Photosynthesis Quiz

In photosynthesis, CO₂ is —-

Reduced

In photosynthesis, H₂O is —-

Oxidized

Chlorophyll

Green pigment in chloroplasts

Stomata

Where carbon dioxide enters, and oxygen exits the leaf

Thylakoid membrane

Contains pigment molecules, forms thylakoid lumen

Granum

Stack of thylakoids

Stroma

Fluid filled region between thylakoid membrane and inner membrane

2 stages of photosynthesis

• Light reactions

• Calvin cycle

Light Reactions

• Uses light energy

• Takes place in the thylakoid membrane

• Produce ATP, NADPH, and O₂

Calvin Cycle

• Incorporates CO₂ into organic molecules

• Uses ATP and NADPH

• Occurs in stroma

Light energy

Type of electromagnetic radiation

Light energy travels as —-

Waves

Photosynthetic pigments

Absorb some light energy and reflect others

—- boosts electrons to higher energy levels (higher shells)

Absorption

— in pigments can be transferred or “captured”

Excited electrons

Top part of this diagram of Chlorophyll

Porphyrin Ring

Bottom part of this diagram of chlorophyll

Phytotail

Absorption spectrum

Wavelengths that are absorbed by different pigments in the plants

Action spectrum

Rate of photosynthesis by the whole plant at specific wavelengths

Captured light energy can be transferred to other molecules to produce —-

Energy intermediates

—- of chloroplast contain PS1 and PS2

Thylakoid membranes

After PS2, —- travel to PS1

Excited Electrons

PS2

• Water is oxidized, generates O₂ and H⁺

• Releases energy in electron transport chain

• Energy used to make H⁺ electrochemical gradient

PS1

• Primary rule to make NADPH

• Addition of H⁺ electrochemical gradient

ATP synthesis is a —- mechanism

Chemiosmotic

ATP synthesis is driven by flow of H⁺ from thylakoid lumen into stroma via ——

ATP synthase

H⁺ gradient is generated by

• An increase in H+ in the thylakoid lumen by splitting water

• An increase in H+ by electron transport chain pumping H+ into lumen

• A decrease in H+ formation of NADPH in stroma

Photolysis

Using light to break water

In the electron transport chain, electrons go to —-, which grabs H+ from the stroma. Electrons become low energy.

Cytochrome Complex

In the electron transport chain, electrons end up at —-, when they need to get an energy boost after visiting the cytochrome complex

PS1

In the electron transport chain, —- gives newly boosted electrons to NADP⁺ Reductase

Faradoxin

In the electron transport chain, NADP⁺ Reductase forms —-

NADPH

Faradoxin can pass electrons —- to Cytochrome complex to make ATP Synthase make more ATP

Backwards

Noncyclic electron flow

• Electrons begin in PS2 and transfer to NADPH

• Linear process produces ATP and NADPH in equal amounts

Cyclic Photophosphorylation

Electron cycling releases energy to transport H+ into lumen driving synthesis of ATP

Z Scheme

Zigzag shape of energy curve

Calvin Cycle

ATP and NADPH used to make carbs, CO2 incorporated

In the Calvin cycle, —- requires a massive input of energy

CO2 incorporation

3 phases of the calvin cycle

• Carbon fixation

• Reduction and carbohydrate production

• Regeneration of RuBP

Carbon Fixation

• CO2 incorporated in RuBP using rubisco

• 6 carbon intermediate splits into 2 3PG

Reduction and carbohydrate production

• ATP is used to convert 3PG into 1,3 BPG

• NADPH electrons reduce it to G3P

Regeneration of RuBP

Rest of G3P are used to regenerate RuBP via several enzymes. ATP is required

Calvin cycle occurs in —-

Stroma