Today is Tuesday,November 3rd, 2015

Pre-Class: [choose one of the following]1. Take a big deep breath in and out. What happened when you did that? Try to follow the path from your

nose/mouth all the way in…and then all the way out…

2. What is your body’s overall respiration rate called? If you don’t know what respiration is, choose #1.

In This Lesson:Respiration

(Lesson 3 of 3)

Today’s Agenda• Respiration (in outline form)• Respiration (in specific form)• And maybe Gaboon Vipers

http://www.kostich.com/gaboon%20viper%20snake.JPG

By the end of this lesson…

• You should be able to identify reactants and products of the detailed steps of each respiration reaction.

By the end of this lesson…

• You should be able to identify the general input and output of the respiration reactions.

A brief note…

• Since we’re talking about respiration, we’re basically talking about food.

• 1 calorie is the amount of energy needed to heat 1 gram of water by 1 degree Celsius.

• Food calories are actually measured as Calories.– 1 Calorie = 1000 calories.

• Your body needs a certain amount of calories to function properly, so that all your cells can have the energy needed to do their jobs.

Aside: High Calorie Foods

• Recommended daily intake of Calories is 2000 for an adult woman, 2500 for an adult male (average).– White Castle: Chocolate Shake [Large]

• 1680 Calories.

– Outback Steakhouse: Bloomin’ Onion• 2210 Calories.

– Uno Chicago Grill: Classic Deep Dish Pizza• 2310 Calories

– and 162g Fat, 123g Carbs, 4470mg Sodium.

– Cheesecake Factory: Bistro Shrimp Pasta• 3120 Calories

Let’s start with the basics…• Where is this in my book?

– P. 90 and following…• So what is respiration?

– Cellular respiration is the process by which cells use energy to carry out life functions.

– BOTH PLANTS AND ANIMALS UNDERGO CELLULAR RESPIRATION!• Plants do it during the day and night.

• Overall rate of respiration?– Metabolism

• Gaboon vipers have a VERY low rate of respiration.

• Where does it take place?– The mitochondria, whether it’s an animal cell or a plant cell, as well

as the cytoplasm.

The Magic Respiration Machine

YE OLDERespirationMACHINE

?INPUT OUTPUT

?

Respiration: An Outline

• Respiration is basically this:

• C6H12O6 + 6O2 6CO2 +6H2O

– In other words, it’s a conversion of chemical energy to chemical energy

– Using glucose to make ATP

• What you should do is this:– Write down the chemical formula.

– Write down the formula in English

– Draw the formula in mini-diagrams.• (2 minutes to work)

Respiration: An Introduction

• Respiration occurs in plant and animal cells.• Two kinds:– Aerobic– Anaerobic

• Before we get any further, let’s start with a flowchart.– That kinda rhymes.

Two Basic Steps

• The first step is called glycolysis. That one always happens, and it happens in the cytoplasm.– That means that even those cute little prokaryotes

can do it, too!• From there, either aerobic or anaerobic

respiration takes place.– Let’s start by looking at glycolysis.

Cell Respiration

• Glycolysis is the breakdown of glucose. It makes 4 ATP molecules, but costs 2 ATP molecules.– Net gain of 2 ATP (produces 4, costs 2).– Anaerobic process.

Steps of Respiration

• Glycolysis is the first step in respiration.– Remember, it’s anaerobic.

• The second step in respiration can be either aerobic or anaerobic.– We’ll start with the aerobic version.

If it’s aerobic…

• …it’s called the Krebs Cycle (sometimes called the Citric Acid Cycle), followed by the Electron Transport Chain.

• These two steps make LOTS of ATP.– Krebs Cycle: 2 ATP.– Electron Transport Chain: 34 ATP.

• Both steps happen in the mitochondria.• The ETC “resets” the process and allows

glycolysis to start again.

Anaerobic Respiration

• Without oxygen, the Krebs Cycle does not function, so neither can the ETC.

• Another process must occur.– Hint?

http://125.164.208.76/how/b

Fermentation!

• Mostly a prokaryote thing, but it happens in humans and other animals too (under not-so-ideal conditions).

• Fermentation is a “reset button” for glycolysis, allowing it to continue running.– Does not make any ATP on its own.

• Where do we see fermentation?– Fermentation by yeast or prokaryotes.

• Beer, wine, and bread (rises from CO2 release).– Alcohol fermentation creates ethanol, which kills yeast

when it rises above a 12% concentration.• So, naturally-fermented wine has how much alcohol?

