KIRSTIN MILKS: Hi, everybody.
I'm Kirstin Milks coming to you from Bloomington, Indiana.
So glad you could be with us today
to practice some AP bio questions.
Today, we are going to be thinking about multiple choice
practice with a focus on visual responses.
I've selected content and science skills
from across the units with a focus on answer choices
that are a graph or diagram.
The way the video will work is I'll show you a question.
You can pause the video to read it and select your best answer.
And then we'll go over it.
Or you can use the question PDF that accompanies this video.
All right, here's our first question.
Let's go ahead and take a look at the choices.
Pause the video and pick your answer.
OK, let's go through the choices.
It turns out that only eukaryotes have mitochondria.
And even in organisms that do, glycolysis
happens in the cytoplasm.
So A is wrong for a couple of reasons.
Let's take a look at C. We do aerobic respiration
using oxygen as the final electron
acceptor in the electron transport chain,
so that's not a correct answer.
And then for D, it says convergent evolution.
Convergent like conference means here
that similarity has evolved from separate ancestry.
But we know that the university of glycolysis
is an important piece of evidence for common ancestry.
And so the correct answer is B.
All right, here's your next question.
Go ahead and pause the video and select your best answer.
Now in this question, there's help
in the question stem itself.
It's reminding us that oxygen and hydrogen have
positive charges that attract.
If we look at the choices, we can
see that both C and D have that arrangement
in the dotted lines.
But C also indicates an incorrect alignment
for a hydrogen bond.
So it's only D that shows the attractive force
between the hydrogen atom of one water molecule
and the oxygen atom of the adjacent one.
Again, the question text hints at what you look for.
That doesn't always happen.
Sometimes, you need to remember more on your own.
But sometimes, it does so make sure you're on the lookout.
Go ahead and pick your best answer choice from these four.
Pause the video.
Now the data table in these questions
can take lots of forms.
You can be looking at DNA or protein sequences
to derive characters as seen here.
So for me, the first thing I do is
see if I can find the organism with the most and the least
of those characters.
So for birds, it's the most and fish is the least.
That's a signal for me that we're
looking for fish to branch out first,
to share the oldest common ancestor
with the other organisms.
So next, we're going to look for the two that
are the most similar.
In that case, that is birds and crocodilians.
And with this analysis, it becomes doubly clear
that A is the correct answer.
Just a reminder that this type of picture,
you can actually rotate around that center point
that I've indicated with a blue arrow.
So the relationship in and C where birds and crocodilians
are the most closely related, that relationship
circled in purple is the same in both pictures.
So don't let that fool you on a question.
All right, here's question 4.
Go ahead and take a look at the choices, pause the video,
and answer the question.
So we're going to take a look and see what is
happening in this experiment.
What's inside this dialysis bag?
The question tells us it's 25 milliliters of distilled water
in both beakers.
Next we ought to try to figure out what solution they're in.
This case, you can see they're filled with 200
milliliters of distilled water.
And then there's something that changes in one of the beakers.
And we can see here it's a concentrated
solution of albumin protein.
And so if we take a look here, only B
shows no change after that albumin is added.
It shows no change because it's in an isotonic environment
to start with distilled water on the inside and outside,
and then shows a decrease in mass
when the environment becomes hypertonic with the addition
of albumin.
All right, next question.
Go ahead and read it.
Pick your best choice.
Pause the video.
OK, cool.
So let's take a look and think about what's
happening with these plants.
So the plants that are having a kind of hard time
and end up shorter are ones that are planted in cellulose.
You'll remember from unit 1 that cellulose
is a carbohydrate polymer.
So that means that our plants have
no shortage in their environment of carbon, hydrogen,
and oxygen. But that's doubly wrong because as you remember,
the carbon in plants comes from the air.
It comes from carbon dioxide.
But that does mean that there are no other nutrients
available to the plant that you need
to build other macromolecules like nitrogen and phosphorus
and sulfur.
And so if we go through the questions,
you're automatically not selecting
choices that are made of carbon, hydrogen, and oxygen.
It turns out that you need more than just nitrogen,
so B is incorrect.
The correct answer is C.
OK, here's the question.
Go ahead and take a look at the answers,
and make your best guess.
So in questions like this, it's really helpful
to think about what parts of the table you need to look at.
In this particular question, they're
asking about test tube 5.
So I'm going to go ahead and highlight test tube 5 here.
Now, we're going to go through the choices.
A says that 5 would act as a control for test tube 4,
so let's go ahead and highlight 4 here.
And it says that we want to look to see
if it's going to show the presence
or absence of the substrate.
But when I go through and look at that column,
I can see that both test tubes have the substrate added.
So A is an incorrect answer.
Let's take a look at B. Again, we're looking at test tube 4.
In this case, we're thinking about a change
in environmental temperature.
Well, is there a change between 4 and 5 in temperature?
They're both 20 degrees--
23 degrees Celsius.
And so that's no.
Let's take a look at the next two choices.
They're both looking at test tube 6.
By the way, even if you get stuck choosing between C and D,
making it so you can pick answer choices that you know
are incorrect and then having to randomly guess
is a really good multiple choice strategy.
So here we are in C and D. We're looking at test tube 6,
so I'll go ahead and highlight that row.
And in this case, hopefully you can
see we're looking at presence or absence of the enzyme.
That's pectinase in this process.
It tells you in the first sentence of the question.
So here's that row.
And then the other one is sodium chloride concentration.
I'm showing that in yellow here.
As you can see, it's pectinase added, yes or no,
that is different in these.
So in this particular case, the correct answer is C.
All right.
