What type of reaction breaks down the bonds that join the phosphate groups in an ATP molecule?
hydrolysis (involves breaking bonds with the addition of water)
animals have enzymes that break apart starch molecules but not cellulose
despite the fact that both are made up of glucose subunits. Which enzyme characteristic BEST explains this?,Enzymes are highly specific
Most enzymes do not work if the temperature is raised too much. Why is this?
enzymes denature at higher temperatures (incorrect temperature, pH, and salt concentrations cause an enzyme to change shape)
The light reactions of photosynthesis use ____ and produce ____.
water....NADPH (during the light reactions, water is split to produce oxygen. Excited electrons from water join with NADP+ to produce NADPH
What is the purpose of a cuticle on a leaf?
to prevent water loss (the was cuticle makes the leaf waterproof, to preven water from leaving by evaporation. The oil on your skin performs a similar function)
How is O2 involved in photosynthesis?
O2 is a product of the light reactions. (O2 is produced when water is consumed in the light reactions.)
You place a plant in a transparent box made of greenish-yellow plastic. How does this affect photosynthesis for the plant?
None of the plant pigments will be able to absorb the light. Photosynthesis will stop. (none of the major pigments absorb at this wavelength)
Why do plants produce O2?
because O2 is produced as a by-product when the plant creates H+ ions and free electrons from water
Where are the electrons used in a photosystem II found at the very end of the light reactions?
in NADPH (the electrons and a few of the hydrogen ions released from water in photosystem II are bound to NADP+ to form molecules of NADPH)
Suppose that you are experimenting with different types of lighting for your indoor green plants. Which of the following colors of light will be most effective?
The energy of the movement of electrons down a concentration gradient via electron transport within chloroplasts and mitochondria is used to generate molecules of:
Suppose you are studying photosynthesis in a research lab. You grow your plants in a chamber with a source of water that has a radioactively labeled oxygen atom. What photosynthetic product will be radioactive?
The primary function of the light reactions of photosynthesis is to:
produce energy-rich ATP and NADPH
why do chloroplasts make energy carriers during the light reactions?
to provide energy for the synthesis of sugar. (sugar synthesis is endergonic and requires the energy in ATP and NADPH to proceed)
Carbon fixation involves the addition of carbon dioxide to _____.
RuBP (in the calvin cycle, carbon dioxide is added to RuBP)
How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
6 (6 carbon dioxide molecules are required to produce two G3P molecules, which can be combined to make one glucose molecule)
in the calvin cycle
how many ATP molecules are required to regenerate RuBP from five G3P molecules?,3
What two molecules are produced by the light reactions and used to power the calvin cycle?
ATP and NADPH
What provides the carbon atoms that are incorporated into sugar molecules in the calvin cycle?
Carbon dioxide (CO2)
The light reactions take place in the _______ and the calvin cycle takes place in the ______.
The term "cycle" is used to describe the calvin cycle because:
the process begins and ends with RuBP
Which of the following occurs during the calvin cycle of photosynthesis?
carbon dioxide is converted to chemicals that can be used to make sugars.
The energy of the movement of electrons down a concentration gradient via electron transport within the thylakoid membrane is used to generate:
Many plants have evolved leaves that have adjustable pores
called ______, which allow for gas exchange and water loss.,stomata
Glucose synthesis during photosynthesis requires that:
the products of energy-capturing reactions must be available