Deck 13: How Cells Obtain Energy From Food

Question 1

Foods are broken down into simple molecular subunits for distribution and use throughout the body.Which type of simple subunits, listed below, is used preferentially as an energy source?

A)simple sugars
B)proteins
C)free fatty acids
D)glycerol

Answer 1

A

Question 2

On a diet consisting of nothing but protein, which of the following is the most likely outcome?

A)loss of weight because amino acids cannot be used for the synthesis of fat
B)muscle gain because the amino acids will go directly into building muscle
C)tiredness because amino acids cannot be used to generate energy
D)excretion of more nitrogenous (ammonia-derived) wastes than with a more balanced diet

Answer 2

D

Question 3

Glycolysis generates more stored energy than it expends.What is the net number of activated carrier molecules produced in this process (number and type of molecules produced minus the number of those molecules used as input)?

A)6 ATP, 2 NADH
B)4 ATP, 4 NADH
C)2 ATP, 2 NADH
D)4 ATP, 2 NADH

Answer 3

C

Question 4

The advantage to the cell of the gradual oxidation of glucose during cellular respiration compared with its combustion to CO₂ and H₂O in a single step is that

A)more free energy is released for a given amount of glucose oxidized.
B)no energy is lost as heat.
C)energy can be extracted in usable amounts.
D)more CO₂ is produced for a given amount of glucose oxidized.

Question 5

Which of the following descriptions best matches the function of a kinase?

A)an enzyme that catalyzes the rearrangement of bonds within a single molecule
B)an enzyme that catalyzes a change in the position of a specific chemical group within a single molecule
C)an enzyme that catalyzes the oxidation of a molecule by removing a hydride ion
D)an enzyme that catalyzes the addition of phosphate groups to other molecules

Question 6

Which of the following steps or processes in aerobic respiration include the production of carbon dioxide?

A)breakdown of glycogen
B)glycolysis
C)conversion of pyruvate to acetyl CoA
D)oxidative phosphorylation

Question 7

Which reaction does the enzyme phosphoglucose isomerase catalyze?

A)glucose → glucose 6-phosphate
B)fructose 6-phosphate → fructose 1,6-bisphosphate
C)glucose 6-phosphate → fructose 6-phosphate
D)glucose → glucose 1-phosphate

Question 8

The conversion of glyceraldehyde 3-phosphate to 1,3 bisphosphoglycerate in step 6 of glycolysis generates a "high-energy" phosphoanhydride bond.Which of the following BEST describes what happens to that bond in step 7?

A)It is hydrolyzed to drive the formation of ATP.
B)It is hydrolyzed to drive the formation of NADH.
C)It is hydrolyzed to generate pyruvate.
D)It is oxidized to CO₂.

Question 9

Select the best option to fill in the blanks of the following statement: Fermentation is a/an __________ process that converts __________into carbon dioxide and __________.

A)anaerobic, pyruvate, ethanol
B)anaerobic, lactate, ethanol
C)eukaryotic, glyceraldehyde 3-phosphate, ethanol
D)prokaryotic, lactate, propanol

Question 10

In anaerobic conditions, skeletal muscle produces

A)lactate and CO₂.
B)ethanol and CO₂.
C)lactate only.
D)ethanol only.

Question 11

Which of the following descriptions best matches the function of a mutase?

A)an enzyme that catalyzes the rearrangement of bonds within a single molecule
B)an enzyme that catalyzes a change in the position of a specific chemical group within a single molecule
C)an enzyme that catalyzes the oxidation of a molecule by removing a hydride ion
D)an enzyme that catalyzes the addition of phosphate groups to other molecules

Question 12

Which of the following descriptions best matches the function of a dehydrogenase?

A)an enzyme that catalyzes the rearrangement of bonds within a single molecule
B)an enzyme that catalyzes a change in the position of a specific chemical group within a single molecule
C)an enzyme that catalyzes the oxidation of a molecule by removing a hydride ion
D)an enzyme that catalyzes the addition of phosphate groups to other molecules

Question 13

Glycolysis is an anaerobic process used to catabolize glucose.What does it mean for this process to be anaerobic?

A)No oxygen is required.
B)No oxidation occurs.
C)It takes place in the lysosome.
D)Glucose is broken down by the addition of electrons.

