Unit 3 Review Photosynthesis Cellular Respiration & Carbon Cycle Worksheet

Link back to the Teacher'southward Guide Table of Contents

Unit 3 Table of Contents

1. Introduction: Sequencing Unit 3
2. Week 8: Enzymes
3. Weeks 9 and 10: Jail cell Respiration
4. Weeks 11 and 12: Photosynthesis, start Mitosis/Cell Division
5. Transpiration and the Transpiration Lab
6. Summative Activities for Unit 3

Introduction: Sequencing Unit 3

Unit three of AP Bio focuses on Enzymes, Cellular Respiration, and Photosynthesis. This is one of my favorite units of the course. The biology is fabulous, with opportunities to talk almost every central theme in biology. In addition, there are 3 major labs.

In terms of sequence, I suggest that you practise the following (which is different from the College Lath's sequence in their Course and Examination Description).

1. Start with Enzymes (Topics 3.one – 3.3)
2. Then exercise Cellular Respiration. This includes Topics 3.4 (general issues related to cell free energy), followed by Topic three.6  (Cellular Respiration)
3. End with Photosynthesis (Topic iii.5)

Why cellular respiration before photosynthesis? For me, this is partly based on my own professional history. I started pedagogy AP Biology using Neil Campbell's Biology,which puts cellular respiration starting time. That sequence is besides what'southward used in my other favorite textbook: Principles of Life (Hillis, Sadava, Hill, and Price). Information technology's besides used in Principles of Biology (Brooker, Widmaier, Graham, and Stiling). But it's not a slam-douse: Sylvia Mader teaches photosynthesis first, then moves on to cellular respiration.

In whatever case, cellular-respiration-first is the sequence I've adopted in my own didactics, and in the interactive modules on Learn-Biological science.com. What you'll see is that education the electron transport chain, chemiosmosis, and ATP production in mitochondria sets the stage to easily transfer agreement of these processes to what happens in  in chloroplasts during the light reactions of photosynthesis.

Topic 3.7, Fettle, is kind of a weird outlier. I'm non certain why the College Board placed it in unit 3. Nosotros'll deal with it when we talk about evolution in Unit of measurement 7, and in Topic 8.6 (Biodiversity).

Finally, nosotros skipped some of the cell biology related to mitochondria and chloroplasts in Topic 2.2. You'll see that embedded beneath in the objectives for cellular respiration and photosynthesis.

Week viii, Enzymes

Objectives for Enzymes (Topics 3.1 – 3.3)

You can see the Higher Lath'southward original objectives for Topics iii.1-3.3 in their Course and Examination Clarification, or in my condensed version of the aforementioned document. Here are these objectives in a friendlier form.

1. Draw the key backdrop and function of enzymes. This clarification should include the post-obit:
   1. Enzymes are complex, large proteins that facilitate chemical reactions by reducing activation free energy.
   2. Enzymes are highly specific, and by and large collaborate with only one substrate.
   3. Enzyme specificity is based on the complementary shape and charge between the enzyme's agile site and the substrate.
2. Explain how changes in an enzyme's shape bear on the enzyme's function. The explanation should include:
   1. Considering enzymes are proteins, their shape is stabilized past internal bonds that can exist disrupted past changes in the enzyme's environment.
   2. Denaturation is when a change in an enzyme'due south shape reduces its ability to demark with its substrate.
   3. Denaturation tin can be reversible or irreversible.
3. Explain the effect of changes in temperature on enzyme activity
   1. At moderate temperatures, temperature increase will increase enzyme-substrate collisions, increasing enzyme activity.
   2. At loftier temperatures, enzymes can denature, reducing their activity
4. Explain the consequence of changes in pH or ion concentration on enzyme activity.
   1. Enzymes have a pH and ion concentration optimum.
   2. Ecology changes that move the pH and ion concentration higher up or below that optimum will disrupt the enzyme's internal bonds, changing the shape of the enzyme'due south active site, reducing its activity.
5. Explain the effects of enzyme and substrate concentration on enzyme activity
   1. Enzyme activity will increment with increased enzyme and substrate activity until the enzymes' active sites are saturated. At that point, enzyme action reaches its maximum rate.
6. Explain the part of competitive and non-competitive inhibitors on enzyme activity
   1. Competitive inhibitors reduce enzyme activity past competing with substrates for the enzyme's agile site.
   2. Non-competitive inhibitors bind at a region away from the active site (an allosteric site). However, that binding changes the shape of the active site, reducing the enzyme's activity.
7. *Explain how cells can regulate enzyme activity through feedback inhibition and allosteric regulation.
   1. In feedback inhibition, the product of an enzymatic reaction acts equally a competitive or non-competitive inhibitor of enzyme activeness, creating negative feedback that reduces enzyme activity.
   2. In allosteric regulation, a substance produced past a metabolic pathway binds with an enzyme at an allosteric site. This can inhibit or stimulate enzyme activity.

