All activities that occur within living cells are driven by ___________________ ___________________.

During these reactions, atoms of the _____________________ are rearranged to form the ___________________.

REACTANTS (what you start with) -------------> PRODUCTS (end result of reaction)

In your cells, chemical reactions rearrange the atoms in ____________________ (C₆H₁₂O₆) molecules, making new products, and releasing ___________________.

Chemical reactions can ____________________ or ____________________ energy. (fig 5-1; 5-2)

____________________ - All of the thousands of chemical reactions occurring in the cells of an organism.

Chemical reactions need some _____________________ to get started.

___________________ ____________________ - Energy needed to start a reaction.

Ex: If you want to roll a boulder down a hill, you need to give it a push. That PUSH would be "activation energy" needed to start that boulder rolling down the hill.

Chemical reactions in cells require ________________________________ to proceed, generating activation energy necessary to start the reaction. Such high temperatures would kill cells. Solution???

Cells use ___________________, proteins that are capable of increasing the rate of a reaction by lowering activation energy. Ex: You would be lowering your activation energy needed to roll a boulder down a hill by decreasing the size of the hill. This is similar to the actions of an enzyme. (fig 5-3)

_____________________ - Makes a chemical reaction proceed faster without being used up by the reaction. Enzymes are biological catalysts.

Enzymes speed up reactions by binding with specific molecules, or _____________________ at the ____________________ of the enzyme. (fig 5-5)

Cells can control enzyme activity by altering the enzymes _____________________. Shape can be altered by binding ____________________ molecules to their surfaces.

Cells have _____________________ of enzymes, each one ____________________ to every reaction that goes on within the cell.

Factors that affect enzyme activity:

• _______________________________________________

• _______________________________________________

Cells require energy for:

• ______________________________________________________________________________

• ______________________________________________________________________________

• ______________________________________________________________________________

• ______________________________________________________________________________

• ______________________________________________________________________________

______________________________________________________________________ and

_________________________________________________________________________________ requires considerable amounts of energy.

Energy stored in ___________________________________ is _____________________ at each step in a series of enzyme-catalyzed, linked reactions called a __________________________________________. There are _______________________ of these pathways that take place in living things.

In biochemical pathways:

• __________________________________________________________________________________________

• __________________________________________________________________________________________

When cells break down molecules, energy is:

• ___________________________________________________________________

• ___________________________________________________________________

________________ - Adenosine Triphosphate

• ATP is essential for a cell to perform all tasks necessary for life
• Contains 3 phosphate groups
• Temporarily stores energy from broken down food molecules
• Supplies energy to reactions that build new molecules
• Referred to as a "cells energy currency" because most of the energy that drives metabolism is supplied by ATP

ATP + H₂O --> ADP + P + energy

When a reaction that absorbs energy in a cell is driven by the conversion of ATP -> ADP, it is called a

____________________ _____________________. These reactions occur during metabolism. (fig 5-8)

The ________________ is the ultimate source of energy for all living things.

Energy obtained from the sun is __________________________ into organisms throughout the food chain.

(fig 5-10)

_____________________, _____________________, & some ____________________ take part in a process called photosynthesis.

______________________________ - A process in which energy is captured from the sun, and used to produce ATP, energy storing carbohydrates, and other organic molecules for all other organisms on earth.

Organisms that cannot capture light directly from the sun get energy by ________________________ food, which contains carbohydrates & organic molecules.

All living things use a process called __________________________ __________________________ to obtain energy from carbohydrates & other organic molecules.

During cellular respiration, energy that was ____________________ in organic molecules is used to make ________ needed for life processes.

During photosynthesis, _____________________ captured from the sun is used to obtain ____________________, which carry the energy through a series of chemical reactions.

6 CO₂ + 6H₂O + light energy -> C₆H₁₂O₆ + 6O₂

Photosynthesis has THREE STAGES:

1. _______________________ is captured from ________________________.
2. The ______________________ is used to make ________________ and ___________________, an energy carrying compound
3. ________________ & ___________________ are used to power the _________________________ of energy-rich ___________________________________ using _______________ from the air.

Stage 1: Capturing Light Energy

(fig 5-12) – The Electromagnetic Spectrum

Shorter wavelengths of light = more energy
Longer wavelengths of light = less energy
Intermediate wavelengths of light = visible light

__________________________ - Molecules that absorb light photons. When a pigment absorbs light, _____________________ of certain atoms in pigment molecules are boosted to a _______________________ _________________________ ________________________.

Ex of pigments: Retinal pigments exist in human eyes, chlorophyll pigments exist in plants.

Light -> _{(energy transferred)} -> Electrons

__________________________ - The major pigments in plants. Absorbs mainly ____________ & ____________ photons of light, and reflects _______________ photons of light.

_________________________ - Other pigments found in plants that help gather energy for photosynthesis. These pigments absorb slightly different wavelengths of light, reflects ____________________ & ___________________ light.

Interesting fact: Chlorophyll breaks down in colder temperatures and allows colors of carotenoids to be seen in yellow and orange leaves of autumn.

Pigments for photosynthesis are located in ____________________________ of plant cells. Chlorophyll molecules are contained in disk-like membranes called ____________________________.

__________________________ - Stacks of thylakoids suspended in the fluid stroma of chloroplasts.

(fig 5-13)

• Light strikes _________________________ in a chloroplast

• _________________________ in certain chlorophyll molecules are boosted to a _______________________ energy level

• "Excited" _________________________ jump from their chlorophyll molecules to a nearby __________________________ molecule in the thylakoid membrane

• Each _______________________ ________________________ is then passed through the membrane from one _____________________________________________________ to another.