Question 14

What purpose does the phosphorylation of glucose to glucose 6-phosphate by the enzyme hexokinase serve as the first step in glycolysis?

A)It helps drive the uptake of glucose from outside the cell.
B)It generates a high-energy phosphate bond.
C)It converts ATP to a more useful form.
D)It enables the glucose 6-phosphate to be recognized by phosphofructokinase, the next enzyme in the glycolytic pathway.

Question 15

Which of the following stages in the breakdown of the piece of toast you had for breakfast generates the most ATP?

A)the digestion of starch to glucose
B)glycolysis
C)the citric acid cycle
D)oxidative phosphorylation

Question 16

The final metabolite produced by glycolysis is

A)acetyl CoA.
B)pyruvate.
C)3-phosphoglycerate.
D)glyceraldehyde 3-phosphate.

Question 17

In step 4 of glycolysis, a six-carbon sugar (fructose 1,6-bisphosphate) is cleaved to produce two three-carbon molecules (dihydroxyacetone phosphate and glyceraldehyde 3-phosphate).Which enzyme catalyzes this reaction?

A)aldolase
B)phosphoglucose isomerase
C)enolase
D)triose phosphate isomerase

Question 18

Steps 7 and 10 of glycolysis result in substrate-level phosphorylation.Which of the following best describes this process?

A)ATP is being hydrolyzed to phosphorylate the substrate.
B)The energy derived from substrate oxidation is coupled to the conversion of ADP to ATP.
C)Two successive phosphates are transferred, first to AMP, then to ADP, finally forming ATP.
D)The substrate is hydrolyzed using ATP as an energy source.

Question 19

Which of the following processes do NOT take place in the mitochondria?

A)citric acid cycle
B)conversion of pyruvate to activated acetyl groups
C)oxidation of fatty acids to acetyl CoA
D)glycogen breakdown

Question 20

Which of the following cells rely exclusively on glycolysis to supply them with ATP?

A)anaerobically growing yeast
B)aerobic bacteria
C)skeletal muscle cells
D)plant cells

Question 21

In the final stage of the oxidation of food molecules, a gradient of protons is formed across the inner mitochondrial membrane, which is normally impermeable to protons.If cells were exposed to an agent that causes the membrane to become freely permeable to protons, which of the following effects would you expect to observe?

A)The ratio of ATP to ADP in the cytoplasm would fall.
B)NADH would build up.
C)Carbon dioxide production would cease.
D)The consumption of oxygen would fall.

Question 22

In step 1 of the citric acid cycle, citrate is generated by the enzyme citrate synthase.The enzyme combines the two-carbon acetyl group from acetyl CoA and the four-carbon oxaloacetate.What is the source of energy that drives this reaction forward?

A)a high-energy phosphodiester bond
B)a transfer of high-energy electrons
C)a high-energy thioester bond
D)the heat of molecular collision

Question 23

The citric acid cycle is a series of oxidation reactions that removes carbon atoms from substrates in the form of CO₂.Where do the oxygen atoms in the carbon dioxide molecules come from?

A)water
B)phosphates
C)molecular oxygen
D)acetyl CoA

Question 24

The first energy-generating steps in glycolysis begin when glyceraldehyde 3-phosphate undergoes an energetically favorable reaction in which it is simultaneously oxidized and phosphorylated by the enzyme glyceraldehyde 3-phosphate dehydrogenase to form 1,3-bisphosphoglycerate, with the accompanying conversion of NAD⁺ to NADH.In a second energetically favorable reaction catalyzed by a second enzyme, the 1,3-bisphosphoglycerate is then converted to 3-phosphoglycerate, with the accompanying conversion of ADP to ATP.Which of the following statements is TRUE about this reaction?

A)The reaction glyceraldehyde 3-phosphate → 1,3-bisphosphoglycerate should be inhibited when levels of NADH fall.
B)The ΔG° for the oxidation of the aldehyde group on glyceraldehyde 3-phosphate to form a carboxylic acid is more negative than the ΔG° for ATP hydrolysis.
C)The energy stored in the phosphate bond of glyceraldehyde 3-phosphate contributes to driving the reaction forward.
D)The cysteine side chain on the enzyme is oxidized by NAD⁺.

