[Music] hey I'm Melanie King from the absolute recap and today's video we're going to recap the entire AP biocurriculum that's right all eight units from start to finish with the top terms Concepts and equations that you need to remember for the exam in May if you find this video helpful make sure to like subscribe and share with a friend let's zoom out the goal of this video is to help you tell the difference between the things you remember and the things you don't emergency room doctors don't see patients in the order they arrive and you shouldn't study in the order that you first learned things just like doctors we need to survey the scene and bump things that are most urgently in need of our attention to the top of the list this process is called triage we're going to do this with the main AP Bio Concepts so you can figure out what you need to study first before we start print out the speed review document linked for free in the description below and get ready to color code like a stoplight as you follow along here's how the stoplight method Works Mark the topic box green if you absolutely remember and can think of additional information that I don't give you color it in yellow if the concept sounds familiar to you but the terms aren't coming to the tip of your tongue and red this is reserved for what is she talking about I never learned this as a clock winds down for AP Prep study what's red first yellow second and skip the green you already know it if you're looking for additional study resources to dive deeper into these Concepts you've marked red I've linked our podcast study guides and the AP biology ultimate review packet with full length practice tests in the description below okay let's zoom in unit 1 chemistry of life it all starts with water the polar molecule of H2O that forms hydrogen bonds and it's this bonding ability that gives water nearly every property it has cohesion adhesion surface tension high specific heat and the universal solvent unit 1 also includes the most common elements carbon hydrogen nitrogen oxygen phosphorus and and sulfur we find these in our four categories of biological molecules carbohydrates lipids proteins and nucleic acids carbs have a one to two to one ratio of carbon hydrogen to oxygen and form Rings or long chains their monomers often end in osc and function as both short and long-term energy storage as well as Structural Materials lipids are nonpolar form hydrocarbon chains and steroid rings and they have a hydrogen to oxygen ratio that is greater than two to one you'll find their fatty acid Tails as saturated or unsaturated with hydrogens which contributes to the fluidity of the phospholipid bilayer proteins are polypeptides of amino acid monomers which Bend and fold through hydrogen bonding and R Group interactions and since structure dictates function proteins have some of the most diverse cellular roles like enzymes transport channels and receptors the rule of thumb if a cellular job needs doing it's probably done by a protein the last biology molecule for the exam are nucleic acids which are formed from nucleotide monomers we will dive a lot deeper on DNA and RNA in unit 6. all of these polymers are formed through dehydration synthesis and split through hydrolysis reactions unit 2 is cell structure and function cells are classified as either prokaryotic or eukaryotic and they stay relatively small because this allows for a greater surface area to volume ratio for Material Exchange efficiency you'll want to review the differences between cell types and the many examples of folding for surface area the majority of eukaryotic organelles are membrane-bound and some are even part of the endomembrane system like rough ER smooth ER and Golgi ribosomes are excluded from the club since they're made of rrna and protein and although mitochondria and chloroplasts have double membranes they're also excluded due to their Origins with the endosymbiosis Theory unit 2 also includes types of transport which emphasizes the concentrations of solutes not quantities you'll see compare of terms such as hypertonic isotonic and hypotonic to describe solute concentration active transport requires the use of ATP and moves large or charged molecules against their concentration gradient through a protein passive transport moves small non-polar molecules down their concentration gradient by diffusion or through a protein by facilitated diffusion water moves by osmosis following its own concentration gradient and water potential sometimes through an aquaporin remember molecules are still in motion with isotonic Solutions there's just no net movement you can also move larger molecules across membranes with vesicles through endo and exocytosis unit 3 cellular energetics this unit is dense but follow the energy and focus on the big picture what goes in what comes out and where enzymes are made of protein which have an active site for the substrate to bind they decrease the activation energy required for reactions to occur making them more favorable but keep in mind that the energy difference between reactants and products stays constant also enzymes are not used up by their reaction but the candy nature can be inhibited through environmental factors next photosynthesis which uses chlorophyll to capture light energy transfers it to electron carriers and fixes the energy into a three-carbon molecule the light reaction occurs in the thylakoid membranes of the chloroplast while the Calvin cycle occurs in the stroma in contrast cellular respiration oxidizes glucose in the presence of oxygen generates an electrochemical gradient of hydrogen ions and transfers the energy to ATP glycolysis occurs in the cytoplasm of cells the Krebs cycle in the mitochondrial Matrix and electron transport chain in the cristae in the absence of oxygen cells perform fermentation which regenerates nadh for glycolysis to continue if you remember nothing else from this video please let it be this mitochondria are not the PowerHouse of the cell this is AP Bio and we can do better instead mitochondria ATP through oxidative phosphorylation remember plants do photosynthesis and cellular respiration so they have chloroplasts and mitochondria unit 3 ends with Fitness which just means that organisms best suited to their environment will have a greater rate of survival and reproduction thus passing on their genotype unit 4 is cell communication and cell cycle cell communication involves autocrine paracrine and endocrine signaling depending upon the distance the message is traveling once a signal known as a ligand binds to a Target cell it triggers a signal transduction pathway this three-step process involves reception often through protein modification transduction which amplifies the signal through phosphorylation and response which varies greatly but could be gene expression additional signaling or even apoptosis just like the