Included here are a series of questions used on previous Biology EOCs. They have been “retired” for use as sample “practice” questions. It is important.

Biology EOCPractice: Part 1

Included here are a series of questions used on previous Biology EOCs. They have been “retired” for use as sample “practice” questions.

It is important to keep in mind this is NOT about memorizingthe answers to these questions (wouldn’t do you any good ifyou did since they’re retired) but rather…

--get a “feel” for the format--consider the topics (what biological concepts are

they addressing?)--for the extended-response questions, it often isn’t

as much biological concept as it may be ascientific approach to problem solving

Hope you find this useful…(feedback is welcome!!)Hint…use the up/down arrow keys to navigate this power pt.

Question #1 is about (duh) feedback loops. Considered part of your knowledgeof “Systems”, this stand-alone question (not part of a scenario) is really asking,“do you know the definition of positive (and negative) feedback loops?” Bigpicture? Complex systems must have ways of reinforcing and/or balancing theirflows of matter and energy and you need to be able to express your competenceof such things. This is also the type of question that frankly, is a test of yourvocab as well. For example, you may have heard of positive feedback loops asreinforcing loops while negative are often referred to as balancing feedback.In other words, as you get more of A, you then get more of B too. Get it? Theloop is reinforced…called positive because you get more and more and more…Whereas if getting more of A meant you would get less of B, the feedback bringsbalance…the more being balanced by its opposite. Let’s use an example froma lab you did recently.

As you may (or may not) recall, you dropped alka seltzer tablets into a coupletest tubes (CH 11, Carbon Lab #3) which generated CO2 gas. That gas can easily turn right around and react with the water in the test tubeforming carbonic acid. Your results showed the acid-tube generatedmore gas (finger height) than the water-tube (red arrow). That means the now-acidic-tube will generate an even GREATER amount of gas…which will, in turn, react with the solution making it even more acidicwhich will, of course, generate even greater quantities of CO2 . Like avicious circle…asnowball rollingdownhill, gatheringever-greater amountsof snow!

A POSITIVE FEEDBACK LOOP

An example of a negative?Consider your iTunes libraryand an iTunes gift card. As youincrease the # of songs in yourlibrary, the amount on thecard is reduced. As your $$ goesdown and down, the sizeof your library grows….& grows.

ANSWER

Sweating is your body’s attempt to lower body temperature.As the amt of sweat INCREASES, body temp DECREASES

This is your body’s attempt to re-achieve BALANCE

A balancing loop…NEGATIVE FEEDBACK

Here’s another example of a FEEDBACK LOOP-type question…

NEGATIVE (“balancing loop”) = as A increases B decreases (or vice versa)

Choice C…adding insulin increases the amt of glucose…would be a reinforcing loopor POSITIVE feedback…only choice…

…D… “balances” high levels of one by decreasing the other

Question #2 addresses your knowledge of the major chemical cycles on earth.There’s the WATER cycle, the CARBON cycle, the OXYGEN cycle, and the NITROGENcycle (to name a few). Considering the fact that nearly 80% of earth’s atmosphereis NITROGEN, yet exists in a form NOT USABLE by most life forms, and yet is a fundamental element in ALL life forms (it’s the reason amino acids are literallycalled AMINO!!), this is a question assessing whether or not you’ve learned ofthe existence of (and dependence of life on) what are called “nitrogen-fixing”bacteria (like those commonly found in root nodules of pea plants).

BACTERIA

The next four Questions #3-6 are an example of scenario-based questions. WhileYou can obviously approach these by whatever means suits you best, many folksthat are uniquely-successful find the following technique most productive…

--skip over the scenario--go straight to the questions--read each question so you get an idea of the specific kinds of things they are

looking for (allows for a more “focused” read of the scenario)--go back and read the scenario, keeping the questions in mind

Go ahead…give this method a try. I’ll wait (I’m not going anywhere ;-)…use the up/down arrow keys to skip ahead/back

DON’T READ THIS UNTIL YOU’VE SKIPPED AHEAD AND BACK

…as you can see, questions 3 and 5 (the two multiple choice questions) reallyhave NOTHING to do with the scenario!! They are there to assessyour knowledge of experimental design (and if you are one of MYstudents, you are THE BOSS when it comes to addressing RELIABILITYand VALIDITY of experimental designs!!).

…questions #4 & #6 are extended response items which will take a littleexplaining. Now, skip to the answers…

STOP. GO NO FURTHER UNTIL YOU’VE SKIPPED FORWARD/BACK LIKE IT SAYS ONSLIDE #8. Good-to-go? Then let’s tackle 3 & 5 first…

Even if you totally forgot that REliability involves REpeated trials*, look closerat the options. Choices A, C, and D ALL involve CHANGES (“other acidities”, “increasethe volume”, and “use a different”)…only B keeps all conditions… *the same.

Question 5 involves good ol…

As a veteran of LoomDog’s class you know full-well there are several ways toincrease the validity of an experimental design. In addition to a Peer Review,running an experimental control group, and having LOTS of controlled variables,only choice D is a step that will reduce the impact of human error/variance.Choices B & C both involve RELIABILITY (multiple trials) and choice A…really?