Question 25

The simultaneous oxidation and phosphorylation of glyceraldehyde 3-phosphate forms a highly reactive covalent thioester bond between a cysteine side chain (reactive group ?SH) on the enzyme (glyceraldehyde 3-phosphate dehydrogenase) and the oxidized intermediate (see the arrow in Figure 13-23A).If the enzyme had a serine (reactive group ?OH) instead of a cysteine at this position, which could form only a much lower energy bond to the oxidized substrate (see the arrow in Figure 13-23B), how might this new enzyme act? (A)


(B)

Figure 13-23

A)It would oxidize the substrate and phosphorylate it without releasing it.
B)It would oxidize the substrate but not release it.
C)It would phosphorylate the substrate on the 2 position instead of the 1 position.
D)It would behave just like the normal enzyme.

Question 26

Step 6 of the citric acid cycle is catalyzed by succinate dehydrogenase.Keeping in mind that dehydrogenases catalyze redox reactions, which are the products of the reaction in which succinate is oxidized?

A)fumarate, NADH
B)fumarate, FADH₂
C)fumarate, FADH₂
D)succinyl CoA, NADH

Question 27

In step 4 of the citric acid cycle, the reduction of NAD⁺ to NADH is coupled to the generation of CO₂ and the formation of a high-energy thioester bond.Which molecule provides the sulfhydryl group necessary to form the thioester bond?

A)pyruvate
B)acetyl CoA
C)CoA
D)cysteine side chain in the catalytic pocket

Question 28

The oxygen-dependent reactions required for cellular respiration were originally thought to occur in a linear pathway.By using a competitive inhibitor for one enzyme in the pathway, investigators discovered that these reactions occur in a cycle.Which enzyme was inhibited?

A)aconitase
B)isocitrate dehydrogenase
C)malate dehydrogenase
D)succinate dehydrogenase

Question 29

In step 3 of the citric acid cycle, the oxidation of isocitrate and the production of CO₂ are coupled to the reduction of NAD⁺, generating NADH and an α-ketoglutarate molecule.In the isocitrate molecule shown in Figure 13-32, which carbon is lost as CO₂ and which is converted to a carbonyl carbon? Figure 13-32

A)4 and 6
B)6 and 5
C)5 and 4
D)6 and 4

Question 30

In the final step of the citric acid cycle, oxaloacetate is regenerated through the oxidation of malate and this is coupled with the production of which other molecule?

A)FADH
B)NADH
C)GTP
D)CO₂

Question 31

In the absence of oxygen, yeast cells can switch to a completely anaerobic metabolism called fermentation.Which of the following is a final product of fermentation in yeast? (a)


(c)


(b)


(d)

Figure 13-24

A)Figure (a)
B)Figure (b)
C)Figure (c)
D)Figure (d)

Question 32

Pyruvate must move from the cytosol into the mitochondria, where it is oxidized to form CO₂ and acetyl CoA by the pyruvate dehydrogenase complex.How many different enzymes and what total number of polypeptides, respectively, are required to perform this oxidation process in the mitochondrion?

A)1; 60
B)3; 3
C)3; 26
D)3; 60

Question 33

The oxygen-dependent reactions required for cellular respiration were originally thought to occur in a linear pathway.By using a competitive inhibitor for one enzyme in the pathway, investigators discovered that these reactions occur in a cycle.Which product in the reaction pathway builds up when the inhibitor is added?

A)citrate
B)succinate
C)fumarate
D)malate

Question 34

The citric acid cycle is a series of oxidation reactions that removes carbon atoms from substrates in the form of CO₂.Once a molecule of acetyl CoA enters the citric acid cycle, how many complete cycles are required for both of the carbon atoms in its acetyl group to be oxidized to CO₂?

A)1
B)2
C)3
D)4

Question 35

Glyceraldehyde 3-phosphate dehydrogenase operates by stripping a hydride ion from its substrate.Which molecule is the recipient of the proton and two electrons during this transfer?

A)oxygen
B)acetyl CoA
C)NAD⁺
D)FADH

Question 36

In step 2 of the citric acid cycle, the enzyme aconitase generates isocitrate from citrate.Which of the following statements about this reaction is TRUE?