*this is non in the Grade and Exam description, but you should definitely teach it hither.

Enzyme tutorials on Learn-Biology.com

Learn-Biological science organizes learning about enzymes into two tutorials, supported by this student learning guide.

1. Enzymes Tutorial 1 (Enzyme Construction and Office)
2. Enzymes Tutorial 2(Enzyme Inhibition and Regulation)

Enzyme Labs and other Activities

If you didn't do the Starch Amylase Lab when y'all were teaching about monomers and polymers, and so now you have another opportunity. If you did, then remind students that this was all about enzymatic hydrolysis.

Another spectacularly fun demonstration involves using catalase from liver tissue to decompose hydrogen peroxide. I like to do this as a demonstration earlier doing the potato catalase lab. Here's a handout. You could easily catechumen this into a lab (only you'd need be prepared to clean up a lot of examination tubes).

The "official" lab for this unit is the Irish potato Catalase Lab. I'one thousand indebted to Pam Phelps for sharing her version of this lab with me, and education me (and a bunch of other teachers) how to do the lab via Zoom during the in fall of 2020. I've revised Pam'due south lab handout to include standard mistake calculations. Here's my version from last year (designed for students to practise at abode; some slight modifications might make information technology work better in a classroom context).

If you desire to add some music to your instruction, testify my Enzymes! Music Video.

Weeks 9 and x, Cellular Respiration

Some Big Film Ideas about Cellular Respiration

Cellular respiration is heady to teach because it allows you to make use of pretty much everything you lot've taught in the class so far.

• It (more often than not) happens in the mitochondria, an endosymbiotic organelle.
• The whole process is carried out past enzymes.
• The procedure of ATP production relies on
  • cellular compartmentalization (the intermembrane space);
  • poly peptide structure (remember of ATP synthase as a astounding example of a structure/function human relationship at the molecular level);
  • agile send (protons getting pumped into the intermembrane space), and
  • facilitated improvidence (proton diffusion through ATP synthase back to the mitochondrial matrix).
• ATP and ATP synthesis via chemiosmosis is powerful show for the unity of life. Information technology'south nowadays in every Domain. Not only that, only the ATP synthase aqueduct that's used in cellular respiration is a clear homologue for the one used in photosynthesis.

I encourage you lot to challenge your students to do this kind of connecting. That tin can be equally simple as listing the processes above (endosymbiosis, compartmentalization, protein structure, etc.), and request students to begin where they show up in the procedure.

I use this diagram as my touchstone during this unit.

If y'all've been influenced pastUnderstanding past Design,one of my favorite books about curriculum blueprint, then you can think of the goal of the the entire unit of measurement as this: students, when presented with this image, can explain the cellular and biochemical processes by which the chemical bond free energy in glucose tin exist converted into ATP.  During your unit, as you lot teach glycolysis, the link reaction, Krebs and the ETC, you tin can come up back to this diagram once more and once again, and have your students expand the item with which they explain the process.

It'south actually important that students understand that cellular respiration is built upon on two types of sub-processes: REDOX, and phosphorylation. I go to some length to explain both in my Cellular Respiration Overview interactive tutorial, using diagrams like this for REDOX

and this for substrate level phosphorylation.

