Lecture 8- Photosynthesis Flashcards
What are photoautotrophs?
Organisms that can make their own energy using light and carbon dioxide
True or false: Photosynthesis is an exergonic process
False; photosynthesis is an endergonic process
In which organelle does photosynthesis take place?
Chloroplast
Where do the light-independent reactions take place?
In the stroma
What are heterotrophs?
Organisms that obtain their carbon from organic sources
Where is chlorophyll located in a chloroplast?
Thylakoid membrane
True or false: Under normal conditions, electrons in photosynthesis undergo a cyclic flow
False; under normal circumstances, electrons in photosynthesis undergo linear flow
What is a photon?
Small particle of light energy
Which enzyme is primarily responsible for ATP synthesis in photosynthesis?
ATP synthase
Why are leaves green?
Chlorophyll reflects green light
What does the wavelength of a photon tell us about it?
The shorter the wavelength, the more energy & the longer the wavelength, the less energy
What are the three simplified steps of the light-dependent reactions?
Split water and release atmospheric oxygen → reduce NADP+ to NADPH → generate ATP from ADP
Which pigment is present in photosystem two (PSII)?
P680
Which molecules undergo redox in photosynthesis?
Water is oxidized and carbon dioxide is reduced
True or false: ATP synthase requires energy in the form of ATP to synthesize ATP from ADP
False; the synthesis of ATP from ADP through ATP synthase is driven by an electrochemical gradient (facilitated diffusion)
What is the cytoplasm of a chloroplast called?
Stroma
What are the three stages of the Calvin cycle in order?
Carbon fixation → reduction → regeneration
The reaction between carbon dioxide and RuBP takes place in which stage of the light-independent reactions? Which enzyme catalyzes this reaction?
Carbon fixation & RuBisCo
Which enzyme is responsible for reducing NADP to NADPH?
NADP reductase
Where do the light-dependent reactions take place?
Thylakoid membrane
Which pigment is present in photosystem one (PSI)?
P700
What are the reactants of the carbon fixation stage of the light-independent reactions?
Carbon dioxide and RuBP
What is the second stage of the Calvin cycle? What occurs during this stage?
Carbon reduction & ATP/NADPH are used to convert 3-Phosphoglycerate (PGA) to glyceraldehyde-3-phosphate (G3P)
In the first step of the Calvin cycle, carbon fixation, carbon dioxide and RuBP react to form what?
3-Phosphoglycerate (PGA)
Which molecule(s) are reduced during the Calvin cycle?
PGA
What are the sources of electrons for PSII and PSI?
PSII electrons from water & PSI electrons from PSII
Where do protons go when water is split at PSII?
Protons create an acidic environment in the thylakoid lumen
