Chapter 6 Cellular Respiration

Chapter 6 Cellular Respiration

All energy ultimately comes from the sun. The chemical components are recycled as they move through an environment (producers to consumers to decomposers and back) with some leaving as heat.
Write the reaction for photosynthesis and label the reaction as exergonic or endergonic.

Write the reaction for cellular respiration and label the reaction as exergonic or endergonic.

Distinguish, in your own words, respiration as it applies to organisms and as it applies to cells.
Organismal respiration (‘breathing’)

Cellular respiration

How are the 2 processes defined above related to one another, briefly?

Whether cellular respiration occurs or not is dependent on the presence or absence of ______. What are the 2 terms associated with these conditions?
Glucose is considered to be the primary fuel source for cells, but our bodies can’t use glucose directly. Therefore it must be broken down into a more usable form. ______is used to store the energy associated with glucose bonds until the body needs it to do work later on.
Breaking down glucose in one step would release a significant amount of energy, so the body has developed ways to manage the breakdown so that it occurs in a step-by-step fashion. How many ATP molecules as thus potentially able to be produced by the complete breakdown of 1 molecule of glucose?
In chapter 2 we learned that electrons in orbitals closer to the nucleus have more potential energy because they are more strongly attracted to the nucleus. Because of this, as electrons move closer to the nucleus, energy is released (exergonic). To move electrons further from the nucleus, energy is required (endergonic). Briefly explain why this makes sense. (It may help to draw a picture.)

Redox reactions, short for reduction and oxidation, are types of reactions that always occur together as electrons move between molecules. Explain what happens in each below and give an example. See the mnemonic device listed to help remember which is which.
Oxidation (LEO):

Reduction (GER):

(Electrons move with hydrogens so a product that has gained a hydrogen is likely to have also gained an electron = GER)

During cellular respiration, the carbons of glucose are oxidized by a dehydrogenase. How can this word be broken down to explain what it does?
De-(______) –hydrogen- (______) -ase (______)
Where is this occurring in the cell, specifically?

What element is ultimately responsible for facilitating this reaction?

NAD+ is considered an electron carrier because it can pick up any removed hydrogens (H) and the associated electrons. Is this reaction an oxidation or reduction?
How does it explain the change in NAD+ to NADH?

The oxygen, a more electronegative element, is better able to pull the electrons from NADH. This doesn’t occur as a single step process; instead the electrons are passed, like slinky moves down stairs, to a series of electron carriers. ______is the ultimate electron acceptor.
Each time the electrons are passed to the next electron carrier energy is released to produce ATP. The creation of ATP is related to the movement of the associated hydrogen ions (H+) and will be discussed later. This process in general is called and ______(3 words).

Cellular respiration occurs is 3 major stages, with an intermediate step in between stage 1 and 2. List the 3 stages below, including the intermediate step, and list where they occur.

(You will be responsible for knowing each stage, where it occurs, as well as the starting and ending products of each. Also, you are only responsible for the names of molecules I specifically list. Otherwise, just know the number of carbons associated with the molecule, as it will help you know the process.)

Glycolysis ultimately converts glucose (a _____ carbon molecule) is converted into pyruvate (a ______carbon molecule). In the process, ______(NET) ATP are produced by the process of ______(3 words).
How many molecules of pyruvate are made from 1 molecule of glucose?
Is oxygen required for this process?
Transition step converts pyruvate (a _____ carbon molecule) into acetyl-Coenzyme A (a ______carbon molecule), carbon dioxide (a ______carbon molecule) and NADH (an ______(2 words).
What is the fate of the CO2 produced in this step?
There are 2 molecules of pyruvate from the 1 molecule of glucose though, so how many times must this step occur per single molecule of glucose?
Citric acid cycle converts acetyl-CoA (a ______carbon molecule) to ______, 3 ______(electron carriers), FADH2 (electron carrier too), and CO2.
Acetyl-CoA (2 C’s) joins with an existing ______carbon molecule to form a ______carbon molecule. This molecule will then lose 2 molecules of CO2 creating a new ______carbon molecule. This molecule is similar to the one that was used to combine with the acetyl-CoA initailly.
There were ______molecules of acetyl-CoA prior to starting this stage which means how many turns of this cycle must occur per 1 molecule of glucose?
Substrate level phosphorylation also occurs in this stage which means ______molecules of ______are ultimately produced.
Oxidative phosphorylation combines the electron carriers, ______and ______, produced in earlier stages with ______(the ultimate electron acceptor) to create 32-34 ______, and ______. When the ATP produced here combines with the ATP produced by substrate level phosphorylation in earlier stages, a total of ______- ______ATP can be produced from 1 molecule of glucose, under aerobic conditions.
This stage involves the following 2 distinct processes.
______was mentioned earlier. As the electrons are passed down to other electron carriers ATP is synthesized. This accomplished by a production of an H+ concentration gradient. The electron carriers pass off only electrons, but had also been associated with H+ ions. These ions leave the ______(3 words) and accumulate in the ______(2 words). Additionally, the oxygen has now picked up ______electrons and can combine with ______H+ to form ______.
______is driven by the H+ gradient. ATP ______(break down the word to understand what it does) is a protein complex that allows H+ to move down its concentration gradient. As H+ move back in to the ______they fuel the ADP + P  ATP reaction. This anabolic (building) reaction requires energy which also makes it endergonic or exogonic?