In terms of REDOX, yous don't need to go deeply into the chemistry. It's plenty for students to know that things that are reduced accept more energy than things that are oxidized. Where's the energy? In their electrons. It'due south a bit confusing, but that electron energy is unremarkably shown by the presence of a hydrogen. That'southward why NADH is the reduced form, and NAD⁺ is the oxidized form. To give this chemical science some existent world context, y'all can tell your students that a substance similar peanut butter is reduced. So is bread. So are nosotros. These are all examples of things with lots of chemic free energy. By contrast, carbon dioxide is oxidized. So is ash. And then is rust. These are all low-energy substances.

One time you lot've built that foundation, then it'southward all downhill when you're teaching about glycolysis (in which the oxidation of glucose is coupled to the reduction of NAD⁺ to NADH) or the Krebs bike. In fact, that's the fashion to control the detail so that your students don't get overwhelmed. When yous're questioning your students to check for understanding, ask questions like What's happening at 3 in the diagram below? You're looking for an answer similar this: The vi carbon chemical compound is oxidized, so that NAD⁺ tin can be reduced to NADH. What's happening at 5? A dissimilar enzyme is using the chemical energy in the iv-carbon compound to phosphorylate ADP to ATP.

Note that you don't need to teach any of the intermediates (though they are mentioned in my Krebs Cycle Song). All that our students need to know about is acetyl-CoA, Citric Acid, and oxaloacetate. And they should be able to effigy out that the v carbon compound at 4 in the diagram above is more reduced than the iv-carbon chemical compound at 7. How would your students know? Considering the chemical energy in the v-carbon chemical compound that'due south the reactant for step four was used to power the reduction of NAD⁺ to NADH, and and so (after other transformations) of FAD to FADH2 at step 6. Reductions are always coupled to oxidations (and vice versa).

A last way to make this real is to follow the carbon dioxide molecules. I ever teach my students that this is where the carbon dioxide they breathe out is coming from. Specifically, two out of every three carbon dioxide molecules that you breathe come up from the Krebs wheel. The other i/iii comes from the Link Reaction.

Learning Objectives for Energy and Cellular Respiration (Topics iii.four and 3.six)

Y'all can encounter the Higher Board's original objectives for Topics 3.1-3.3 in their Course and Exam Description, or in my condensed version of the same certificate. Here are this week's objectives in a friendlier form.

For Cell Energy (Topic three.4) Describe the role of energy in living organisms. A clarification should include the following:

1. Creating and maintaining the complex order in living things requires a constant input of energy.
2. For life to be maintained, energy input has to exceed free energy loss.
3. Energy-requiring processes (endergonic processes) are typically coupled with energy releasing (exergonic) processes.
4. Among the well-nigh common coupled reactions are
   1. Linking oxidation of nutrient to reduction of electron carriers
   2. Linking the hydrolysis of ATP to ADP and phosphate (an exergonic reaction) to any endergonic process (synthesis, motility, and any other kind of work).
5. Creating ATP from ADP and phosphate is endergonic, and is coupled to exergonic reactions.
6. Energy pathways are sequential, controlled, and efficient.

For Cellular Respiration (Topic 3.half dozen): Explicate how cells obtain energy from biological molecules (typically glucose) in order to create ATP.

1. Explain the overall pathway of cellular respiration (glycolysis, link reaction, Krebs, and the electron send chain).
2. Explain what happens during glycolysis (oxidation of glucose is coupled to the reduction of NAD⁺ to NADH, and the phosphorylation of ADP to ATP.
3. Explain what happens during the link reaction (pyruvic acrid enters the mitochondria, and gets converted to acetyl CoA
4. Explicate the cardinal reactions of the Krebs wheel (oxidation of acetyl-CoA) to power reduction of NAD⁺ and FAD to NADH and FADH₂; and phosphorylation of ADP to ATP.
5. Explain how electron free energy from NADH and FADH_two is used to create a proton gradient, which is in plow used to power ATP synthesis through chemiosmotic diffusion of protons through the ATP synthase aqueduct.
6. Explicate the role of oxygen in the electron transport chain.
7. Compare and dissimilarity lactic acid and alcohol fermentation.
8. Connect the construction of the mitochondrion to the key processes of aerobic respiration (Krebs in the mitochondrial matrix; ETC along the inner membrane; protons are pumped to the inter membrane space; inner membrane folding increases surface expanse, allowing for more ETC components and more than ATP synthase).