A)There is a substantial free-energy difference between the reactants and products of this reaction.
B)The unbonded electrons from hydroxide ions provide energy for this reaction.
C)The aconitase enzyme functions as a mutase in this reaction.
D)The reaction sequence first generates one molecule of water and then consumes one molecule of water.

Question 37

In step 4 of the citric acid cycle, the reduction of NAD⁺ to NADH is coupled to the generation of CO₂ and the formation of a high-energy thioester bond.The energy of the thioester bond is harnessed in step 5.What is the energy used for?

A)to generate a molecule of GTP
B)to generate a molecule of ATP
C)to generate a proton gradient
D)to generate a molecule of NADH

Question 38

Fatty acids can easily be used to generate energy for the cell.Which of the following fatty acids will yield more energy? Explain your answer.

A)CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH = CH-COOH
B)CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-COOH
C)CH₃-CH = CH-CH₂-CH₂-CH₂-CH₂-CH = CH-COOH
D)CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-COOH

Question 39

The oxygen-dependent reactions required for cellular respiration were originally thought to occur in a linear pathway.By using a competitive inhibitor for one enzyme in the pathway, investigators discovered that these reactions occur in a cycle.What compound served as the inhibitor?

A)malonate
B)malate
C)fumarate
D)succinate

Question 40

The citric acid cycle is a critical sequence of reactions for energy production, which take place in the matrix of the mitochondria.The reaction cycle requires materials from the cytosol to be converted into acetyl CoA, which represents the starting point of a new cycle.Which of the following statements about acetyl CoA is TRUE?

A)Amino acids can be converted into acetyl CoA.
B)Pyruvate is converted into acetyl CoA in the cytosol.
C)Triacylglycerol molecules are transported into the mitochondrial matrix and cleaved by lipases to produce acetyl CoA.
D)Oxaloacetate is converted directly into acetyl CoA to feed the citric acid cycle.

Question 41

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
Biological systems __________ hydrocarbons in stepwise __________ reactions.Glucose is the preferred energy source in eukaryotes, and must be converted into __________ before it can be transported across the __________ mitochondrial membrane for use in the citric acid cycle.The citric acid cycle is critical for the mitochondrion's subsequent production of __________.
ATP catabolic inner outer permeable
acetyl CoA electrons isomerize oxidize protons
anabolic glycolysis kinase peptides pyruvate
anaerobic GTP NADH

Question 42

Which of the following descriptions best matches the function of an isomerase?

A)an enzyme that catalyzes the rearrangement of bonds within a single molecule
B)an enzyme that removes a specific chemical group from a molecule
C)an enzyme that catalyzes the oxidation of a molecule by removing a hydride ion
D)an enzyme that catalyzes the addition of phosphate groups to other molecules

Question 43

Pyruvate can be converted into many other molecules by various biosynthetic and metabolic pathways, which makes it a central hub in the regulation of cellular metabolism.Which of the following molecules is NOT made from pyruvate?

A)oxaloacetate
B)ethanol
C)lactate
D)NADH

Question 44

Name the catabolic process that use substrate-level phosphorylation, identify where it takes place and how it is connected to oxidative phosphorylation.

Question 45

Provide a brief description of the process by which the body derives energy from food.Include in your description the three stages of catalysis, and delineate the input and output that connect each stage.

Question 46

When glucose is being used up and not replaced from food intake, the blood sugar level can be maintained by synthesizing glucose from smaller molecules such as pyruvate or lactate.This process is called gluconeogenesis.Which organ is principally responsible for supplying glucose to the rest of the body when glucose reserves are low?

A)liver
B)pancreas
C)spleen
D)gall bladder

Question 47

Pyruvate is an important metabolic intermediate that can be converted into several other compounds, depending on which enzyme is catalyzing the reaction.Which of the following CANNOT be produced from pyruvate in a single enzyme-catalyzed reaction?

A)lactate
B)oxaloacetate
C)citrate
D)alanine

Question 48

Explain how the generation of ATP by oxidative phosphorylation differs from ATP generation by substrate-level phosphorylation.

Question 49

Where does oxidative phosphorylation take place and what materials are the reactants and the products in this process?

