Exam 3 BIO181

Element that is reduced during chemosynthesis.

carbon

Element that is reduced in the Earth's crust.

sulfur

fill in the blanks

Chemosynthesis is the process by which organic compounds are made from inorganic compounds using chemical potential energy, whereas photosynthesis is the process by which organic compounds are made from inorganic compounds using electromagnetic energy from the sun.

Estrogen is a lipid sex hormone. It is carried to cells via the blood, and never reaches a higher concentration inside cells than in the blood. Which of the following mechanisms of membrane transport would you predict is used by cells in this case?

simple diffusion

"The destabilization reactions of glycolysis..."

- +15 - produce 2 molecules of G3P, or 1 molecule of G3P and one of DHAP.

Which of the following statements is (are) correct? Mark all that apply.

- All living things must eat in order to satisfy the second Law of Thermodynamics. - Metabolic process do nothing more than transfer energy from one form to another. - Food is chemical potential energy. - Whenever a system changes state, energy is transferred in some way. - Energy can be described as the abiliy to apply a force across a distance.

Consider the following experiment. A mint plant was placed in a sealed chamber in which researchers could control the atmosphere and soil. The plant was watered with normal water; that is, the oxygen on the water was normal, non-radioactive 16O. However, the CO2 given to the plant was radioactive because the oxygen it carried was radioactive 18O. After a week, they discovered that some of the sugar in the plant was radioactive, some of the water in the plant was radioactive, but all of the oxygen released by the plant was not radioactive. Which of the following conclusions is supported by these observations? Mark all that apply. HINT: This experiment is a variation of the one shown in lecture, but the results agree with those from the lecture.

- All oxygen produced by the plant came from water. - Oxygen on organic compounds produced by the plant comes from carbon dioxide. - The plant creates water metabolically. - Some water in the plant has oxygen that came from carbon dioxide.

Which of the following statements about light is correct? Mark all that apply.

- Blue light has a higher frequency than red light. - Blue light has a shorter wavelength than red light. - The wavelength of light varies depending on its color. - The frequency of light varies depending on its color. - If the wavelength of light decreases, the frequency will increase. - The velocity of light is always the same.

Which of the following statements about enzyme is (are) correct? Mark all that apply.

- Enzymes change the rate of chemical reactions without being permanently altered by those reactions. - All enzymes operate by lowering activation energy. - All enzymes are proteins.

Which of the following statements is (are) correct? Mark all that apply.

- For some life on Earth, the ultimate source of free energy is NOT light. - Tubeworms in deep-ocean hydrothermal vent ecosystems obtain their free energy from chemical potential energy in prokaryotes. - The ultimate source of free energy for some life on Earth is generated by nuclear reactions in the Earth's core. - Crabs in deep-ocean hydrothermal vent ecosystems obtain their free energy from chemical potential energy in tube worms. - All life requires sources of free energy outside of themselves.

Fructose 6 phosphate --> fructose 1,6 bisphosphate

- Is part of the destabilzation reactions of glycolysis. - Decreases ATP concentration in cells. - Transfers energy from ATP to fructose.

2- Phosphogycerate --> phosphoenolpyruvate

- Is part of the oxidation reactions of glycolysis.

gyceraldehyde 3phosphate --> 1,3 bisphosphoglycerate --> 3 phosphoglycerate

- Is part of the oxidation reactions of glycolysis. - Reduces NAD to NADH. - Both reactions have negative delta-G, reading left to right.

Which of the following statements about Joseph Priestley's experiments is (are) correct? Mark all that apply.

- Mice enclosed in a container with a burning candle die when the candle goes out. - The chemical reactions of a burning candle are similar to the chemical reactions of metabolism. - Living plants produce a gas required by both a burning candle and metabolism. - A burning candle and a living mouse both require the same atmospheric gasses.

Which of the following statements about chemical reactions is (are) correct? Mark all that apply.