Resources for pedagogy energy and cellular respiration on Learn-Biology.com

Our cellular respiration tutorials on Learn-Biology.com are supported by this student learning guide.

The module consists of 6 tutorials:

1. ATP and Prison cell Energy (interactive tutorial)
2. Cellular Respiration Overview (interactive tutorial)
3. Glycolysis (interactive tutorial)
4. The Krebs Wheel (interactive tutorial)
5. The Electron Transport Concatenation (interactive tutorial)
6. Anaerobic Respiration and Fermentation (interactive tutorial)

Additional cellular respiration resources and activities

Labs and demonstrations

The greatest thing about cellular respiration is that you can see it in activity. You can measure CO_two production, or oxygen consumption. I prefer to do the latter, the quondam-fashioned fashion, with respirometers.

• Here's a link to a video that explains how these devices work: Measuring Respiration with a Respirometer (Video)
• Here'southward my lab handout. My main slice of advice: long equilibration for the respiring beans in common cold temperature.

You can likewise do some very uncomplicated demonstrations of fermentation. This includes demonstrations of alcohol fermentation past yeast, and making yogurt (a lactic acid fermentation). Hither'southward a handout.

For the booze fermentation sit-in, get three flasks. Add water. Add a spoonful of yeast to flask 1. Seal with a balloon. Add a spoonful of sugar to flask 2. Seal with a balloon. As a spoonful of yeast and a spoonful of carbohydrate to flask iii. Seal with a balloon. You'll see results by the next day. It goes without saying that this could be the basis for a lot of inquiry.

Making yogurt is similarly elementary. Start with Pasteurized milk (and explain how Pasteurization works). I similar to add some nonfat dry milk powder to brand a thicker yogurt. And then mix in a flake of yogurt civilisation (a spoonful of yogurt from whatsoever make). Incubate nigh 37 C overnight, and you'll take yogurt the adjacent twenty-four hours. An Instant Pot has a yogurt setting…fifty-fifty easier.

Music

I've written iii three songs about cellular respiration. Glycolysis!, Krebs!, and the Electron Transport Chain. They all take Karaoke versions, so delight encourage your students to sing! All of these songs are available on YouTube, but to brand access really easy, they're all on this page: Cellular Respiration: A Musical Review

Video Lectures

To requite your students an overview of the entire process, have them watch the these two videos: Cellular Respiration Overview Videos (video lectures)

Additional Handouts

1. Hither'south the review canvass I give to my students to help them fix for my cumulative cess on cellular respiration.
2. Before I flipped my classroom, I used to do comprehensive lecturing about virtually cellular respiration topics. During my lectures, I found that distributing this guided note taking sheet was something that my students plant very useful. With some pocket-sized modifications, you lot tin can make it into a visual review guide.

Flinn has cracking POGILs about ATP, Glycolysis/Krebs, and Oxidative Phosphorylation.

Extension

If yous desire to push your students a chip further, have them read and summarize this commodity from the NY Times about how ocean otters utilize proton leakage to generate estrus (but not ATP).

Weeks xi and 12: Photosynthesis

Notation about timing: Information technology shouldn't accept yous a full two weeks to stop photosynthesis. You'll be done about two days into next week, and then y'all can start Unit iv.

Almost people don't get what'south happening during photosynthesis

Well-nigh people deeply misunderstand photosynthesis. Yous can see this for yourself by asking your students (or your friends and family members) two questions:

1. When a plant grows, where does most of the new mass come up from?
2. Where does the oxygen that photosynthesis produces come from?

In terms of the first question, nigh of my students (and my friends who aren't science-savvy) think that plants add new mass from the soil. In other words, they think  that "institute food" is like animate being food: that when a constitute grows, it'south absorbing thing from the soil and incorporating it into its growing trunk. They're missing, in other words, the concept of carbon fixation, and the amazing idea that the added mass is mostly from CO₂ in the air.