Fermentation for Us

• Lactic Acid Fermentation– As in some prokaryotes, it does not allow the

Krebs Cycle or anything aerobic to continue.• What are the side effects?– Let’s experience ‘em ourselves!

Fermentation for Us

• What do you feel immediately after running a long distance, or maybe lifting a lot of weights, or after what we just did?– Most of us call it “muscle soreness.”*– Biologists call it lactic acid.

• *Note: This is NOT the muscle soreness you feel the next day.• **Note: Some research suggests that what you feel is due to K+ ions.

• Builds up in muscles when they’re not getting enough oxygen.– Why do athletes have better endurance, then?– Why do our bodies do this even though it’s so inefficient?

Fermentation Summary

• In prokaryotes and some eukaryotes:– Alcohol fermentation.– Metabolize sugars into ethanol.

• In eukaryotes and prokaryotes:– Lactic acid fermentation.– Muscles can continue to work without oxygen, but

lactic acid builds up.

One last thing…

• Anaerobic Respiration produces:– 2 ATP (from glycolysis)

• Aerobic Respiration produces:– 2 ATP (from glycolysis)– 36 ATP (!!!) (from Krebs Cycle and ETC combined)

• 38 total!

• Which one do most cells “want” to use?• BIG HUGE IMPORTANT THING TO REMEMBER:– These numbers are all “ideal.”– In reality, many conditions, including intermediate molecules that

move stuff from the cytoplasm to the mitochondrion, affect these numbers.• Typically they’re actually lower.

RapidTrivia!

• Grab a whiteboard and talk to your partner (quickly) about each of the questions.– That means you need to write FAST!

• There will still be an off-topic question today.

Question #1

• Is glycolysis aerobic or anaerobic?– Anaerobic.

Question #2

• Where does glycolysis take place?– The cytoplasm.

Question #3

• What substance builds up in muscles during fermentation?– Lactic Acid

Question #4*

• What’s a female peacock called?– Peahen

*Off-topichttp://www.mayanmajix.com/ma.jpg

Question #5

• How much combined ATP do the Krebs Cycle and ETC produce?– 36 ATP molecules!

Now let’s test it…

• Log onto Quia and find the quiz labeled, “Cell Energy Cycle Gizmo.”

• That quiz will give you instructions for opening a gizmo in another tab from the ExploreLearning website.

• [Log-in Instructions]

Comparing Photosynthesis & Respiration

Photosynthesis Cellular Respiration

Function Energy Storage Energy Release

Location Chloroplasts Mitochondria

Reactants CO2 and H2O C6H12O6 and O2

Products C6H12O6 and O2 CO2 and H2O

Equation 6CO2 + 6H2O C6H12O6 + 6O2

C6H12O6 + 6O2 6CO2 + 6H2O

Cellular Respiration

• Cellular respiration, as you might remember, works in three stages.– Only two stages if there’s no oxygen.

• First, we have glycolysis.

Glycolysis

• Costs 2 ATP molecules• Makes 4 ATP molecules– Net gain of 2 ATP.

• Uses NAD+.– (Plants use NADP+, remember?)

• Makes two pyruvate molecules.– Pyruvate is an intermediate molecule

that still holds some energy• Glycolysis also transfers protons to

NAD+ and makes it into NADH as an electron carrier.

http://content.answers.com/main/content/img/oxford/Oxford_Sports/0199210896.glycolysis.1.jpg

Summarizing Glycolysis

• Glycolysis:– Anaerobic– Costs 2 ATP– Happens in the cytoplasm– Ingredients:

• Glucose• NAD+

• ATP

– Products:• Pyruvate (temporary energy-storer)• Makes 4 ATP (Net gain of 2 ATP)• NADH (byproduct used later)• CO2

Now then…

• Remember that after glycolysis, assuming there’s some oxygen around, the cell begins to use the Krebs Cycle.

• The Krebs Cycle occurs inside the mitochondria.

Aerobic Respiration

• The Krebs Cycle– Sometimes called the

Citric Acid Cycle.– Named for Hans Krebs.• Not as goofy a name as

Melvin Calvin.

http://media-2.web.britannica.com/eb-media/43/21043-004-D206E5D2.jpg

Hans Krebs

Krebs (Citric Acid) Cycle

http://www.transtutors.com/Uploadfile/CMS_Images/22583_KREBS-CYCLE.JPG

The Krebs Cycle

• The Krebs Cycle always needs to repeat twice.– In doing so, it breaks down pyruvate into CO2.

