BIO EXAM 4

In mechanism, photophosphorylation is most similar to:

. oxidative phosphorylation in cellular respiration.

Variegated leaves are rarely found in wild plants but are common in garden plants and houseplants because people like their appearance. They are most likely rare in wild plants because variegated plants

. photosynthesize less than non-variegated plants.

Now that you know how much energy is required to break all of the bonds in pyruvate, calculate the net energy change after the bonds reform around oxygen (a total of 696 kcal/mole of energy is released after all of the bonds associated with the breakdown of pyruvate in the presence of oxygen reform).

271 kcal/mole 696-425= 271

Each C-C bond requires 76 kcal/mole to break, and each C-H bond requires about 91 kcal/mole to break. How much energy is required to break all of these bonds in one pyruvate molecule?

425 kcal/mole 3 C-H bonds= (91)(3)= 273 2 C-C bonds= (76)(2)= 152 273+152= 425

The voltage between the inner mitochondrial membrane and matrix is variable. Which of the following conditions would lead to a decrease in voltage?

A decrease in oxygen

The figure on the above left shows the absorption spectrum for chl. a, and on the above right the wavelengths for photosynthesis. The two patterns are similar, but why are they not exact?

A number of pigments, not just chlorophyll a, absorb light that contributes energy to photosynthesis.

Which of the following are produced by reactions that take place in the thylakoids and consumed by reactions in the stroma?

ATP and NADPH

If the electron transport chain between Photosystem II and Photosystem I begins to work inefficiently then

ATP production will decrease.

Drugs known as uncouplers facilitate diffusion of protons across the mitochondrial membrane. When such a drug is added, what will happen to ATP synthesis and oxygen consumption, if the rates of glycolysis and the Krebs cycle stay the same?

ATP synthesis will decrease; oxygen consumption will stay the same.

In which organisms does glycolysis occur?

Both aerobic and anaerobic organisms

Fungi are more closely related to plants than to animals.

False

A. Aerobic cellular respiration involves the flow of electrons from one chemical molecule to another which of the following best describes this process?

From glucose to oxygen

Which of the following fungal groups form mycorrhizal symbioses with plant roots? Select all that apply.

Glomeromycota E. Ascomycota F. Basidiomycota

A biochemist wanted to study how various substances were used in cellular respiration. In one experiment, she allowed a mouse to breathe air containing O2 labeled by a particular isotope. In the mouse, the labeled oxygen first showed up in

H2O

How do most fungi feed?

Hyphae secrete enzymes that break down organic rich molecules and then absorb the nutrient-rich fluid.

What are mycorrhizae?

Mutualistic associations between plant roots and fungi.

Which one of the following molecules is necessary for glycolysis to proceed normally?

NAD+.

Which of these molecules in cell respiration is the most electronegative?

Oxygen

Which of the following statements is correct distinction between photoautotrophs and chemoheterotrophs?

Photoautotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.

Endophytic fungi (fungi that live within plant tissue) are very common. Almost all plants studied have them. Some grasses have endophytic fungi that modify plant-herbivore interactions. What type of symbiotic interaction exists between plants and herbivores?

Predation

You are working with a mutant plant that you think has chloroplasts that lack photosystem II (PS II), even though it is able to live. How could you determine if PS II is missing from the plant's chloroplasts?

Test for the presence of oxygen

The Calvin cycle is considered light-independent because it can occur in darkness. However, most often the Calvin cycle takes place in sunlight. Which of the following explains why?

The Calvin cycle requires ATP and NADPH, which require sunlight to be produced.

. What powers the ATP synthase rotary motor?

The H+ gradient

You have a friend who lost 15 pounds of fat on a diet. Where did the mass (atoms) of the fat go?

The atoms were releases as CO2 and H2O

Photosynthesis can be divided into two steps: the light-dependent reactions and the Calvin cycle. Which of the following is true regarding these two steps?

The light-dependent reactions take place in the thylakoid membrane, and the Calvin cycle takes place in the stroma.

A new disease arises in humans who live in the rain forest. Which of the following might be a first attempt at determining whether or not the disease is caused by a fungus?

Treat affected people with a chemical that interferes with chitin synthesis.

About 50% of the organic material made by photosynthesis is consumed as fuel for cellular respiration in plant cell mitochondria.

True

Evaluate the following statement and determine whether it is True or False: During cellular respiration in plants, the Krebs cycle takes place within the mitochondria and releases carbon dioxide.

True, because plants do have mitochondria and the Krebs cycle releases carbon dioxide. They do perform cellular respiration in addition to photosynthesis.

The most important adaptive advantage associated with the filamentous nature of fungal mycelia is

an extensive surface area well suited for growth and absorptive nutrition.

Select all that apply. The vegetative (nutritionally active) bodies of most fungi are

composed of hyphae. referred to as a mycelium. usually underground.

A molecule that is reduced:

gains electrons from another molecule.

You are up late studying, and your friend orders a pizza for you both. When the pizza arrives, you tell your friend that you are learning about fungi in bio 110 and you tell them that the toppings on your pizza belong to

mushrooms from Basidiomycota.

If the following redox reaction occurred NAD+ would be

reduced to NADH + H+

. Which of the following does not occur during the Calvin cycle?

release of oxygen

When light strikes chlorophyll molecules in the reaction center complex, they lose electrons, which are ultimately replaced by

splitting water

In terms of haploid vs diploidy, how do the life cycles of fungi and humans differ?

the majority of the fungal life cycle is spent in the haploid stage, whereas the majority of the human life cycle is spent in the diploid stage

Which process is most directly driven by light energy?

transfer of energy from pigment molecule to pigment molecule

. In photosynthesis, ________ is oxidized and ________ is reduced.

water; carbon dioxide