In terms of the second question, many folks who know that oxygen is produced past photosynthesis often mistakenly think that carbon dioxide is the source of that oxygen (not h2o). As pointed out by Nick Lane inLife ascending, this mistake was famously made by the Italian pharmacist and Nobel Laureate Primo Levi who wrote in his bookThe Periodic Table:

Our cantlet of carbon enters the leaf, colliding with other innumerable (just here useless) molecules of nitrogen and oxygen. It adheres to a large and complicated molecule that activates information technology, and simultaneously receives the decisive message from the sky, in the flashing grade of a bundle of solar light: in an instant, similar an insect defenseless past a spider, it is separated from its oxygen, combined with hydrogen and (one thinks) phosphorus, and finally inserted in a concatenation, whether long or brusk does not matter, but it is the chain of life.

The oxygen produced by photosynthesis comes from h2o (or another electron donor), non carbon dioxide.

Here's the general equation:

Note that the "H₂A" varies among prokaryotic photosynthesizers. For example, in purple sulfur bacteria, the hydrogen donor tin be hydrogen sulfide (H_iiS).

But in all eukaryotic photosynthesizers, and in cyanobacteria, the hydrogen donor is water. Then the general equation is

For the purposes of AP Biology, you tin can balance the equation and driblet the H_iiO that appears as a product of the reaction, leaving us with

On several past AP exams, the College Board has tested this by showing the oxygen atoms in the products as labeled with isotopes of oxygen (O¹⁸). If you lot label the oxygen in carbon dioxide (CO¹⁸ ₂), and then the heavy oxygen shows upward in the carbohydrate. But if you characterization the oxygen in the water (H₂O¹⁸), so the heavy oxygen shows upward in the oxygen gas that's released as a waste product (O₂ ^xviii)

I try to avert this misunderstanding by having students interact with diagrams like this one from my showtime photosynthesis tutorial (come across below).

Similarly, this one, focusing on the inputs to the chloroplast from my second tutorial, serves the same purpose.

When you get to the Calvin cycle, you can emphasize some of its astonishing features. Some of these were highlighted in this story from NPR,

The Calvin Bicycle

• Rubisco (ribulose bisphosphate carboxylase) is the enzyme that's capable of snatching carbon dioxide out of the air and incorporating it into biological molecules. It might be the most arable protein on globe.Makes sense: it's in every chloroplast, in every leaf, in every tree, shrub, herb, bract of grass, and algae on Earth. It'southward also in every blue-green alga.
• If your students always complain that this detailed (but wondrous) process is far removed from their daily concerns, remind them that every carbon atom in their body was one time a molecule of carbon dioxide floating in the air. Nosotros all owe our very being to the Calvin Cycle.
• Rubisco and the Calvin Cycle as a whole evolved very early in the history of life — way before there was appreciable amounts of molecular oxygen in the temper or dissolved in the the oceans. As a outcome, Rubisco has an enzymatic quirk: its active site tin can demark oxygen (and non just carbon dioxide). This is especially truthful at high temperatures, and causes Rubisco to incorporate oxygen into the Calvin Bicycle, producing a toxic compound that plants accept to detoxify, lowering the efficiency of constitute growth. Plants similar cacti and corn take, every bit a event, evolved supplementary pathways for fixing carbon dioxide. These are the C4 bicycle and CAM photosynthesis, respectively. They're no longer function of our curriculum, but they used to exist (earlier AP bio was redesigned in 2012). If you take some students that demand some enrichment, these pathways are great topics for students to explore.

Photosynthesis Learning Objectives

You lot can see the College Board's original objectives for Topic 3.5 in their Form and Examination Description, or in my condensed version of the aforementioned certificate. Here are these objectives in a friendlier course.