• Products from 1 molecule of glucose (2 turns):– 4 CO2 (you exhale this part)– 6 NADH (Electron Carrier)– 2 FADH2 (yet another Electron Carrier)– 2 ATP

Summarizing the Krebs Cycle

• Krebs Cycle:– Sometimes called the Citric Acid Cycle.– Aerobic.– Happens in the mitochondrial matrix.

• There is no spoon.

– Ingredients:• Pyruvate

– Products:• 4 CO2

• 2 ATP• 6 NADH• 2 FADH2

After the Krebs Cycle

• An Electron Transport Chain (ETC)!– Uses NADH and FADH2 (electron carriers like

NADPH in photosynthesis).• Occurs in inner membrane of mitochondria.

http://www.sp.uconn.edu/~terry/images/anim/ETS_slow.html

Electron Transport Chain

• Electrons power a pump which moves protons out of the innermost space, from what is called the mitochondrial matrix).– Where did the electrons come from?

• From the electrons carriers charged in the Krebs Cycle!– How is this different from photosynthesis?

• Protons are pumped out, not in.

• ATP Synthase makes ADP into ATP.• Hydrogen ions (H+) and electrons combine with O2 to make

H2O.– How is this different from photosynthesis?

• Photosynthesis split water!

An Animation of the ETC

http://www.sp.uconn.edu/~terry/images/anim/ETS_slow.html

Summarizing theElectron Transport Chain

• Electron Transport Chain:– Sometimes called Oxidative Phosphorylation.– Happens in the mitochondrial membrane.– Electrons move from NADH and FADH2 to oxygen atoms.– Ingredients:

• NADH and FADH2

– Products:• 34 ATP (in ideal conditions)• NAD+ (which is recycled to restart glycolysis) and FAD

• ATP Produced from the overall aerobic respiration process from 1 glucose molecule:– 38!!!

Cell Respiration Summary

C6H12O6 + 6O2 6CO2 + 6H2O

Electron Transport Chain

Glycolysis and

Electron Transport Chain

Glycolysis

Glycolysis and Krebs Cycle

One last thing (not on the test)…

• We already know that the ATP numbers I’ve given you so far are for ideal circumstances.

• Some textbooks will even tell you that aerobic respiration produces only 36 ATP maximum (not 38).– This is due to how the electrons are “shuttled”

into the ETC.– NADH tends to contribute more ATP than does

FADH2.

Fermentation: The Anaerobes

• Fermentation occurs in one of two situations:– In prokaryotes – normal conditions.– In eukaryotes – stressful conditions (no oxygen!)

• Just like glycolysis except:– NADH needs to be recycled to NAD+.

• Normally, where does this happen?– The Electron Transport Chain!

• Since there’s no oxygen around, the ETC doesn’t run.

– Fermentation provides the recycling step necessary to make NADH into NAD+.

Fermentation

• In essence, you can think of fermentation as glycolysis happening without the Krebs Cycle starting later.

• In many prokaryotes, like yeast, fermentation produces ethanol.

• In many eukaryotes, like us, fermentation produces lactic acid.– Causes muscle soreness…maybe.– Not fun, but at least it allows your muscles to keep

working.

The Grand Summary

• And now…(drum roll please)…a comprehensive summary of photosynthesis and respiration from start to finish.

• Remember, the goal is to make ATP (and lots of it).– Autotrophs make their own glucose to make ATP.– Heterotrophs can’t make their own glucose, so

they skip the photosynthesis step and go straight for someone else’s glucose.

The Grand Summary

• Morning. Light from the glow of sunrise strikes a leaf, still coated in the dew of a springtime night.

• Light specifically strikes the plant cells responsible for photosynthesis, and within them it strikes the chloroplasts.

• Even more specifically, light strikes the chlorophyll within the chloroplasts.

The Grand SummaryStart of Photosystem II

• The chlorophyll is located in the membrane of the thylakoid, a disk arranged in multiple stacks within the innermost space of the double-membraned chloroplast.

• Chlorophyll molecules lose some electrons, which go bounding down the thylakoid membrane.

• At the same time, an enzyme tears two water molecules to pieces, generating O2 as waste and freeing up electrons and protons (H+).

The Grand SummaryPhotosystem II

• Remember those electrons that bounded off?• They power a proton pump, which brings H+ ions into

the thylakoid.– Don’t forget about those electrons; they’ll come back later.

• The protons – and thus a positive charge – builds up inside the thylakoid, creating an electrochemical gradient.

