Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
30 Cards in this Set
- Front
- Back
|
What are the three main kinds of work that a cell does?
|
1) Chemical work
2) Transport work 3) Mechanical work |
|
|
What is chemical work?
|
The pushing of endergonic reactions, which would not occur spontaneously.
|
|
|
What is transport work?
|
The pumping of substances across membranes against the direction of spontaneous movement.
|
|
|
What is mechanical work?
|
Ex: the beating oc cilia, the contractions of muscle cells, and the movement of chromosomes during cellular reproduction
|
|
|
What is energy coupling?
|
The use of an exergonic process to drive an endergonic one.
|
|
|
What is responsible for most energy coupling in cells?
|
ATP
|
|
|
True or False: In most cases ATP acts as the immediate source of energy that powers cellular work.
|
True. p. 149
|
|
|
What does ATP stand for?
|
adenosine triphosphate
|
|
|
What three things make up ATP?
|
1) sugar ribose
2) nitrogenous base adenine 3) chain of 3 phosphate groups |
|
|
Other than energy coupling, what else does ATP do?
|
ATP is one of the nucleoside triphosphates used to name RNA
|
|
|
How are the bonds between the phosphate groups of ATP broken down?
|
hydrolysis
|
|
|
When ATP goes through hydrolysis, what does it become?
|
ADP
|
|
|
True or False: In the cell, conditions conform to stardard conditions in the case of free-energy.
|
False. Consitions do not conform to standard conditions, primarily because reactant and product concentrations differ from 1 M. p. 149
|
|
|
Why are the phosphate bonds of ATP sometimes referred to as high-energy phosphate bonds?
|
Because their hydrolysis releases energy
|
|
|
Why is the term high-energy phosphate bonds misleading?
|
The phosphate bonds of ATP are not unusually strong bonds as "high-energy" may imply.
|
|
|
Relative to each other, which has a higher energy, (ATP and water) or (ADP and Pi).
|
ATP and water
|
|
|
Where does the release of energy during the hydrolysis of ATP come from?
|
the chemical change ot a state of lower free energy
|
|
|
True or False: If the /\G of an endergonic reaction is less than the amount of energy released by ATP hydrolysis, then the two reactions can be coupled so that, overall, the coupled reactions are exergonic.
|
True. p. 150
|
|
|
What happens when we say that something is phosphorylated?
|
it receives a phosphate group
|
|
|
Why is the formation of a phosphorylated intermediate the key to coupling exergonic and endergonic reactions?
|
because it is more reactive (less stable)
|
|
|
Which two types of work in the cell are nearly always powered by the hydrolysis of ATP?
|
transport and mechanical
|
|
|
True or False: ATP cannot be regenerated.
|
False. ATP is a renewable resource that can be regenerated by the addition of phosphate to ADP.
|
|
|
Does the free energy required to phosphorylate ADP come from exergonic or endergonic reactions?
|
exergonic
|
|
|
What is the ATP cycle?
|
The shuttling of inorganic phosphate and energy
|
|
|
Is the cell's energy yielding considered exergonic or endergonic?
|
exergonic
|
|
|
Is energy-consuming considered exergonic or endergonic?
|
endergonic
|
|
|
True or False: The ATP cycle moves at a slow pace.
|
False. The turnover can be 10 million molecules of ATP consumed and regenerated per second per cell.
|
|
|
What would happen if humans couldn't regenerate ATP?
|
Humans would use up nearly their body weight in ATP each day.
|
|
|
Is the regeneration of ATP exergonic or endergonic?
|
endergonic
|
|
|
In most cases, how does ATP transfer energy from exergonic to endergonic reactions in the cell?
|
ATP transfers energy to endergonic processes by phosphorylating (adding phosphate groups to) other molecules. (Exergonic processes phosphorylate ADP to regenerate ATP)
|
