

A

*draw out on white board

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11
Q

Important Products (Non-Cyclic)

A
  • 12Oxygen
  • 12NADPH
  • 12 ATP (4H = 1ATP)
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12
Q

What is cyclic phosphorylation?

A
  • used for making ATP
  • ratherthan losing e- to NADP, fd oxidized by PQ
  • more H pumped across membrane, results in synthesis of ATP without H20
  • no NADPH produced
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13
Q

How much ATP produced in non-cyclic/cyclic?

A

non-cyclic: 12 ATP

cyclic: 6 ATP
total: 18 ATP

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14
Q

What is light independent rxns?

A
  • occur in stroma, known as Calvin Cycle
  • enzyme catalyzed rxns, endergone (use ATP from LDR)
  • 6 turns of Calvin Cylce produce 1 glucose
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15
Q

What is stage 1 of LIR?

A

Carbon Fixation: CO2 joins to 5C molecule of ribulose biphosphate (RuBP)
-forms 2 molecules of 3C molecules (2, 3-phosphoglycerate, PGA)

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16
Q

What is stage 2 of LIR?

A

Reduction Reactions: phosphoglycerate molecules add Pi (use ATP) and red. NADPH to form 3C, glyceraldehyde-3-phosphate (G3P)
-some of G3P leaves converted into glucose

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17
Q

What is stage 3 of LIR?

A

RuBP Regeneration: requires net input of ATP, changes gylceraldehyde-3-phosphate into RuBP

18
Q

Important Products (Calvin Cycle)

A

water
NADP
glucose!!

19
Q

What is fate of glucose?

A
  • synthesis, storage, respiration
  • glucose converted into sucros for transport around plant
  • used for respiration
  • synthesis cellulose for cell walls, AA, fats & other organic molecules
  • stored as starch for later use
20
Q

Describe the structures of a Leaf.

A

Upper Epidermis~ single layer of transparent cells, covered with waxy cuticle, sometimes hair
Palisade Parenchyma~ arranged longitudially, LOTS of C
Spongy Parenchyme~ loosely arranged LOTS of C
Vascular Bundles~xylem & phloem, surrounded by bundle sheath supporting cells
Lower Epidermis~thinner or no cuticle, no hair
Stomata~surrounded by guard cells

21
Q

What is the stomata and what is its function?

A
  • surrounded by guard cells~only epidermal cell that contains C
  • pores in leaf
  • functions: transpiration & gas exchange
22
Q

What happens when water enters guard cells? What is their structure?

A
  • when guard cell fills with water, open allowing gas exchange to occur
  • thinner outer layer and thicker inner layer allow guard cell to bend
  • guard cell can change own osmotic pressure
23
Q

Describe actions of the stomata through day/night.

A

Night~K leaks out followed by water, results in stomata to close, guard cells shrink
Day~light stimulates photosynthesis, ATP used to actively transported K in, water through osmosis

24
Q

How do roots absorb water and minerals?

A
  • water through osmosis

- minerals actively transported in (choice)

25
Q

What is xylem and what does it transport?

A
  • dead when functioning
  • transports from roots to leaves
  • water transport
26
Q

What are the 2 mechanisms of water transport?

A
  • root pressure

- transpiration pull

27
Q

What is root pressure?

A
  • actively transport salts into root, pith becoming hypertonic draws in water
  • water than pushed up roots
28
Q

Describe Transpiration Pull

A

-water cohesive and adhesive (to cell walls), as water evaporates from leave, pulls adjacent molecules into place and pull through column

29
Q

Why water flow?

A
  • transpiration plant’s transport mechanism
  • delievered to leaves for photosynthesis
  • mixed with nutrients
  • keeps plant cool by evaporating
30
Q

Describe nutrient transport

A
  • phloem, composed of sieve tubules (no nucleus) and companion cells (nucleus)
  • cells alive, use E to transport cell products
31
Q

What is the mechanism of pressure flow?

A
  • source (point of origin of sugar)
  • sink (destination of sugar, roots)
  • at source, sugar actively transported into sieve tubes
  • phloem fluid hypertonic, H2O follows and diffuses in
  • pushes solution through sieve tubes and down phloem
  • at sink, sugar actively transported out
  • H2O diffues back out (xylem)
  • sugar transported into storage (starch)
32
Q

What is photorespiration? Compare products to Calvin Cycle

A
  • occurs when oxygen binds with rubisco instead of CO2

- produceing PGA and glycolate

33
Q

How does affect plants on hot dry day?

A
  • stomata closed to conserve water
  • results in [CO2] decrease and [O2] increase because gas exchange cannot occur
  • photorespiration increases
  • CO2 & O2 competitive inhibitors
34
Q

How do C4 plants avoid photorespiration?

A
  • serperate photosynthesis into two different areas
  • in mesophyll, LDR occur, absorb CO2 and bind with 3C molecule (PEP) to create malate
  • malate delivered to bundle sheath cell, where CO2 released
  • used for LIR
35
Q

What occurs in bundle sheath cells?

A
  • malate broken down into pyruvate and CO2

- pyruvate delivered back to mesophyll and uses 1ATP to convert back to PEP

36
Q

What do the malate molecules allow?

A

-allow storage of CO2

37
Q

What are CAM plants and how do they overcome photorespiration?

A

-another type of C4 plants, seperate processes by time of day

38
Q

What happens at night with CAM plants?

A
  • at night stomata open and release accumulated O2 and intake CO2
  • CO2 stored as malate in central vacuole
39
Q

What happens in the morning with CAM plants?

A
  • stomata close, NADPH & ATP made in LDR to use in Calvin Cycle
  • afternoon, O2 accumulated & slow down respiration but NADPH & ATP produced to use
40
Q

How do plants deal with hot/dry environment?

A
  • deep/shallow spread out roots
  • store CO2/H2O
  • time growth season to rainy season
  • reduce SA of leaf (temporarily)
  • develope waxy cuticle

Biology Exam Review (8 decks)

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