• Protons want to diffuse back out of the thylakoid, but they can’t go through the membrane directly so they use facilitated diffusion.

The Grand SummaryEnd of Photosystem II

• Protons diffuse through the specialized protein channel called ATP Synthase.– Why specialized? Because, like the name

suggests, it’s both a channel and an enzyme.• The passage of protons through ATP Synthase

causes the enzyme to make ATP from ADP.• This part is the end of Photosystem II, which is

the first phase of the Light-Dependent Reactions of Photosynthesis.

The Grand SummaryPhotosystem I

• But wait! Photosystem I begins with those same electrons that powered the proton pump of Photosystem II.

• Those electrons now move to an electron carrier molecule called NADP+.

• They, along with protons, activate the molecule into its high-energy form: NADPH.

• NADPH will power the next step of photosynthesis.

The Grand SummaryCalvin Cycle (AKA Dark/Light-Independent Reactions)

• The Calvin Cycle begins with the ATP and NADPH made from the light-dependent reactions (Photosystems II and I).

• The chloroplast – this process is happening in the stroma by the way – uses CO2 and the power contained in NADPH and ATP to build up glucose molecules.

• No light is needed for the Calvin Cycle to occur.

The Grand SummaryRespiration

• Photosynthesis is great in that we get glucose from the power of the Sun, but it doesn’t do much for our cells.

• For our cells to do their jobs, they use energy based in a different form.– Not a carbohydrate like glucose, but a nucleotide

like ATP.• So how do we get ATP? Respiration.

The Grand SummaryStart of Glycolysis

• Respiration starts with the breakdown of glucose, called glycolysis.– If you’re an autotroph, you’ll use the glucose

made during photosynthesis.– If you’re a heterotroph, you’ll eat something that

has organic molecules that can be broken down into glucose and use that.

• Glycolysis takes place in the cytoplasm of the cells and therefore even prokaryotes do it.

The Grand SummaryEnd of Glycolysis

• Glycolysis costs 2 ATP to run.• During the process, a 6-carbon glucose molecule is

broken down into two 3-carbon molecules called pyruvate.– Pyruvate still has more energy that can be given off if we could

just break it down further.– That’ll happen in the next step.

• 4 ATP are made (thus net gain of 2) and we are able to charge up NAD+ into NADH.– NADH is an electron carrier just like NADPH.

• CO2 is given off as waste.

The Grand SummaryAerobic Respiration: Krebs Cycle

• The Krebs Cycle (AKA Citric Acid Cycle) is a complex cyclical series of reactions that take place inside the mitochondria.– It serves to further break down those pyruvates.

• In all, the Krebs Cycle generates 2 ATP, more NADH, and another electron carrier known as FADH2.– FADH2 functions similarly to NADH.

• More CO2 is given off as waste.

The Grand SummaryAerobic Respiration: Start of Electron Transport Chain

• For the final step, electrons are pulled from the electron carriers FADH2 and NADH and are fed into another electron transport chain.– This one occurs in the inner membrane of the

mitochondria.• Electrons power a proton pump again this time, which

brings protons from the innermost part of the mitochondrion (the matrix) into the intermembrane space.

• The protons diffuse back into the intermembrane space through ATP Synthase, generating more ATP.

The Grand SummaryAerobic Respiration: End of Electron Transport Chain

• The electron transport chain has now reset NADH and FADH2 to their low-energy forms (NAD+ and FAD).

• The electrons removed from the carriers are combined with protons and oxygen in order to make H2O.

• The ingredients for glycolysis are now reset.

The Grand SummaryAnaerobic Respiration: Fermentation

• On the other hand, if the organism in question is an anaerobe, a prokaryote, or if no oxygen is available, the Krebs Cycle cannot run.– Which means NADH made in glycolysis can’t be

returned to NAD+ and will eventually run out, stopping ATP production.

• Instead, the cell must employ fermentation.• Fermentation is a process that generates no ATP

but does allow for NADH to be recycled to NAD+.

The Grand SummaryAnaerobic Respiration: Fermentation

• In prokaryotes and some simple eukaryotes, fermentation produces ethanol (alcohol).

• In more complex eukaryotes, fermentation produces lactic acid.

• Though both substances are toxic, fermentation allows glycolysis, and thus ATP formation, to continue.

Closure

• To your lab tables!• With your lab table, write down four

questions that each are one of two types.– You can either write a possible test question and

its answer.– OR you can write a question you have (don’t

include the answer for this, since, uh, you don’t know it).