cell bio chapter 13
the electron transport chain
The NADH generated during glycolysis and the citric acid cycle feeds its high-energy electrons to which of the following?
Mitochondria
Where does the oxidative (oxygen-dependent) stage of the breakdown of food molecules occur in a eukaryotic cell?
mitochondrion
Where does the oxidative (oxygen-dependent) stage of the breakdown of food molecules occur in a eukaryotic cell?
NADH
Which carrier is in its activated state as used in the cell?
It consumes four molecules of ATP and two molecules of GTP to produce one molecule of glucose.
Which is true of gluconeogenesis?
O2, NAD+, GDP, oxaloacetate
Which molecules are required for the citric acid cycle to fully oxidize the carbons donated by acetyl CoA?
Electron transport chain
Which of the following processes generates the largest number of ATP molecules?
electron Transport chain
Which of the following processes generates the largest number of ATP molecules?
fatty acids
After an overnight fast, most of the acetyl CoA entering the citric acid cycle is derived from what type of molecule?
NAD+
Although the citric acid cycle itself does not use O2, it requires a functioning electron transport chain (which uses O2) in order to regenerate which molecule for further use in the citric acid cycle?
ATP and other activated carriers
Most of the energy released by oxidizing glucose is saved in the high-energy bonds of what molecules?
true
Determine whether the following statement is true or false: In isolation, the formation of an activated carrier, such as ATP, NADH, or NADPH, is an energetically unfavorable reaction.
pyruvate and NADH
In cells that cannot carry out fermentation, which products derived from glycolysis will accumulate under anaerobic conditions?
Acetyl CoA, glucose, lactate, alanine, oxaloacetate
In cells, pyruvate can be converted to which of the following?
The substrates involved in metabolic reactions can be used by a number of different enzymes.
In eukaryotic cells, why must metabolism be tightly regulated?
liver cells
In humans and other mammals, gluconeogenesis is most likely to occur in which type of cells?
the oxidation of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate
In the absence of oxygen, in cells that cannot carry out fermentation, glycolysis would halt at which step?
triacylglycerol
In what form do plant and animal cells store fat?
oxygen
The ethanol in wine and beer is produced from metabolic reactions carried out by the yeast Saccharomyces cerevisiae. Since it is of great commercial value, researchers have studied factors that influence ethanol production. To maximize ethanol yield, which environmental factor should be limiting?
fermentation
Under anaerobic conditions, which metabolic pathway regenerates the supply of NAD+ needed for glycolysis?
glycolysis, the citric acid cycle, and oxidative phosphorylation
Useful energy is obtained by cells when sugars derived from food are broken down by which processes?
NADH carries an extra proton and two high-energy electrons.
What is the difference between NAD+ and NADH?
A two-carbon molecule is combined with a four-carbon molecule to form citrate.
What occurs in the first step of the citric acid cycle?
Enzymes involved in gluconeogenesis will use energy to produce glucose.
When ATP and food molecules such as fatty acids are abundant, which will occur?
glycogen
When food is plentiful, animals can store glucose as what?
starch
When nutrients are plentiful, plants can store glucose as what?
NADPH and NADH are used in separate biochemical pathways in cells.
Which of the following statements regarding NADPH and NADH is true?
The reaction is energetically favorable.
Which statement is true about the removal of a terminal phosphate from ATP?
acetyl CoA
Which two-carbon molecule enters the citric acid cycle?
fat
You are packing for a hiking trip during which you'll be burning a lot of calories with physical activity. You want to pack as efficiently as possible since you need to carry a tent and all your food. You can get the most calories out of 5kg of food if it is in the form of
They will accumulate fats because cells can convert glycolytic metabolites into lipids.
Your friends are on a low-fat, high-carbohydrate diet, which they claim will prevent fat accumulation within their bodies. They eat tons of pasta and bread without worrying about calorie count. What can you correctly say to your friends about their potential to accumulate lipids on their low-fat diet?
Gluconeogenesis
the synthesis of glucose from small organic molecules such as pyruvate
