Ch. 06 - An Introduction to Metabolism 2016 PDF

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Ch. 6. An Introduction to Metabolism Key Concepts for Ch. 6 6.1

An organism _____________ transforms matter and energy.

6.2

The ___________ change of a reaction tells us whether or not the reaction occurs ___________ .

6.3

_______ powers cellular work by coupling _____________ to _____________.

6.4

_____________ speed up metabolic reactions by lowering energy barriers (ACTIVATION ENERGY).

6.5

Regulation of _____________ helps control metabolism.

1)

The sum total of all chemical reactions in an organism is called _____________.

2)

A _____________________ begins with a starting molecule which is then altered in a series of defined steps, resulting in a certain _____________.

3)

The overall metabolic process involves two processes. A. _____________ - pathways which release NRG together when complex molecules are broken down. (ex: cellular respiration) B. _____________ - pathways which requires NRG to put together complex molecules (ex: synthesis of protein from amino acids)

4)

_____________is the study of how energy flows through living systems and is essential to look at in order to understand metabolic processes of the cell.

5)

Energy is the capacity to cause _______. It is important because some forms of energy can be used to do ___________such as moving matter against opposing forces such as _____________and ____________.  energy is the ability to rearrange matter

Forms of Energy

6)

Energy associated with the relative motion of objects is called ____________

7)

_____________or _____________energy is associated with the random movement of atoms or molecules.

8)

An object that is not moving may still possess _____________energy which is the energy it holds due to its ________________________or structure.

 Molecules possess energy because of the arrangement of electrons in the bonds between their atoms.  The atoms of high energy reactants can be rearranged into lower-energy breakdown products.

9)

_____________energy refers to the _____________energy available for release in a chemical reaction. The Laws of thermodynamics: 10)

The study of the energy transformations that occur in a collection of matter is called ________________________

11)

In an _____________system, _____________and _____________can be transferred between the system and its environment. Organisms are _____________systems, they absorb energy (eat molecules) and release heat.

12)

Define: 1st Law of Thermodynamics-

2nd Law of Thermodynamics-

13)

A consequence of the loss of usable energy during energy transfers is that it makes the universe more disordered. Scientists use a quantity called _____________to measure _____________or _____________. *unusable heat is associated with _____________entropy *_____________must be constantly added to offset entropy (maintain order)

14)

A reaction that is can proceed without requiring the input of energy*** – “is energetically favorable” and increases entropy of the universe is said to be _____________. ***not totally true – needs the input of some activation energy, but then can drive itself with -G*** see later in notes!!!

15)

A reaction that will happen only if energy is supplied and leads to a decrease in entropy is said to be _____________________.

The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously 16)

_____________: the proportion of a system’s NRG that can perform work when temperature and pressure are uniform throughout the system. (G) G = Gfinal state – Ginitial state

17)

A spontaneous reaction that proceeds with the release of free energy is known as an _____________reaction (-G)

Cellular respiration G = -686 kcal/mol *breaking bonds ________________release energy, it _____________energy. The release of energy in a chemical reaction occurs when bonds are broken and new bonds are formed and the products have less free energy than the reactants had (-G)

18)

Other reactions (nonspontaneous) can be made to proceed only with the addition of free energy are known as _____________ (+G) Photosynthesis G = 686 kcal/mol

Equilibrium and metabolism 19)

Reactions in isolation eventually reach _____________and can do no work.

20)

Metabolic equilibrium =

21)

A cell that reaches metabolic equilibrium is _____________

22)

Disequilibrium is maintained because the _____________of one reaction do not build up, but are used in another reaction or _____________as waste from the cell.

ATP powers cellular work by coupling exergonic reactions to endergonic reactions 23)

Three main types of work in a cell are: a. b. c.

24)

Energy coupling: The use of an _____________reaction to power an _____________reaction. _____________is responsible for these coupled reactions in organisms. Know the components of ATP!

25)

The bonds of ATP can be broken by _____________this is considered an _____________reaction (G = -7.3 kcal/mol) in cellular respiration.

26)

The hydrolysis of ATP under cellular conditions releases _____________

27)

The three phosphate groups in ATP have a _____________which contributes to the instability of the molecule and _____________ free energy. This portion of the molecule could be compared to a _____________.

28)

With the help of enzymes, cells are able to use energy released by ATP hydrolysis to drive a chemical reaction that is _____________ (nonspontaneous).

29)

If the G of the endergonic reaction is _________than the amount of energy released by ATP hydrolysis, the two reactions can be coupled so that the overall reaction is ____________ (spontaneous).

30) The key to coupling exergonic and endergonic reactions is the formation of a __________________________which is _____________ (less stable).

ATP – ADP Cycle 31)

ATP can be regenerated at an astonishing rate. A muscle cell will recycle all its ATP in _____________ (_____________________of ATP consumed and regenerated per second per cell)

32)

The energy required for the regeneration of ATP comes from _____________ (_____________) reactions in the cell (cell respiration)

33)

ATP is converted to _____________ and a _____________ which is more stable.