- Non-spontaneous reactions are always endergonic. - The direction of a complex chemical reaction is determined by the sum of the Δ GΔ GΔ Gs of the individual reactions. - delta g is unaffected by enzymes - spontaneous reactions are exergonic

The reaction, glutamic acid + ammonia --> glutamine, has a Δ G = + 3.4 kcal/mol. Which of the following statements about this reaction is (are) correct? Mark all that apply.

- One mole of ATP could be used to produce 1 mole of glutamine. -endergonic - not spontaneous - needs outside energy source

succinate --> fumerate

- Shows reduction of FAD to FADH2. - Is part of the Krebs cycle. - Shows oxidation of succinate to fumarate.

pyruvate --> acetyle CoA

- Shows reduction of NAD to NADH. - Is part of pyruvate oxidation. - Shows oxidation of pyruvate to acetyl CoA. - Produces carbon dioxide.

isocitrate --> alpha- ketoglutarate

- Shows reduction of NAD to NADH. - Shows a tricarboxylic acid becoming a dicarboxylic acid. - Produces carbon dioxide. - Shows oxidation of isocitrate to alpha-ketoglutarate. - Is part of the Krebs cycle.

(See slides for an explanation of the abbreviations.) Which of the following statements follows from this data set?

- This does not prove the Krebs and Johnson hypothesis. - This supports the Krebs and Johnson hypothesis. - This supports the conclusion that malonate inhibits the Krebs cycle. - This neither supports nor contradicts the conclusion that malonate inhibits glycolysis. - This supports the conclusion that fumarate counteracts the effects of malonate.

In 1940, Krebs and Eggleston discovered that living cells, when fed one mole of pyruvate, consumed 2.54 moles of oxygen gas and produced 3.01 moles of carbon dioxide. Compare this result to the balanced equation for complete oxidation of pyruvate: C3H4O3 + 2.5 O2 ⟶3 CO2 + 2 H2O. Which of the following statements is supported by this observation and comparison?

- This neither supports nor contradicts the hypothesis that pyruvate is required to produce fumarate from succinate. - This supports the hypothesis that a product of pyruvate is used to regenerate citrate from malate. - All of the pyruvate fed to the cells is oxidized; none is used for any other purpose. - The amount of oxygen consumed is nearly exactly the same as the amount predicted by the equation shown. - The amount of carbon dioxide produced is nearly exactly the same as the amount predicted by the equation shown.

Which of the following statements about the light-dependent reactions is true? Mark all that apply. (NOTE: ETC means, "electron transport chain.")

- Two electrons oxidized from P700 both end up on NADPH. - The ETC from photosystem II actively transports H+ across the thylakoid membrane. - Two electrons oxidized from P680 are both used to produce 1 ATP. - The ETC from photosystem I reduces NADP+ to NADPH.

Which of the following conclusions is (are) supported by these experimental results? Mark all that apply, and use information presented in lecture in addition to the graph. (blue and red)

- Without oxygen, cells would not be able to oxidize succinate. - When living cells are fed certain organic acids, they consume more oxygen gas and produce more carbon dioxide than controls do. - Living cells given vinegar will increase their production of carbon dioxide. - Metabolic oxidation is tied to metabolism of organic acids somehow. - Living cells given vinegar will increase their consumption of oxygen.

Reconsider the figure 2 questions above this one. In particular, consider the second reaction, labeled 7. Which of the following statements about that reaction is correct

- catalyzed by kinase - BPG is oxidized - step 7 produces 1 atp exergonic

Complete the following statement: During enzyme-catalyzed reactions, the substrate... (mark all that apply)

- electrons resonate with electrons of the enzyme. - experiences physical events best described by quantum physics. - may or may not be permanently altered during the reaction. - binds to the catalytic site.

Complete the following statement: Hexokinase... (mark all that apply)

- has a catalytic site determined by its tertiary structure. - lowers activation energy - constructed by ribosomes

"To construct a human being, a mother must..." (Mark all that apply.)

- increase entropy somewhere in the universe - release free energy - absorb free energy from some source - decrease entropy in body

"In plants, the energy from photons ..."

