Transporting Molecules

Outline of the day 1.Turn in your lab reports at the front –More than 10 minutes late = bad 2.Any questions on last week’s lab? 3.Quiz 4.Introduction to the lab 5.Lab! 6.Check out Get a stamp Make sure I mark you down for attendance

Quiz Ends 8 minutes after it’s started –Ends at: ____

Lab this week! Exploring transportation! –Plants Xylem, phloem, etc. –Animals Open vs. closed circulatory systems –Class experiment! Effect of ______ on recovery from exercise –Yes, we’ll be exercising!

Water transport in vascular plants Water is absorbed by roots Travels through stems to leaves, fruits, flowers, etc. Pinus sylvestris (Scotts pine) GDL image from: Missing image: Image showing plant roots, shoots, and leaves with transporting elements (xylem, phloem) connecting them.

Water travels through xylem Xylem cells are dead, hollow tubes Hardwood pores - cc by a by McKDandy Missing image: Image showing plant roots, shoots, and leaves with transporting elements (xylem, phloem) connecting them.

What causes water to move in plants? Evaporation of water from the leaves! –Water evaporates from the leaves –Leaf cells replace their lost water From the xylem –Movement of water into leave cells pulls water up xylem Leaf image from: Missing image: Detailed image showing water entering roots, moving through xylem, and then leaving through stomata in leaves.

How does pulling on water work? Water molecules hydrogen bond to each other hydrogen bonding in water - cc by asa by Thomas Splettstoesser H OO H O O H O O H O O Missing image: Image showing water moving up a capillary tube

Animal circulation

Open vs. Closed Circulatory systems Blood in vessels (arteries, capillaries, veins) all of the time Blood moves in some vessels –But bathes organs in the body cavity –e.g. Insects have no capillaries or veins No capillaries! Missing image: Image illustrating an open circulatory system Missing image: Image illustrating a closed circulatory system

Blood vessels: Arteries Veins Missing image: Image contrasting artery and vein anatomy

Regulation of blood flow Capillary bed - PD by US Government from

Examples today: Arthropods – open circulatory system –Crayfish (no veins or capillaries) Annelids (segmented worms) – closed –Earthworm Mollusks - mixed –Clam: open (no veins or capillaries) –Squid: closed Vertebrates – closed

Let’s get started! In about 10 minutes we’ll discuss the exercise portion of the lab

Today’s experiment! In your group, come up with a list of at least four variables that you think might affect recovery from exercise –Write these on page 7-8 We’ll talk about these as a group in a bit

The variables We’re going to choose one to experiment on today

Doing the experiment Take your pulse now –Record it in your lab manual Jog around the science wing twice! When you get back, measure your pulse rate every two minutes –Record the data in the lab manual Do NOT participate if you have a health condition that prevents you from exercising or if you, for any reason, do not want to participate; there is no need to inform me why you are not participating. Stop exercising if you feel out of breath of experience physical pain. Report any injuries to me.

Before you leave Clean up your work area Show me your lab report so I can stamp it –Need to have all data fields filled in –Complete at home and then turn in at the beginning of next lab Remember that we’ll have a quiz at the beginning of the next class –6-7 questions on today’s lab –3-4 questions on the lab we’ll do next week

Notes for the instructor: Add any relevant cleanup instructions to the final slide (that slide is a generic one I’m adding to each presentation). As it’s difficult to tell open from closed circulatory systems on our models (e.g., our chordate model doesn’t draw in capillary beds, and thus has blood vessels ending in open holes, as you’d expect an open circulatory system to have), I simply tell the students which organism has each type of system. I do, however, inform them that they must recognize each type of system, even on a different model. If you have better models, I’d suggest not giving them the answers ahead of time. I apologize about the high number of missing images; I haven’t been able to find good, license-free, images of this content. If you find any, please let me know! Transportation of water in plants can be a difficult topic to introduce; I find that using this animation: ation.swf&width=0&height=0 can help. ation.swf&width=0&height=0

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History August 2007: Marc Perkins released first version. (If you modify these slides and redistribute them, add your information to the list)