1. Draw the cellular location of the reactions of photosynthesis
   1. Chloroplasts are the organelle that carries out photosynthesis.
   2. Inside chloroplasts are thylakoids: membrane-jump sacs, organized into stacks called grana.
   3. The photosystems and electron transport chain involved in the lite reaction are located in the thylakoid membranes.
   4. The carbon-fixing reactions of the Calvin bicycle occur in the stroma.
2. Describe key evolutionary milestones in the evolution of photosynthesis
   1. Photosynthesis first evolved in photosynthetic bacteria (cyanobacteria)
   2. Prokaryotic photosynthesis created Earth's oxygen-rich atmosphere.
   3. Chloroplasts are endosymbionts, descended from cyanobacteria that took up residence within a eukaryotic prison cell.
3. Explain the low-cal reactions of photosynthesis
   1. Light energy is converted into electron free energy past two chlorophyll rich photosystems. (PS Two and PSI)
   2. Electron menstruation through the electron send chain of photosystem Two is used to create a proton gradient that powers ATP synthesis. The mechanism (pumping protons to a compartment, followed by chemiosmotic period through ATP synthase) parallels what happens in mitochondrial ATP synthesis.
   3. Electron flow through the ETC of photosystem I is used to reduce NADP⁺ into NADPH.
4. Explicate the key reactions of the Calvin bike
   1. The Calvin cycle is responsible for carbon fixation (bringing organic carbon into the biosphere)
   2. The inputs are the products of the light reactions (NADPH and ATP), and carbon dioxide
   3. NADPH  provides reducing ability (for hydrogenating CO₂)
   4. The reduction of carbon dioxide into sugar is endergonic. Hydrolysis of ATP provides the energy to drive this reaction forward.
   5. Rubisco is the key enzyme involved in carbon fixation (and is the most arable protein on World).

Resources for education photosynthesis on Learn-Biology.com

The five tutorials most photosynthesis on Acquire-Biological science.com are supported past this Photosynthesis Student Learning Guide

1. Photosynthesis 1: An Introduction
2. Photosynthesis 2: The Two Phases of Photosynthesis
3. Photosynthesis three: Light and Pigments
4. Photosynthesis 4: The Low-cal Reactions
5. Photosynthesis five: The Calvin Bicycle and Comparing Photosynthesis and Respiration

Labs

The spinach leafage disc lab is a fabulous manner to get your students to experiment with photosynthesis. The version in the previous link was adapted from i shared by Susan Wentzien at Lake Oswego Loftier School. I've modified it to work as an inquiry lab. Also, if  you wanted to print information technology out, you'll probably need to modify the formatting (I've taken to giving each lab group a Chromebook or two)

While the spinach leaf disk is what most AP Biological science teachers practice these days, the College board loves asking questions almost a photosynthesis lab from the old lab transmission that measures photoreduction of the dye DPIP. DPIP is nighttime blue when it's oxidized, and turns clear when it's reduced. In this version of the lab, yous'd extract chloroplasts from spinach leaves. The resulting chloroplast suspensions would be mixed with DPIP, and then placed in the light under a multifariousness of experimental atmospheric condition. For case, some chloroplasts would be boiled. Others would be covered in foil. A third would group would be the positive control (exposed to lite).

DPIP's role in the lab is to intercept electrons earlier they go far to NADP⁺ reductase. Instead of NADP⁺ getting reduced, DPIP gets reduced. Equally it gets reduced, DPIP becomes clear.

DPIP'due south clarity under various conditions can be quantified with a spectrophotometer, or it tin be recorded in a more qualitative way (darker to lighter, on a comparative scale). Either way you lot measure it, yous can think of what's happening every bit increased transmittance, or decreased absorbance. In this context, increased transmittance occurs equally the DPIP gets reduced and becomes clearer. In a test tube, the clearer liquid (more than reduced) allows for more transmittance more low-cal). Conversely, decreased absorbance is what happens as the nighttime, oxidized DPIP (which absorbs a lot of low-cal, because it's dark) becomes clearer, and absorbs less and less as it transmits more and more.

If this feels too abstruse, you can read about this version of the lab here. Even better, download a pdf of the lab with sample data here. I as well have a couple of one-time AP exam questions that you can share with your students on this review sheet.

Music videos about photosynthesis

I've written 3 three songs nigh the light reactions of photosynthesis. Y'all tin view them on this page: The Lite Reactions: A Musical Review.