Question 50

It can be useful to analyze the steps of glycolysis with respect to the four basic types of enzymes required by this central catabolic pathway and to consider whether each enzyme produces or harvests the energy of an activated carrier.For each step of glycolysis (see Figure 13-60 or Panel 13-1), indicate which type of enzyme (of the four listed below and in Table 13-60) is required-or if none apply.Also, indicate whether an activated energy carrier is involved, and, if so, how.
Step 1 __________
Step 2 __________
Step 3 __________
Step 4 __________
Step 5 __________
Step 6 __________
Step 7 __________
Step 8 __________
Step 9 __________
Step 10 __________
Enzyme types: kinase, isomerase, mutase, dehydrogenase

Question 51

The concentration of H⁺ ions inside the mitochondrial matrix is lower than it is in the cytosol or the mitochondrial intermembrane space.What would be the IMMEDIATE effect of a membrane-permeable compound that carries and releases protons into the mitochondrial matrix?

A)inhibition of the electron-transport chain
B)inhibition of ATP synthesis
C)increased import of ADP into the matrix
D)inhibition of the citric acid cycle

Question 52

Compare and contrast the catabolism of carbohydrates, proteins and fats.Specifically, highlight the similarities and differences in how they are broken down (extracellular, and intracellular) for conversion into acetyl-CoA, the entry point into the citric acid cycle.

Question 53

Although ATP and NADH are both important activated carrier molecules, ATP hydrolysis provides the direct molecular energy for most biochemical reactions.Why do the mitochondria also need to generate high levels of NADH?

Question 54

Step 3 in glycolysis requires the activity of phosphofructokinase to convert fructose 6-phosphate into fructose 1,6-bisphosphate.Which of the following molecules is an allosteric inhibitor of this enzyme?

A)P_i
B)AMP
C)ADP
D)ATP

Question 55

Anaerobically growing yeast further metabolizes the pyruvate produced by glycolysis to CO₂ and ethanol as part of a series of fermentation reactions.
A.What other important reaction occurs during this fermentation step?
B.Why is this reaction (that is, the answer to part A) essential for the anaerobically growing cell?

Question 56

The conversion of fructose 1,6-bisphosphate to fructose 6-phosphate is catalyzed by a fructose 1,6-bisphosphatase and is one of the final steps in gluconeogenesis.Which of the following molecules is an allosteric activator of this enzyme?

A)P_i
B)AMP
C)ADP
D)ATP

Question 57

The intermediates of the citric acid cycle are constantly being depleted because they are used to produce many of the amino acids needed to make proteins.The enzyme pyruvate carboxylase converts pyruvate to oxaloacetate to replenish these intermediates.Bacteria, but not animal cells, have additional enzymes that can carry out the reaction acetyl CoA + isocitrate → oxaloacetate + succinate.Which of the following compounds will NOT support the growth of animal cells when used as the major source of carbon in food, but will support the growth of nonphotosynthetic bacteria?

A)pyruvate
B)glucose
C)fatty acids
D)fructose

Question 59

Which of the following polymers of glucose is used as a vehicle to store energy reserves in animal cells?

A)glucagon
B)glycogen
C)starch
D)glycerol

Question 60

In humans, glycogen is a more useful food-storage molecule than fat because

A)a gram of glycogen produces more energy than a gram of fat.
B)it can be utilized to produce ATP under anaerobic conditions, whereas fat cannot.
C)it binds water and is therefore useful in keeping the body hydrated.
D)for the same amount of energy storage, glycogen occupies less space in a cell than does fat.

Question 61

The oxidative reactions of cellular respiration were the focus of intense study in the 1930s.These reactions are represented in a linear pathway, as they were thought to occur.Each product is designated as a lettered compound (A through H) in Figure 13-16.
Figure 13-16
A.What was the first observation that Krebs made when he added malonic acid to the minced muscle samples, and what was his conclusion about how and where it was acting in the reactions he was studying?
B.What happens when the malonate block is introduced and subsequently compound A is added in excess? What is the result if compound G is added after the block, instead of A? How did Krebs attempt to reconcile these two results?
C.What additional observation led Krebs to hypothesize that what was previously thought to be a linear sequence of reactions is actually a cyclic sequence of reactions? How did this idea further explain the earliest observations that the addition of any single compound in the pathway greatly increases oxygen uptake by the muscle tissue?