34)

The loss of a phosphate makes ADP have _____________NRG and be more stable.

35)

The regeneration of ATP is an _____________reaction while the breaking of ATP is an _____________reaction.

Enzymes speed up metabolic reactions by lowering energy barriers: 36)

Rate of Reaction: the speed at which a reaction moves towards _____________ *controlled by concentration gradients and enzymes

37)

An _____________is a macromolecule that acts as a _____________to speed up a reaction without being consumed by the reaction. Examples: (-ase) a) _____________ (breaks down sucrose)

b) _____________ (breaks down protein) c)

_____________ (breaks down lipids)

38)

The initial investment of energy necessary to break bonds in the reactants and get the reaction started is called the __________________EA. This is often supplied in the form of _____________that the reactant molecules absorb from the surroundings.

This energy allows the reactants to reach their ___________________ at which point they are unstable and primed to break and reform bonds. ***reactions with a low activation energy requirement proceed at a very fast rate, while those with a high requirement proceed at a slow rate***

39)

40)

Why are spark plugs essential for cars to run?

Why is the barrier of activation energy essential to life?

41)

Adding _____________will speed up a reaction but is inappropriate for most biological systems because: A) High temperatures _____________proteins and _____________cells. B) It would speed up _____________reactions not just the ones needed.

42)

An enzyme catalyzes a reaction by lowering the ____________________ enabling the reactant molecules to absorb enough energy to reach the _____________at moderate temperatures.

43)

Enzymes are _____________, _____________ reactions that would occur slowly, and are _____________consumed in these reactions.

44)

The reactant an enzyme acts on is called the _____________.

45)

The enzyme binds to its substrate(s) forming an ___________________ complex.

46)

Only a restricted region of the enzyme, called the _____________actually binds with the substrate.

47)

The _____________of an enzyme is attributed to the compatible fit between the active site and the substrate.

48)

The active site does not fit rigidly like a lock and key. As the substrate enters the active site interaction of the R groups of the _________________causes the enzyme to change its shape slightly so that the active site fits even more snuggly around the substrate. This is called _____________

49)

Enzymes can be _____________ (above) or _____________ (right) depending on whether the break down or combine molecules respectively.

50)

4 Enzyme mechanisms that lower activation energy 1)

2)

3)

4)

38) Factors affecting the rate of reaction A) Substrate concentration Increasing substrate concentration will _____________ the rate of reaction in direct proportion until all enzyme molecules __________________. At that point the enzyme is said to be _____________The only way then to increase the rate of reaction is to________________________________.

B) Enzyme concentration Increasing the enzyme concentration will _____________the rate of reaction as long as there is ____________________________________________________ a. Draw the curve that you might think would represent the rate of reaction as more and more enzyme is added to a constant level of substrate. Explain

C) Temperature – enzyme rate will increase until a point where the enzyme _____________. (in humans this optimal temp. is normally _____________) C) pH – most work best at a pH of ___ but will vary depending on the enzyme ex. Pepsin in the _____________----> pH ____ Trypsin in the _____________ -----> pH ____

39)

Many enzymes require non-protein helpers for catalytic activity. A) __________________ are organic molecules that aid enzymes in lowering activation energy. Many of these are _____________that we get in our diet. B) Inorganic enzyme helpers are called _____________and are usually _____________. Enzyme Inhibitors 40)

If an inhibitor attaches to the enzyme by _____________bonds it is usually _____________but if it attaches by weak interactions the inhibition is _____________.

41)

______________________reduce the productivity of enzymes by blocking substrates from entering the _____________. This type of inhibition can be reversed by increasing the ____________________________

Example: carbon monoxide 42)

______________________do not directly compete with the substrate for active sites. Instead they bind to another part of the enzyme changing the enzyme’s shape so that it is less effective. This site of attachment is called the _____________ site.

Allosteric Regulation of Enzymes 43) __________________________is the used to describe any case in which a protein’s function at one site is affect by binding of a regulatory molecule to a separate site. It may result in either

a. _____________

b. _____________

44)

In _____________, the binding of one substrate molecule can stimulate the binding or activity at other active sites.

term the

45)

In __________________________, the end product of a metabolic pathway allosterically inhibits the enzyme from a previous step in the pathway. Most commonly used to maintain _____________by preventing overproduction of products in a cell. (_____________feedback)

Using a series of arrows, DRAW the branched metabolic reaction pathway described by the following statements. Then answer the question at the end. Use red arrows and minus signs to indicate inhibition. L can form either M or N M can form O O can form either P or R P can form Q R can form S O inhibits the reaction of L to form M Q inhibits the reaction of O to form P S inhibits the reaction of O to form R.

Which reaction would prevail if both Q and S were present in the cell at high concentrations? A) L  M B) M  O C) L  N D) O  P...