AP Biology Photosynthesis Quiz / Review

What is photosynthesis?

The biological process that captures energy from the Sun and produces sugars

What is responsible for atmospheric oxygen?

Cyanobacteria - prokaryotic photosynthesis - early prokaryotes responsible for such

How do light-dependent reactions work?

Capture light energy by using light-absorbing molecules called pigments

What do pigments do

Help transform light energy into chemical energy

What is chemical energy temporarily stored in?

Chemical bonds of carrier molecules, called NADPH

Initial order of photosynthesis

Light energy -> chemical energy -> stored in chemical bonds of carrier molecule (NADPH)

Light-dependent reactions help facilitate what?

ATP synthesis

ATP and NADPH transfer stored chemical energy to power the production of what?

Organic molecules in another pathway, called the Calvin cycle

What is oxygen produced as a result of?

Water hydrolysis

Plants and other autotrophs use what to trap light energy and make what

pigments; organic molecules

What are the products of light-dependent reactions?

ATP and NADPH

What products are used in the Calvin cycle to produce carbohydrates?

ATP and NADPH

During photosynthesis, what absorbs energy from light?

Chlorophylls

What role do chlorophylls play in photosynthesis?

Capture energy from sunlight and convert it to high-energy electrons

What happens to chlorophyll reactions when light absorption occurs?

Electrons will be energized

What are energized electrons used for?

Used to establish a proton gradient and reduce NADP+ to NADPH (reduction reaction)

Photosystems 1 and 2 are embedded where

Internal membranes of chloroplasts

What is a photosystem?

A light-capturing unit in a chloroplast’s thykaloid membrane (sunlight captured)

Why is the hydrolysis of water necessary as it relates to PSII and the light-dependent reactions?

The hydrogen molecules from the spitting of water are released into the thykaloid space and used to create an electrochemical/proton gradient

What do you follow?

the H+

When electrons are transferred between molecules in a reaction, they pass through what

ETC / Electron Transport Chain

How are photosystem 2 and photosystem 1 functionally related to the electron transport chain? (ETC)

PS2 and PS1 pass high-energy electrons to the ETC

What is the function of the ETC?

Pass electrons along the line

What is an electrochemical/proton gradient?

It is a difference in concentration of protons (hydrogen ions) across a membrane

The formation of the proton gradient is linked to the synthesis of what

ATP

Photosynthesis uses a form of passive transport to generate what from what?

ATP; ADP

What is ATP synthase?

ATP synthase is an enzyme that creates ATP when protons pass through the enzyme

The energy captured in light powers the production of carbohydrates in the

Calvin Cycle

What does the Calvin cycle use?

ATP, NADPH, and CO2

What does the Calvin cycle produce?

Carbohydrates

What is the ultimate goal of the Calvin cycle reactions?

Make organic products that plants need the products from the light reactions of photosynthesis

Where do plants and other organisms mainly get their carbon dioxide from?

Plants and other organisms mainly get their carbon dioxide from the environment

Chlorophyll captures energy from what and excites what

sunlight; electrons

As the electrons pass through the electron transport chain, protons are actively transported across a

membrane, establishing a gradient.

Protons diffuse through what, powering what

ATP synthase; ATP synthesis