The botanical term for the tiny adjustable openings in a leaf surface, each bordered by two guard cells, is stomata.
Missing Word
stomata
Stomata are pores in the leaf surface that open and close to control gas exchange. Carbon dioxide enters and oxygen and water vapor leave through them.
Category: Leaf and Chloroplast
Question 2
The middle tissue layer of a leaf, packed with chloroplast-rich cells, is the mesophyll.
Missing Word
mesophyll
The mesophyll lies between the upper and lower surfaces of the leaf. Its cells hold many chloroplasts, so it is where most photosynthesis in the leaf takes place.
Category: Leaf and Chloroplast
Question 3
A single stack of flattened membrane sacs inside a chloroplast is called a granum.
Missing Word
granum
A granum is a stack of thylakoids, the disc-shaped membranes that hold chlorophyll. The plural is grana.
Category: Leaf and Chloroplast
Question 4
The Calvin cycle takes place in the stroma, the fluid that fills the chloroplast around its membrane stacks.
Missing Word
stroma
The stroma is the fluid inside the chloroplast that surrounds the grana. It contains the enzymes, including RuBisCO, that run the Calvin cycle.
Category: Calvin Cycle
Question 5
The main light-absorbing molecule of plants, which gives leaves their green color, is chlorophyll.
Missing Word
chlorophyll
Chlorophyll is embedded in the thylakoid membranes and absorbs mainly blue and red light. It reflects green light, which is why leaves look green.
Category: Light and Pigments
Question 6
The term for an organism that must eat other organisms for carbon and energy, from Greek roots meaning other feeder, is heterotroph.
Missing Word
heterotroph
A heterotroph cannot make its own food and gets carbon and energy by consuming other organisms. Animals, including humans, are heterotrophs.
Category: Photosynthesis Overview
Question 7
Making ATP from ADP and phosphate using energy that light supplies in the chloroplast is called photophosphorylation.
Missing Word
photophosphorylation
Photophosphorylation is light-driven ATP synthesis. Light powers the pumping of hydrogen ions, and their flow back through ATP synthase adds a phosphate to ADP.
Category: Light-Dependent Reactions
Question 8
The enzyme that attaches CO2 to a five-carbon sugar in the first step of the Calvin cycle is RuBisCO.
Missing Word
RuBisCO
RuBisCO catalyzes carbon fixation, joining CO2 to RuBP. The six-carbon product splits at once into two molecules of 3-PGA.
Category: Calvin Cycle
Question 9
A single packet of light energy, which can excite an electron when absorbed, is called a photon.
Missing Word
photon
Light travels as photons, each carrying a set amount of energy that depends on its wavelength. When a pigment absorbs a photon, one of its electrons is raised to a higher energy level.
Category: Light and Pigments
Question 10
In light, the crest-to-crest distance is called the wavelength, and a shorter one means higher energy.
Missing Word
wavelength
Wavelength is the distance between two consecutive matching points on a wave, such as two crests. Shorter wavelengths, like violet and blue light, carry more energy than longer ones like red.
Category: Light and Pigments
Question 11
The class of yellow, orange and red accessory light absorbers found in chloroplasts is the carotenoids.
Missing Word
carotenoids
Carotenoids are accessory pigments that absorb wavelengths chlorophyll captures poorly and pass energy along. They give carrots and autumn leaves their orange and yellow colors.
Category: Light and Pigments
Question 12
Building one glucose molecule requires 6 turns of the Calvin cycle.
Missing Word
6
Each turn of the Calvin cycle fixes one carbon from CO2, and glucose has six carbons, so 6 turns are needed for each glucose.
Category: Calvin Cycle
Question 13
Photosynthetic prokaryotes, the group that includes the organisms once called blue-green algae, are cyanobacteria.
Missing Word
cyanobacteria
Cyanobacteria are bacteria that carry out photosynthesis and release oxygen. Because they are prokaryotes they have no chloroplasts and use folded inner membranes instead.
Category: Photosynthesis Overview
Question 14
A molecule that absorbs only certain colors of light and reflects the others is a pigment.
Missing Word
pigment
A pigment absorbs specific wavelengths and reflects the rest, and the reflected wavelengths give it its color. Each pigment has its own absorption spectrum.
Category: Light and Pigments
Question 15
Besides ATP, the light-dependent reactions produce the electron carrier NADPH, formed when NADP+ gains electrons and a hydrogen ion.
Missing Word
NADPH
NADPH is made at the end of the electron pathway after photosystem I. It carries high-energy electrons to the Calvin cycle, where they reduce 3-PGA to G3P.
Category: Light-Dependent Reactions