- is absorbed in the chloroplast. - boosts electrons to higher energy states. - is used to produce NADPH. - is absorbed in the thylakoid membrane. - is used to produce ATP.

Complete the following statement: Disaccharidase... (mark all that apply)

- is expressed primarily in the intestine. - is an enzyme. - catalyzes the breaking and formation of a bond between glucose and fructose. - protein and a catalyst

reduction and oxidation of the nucleotides

- molecule gains 2 electrons - 2 nucleotide bound together

The following reaction: Glyceraldehyde 3-phosphate --> 1,3 bisphosphoglycerate is a critical reaction in a metabolic process called glycolysis, which we will study very soon. It occurs spontaneously. Which of the following statements about this reaction is (are) correct? Mark all that apply.

- negative delta g and exergonic - The free energy of glyceraldehyde 3-phosphate is greater than the free energy of 1,3 bisphosphoglycerate. - This reaction could be used to drive an endergonic reaction.

If you leave a marshmallow in a campfire too long it will catch on fire. When you pull it out, it continues to burn. Therefore, a burning marshmallow (mark all that apply)

- releasing free energy - negative delta g - releasing entropy - exergonic

Which of the following can be made from the products of the Calvin-Benson cycle? Mark all that apply.

- sucrose - fatty acids - fructose - glucose - nucleic acids - proteins - nucleotide - amino acids

CO2 + H2O → C6H12O6 + O2

- unbalanced -endergonic - positive delta g - anabolism - synthesis, based on technical definition

What is the Δ G for the complete oxidation of glucose in standard conditions, in kcal/mol?

-686

steps 6, 7, 8 in glycolysis

-NAD+ is reduced - 6 and 7 are exergonic - G3P is on top - step 6 is the most negative of the reactions

In the Calvin-Benson cycle, also called the carbon fixation cycle, exactly how many RuBP molecules are needed to create one extra, or "golden," G3P?

3

Consider the previous question. How much energy would a mole of yellow light with wavelength 685 nm have? Express your answer in kcal per mole to 3 significant figures.

41.6

What is the energy of a single photon of yellow light with wavelength 685 nm?

6.91 E -20

Fill in the blanks

Amino acids in the membrane domaine of integrak membrane proteins are nonpolar, whereas those in the intra and extracellular domains are either polar or ionic

Inorganic source of carbon.

CO2

Compound that provides the energy for chemosynthesis.

H2S

fill in the blank

In resting cells, the intracellular concentration of K+ is greater than the extracellular concentration; therefore, K+ will tend to diffuse from inside the cell to outside and the cell would tend to increase in volume until it lyses (explodes) .

Fill in the blanks.

In the calvin benson cycle, production of a single G3P requires 9 ATP, 6 NADPH, 3 CO2 and the enzyme rubisco.

Which of the following are part(s) of the endomembrane system? Mark all that apply.

Smooth ER, Rough ER, Golgi Apparatus, Nuclear Membrane

Element that is oxidized during chemosynthesis.

Sulfur

The concentration of Na+ outside cells is maintained at approximately 10 times higher than the concentration inside cells. Which of the following mechanisms of membrane transport would you predict is used by cells in this case?

active transport

Compound that is synthesized.

carbohydrate

In living beings, magnesium is typically found in its ionized form, Mg2+. In response to certain simuli, plant cells will allow Mg2+ to flow across cell membranes down its concentration gradient. Which of the following mechanisms of membrane transport would you predict is used by plant cells in this case?

channel protein

Threonine is a polar amino acid carried to cells via the blood. The concentration of threonine in the blood is equal to or greater than the concentration inside cells. Which of the following mechanisms of membrane transport would you predict is used by cells to absorb threonine?

facilitated diffusion

Phospholipid

fatty acid and polar ends

In living membranes, cell adhesions, ion channels and receptors are all examples of what?

integral membrane proteins

gain oxygen lose oxygen

oxidation reduction