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Ch 9 biology
Cellular Respiration
Question | Answer |
---|---|
What's the definition for fermentation? | a partial degradation of sugars that occurs without oxygen. This yields small amounts of ATP. |
What's the definition of cellular respiration? | Process that with OXYGEN, releases energy by breaking down glucose (and other food) to release ENERGY |
What's the definition of oxidation? | a substance loses electrons, or is oxidized |
What's the definition of reduction? | a substance gains electrons, or is reduced (the amount of positive change is reduced) |
Explain in general terms how redox reactions are involved in energy exchanges. | Some do not transfer electrons but the electron sharing in covalent bonds NAD and FADH are electron carriers that transfer electrons. |
They are also known as what? | electron shuttles |
Describe the role of NAD+ in cellular respiration. | Electrons from organic compounds are usually first transferred to NAD+, a coenzyme. NAD dehydrogenase is the enzyme that extracts 2 electrons and 2 protons (H+) from organic food molecule. |
What happens at the very end of the chain in cellular respiration? | oxygen pulls electrons down the chain in an energy-yielding tumble. The energy yielded is used to regenerate ATP. |
Name the three stages of cellular respiration. | Glycolysis, The Citric Acid Cycle, and Oxidative Phosphorylation |
In cellular respiration, what does glycolysis do? | it breaks down glucose into two molecules of pyruvate |
In cellular respiration, what happens during The Citric Acid Cycle? | this completes the breakdown of glucose |
In cellular respiration, what does oxidative phosphorylation do? | electron transport and chemismosis (this accounts for most of the ATP synthesis--90%) |
Explain where and how the respiratory electron transport chain creates a proton gradient. | the protons in the intermembranous space are at a higher concentration than in the matrix. This produces a gradient of difference in ion gradient. The energy stored in this gradient is used the synthesis of ATP. |
What's the definition of substrate level phosphorylation? | it's the production of ATP from ADP by a direct transfer of high-energy phosphate group from a phosphorylated intermediate metabolic compound in an exergonic catabolic pathway. |
What's the definition of oxidative phosphorylation? | is the production of ATP using energy derived from the transfer of electrons in an electron transport system and occurs by chemiosmosis. |
What is fermentation all about? | produces ATP without the use of oxygen, cellular respiration requires O2 to produce ATP, glycolysis can produce ATP with or without O2 (in aerobic /anaerobic condtions), and in the absence of O2, glycolysis couples with fermentation to produce ATP |
What are the types of fermentation? | alcohol and lactic acid |
What's alcohol fermentation? | pyruvate is converted to ethanol in two steps, with the first releasing CO2 |
What's lactic acid fermentation? | pyruvate is reduced to NADH, forming lactate as an end product, with no release of CO2. |
What is a good example of lactic acid fermentation? | cheese and yogurt |
What is a good example of alcohol fermentation? | brewing, winemaking, and baking |
Explain what anaerobic respiration is all about. | Glycolysis is part of this process and does not use and oxygen in any of the nine steps. |
What's the definition of obligate anaerobes? | they'll die when exposed to atmospheric levels of oxygen |
What's the definition of faculative anaerobes? | they can use oxygen when it's present |
A molecule is oxidized when it what? | loses an electron In cellular respiration, ____ is oxidized and ____ is reduced. |
Most of the ATP produced in cellular respiration comes from _____. | chemiosmosis |
What best describes the electron transport chain? | electrons passing from one carrier to another, releasing a little energy at each step |
An electron carrier acts as an energy-storage molecule when it's _____. | reduced...NADH |
The function of cellular respiration is to _____. | extract usable energy from glucose |
A small amount of ATP is made in glycolysis ____. | by the transfer of a phosphate group from a fragment of glucose to ADP |
During respiration in an eukaryotic cell, reactions of glycolysis occur, or are located in or on ______. | the cytosol |
Most of the NADH that delivers high-energy electrons to the electron transport chain comes from ______. | chemiosmosis |
Why is the Krebs cycle called a cycle? | the two-carbon acetyl coA binds to a four-carbon molecule that's restored at the end of the cycle |
In the Krebs cycle, the energetic production per glucose molecule is _______. | 2 ATP, 6 NADH, 2 FADH2 |
How many ATPs are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen? | 4 ATP |
After completion of the Krebs cycle, most of the usable energy from the origainl glucose molecule is in the form of _______. | NADH |
The energy given up by electrons as they move through the electron transport chain is used to ____. | pump H+ through a membrane |
The enzyme ATP synthase forms ATP ____. | due to the potential energy of a concentration gradient of hydrogen ions across a membrane |
During aerobic respiration, molecular oxygen is used ____. | at the end of electron transport chain to accept electrons and form H2O |
If humans did not breathe in O2, we wouldn't ___. | make enough ATP to meet our energy requirements |
During respiration in an eukaryotic cell, the electron transport chain is located in or on the _______. | cristae of the mitochondrion |
How much ATP can a cell make from one glucose molecule in the presence of carbon monoxide? | 2ATP |
In glycolysis in the absence of oxygen, cells need a way to regenerate which compound? | NAD+ |
Muscle tissues make lactate from pyruvate in order to _____. | regenerate (oxidized) |
In brewing beer, maltose (a disaccharide) is ___. | the substrate for alcoholic fermentation |
When protein molecules are used as fuel for cellular respiration, ___ are produced as waste. | amino groups |