Bio Exam 3

Define the first law of thermodynamics

We can freely convert energy between potential and kinetic energy

______ can also be stored in the positions of the electrons of a covalent bond

Chemical energy

What happens when a covalent bond is broken down by the cell?

The chemical energy is converted into kinetic energy

The kinetic energy used by the breaking down of a chemical bond is used….

Do to work like active transport

ATP is a type of molecule called a…..

Nucleotide

What are nucleotides made of?

3 connected phosphate groups

What type of bonds hold the phosphates of a nucleotide together called?

Covalent that store a lot of chemical potential energy that can be broken to do work

The sodium potassium pump breaks down the chemical bonds in….

ATP which is used to move sodium and potassium up their concentration gradient

The permanent gradients that the sodium potassium pump creates are a….

Permanent source of chemical potential energy for the cell that can be released again by letting the ions diffuse down their concentration gradient

Define Entropy

The measure of how organized the materials of a system are

A system with low entropy Is…

highly organized with most of the materials in it in the same place(a clean dorm room)

A system with high entropy is…..

Disorganized with the materials randomly shown about the system( A messy dorm room)

The lower entropy there is in a system….

The more potential energy that system has

The concentration gradient is….

A system with low entropy system with lots of chemical potential energy

As molecules diffuse across the membrane the entropy….

Increases because it goes from very organized to very random

Increasing entropy____ the amount of potential energy

Reduces because it forces that potential energy to be released as kinetic energy

Define the second law of thermodynamics

The entropy of a system must always increase over time, which will cause a concentration gradient to spread the molecules out

The increasing entropy of a system causes it to…

release its chemical potential energy

Diffusion continues until the concentration….

The same on both sides of the membrane

If the concnetraton is the same on both sides the entropy…

is at it maximum

When the concentration is the same on both sides of the membrane the potential energy is at its…

Lowest

Define the thermodynamic state of equilibrium

When there is not net movement across a membrane and when the atoms move randomly on there side of the membrane. Lowest level of potential energy

Define Enthalpy(H)

It is the total amount of potential energy in the chemical bonds of a molecule

Every molecule has a _____ amount of Enthalpy

Unique

What is enthalpy based off of?

The kind of bonds it has and the total number of them

To calculate the change in enthalpy….

Add up the total enthalpy of all the products and subtract the total enthalpy of all the reactants

What does change in enthalpy tell us?

Whether energy is absorbed or released by the reaction

Positive absorbs

Negative releases

When we perform chemical reactions we are changing the position and order of the electrons which means we are also changing the systems……

Entropy

Increasing entropy causes energy…

to be released

Decreasing entropy causes energy….

To be absorbed

Sugar metabolism….

Increases entropy(7 molecules to 12)

Photosynthesis….

Decreases entropy(12 molecules to 7)

Define the Gibbs free energy Change

Combined

Chemical reactions that have a positive G….

Must absorb energy from the environment to happen(Non-Spontaneous)

Chemical reactions that have a negative G….

Must release energy into the environment when they happen(Spontaneous)

Active Transport is….

a Non spontaneous process

In a postive G reaction the products have a…..

Higher overall potential energy than the reactants which means it must absorb energy to make it happen

Molecules diffuse down the concentration gradient…

Spontaneously

What is the relation between spontaneous and fast?

They do not equal, many reactions in the cell happen spontaneously but are too slow to be useful

Burning of paper is a ____ reaction

spontaneous

Define Activation energy

It is a certain amount of energy needed to to start a chemical reaction which is why most spontaneous reactions are very slow

The greater the activation energy the…..

Slower the reaction happens

The lower the activation energy the…..

faster the reaction happens

A transition state is required by….

Reactions involving covalent bonds

Define a transition state

A temporary molecule where the old binds are breaking and new bonds are forming at the same time

Transition states are…

Very organized(low entropy) so the cell must use kinetic energy to make them form(activation energy)

The cell uses___ to help with activation energy

Enzymes

How do enzymes speed up chemical reactions?

They bind to molecules of the reaction lowering their activation energy

Define Substrates

The reactants of a chemical reaction

How do substrates attach to enzymes?

Binding through the formation of a NON convalent bond

Define the active site

The place where molecules bind to an enzyme

How do enzymes break old bonds and form new bonds?

The side chains of the amino acids interact with the substrate molecules

Why is 3d shape important to proteins specifically enzymes?

enzymes must build multiple substrates in a precise orientation and The amino acids in the active site must chemically interact with the substrate during the chemical reaction.

Any genetic functions that change the 3D folding of the protein or the amino acids in the active site will….