Question 62

Although the outer mitochondrial membrane is permeable to all small molecules, the inner mitochondrial membrane is essentially impermeable in the absence of specific transport proteins.Consider this information and what you have learned about the citric acid cycle to address the following questions.
A.The ATP generated by oxidative respiration is used throughout the cell.The majority of ATP production occurs in the mitochondrial matrix.How do you think ATP is made accessible to enzymes in the cytosol and other organelles?
B.If the inner mitochondrial membrane were rendered as permeable as the outer membrane, how would that affect oxidative phosphorylation? Which specific processes would stop and which remain?
C.Present two types of benefits derived from separating the reactions of glycolysis in the cytosol from those that occur during the citric acid cycle in the mitochondrion.

Question 63

Glycolysis and the citric acid cycle comprise two different sets of oxidation reactions.The reaction sequence for glycolysis is linear, whereas the reaction sequence for the citric acid cycle forms a circle.How does this difference in the arrangement of reactions influence the rate of these processes when an excess amount of a single intermediate is added?

Question 64

In step 7 of the citric acid cycle, fumarase catalyzes the addition of a water molecule to a carbon-carbon double bond (see Panel 13-2).Can this be considered an oxidation reaction? Explain your answer.

Question 65

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
amino acids galactose nucleotides
carbon fixation glucose oxidative phosphorylation
citric acid cycle glycogen pyruvate
fatty acid insulin starch
fermentation lactate triacylglycerol
A carbon atom in a CO₂ molecule in the atmosphere eventually becomes a part of one of the enzymes that catalyzes glycolysis in one of your cells.The CO₂ first enters a cell in a corn leaf, where photosynthesis fixes the carbon to make it part of a sugar molecule; this travels from the leaf to an ear of corn, where it is stored as part of a polysaccharide __________ molecule in the corn seed.You then eat a corn chip made from the corn seed.You digest the corn seed, and the free __________ travels in your bloodstream, eventually being taken up by a liver cell and stored as __________.When required, this storage molecule breaks down into glucose 1-phosphate, which enters the glycolytic pathway.Glycolysis produces __________, which is converted into acetyl CoA, which enters the __________.Several intermediates in this process can provide the carbon skeleton for the production of __________, which are then incorporated into the enzymes that catalyze steps in glycolysis.

Question 68

In the reaction cycle involved in the oxidation of pyruvate, what are the advantages of having three enzyme activities contained in a single large complex instead of having three smaller and physically independent enzymes?

Question 69

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase may be used more than once.
ADP FADH₂ H⁺ moderately protons
ATP favorable higher NADH severely
cytosol glucose lower NAD⁺ slightly
electrons GTP matrix P_i unfavorable
High-energy electrons are transferred through a series of molecules, and the energy released during these transfers is used to generate a gradient of __________, or __________.Because their concentration is __________ outside than inside the mitochondria, the flow of __________, or __________, down the concentration gradient is energetically very __________ and can thus be coupled to the production of ATP from ADP.Thus, oxidative phosphorylation refers to the oxidation of __________ and __________ molecules and the phosphorylation of __________.Without this process, the yield of ATP from each glucose molecule would be __________ decreased.

Question 70

Do you expect the cell to produce more ATP from one glucose molecule or from one fatty acid molecule? Explain your answer.

Question 71

You are stranded on an island with no way to communicate or signal for help.Your only hope is that somebody has tracked your last known location and will begin a search from there.Nevertheless, it will be a while before you have a chance of seeing another person.You have found a fresh stream of water at the center of the island, but other than green leafy plants, food options appear nonexistent.
A.What substances are used as energy stores within your body? In which organs?
B.Which will be used first in the absence of ingesting external sources of energy? How long will this source last?
C.What other substance will your body then turn to? On average, how long before you run out of that fuel source? Explain why this second fuel source is a better choice than the first-used source as your long-term energy store.
D.What enzyme is required for the breakdown and usage of the energy source you listed in part B? If you are a person with a deficiency in that enzyme, how does this affect your other estimates?