Here’s another past-EOC question of similar style, but tied to a scenario about takinga survey of salmonberry plants in/around a forest. The field study involves sampling 3 types of habitat using three 5-by-5m plots .

4 instead of 3? More reliable

Smaller!? plots…nope

No impact whatsoever

Like another Controlled Variable

An example of a 2-pt, extended response question is Question #4: Write a Conclusion

Best advice here…DOUBLE CHECK to make CERTAIN you answered EVERY BULLET!!!

Lucky for you, as a Tahoma sophomore, you are already quite familiar with thefirst 2 bullets… “According to the data the hypothesis is…” AND BACK IT UP WITHDATA!!!!

The prediction was supported by the data, as the pHINcreased, the amt of foam also INcreased…to a point. TheAVERAGE amt of foam increased from 24ml to 35ml betweenpH 6 and 7 then another 7ml between pH 7 & 8 BUT THEN itdropped an AVERAGE of 12ml between pH 8 and 9.

Enzyme function is impacted by pH. In the case ofcatalase, it appears to function best (judging by maximum foamproduction) in a mild base (pH 8). It’s effectiveness dropssharply in acidic solutions (below 7.0) and again in basesstronger than 8.0 Acids impair the function of catalase(destroy its chemical structure) as do strong bases. Potatocells must have a slightly basic pH.

Let’s examine each bullet…

IMPORTANT: Use AVERAGESif possible &include bothMAX & MIN(range)

Question 6 is another 2-point extended response item: design a follow-up experiment

Again…PAY ATTENTION TO THE BULLETS!!!

In this example, rather than pH (MV) vs amt of foam (RV) you are tasked with aManipulated Variable (MV) of…

…and a responding variable (RV) of…

Let’s take a look at several possible responses…

…I don’t know where to start …the bullets?0 controlled variables, 1 MV but only two “levels” (hot?and unheated?), 1 RV (but how do you???), ignoredthe last bullet, and this is not “logical” because no onecould repeat these steps with reliable results

SCORE = ZERO

Better…but still…2 controlled variables (steps 1 & 3)1 MV and three “levels” (34, rm temp, and 89)1 RV (but again how do you measure “bubble data”?)Again, the last bullet is ignored, no repeated trialsand this is not “logical enough”

SCORE = ONE PT

Getting better…Only 1 controlled variable (1 drop of peroxide) 1 MV and three (weak) “levels” (fridge, rm, m-wave?)1 RV …FINALLY!, something measurable, the last bullet is included, AND repeated trials! But measurementsnot recorded. However, steps ARE logical enough…

SCORE = ONE PT

2 controlled variables (steps 1, 2, & 3)1 MV, 3 evenly-spaced “levels” (72, 82, and 92)1 RV and last bullet (Step 4), enough detail to belogical, reliable, and even a “validity measure” (usingSAME thermometer)

SCORE = TWO PTs

Here’s a few more “stand-alone” type questions…

Respiration and fossil fuels…can you say “CH 11!!!?” ...hmmmm….respiration… …glucose + oxygen carbon dioxide + water…in order to generate energy (in the form of ATP)

and burning fossil fuels…hmmmm…. …carbon compound (fossil fuels) + oxygen(burning) carbon dioxide + water

Photosynthesis??

Respiration yes but…not burning gasoline

Release? NO…consume? yep

Again…this isn’t about memorizing answers…it’s about getting a feel for both the style as well as the “topics” (which you should feel good about)

As you can see, genetics figures prominently…these concepts were from “CH 7”…

Above…while mutation can increase genetic variation, the EPIC generator of diversity hasalways been SEX (mixing of genes to get new/unique combinations)

And below…from that salmonberry scenario again (irrelevant)…this is remembering thedifference between MEIosis and MITosis. If it were asking for the former then you’d wantto respond that the GAMETES (pollen/ova) would have HALF (the diploid #) or 7 but sinceit’s all about a non-reproductive structure (a leaf) and it’s MITOSIS (like cloning) you’d say…

14

or ANY

species

Unsure why they specified “nonnative” plants…read it this way…

You should IMMEDIATELY recognize (throw out) choice D… evolution-by-intent* is oneof those GROSS misunderstandings among people that “don’t get evolution.”

*something mutates to get what it wants/needs

That’d be a neat trick

Huh? Glucose, not ash

From CH 14…a “niche”…a collection of factors that define the living space of a species

After a forest fire a lot of previously-claimed living space is suddenly “up for grabs”(whether you’re a native species or not!)

Speaking of habitats…

As you’ve been learning in CH 16, “There are no such things as PERFECT solutions…thereare ALWAYS unintended consequences.”

In this question, “adding butterfly habitat” (structures providing biotic/abiotic needs forbutterflies) can mean many things, none of which (that I can see) would impact eitherB or D of an entire ecosystem! Along those same lines would lie choice A…how wouldadding say, a netting?, remove nutrients? (caterpillars need trees but adding trees won’tREMOVE nutrients) But Choice C…

Whatever structure is added, no matter how small or seemingly insignificant, WILL introduce something “new.”

END Part 1If interested in more practice

questions, run power pt“Part 2”