structural relationship between enzymes and substrates signal transduction pathways are ligand-specific part of communication involves positive feedback which transitions a process farther away from homeostasis and negative feedback which turns conditions to a set point maintaining homeostasis next we have the cell cycle consisting of interphase with G1 sometimes G naught S phase and G2 then there's mitosis which creates identical daughter cells through nuclear division with the steps prophase metaphase anaphase and telophase you'll know you're in mitosis when you see the diploid number maintained through the splitting of sister chromatids mitosis is followed by cytoplasmic division or cytokinesis each process of the cell cycle is highly regulated by cyclins and cdks with checkpoints for DNA damage and complete DNA replication and unattached spindle fibers unit 5 is heredity and it's the second shortest unit of all eat it begins with meiosis which is the process of nuclear division that forms unique gametes for sexual reproduction meiosis also follows the general process of pmap but instead divides twice you'll know you're in meiosis when you see homologous chromosomes in metaphase one meiosis increases genetic diversity through pairing and crossing over homologous chromosomes as well as through independent assortment genetic diversity increases even more when two haploid gametes fuse during random fertilization however not everything always goes to plan with heredity and chromosomal disorders can occur through processes like non-disjunction deletion inversion and translocation unit 5 also includes patterns of inheritance for mendelian genetics like three to one for monohybrid cross and nine to three to three to one for dihybrid and non-mendelian genetics as well like incomplete dominance co-dominance linked genes and sex-linked traits make sure to practice interpreting allele expressions with Punnett squares and pedigrees I'd also recommend reviewing rules of probability and chi-square analysis for genetic problems unit 6 is gene expression and regulation so let's Circle back to our last biological molecule from unit one DNA and RNA are nucleic acids with heritable information DNA is double stranded with a deoxyribose sugar and bases A T C and G well RNA is single stranded has a ribose sugar and base uracil and Theta thymine recall that a pairs with t or U with two hydrogen bonds and C and G bond with three the S phase of interface stands for synthesis this is where DNA undergoes semi-conservative replication with the enzyme DNA polymerase which synthesizes new strands in the five primed three prime direction also remember that DNA is antiparallel so replication is continuous on the leading strand following helicase and forms okazaki fragments on the lagging strand the central dogma of biology for protein synthesis begins with transcription in the nucleus when RNA polymerase reads the DNA template Strand and synthesizes an mRNA transcript in the five Prime to three prime Direction in eukaryotes this transcript is processed to remove introns at an mg cap and a polye tail before leaving the nucleus for translation at a ribosome during translation a TRNA molecule brings over a corresponding amino acid to the MRNA codon in order to assemble a polypeptide chain this is the step where you will read the provided mRNA codon chart to translate from a nucleic acid language into an amino acid language the codon chart allows for variability in the genetic code while still emphasizing the unity of all living things also if a mutation occurs you just might end up with the same amino acid anyways genes are regulated by operons and prokaryotes and transcription factors promoters and Inhibitors in eukaryotes last concept for unit 6 is biotechnology like PCR gel electrophoresis bacterial transformation and DNA sequencing unit 7 is natural selection for natural selection to occur there needs to be an abundance of organisms with genetic variation that struggle to survive and reproduce successfully this ensures that those traits best suited to the environment are passed on to the next Generation humans can also impact populations through artificial selection as with our food production and domesticated pets evolution is the change in the allele frequency of a population over time and it can occur through natural selection as well as mutation small population size non-random mating and gene flow when none of these factors are in place a population is in hardy-weinberg equilibrium a quick tip always solve for the recessive allele frequency from Q squared first When approaching these problems there is a significant amount of evidence to support evolution and shared common ancestry including fossils biogeography homologous and vestigial structures and molecular comparisons make sure to familiarize yourself with the process of speciation and Extinction as well as how to interpret and construct phylogenetic trees and cladograms from data early earth eventually formulated the ideal recipe for life with organic molecules oxygen and RNA is the most likely first genetic material the final unit Unit 8 is ecology this unit is very example driven while not requiring you to have any specific ones in mind which can be challenging make sure to know the ways in which organisms communicate and respond to their environment particularly how these influence Fitness you'll need to know energy flow through a food web or trophic level from autotrophs to heterotrophs energy availability typically decreases as you move to higher order heterotrophs which supports smaller population sizes is there are several factors which limit population growth including resource availability and carrying capacity you'll want to review the relevant equations like Simpson's diversity index or exponential and logistic growth and be prepared to interpret graphical representations just like with natural selection variation is good for a community and increases resilience to ecosystem changes organisms often fill a niche within their communities such as a keystone or invasive species which has cascading effects on community organisms there are also several types of relationships within a community such as predation competition and symbiosis and lastly humans can sometimes be the worst disrupting ecosystems modifying habitats and causing extinctions to recap the AP biology curriculum has eight units with differential weighting on the exam chemistry of life cell structure and function cellular energetics cell communication and cell cycle heredity gene expression natural selection and ecology now that you've triaged you can prepare for the AP exam in a sequence that makes sense for you focus on red first yellow second and skip the green if you need more support check out the additional resources Linked In the description below I'm Melanie King from the absolute recap good luck on the exam