To review the process, write the formula for cellular respiration again.

Look at each of the reactants and products. See if you can place where each reactant is used and each product is produced during the total process. Remember the 2nd law of thermodynamics to understand the quantities of each reactant and product.

You should now be able to answer the following 3 questions.
Why do we breathe oxygen?
Why do we exhale carbon dioxide?
Why do I eat food?

(Understand how the answers to these 3 questions all work together to sustain life.)

______(2 words) fermentation is responsible for the production of food products such as cheese and yogurt as well as the soreness associated in muscles following strenuous exercise.
Glycolysis breaks glucose down into pyruvate, however without oxygen the other stages of cellular respiration can’t occur. In this type of fermentation the pyruvate is ______(oxidized or reduced) to lactate.
______fermentation is responsible for the production of beer, wine, and the rise in bread.
Pyruvate is converted to ______and CO2.

Chapter 7 Photosynthesis

Plants convert ______energy to ______energy, which is stored in the bonds of the plant’s sugars. We remember too that trees (plants) are necessary for producing ______for us to breathe.
______enters and ______exits through ______in the leaves. ______enters through the plant’s roots and is carried to the leaves where sugars are formed to sustain consumers as well as the plant itself.
The interior of a plant’s leaves as well as other green parts of the plant consist of an inner tissue layer called ______which contains multiple ______, the sites of photosynthesis.
Chloroplasts are ______membrane organelles, similar to ______, the site of cellular respiration. The inner membrane cavity consists of multiple interconnected membranous sacs called ______which are surrounded by a thick fluid called stroma (don’t confuse stroma and stomata).
These thylakoids can exist singularly or can be arranged in stacks called ______. It is within these thylakoids that the pigment ______is housed.

Revisit redox reactions by listing the formula for photosynthesis and cellular respiration. For each, show which reactants are oxidized and which are reduced. In each instance are electrons moving uphill or downhill; how does this relate to whether it is endergonic or exergonic?
Photosynthesis uses energy to get sugars

Cellular respiration uses sugar to get energy

Sunlight is a form of energy known as ______radiation that travels in waves as discrete units called ______. All wavelengths of light make up the ______(2 words). The wavelengths of light are inversely proportionally to the energy associated with them; this means as wavelengths, distance from one crest to the next, decrease, the amount of associated energy ______(can cause more organic damage).
Examples of short wavelengths, high energy include ______.
Examples of long wavelengths, low energy include ______.
The color you perceive something to be is related to the wavelengths that are being ______. White objects ______all light, while black objects ______all light. This will be important when we talk about electron energy next.
Pigments of substances determine what photons are absorbed. Green substances such as plant leaves appear green due to the presence of chlorophyll. This means that all wavelengths of light except ______are being absorbed by the chlorophyll.
As photons are absorbed, the electrons within that pigment are elevated to a ______orbital which means they have ______potential energy.
The electrons are unstable in this location so they quickly ______, moving back to a ______energy level. This change in orbital location results in a ______of energy as heat.
Apply this to why black objects, like t-shirts and cars, are hotter in Georgia summers than white objects. Black objects ______all wavelengths or light which means more electrons are ______to ______levels. They are unstable however and rapidly fall back down. This ______in energy level causes the excess energy to be lost as heat which makes the objects hotter to the touch.