Photosynthesis Video Lecture

To requite your students an overview of the lite reactions, accept them watch this video lecture.  It's about 12 minutes long.

Boosted Handouts

1. Hither's the review sheet I give to my students to help them set up for my cumulative cess on photosynthesis.
2. Before I flipped my classroom, I used to do comprehensive lecturing about photosynthesis. I've modified by note taking sail into a this diagram sheet that I spend a flow or two going over with my students.

Flinn has an excellent POGIL about photosynthesis that covers both the light reactions and the Calvin cycle.

Summative Activities for Unit 3

To help your students pull together what they've learned from unit iii

1. Have your students report the Unit 3 AP Bio Review Flashcards . Note that these were primarily designed for AP test review, so some of the material relates to material that comes later in the course. Therefore, you have to prep your students to be kind to themselves every bit they become through these cards: they shouldn't expect themselves to go these cards correct on the first endeavor. However, spending a few hours working on reciting answers to these wink cards will assist your students consolidate what they've learned, and set them up for success in concepts that they'll learn later in the course.
2. Note that while you lot tin set the flashcards to just serve up flashcards from Unit 3, it'southward probably a proficient idea to have your students review the flashcards from Units one and 2 equally well. In order to exercise that, have your students apply the settings shown beneath:

   

   These settings will give your students practice on units 1, two and 3. Annotation the "all" radio push button on the lower correct.

3. Complete the Unit 3 progress check items on AP Classroom.

Transpiration, the Transpiration Lab, and Water Potential

The term "transpiration" only occurs once in the Higher Board'due south Course and Examination description. It'south a link to the Transpiration Lab, which is Investigation xi in the College Board's AP Bio Lab Manual. To run into the College Board'southward version of the lab, click the preceding link and then search for "Transpiration."

In terms of learning objectives, hither'due south what the College Board lists in their lab manual:

• IST-5.A: Explain how the behavioral responses of organisms affect their overall fitness and may contribute to the success of the population.
• ENE-3.D: Explain how the behavioral and/or physiological response of an organism is related to changes in internal or external environment.
• SYI-1.H: Explain how the density of a population affects and is determined by resources availability in the environment.

For me, transpiration is important to teach because it gives me an opportunity to teach the concept of water potential. I don't teach h2o potential when I teach about osmosis in unit 2. At that point, it seems like overload, especially when the idea that water always flows from hypotonic to hypertonic explains everything that students need to know for the improvidence and osmosis labs. But explaining transpiration requires water potential. I do that through my transpiration tutorial. The tutorial will also provide your students with enough background about the structures associated with plant transport so that they'll have a good understanding of what's happening during the lab.

Like many teachers, I practise a different version of the lab: whole constitute transpiration.

In the first week of school, I have my students plant broccoli seeds in modest containers. For me, that'southward in the third week of Baronial. Ii and a half months later, with light shining 24 hours/24-hour interval in a light tray, the broccoli looks like this:

In the lab, yous have your students place the plant (with its container) in a plastic handbag then that the stems and leaves are exterior the bag. If yous utilize a cipher lock bag and scotch tape, y'all tin can go a pretty proficient seal, every bit shown below.

Now, the merely way that water tin can leave is through the stems and leaves.

Mass the plants, and so fix the plants in a few different environments: typically one with light, i with light + wind, i in darkness. After a twenty-four hour period or two, mass over again.

Yous could terminate there, only it leaves out a big variable: the surface area of the leaves. To control for that, you have to do a scrap of measurement and math. Y'all have students trace the establish's leaves on graph paper, mensurate the surface surface area, and and then calculate the amount of water lost/cm².

Typically, another function of the lab involves viewing leaf stomata. For context, I also have my students view and sketch a cross section of a typical dicot leaf (from a prepared slide).

Here's a handout for both parts of the lab. If you have ideas about improvement, let me know.

Links

• Unit of measurement four AP Bio Teacher'southward Guide
• Link back to the AP Bio Teacher'southward Guide Table of Contents

mendozahithers.blogspot.com

Source: https://learn-biology.com/curriculum/teaching-ap-bio-with-learn-biology-com/unit-3-ap-bio-teachers-guide/

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