Let's go ahead and take a look at question 7.
Here are your choices.
Pause the video and make your best guess.
OK, so this is one of those questions where
it's really helpful before you start looking at the choices,
to pause and think to yourself what should a correct graph
look like.
Here's the information the question gives us
that spinach leaves capture the most energy from light waves.
That's not the data that they're collecting.
It's the claim that they're making
between 500 and 600 nanometers.
So because oxygen is produced as a byproduct of photosynthesis,
a greater level of oxygen production,
if this claim were true, would indicate a greater level
of energy capture from light.
And that means you're hunting for a graph
here where the most oxygen per hour
is generated when the wavelength of light is in that range.
In this case, it's B, the correct answer.
All right, next question.
Go ahead and take a look and make your best guess.
We're going to start with the first graph.
And we're going to do what I call a graph tour.
We're going to look pretty carefully
at the x-axis, the y-axis, and the overall trend in the graph.
So you can see our x-axis here is proboscis length.
And the problem tells you in the question,
it's the mouthparts of the moth.
And it tells you that to feed, you
end up putting that into the flower
to reach the part in the flower where there's nectar.
And the y-axis is telling us it's the number of hawk moths.
And as you can see, the most abundant tobacco species
in the population has a nectary tube that's centimeters long.
And interestingly, that matches the graph
through the mouth parts of the moth.
Now the question asks you what will happen perhaps
in the expected distribution of the size of the mouthparts
at the end of this study during this time
that a virus is attacking and killing
almost all plants of this tobacco species.
Well, if the nectary tube is longer,
you're going to end up with a story about natural selection.
So you'll shift from this thing of 5 centimeters long to one
where longer proboscis lengths allow organisms to better
survive and reproduce.
So you're looking for that same type of graph but shifted.
And indeed, the best graph that matches that is B here.
All right, next up is question 9.
Go ahead and take a look at the choices, pause the video,
and give your best guess.
This is another one of those questions where
it's really useful before you start looking at the choices
to predict what a correct answer is going to look like.
Now in this case, the question tells you
that we're removing consumer X from the population,
and that the size of the circle represents
the population size of the species
relative to other species.
Now, you'll note that I went ahead and drew a down arrow
over that place.
I find that drawing down and up arrows
when things are increasing and decreasing
is a really useful test taking tool.
So let's think about it.
If you suddenly remove that consumer,
you're going to get way more of the things
that this organism eats.
In this case, because it is the only consumer
of the one I've put a blue arrow up above,
you're expecting a big increase there.
Now, you might have an increase on that next one.
It's not clear.
Maybe organism Y picks up the slack.
But you're definitely looking for,
if you're looking at circle size, an increased circle
on that far left hand side.
What happens in the producer level in the trophic levels
as a result?
Well we can think about it.
Primary consumer on the far left eats those two.
So we'd expect if there were more of them,
there'd be less of the stuff they're eating because they're
eating more of it.
And you might see a small decrease in this one.
But again, it depends on the relationships
in the trophic levels when we go.
And take a look at that the far right hand side
of this diagram, all of that is going to stay the same.
The relationships in those parts are not
affected by taking away secondary consumer X. So
with that in mind, if we take a look at the answer
choices, the best match, far and away,
is A, such a correct answer.
All right, question 10.
Go ahead and take a look at the choices, pause the video,
and make your best guess.
OK, we're looking at quite a few acronyms so
let's take a quick look here.
So we're looking at CHX and we're also looking at CPM.
So when I see those, if they feel confusing,
I try to figure out what they mean or whether or not I can
see them in the answer choices.
So here, you can see that cycloheximide, which is CHX,
is a eukaryote protein synthesis inhibitor.
And then that's going to mean the protein synthesis,
the rate of protein synthesis is going to decrease.
CPM, on the other hand, is measuring counts per minute
to measure the growth of a single polypeptide chain.
And so when we go through and read the question,
it tells us that as the chain grows, the counts per minute
increase in this particular type of assay.
So that's what it means when we're looking up here.
The inhibitor is CHX.
And CPM is the counts per minute.
And those should increase as the protein chains grow.
So when we take a look at these four choices,
we know that the inhibitor is added
and then the inhibitor is removed.
And that's what those arrows are showing on the graphs.
Now we're really looking for this idea
that when the inhibitors removed we're
going to get, again, an increase of protein synthesis.
So A suggests that when you add the inhibitor,
there's no change in the rate of protein synthesis.
So A is an incorrect answer.
B implies that when you add the drug,
the polypeptide decreases in length.
And it's important to note that counts per minute
is not the process of synthesis here.
Instead, it's a measure of the amount of synthesis
that the single peptide chain has
undergone as that text that's highlighted in green tells us.
And so for that reason, in real life,
the polypeptide chain would have stopped
growing without decreasing in length until removal
of the drug.
And that means that B is incorrect.
Let's take a look at C. It suggests
that the peptide chain decreases in length with the inhibitor
is removed.
But what should happen is the opposite.
And so C is incorrect.
Only D shows you that correct relationship.
All right, let me give you four quick reminders
about multiple choice.
First off, try predicting a correct answer choice
after you read the question like I've practiced in this video.
Next up is mark up the text.
Don't block any text in the test in case
you go back later to change your mind.
But underline, draw, mark up and down arrows,
write a quick word or two to yourself as a note.
If you must guess on a question, eliminating one
or even two answer choices will increase your odds
of guessing correctly.
And last, make sure you answer every question
before the ending of the testing period.
A guess is better than a blank.
So glad you could join us.
I'm so glad you got some practice in.
Join us on the other AP Daily videos to improve your skills.