• This is known as the _________________________ _________________________ _____________________

• Before excited _____________________ can leave their chlorophyll molecules, they must be ____________________________ by other _________________________. These electrons are supplied by __________________.

• Plants obtain ______________________ from _______________________ by splitting water molecules.

• As water molecules split, chlorophyll takes the ______________________ from the _______________________ atoms, leaving _______________________.

• The remaining oxygen atoms combine to form ____________________________ _____________________.

(fig 5-14)

ATP is made when protons flow through a protein channel.

(refer to fig 5-14)

• Each excited electron from chlorophyll loses some of its energy as it passes through a series of protein carriers in the thylakoid membrane.

• This energy is used to _____________________ _____________________ across the membrane, and into the interior of the thylakoid (5-14b).

• Protons are pumped inward until the thylakoid is "bursting at the seams."

• Protons diffuse through the only available exits, protein channels (5-14d).

• These channels use the force of protons exiting the thylakoid to add a phosphate group to an ADP molecule, making ____________________.

These _________________________ _________________________ in the thylakoid membrane are directly responsible for providing energy to produce ________________ molecules.

Additional light energy is absorbed to make NADPH

(refer to fig 5-14)

• After the energy of excited electrons is used to make ___________________, the electrons are accepted by other chlorophyll molecules.

• These molecules absorb more __________________________, which excites some of their electrons.

• The excited electrons pass through another series of ________________________ _____________________.

• Finally, these electrons are attached to an electron acceptor called ___________________, forming the energy carrier ______________________ (fig 5-14c).

The ________________ and ___________________ generated in Stage 2 help power Stage 3 of Photosynthesis – the building of __________________________________.

Stage 3: Building Carbohydrates

(fig 5-15)

• ___________________________ atoms are captured from ____________ in the air, and used to make organic molecules that store energy.

• A series of reactions called the __________________________ ________________________ produces organic molecules that can be used to assemble more complex organic molecules, such as carbohydrates, lipids, and proteins needed for energy & growth.

The energy to fuel the Cycle comes from the ____________________ & ____________________ made during stage 2 of photosynthesis.

 
CELLULAR RESPIRATION

__________________________ ___________________________ is the release of energy from carbohydrates & other organic molecules.

Energy released is used to power ________________________ _______________________ in the cell.

Stage 1: Glycolysis "Splitting of glucose"

• Occurs in the _____________________________

• Does not require ____________________________

• Net Gain = __________ ATP molecules

What happens during Glycolysis?

• In a series of reactions, of molecule of glucose is split into 2 molecules of ______________________________

• Electrons carried on hydrogen atoms are stripped from glucose molecules

• These electrons and hydrogen atoms are donated to an electron acceptor called _______________, forming the energy carrier ________________.

• For glycolysis to continue, _____________ must be free to accept more ______________________ and ______________________ atoms. (Electrons on the NADH molecule must be donated to another organic molecule).

Electrons and hydrogen atoms carried by _______________ are attached to ______________________________ molecules.

This regenerates _____________, which enables glycolysis to continue.

In _________________________ and some _________________________, _______________________ acid is broken down into _____________ and ________________________________________________________.

In __________________________ and some _________________________, _______________________ acid is converted to _______________________ acid, which forms in muscle cells during rigorous exercise.

(fig 5.17).

Stage 2: Oxidative Respiration (AKA: Oxidative Phosphorylation)

• Occurs in the __________________________________

• Requires _________________________________

• Net Gain = ____________ ATP molecules 

C₆H₁₂O₆ + 6 O₂ ® 6 CO₂ + 6 H₂O + 36 ATP

OXIDATIVE RESPIRATION occurs in the presence of O₂

(fig 5-18)

What happens during Oxidative Respiration? (fig 5-19)

• A _________________________ atom is removed from each __________________________ acid molecule produced by glycolysis.

• This reaction frees _______________________ that carry energy and releases _________________ molecules.

• The ________________________ and a _______________________ atom combine with ________________, forming _____________________ (another carrier of electrons and hydrogen atoms).

• This _______________________ will be used at the end of Oxidative Respiration.

• After the two reactions, only a __________ - carbon fragment remains (fig 5-19a).

• If a cell has enough ___________, the ________ - carbon fragment is used in reactions that produce ____________, which stores energy.

• If a cell NEEDS _____________, the ________ - carbon fragment will continue on to the next step.

The KREBS CYCLE yields ATP, NADH, and CO₂

• ________ - carbon fragments produced by the removal of carbon atoms from ____________________________ enter a series of reactions called the _____________________ ________________________.

• _________ ATP molecule and more NADH molecules are made (fig 5-19b)

• The cycle regenerates its ____________________________ molecule, enabling another _________ - carbon fragment to enter the cycle

 
The Electron Transport Chain makes more ATP

• ___________________________ carried by molecules of ______________ formed during the Krebs Cycle are passed through a series of __________________________ in the ___________________________ membrane

• This series of proteins, or the _________________________________________________________________, uses the energy of these electrons to ______________________________________ across the membrane.

• As in photosynthesis, protons become ____________________________________________________ on one side of the membrane

• Protons pass back through the membrane by diffusing through a ___________________________ ___________________________.

• This movement of protons supplies the energy needed to attach a phosphate group to an ______________ molecule, making _______________.

• The ________________________ and spent __________________________ from ________________ are joined to _________ at the end of the transport chain, forming _______________ (fig 5-19c).

___________________________________________________ - Slowing or stopping of an early reaction in a series of reactions, caused by high levels of the end product of the process.

In the case of oxidative respiration, this would involve ____________________________ binding of _____________.

(fig 5-20)