Campbell Biology 8th Edition - Chapter 7: Photosynthesis

A student has been shrunk to fit inside the thylakoid space of a granum. How many layers of phospholipids would he or she need to cross through to get completely out of the mesophyll cell?

8 layers

Photoautotroph

An organism that obtains energy from sunlight and carbon from CO₂ by photosynthesis

Autotroph

An organism that produces its own food (usually by photosynthesis), thereby sustaining itself without eating other organisms or their molecules; ex. plants, algae, numerous bacteria

Stroma

Thick fluid that comprises the inner compartment of the chloroplast

Stomata

Tiny pores that allow carbon dioxide to enter the cell and oxygen to exit

During the Calvin cycle, CO₂ is incorporated into organic compounds in a process known as ___________.

carbon fixation

A plant's leaves are the primary site of photosynthesis. A plant's leaves would be expected to have a large amount of _____________________.

chloroplasts

The wavelength is the distance between the __________________.

crests/troughs

Sunlight contains energy called _____________________ (2 words).

electromagnetic radiation

Thylakoids are often concentrated in stacks called ________ and have an internal compartment compartment called the ________________________ (2 words).

grana; thylakoid membrane

Wavelength and energy are ______________ proportional. Such is the relationship between wavelength and ____________.

inversely; frequency

1 glucose molecule requires the production of how many G3Ps?

2

A typical mesophyll cell has between ________________ chloroplasts.

30 and 40

Chlorophyll

A light-absorbing pigment in the chloroplasts that plays a central role in converting solar energy to chemical energy

True or false: A photoautotroph is a type of heterotroph that uses solar energy to produce sugars. If false, make it a correct statement.

False. A photoautotroph is a type of autotroph.

True or false: During photosynthesis, CO₂ is split to release oxygen gas. If false, make it a correct statement.

False. O₂ is produced from the splitting of H₂O.

True or false: Red wavelengths of light have more energy than purple wavelengths of light. If false, make it a correct statement.

False; red wavelengths of light have less energy than violet (purple) wavelengths.

Where do the light reactions occur?

In the thylakoids

Describe the ∆H of photosynthesis.

It has a positive value because photosynthesis is endergonic.

Chemoautotroph

Prokaryote that uses inorganic chemicals as its energy source

Thylakoids

Sacs suspended in the stroma; enclose another internal compartment called the thylakoid space

Granum

Stack of thylakoids

Write the basic reaction for photosynthesis.

Sunlight + 6H₂O + 6CO₂ → C₆H₁₂O₆ + 6O₂

A new bacterium is discovered in Lake Superior. Scientists are able to determine that these bacteria produce oxygen gas. What is likely true about these organisms?

The bacteria are photoautotrophs that perform photosynthesis.

Mesophyll

The green tissue in the interior of the leaf

Photosynthesis

The process by which plants, algae, and some protists and prokaryotes convert light energy to chemical energy that is stored in sugars made from carbon dioxide and water

The Calvin cycle is also referred to as the light-independent reactions. Briefly explain why referring to the chemical reactions of the Calvin cycle as the light-independent reactions is only partially accurate.

The reactions do not directly require solar energy, but they depend on the products produced in the light reactions.

Which of the following substances provides the majority of the atoms that make up the sugar produced by photosynthesis? a. Water b. Carbon dioxide c. Oxygen d. Hydrogen

b. Carbon dioxide

A toxin is found to inhibit the uptake of CO₂ into plant leaves. This toxin would most directly affect the a. light reactions b. splitting of H₂O c. Calvin cycle d. absorption of solar energy

c. Calvin cycle

The Calvin cycle is cyclic because a. CO₂ is constantly acquired during carbon fixation. b. it constantly makes G3P. c. RuBP is regenerated in the final chemical reaction. d. NADPH and ATP are used from the light reactions.

c. RuBP is regenerated in the final chemical reaction.

X-rays can cause ____________ and _________________. Gamma rays can ______ you in high enough doses.

mutations; penetrate the skin; kill

Light behaves as discrete pockets of energy called ______________.

photons

According to the widely accepted theory of endosymbiosis, chloroplasts originated from a _________________________________

photosynthetic prokaryote that took up residence in a eukaryotic cell.

Photosynthesis is a _____________ reaction, just as cellular respiration is. CO₂ becomes ___________ to C₆H₁₂O₆ as electrons, as well as H⁺ ions, from water are added to it. Conversely, H₂O becomes _____________.

redox; reduced; oxidized

The Calvin cycle occurs in the ________ of the chloroplast. It is a cyclic series of reactions that assembles ________ molecules using _____ and energy-rich products of the light reactions.

stroma; sugar; CO₂

During the light reactions, _________ is ____________, providing a source of electrons and giving off O₂ as a by-product. _______ is generated from _________ and a phosphate group, and light energy is absorbed by the _____________________ (2 words) to drive the transfer of electrons and H⁺ from H₂O to electron acceptor ________, reducing it to _____________. This compound provides the "reducing power to the Calvin cycle.

water; split; ATP; ADP; chlorophyll molecules; NADP⁺; NADPH