Change the effectiveness of the enzyme

Is the 3D shape of the enzyme locked or static?

No it changes the shape due ti the binding of substrates to the active site

Define Conformational shifts

Changes in the shape of a protein

Define the indeed fit model

The shape of a protein changes and shifts the amino acids in the active site into the correct position to catalyze the chemical reaction

Define the metabolism of the cell

A series of interconnected chemical reactions that are all catalyzed by enzymes

Define metabolic pathways

A series of several chemical reactions

In a metabolic reaction the products of one reaction are the____ of the next

Substrates

If the product of the final reaction is different from the original substrate it is a….

metabolic chain

If the product of the final reaction recreates the initial substrate it is……

metabolic cycle

The ability of a cells enzymes to perform chemical reactions is….

Regulated so that it isn’t all a mess

When a cell “turns on” an enzyme so that it performs its reaction quicker it is considered….

activated

When a cell “turns down/off” so that it performs its reaction slower it is considered…

Inhibited

By making small tweaks to. the shape of a protein the cell can change….

The speed of a chemical reaction

Define Allosteric Regulation

Use a allosteric site that can bind to a regulatory molecule which cause a shape change In the enzyme

Define The allosteric site

Used by allosteric regulation its where the regulatory molecule binds

Define Allosteric activation

It binds the regulatory molecule which causes a shift in shape which activates the enzyme speeding up the reaction(quick,easily)

Define Allosteric Inhibition

This is when th eregualoty molecule binds and it slows down the enzyme(slowly/poorly)

Either type of allosteric control is…

Permanent

When the regulatory molecule unbinds the enzyme…

It retunes to its default shape

Define Phosphorylation

A Phosphate(transferred from a ATP molecule) is covalently bonded to the polar side chain on the enzyme which cause a conformational shift

When a phosphate is added to to a protein we say that that protein is….

Phosphorlyated

Either type of Phosphorpyation is…

Temporary

When a phosphate is removed from the enzyme the enzyme….

Returns to its default shape

Define Competitive Inhibition

A regulatory molecule made by the cell can bind to the active site which stops the substrates from binding thus inhibiting the reaction.

What is the main source of energy in most cells?

Cellular respiration

When our bodies burn sugar the _____ produced is lost to the enviroment

Kinetic energy that cells want to capture and turn into chemical potential energy(molecules of ATP)

How do cells break down glucose to harvest kinetic energy?

Slowly, a few chemical bonds at a time

Energy Storage in cells depends on a process called the….

ATP-ADP cycle

What is it called when ATP is broken down and one of its phosphates are removed?

Hydrolisis(converts the potential energy in the bind to kinetic energy)

What are the products of hydrolysis?

An unattached free phosphate

ADP(adenosine diphosphate)

Dehydration synthesis….

Re-creates ATP

Define Substrate Level Phosphorylation

When ADP is used as a substrate of the enzyme that has a phosphate added to it by the enzyme to create ATP(When energy from chemical reaction is used directly to make ATP)

What are the 2 ways that cells use to capture energy from glucose?

Substrate level phosphorylation

Electron Transfer

Define Electron Transfer

When metabolic enzymes remove electrons from the molecules that they break down, these electrons are then transferred to a electron carrier

What does NAD+ become when carrying electrons?

NADH

What does FAD become when carrying electrons?

FADH2

What is the first major step in cellular respiration?

Gylcolisis

Glycolsis is an example of which type of metabolic process?

A metabolic chain

What are the first 5 reactions of glycolysis?

The energy investment phase

Define the energy investment phase

The first stage of glycolysis where the cell uses 2 ATP molecules to phosphorylate glucose and convert it into glyceraldehyde-3-phosphate, preparing it for energy production.(Spends energy)

What are the last 5 reactions of glycolysis?

The energy payoff phase

In the energy payoff phase what is glucose broken down into?

Pyruvate

Define the energy payoff phase

The second stage of glycolysis where ATP and NADH are produced as glyceraldehyde-3-phosphate is converted into pyruvate, resulting in a net gain of energy for the cell.

How does the cell keep its pool of ATP constant

By regulating how much glucose is broken down by glycolysis

Define Feedback inhibition

Occurring only in the metabolic chain/cycle the regulatory molecule is one of the reactions in the chain, and it will bind to the allosteric site on one of the enzymes earlier in the metabolic chain

Define PFK

It is the enzyme in feedback inhibition that makes the product that goes back to enzyme 1 to tell it to stop

PFK has a allosteric site that can bond to…..

ATP that Binds when levels get high causing a conformational shift and the cell to slow down the metabolic chain(the reverse happen to speed it up again)