Leaves actually contain a variety of pigments which enable them to not only absorb more light, but also protect themselves from excessive damage.
Chlorophyll a reflects ______and is directly involved in photosynthesis reactions.
Chlorophyll b reflects ______but transfers the energy to ______.
Carotenoids (like carrots) reflect ______and ______. They then transfer the energy to chlorophyll a (acting like ______). They are also responsible for photoprotection. We ingest carotenoids in our diets too which provide photoprotection of our retinas. This is likely the reason for the saying that eating carrots is good for our eyes.
Multiple pigments are also the reason we see a wide range of leaf color in the fall. Carotenoids are more resilient than both chlorophyls and so they persist longer as the length of day and sunlight lessons. Sugars are produced, but not removed so the build up and enhance the remaining pigments.
The process of photosynthesis actually consists of 2 different reactions, a ______reaction that occurs in the ______and a ______that occurs in the ______.
The ______reaction requires ______directly so that it can fuel the ______reaction, which doesn’t need ______directly (thus the name).
Light reactions convert solar energy to ATP and ______(an electron carrier similar to NAD+.
Dark reactions assemble sugars through ______(2 words), which converts CO2 into organic compounds. This requires the NADPH from the light reaction to ______(oxidize or reduce) carbon.

(As in cellular respiration, you are responsible for knowing both reactions, where they occur, the reactants for each, as well as the products.)

Photosystems are a collection of ______-______complexes which contain the photon absorbing pigments. These pigments pass energy between one another until it reaches a pair of ______molecules located in the ______(2 words) complex. An electron from chlorophyll a is then elevated an energy level, but instead of falling back down it is caught by a ______(3 words) that hold it in place.
The elevated electrons in chlorophyll a come from ______which is then broken down into oxygen and 2 H+.
There are actually 2 types of photosystems, PS ______and PS ______, each containing slightly different chlorophyll a molecules in terms of wavelength absorption.
An ______(3 words) connects the 2 photosystems, and like we saw in cellular respiration, produces ATP via chemiosmosis. Review this process in terms of hydrogen gradient and ATP synthase so that you can see the similarities.
The ETC is responsible for providing the electrons obtained from water in PS II to PS I. PS I can then use the light energy absorbed by the light-harvesting complexes to raise the electrons to a higher energy level. Here it is once again caught by a primary electron acceptor, however this time it is transferred to an electron carrier (______) which will combine with an H+ to form ______.
The dark reaction uses the ______taken in from the air and combines it with the ______and ______produced in the light reaction to form G3P, a ______carbon molecule. ______G3P’s, which means ______turns of the cycle, are necessary to form glucose or other sugar precursor. (Once again it is recommended that carbons be counted to follow the cycle. Also, only molecules that are explicitly mentioned must be learned.)
The cycle starts and ends with ribulose bisphosphate (a ______carbon molecule RuBP) which is regenerated with each turn.
______is the enzyme that fixes (attaches) ___ molecule of CO2 to RuBP to form 2 (3 C) molecules. (Add your carbons: 5 C’s (RuBP) + 1 C (CO2) = 6 C’s.)
______CO2’s total will be added for each turn of the cycle, which produces ______molecule of G3P. This means that ______CO2’s are added for 2 turns of the cycle to produce ______G3P’s = ______glucose molecule or sugar precursor. (Refer to the original formula for photosynthesis to verify the # of CO2 used and # of glucose produced.)
Each CO2 added produces 2 (3 C) molecules, so 3 CO2’s produce ______(3 C) molecules. 1 G3P (a 3 carbon molecule) molecules leave while the other ______(3 C) molecules remain. These 15 carbons [6 (3 C) molecules = 18 total carbon molecules; 18 carbons – 1 G3P (a 3 carbon molecule) = 15 total carbons] are rearranged to form 3 RuBP’s (the 5 carbon molecules the cycle started with).

(Notice the number of starting RuBP’s and the number of CO2’s added for each turn.)

Use the diagram below to walk through the process of photosynthesis just described in detail above.