AP Bio Speed Review, 2026. All 8 Units in 59 Minutes!

The AP Biology exam is coming up and

you're going to need a plan to

prioritize what you study. That's what

this video is designed to give you.

Here's your review plan. Download this

checklist at apbiosuccess.com/checklist.

Get three highlighters, red, green, and

yellow. Follow along with me during the

video. Use the stoplight method to

identify items that you know well, mark

those in green, that you know a little

bit, mark those in yellow, and that you

don't know at all, mark those in red.

Prioritize your studying. Study the red

items first, then the yellow, and then

just to keep the topics fresh, study the

green. Let's do this. AP Bio unit one,

chemistry of life. Topic 1.1, water and

hydrogen bonding. Water is a polar

molecule. It forms hydrogen bonds, which

are weak intermolecular bonds. Because

of water's polarity and hydrogen

bonding, water acts as the universal

solvent, and water's key properties

include cohesion, adhesion, surface

tension, high specific heat. You don't

only see hydrogen bonds between water

molecules. Hydrogen bonding is

everywhere in biology. You see it in

DNA, you see it in RNA forming RNA

specific shapes, you see it in proteins,

you see it in so many intermolecular

interactions. Topics 1.2 to 1.3,

elements of life, et cetera. The

molecules of life are built from

monomers that combine into polymers. You

combine monomers into polymers through

dehydration synthesis. You take polymers

apart through hydrolysis.

Carbohydrates are used for energy

storage and they create key structures.

That includes monosaccharides,

disaccharides for energy transport, and

polysaccharides which can store energy

like starch or make structures like

cellulose which makes up cell walls.

Lipids are nonpolar, their key unit is

the fatty acid. They can be saturated or

unsaturated. Saturated fatty acids are

more solid, unsaturated fatty acids

which have bends and kinks are more

liquid. Their functions include energy

storage in the fats and oils,

waterproofing in waxes, membrane

formation in phospholipids, and

signaling in steroids. Phospholipids

have a dual nature. They have a

hydrophobic, nonpolar tail that's in a

number three. They have a hydrophilic,

polar head at one. When mixed with

water, the heads bond with water while

the tails form a water-free zone. This

creates a phospholipid bilayer, which is

the basis of membranes. We'll talk about

this much more in unit two. Proteins

have diverse functions that includes

motion as in muscle tissue, enzymes.

Proteins also build structures, they're

used for transport, they're used for

energy storage, and for signaling.

Proteins are composed of amino acids,

that's their monomer. They have an amino

group, a carboxyl group, and most

importantly, they have an R group, a

side chain that can vary in chemistry.

You put those amino acids together

through four levels of structure, and

that includes primary structure, the

linked, genetically determined sequence

of amino acids, the alpha helices and

the beta pleated sheets that form

between interactions between amino acids

in the polypeptide backbone. Then you

have the complex turns and loops that

form as R groups interact with one

another through a variety of bonds that

might include hydrogen bonds and

covalent bonds, as well as hydrophobic

interactions and ionic bonds. And then

you have the aggregation of multiple

polypeptide chains forming quaternary

structure.

Nucleic acids are the molecules of

heredity, especially DNA, which plays

that role in cells. RNA can be the

hereditary material in some viruses, but

it's more important as an information

transfer molecule as a messenger RNA.

And RNA can catalyze reactions, sort of

like enzymes, and you see that in

ribosomes, spliceosomes, and microRNAs.

And the ability of RNA to do that will

come back later when we talk about the

origin of life in unit seven. Nucleic

acid monomers are nucleotides, and that

consists of a five-carbon sugar, a

nitrogenous base, and a phosphate group.

The nucleotides that make up DNA and RNA

are subtly different. There's a

different sugar, deoxyribose versus

ribose in RNA, and the bases are

different, ATCG in DNA, AUCG in RNA. In

terms of DNA structure, know that DNA is

famously double-stranded, that's why

it's the double helix. It has two

sugar-phosphate backbone,

sugar-phosphate, sugar-phosphate. The

base pairing rules for DNA are adenine

bonds with thymine and cytosine bonds

with guanine, and it has an antiparallel

structure. Antiparallel is like this.

Note that in one strand, this is the

five prime end, this is the three prime

end, and the other strand, this is five

prime and this is three prime. Are you

asking yourself, how am I going to get a

four or a five on the AP Bio exam? It's

a good question because it's a hard

test, but we have a plan for your

success. Go to learn-biology.com

and complete our interactive tutorials

and interactive AP Bio exam reviews. We

guarantee you a four or a five on the AP

Bio exam. See you on learn-biology.com.

Unit two, cell structure and function.

Know the difference between prokaryotic

and eukaryotic cells in terms of size,

structure, and the way they package

their DNA. AP Biology is a cell biology

class, and while you might not be asked

specific questions on the AP exam about

specific organelles, you will need to

know the overall geography of cells.

Know the parts on this slide that

relates to animal cells. Many of those

parts are also found on plant cells, and

I've highlighted the parts that are

different in plant cells in bold on this

diagram. Topic 2.2 is cell size, and the

key idea is that cells are small to

maximize their surface area to volume

ratio. As objects get bigger, the amount

of surface area they have relative to

their volume goes down. That's why cells

need to be small so they can have lots

of surface area to allow for lots of

diffusion. There are many, many

adaptations that relate to surface area.

Structures like gills or the big, flat

ears of elephants or the inner folding

of the mitochondrial membrane or the

lining of the intestine, that's all

about increasing surface area to allow

for increased amounts of diffusion,

either of molecules or in the case of

elephant ears, of heat. Things can also

evolve so that there's less surface

area. That's why whales have evolved to

be so big because with less surface area

in their huge bodies, they lose less

heat, which is an important

consideration for a mammal. Here's a

topic that was moved from unit eight

into unit two because it relates to

surface area and volume. It's about

relative metabolic rate or metabolic

scaling, and for mammals, which maintain

a constant body temperature, the

relative metabolic rate, the amount of

energy burned per gram of tissue, is so

much higher in a small animal than it is

in a large animal. And you can see that

in terms of the amount of energy

required per gram of tissue, the

lifespan, things like heart rate. It's

fascinating stuff and it's all related

to surface area and volume. Membrane

structure and function. We'll start with

membrane function. It's all about

selective permeability, controlling what

can enter and leave the cell.

Phospholipids form the framework, but

because we already talked about that in

unit one, well, you can go back and look

at that. The overall structure is a

fluid mosaic, and what that means is

that there's not only phospholipids,

there's also protein and cholesterol,

and they're all moving around. The

membrane molecules and their functions