AP Biology Speedrun
Unit 6.7 Mutations
A mutation is a change in the genome of an organism Substitutions, deletions, and insertions are gene mutations Mutations can be positive, negative, or neutral based on the effect or lack of effect they have on the resulting nucleic acid or protein and the phenotypes that are conferred by the protein Mutations in DNA can be caused from errors in replication, repair, or radiation or chemical exposure Errors in mitosis can change the number of chromosomes in an organism, which can result in increased vigor in plants, sterility, or disorders in humans The environment determines if a mutation is detrimental, beneficial, or neutral Genetic changes that enhance survival and reproduction can be selected for, based on specific environmental conditions. Horizontal acquisitions of genetic information include the transfer of DNA segments between cells, viruses, and cells, or movement of DNA sequences with and between DNA segments Genetic variation is increased through sexual reproduction, independent assortment of chromosomes, and crossing over.
Unit 4.4 Changes in Signal Transduction Pathways
A mutation that alters the ligand/receptor specificity can lead to incompatibility, which can alter the signal transduction pathway. The receptor will not undergo proper conformational shape and change, resulting in an inactive internal pathway.
Unit 8.4 Effect of Density of Populations
A population can produce a density of individuals that exceeds the system's resource availability. When density-dependent and density-independent factors are imposed, a logistic growth model generally ensues.
Unit 4.2 Intro to Signal Transduction
A signal transduction pathway is the binding of signaling molecules to receptors located on the cell surface or inside the cell that trigger events inside the cell to invoke a response. Cells use signal transduction pathways to link signal reception with cellular response (growth, secretion, and gene expression) A signal transduction pathway begins when a receptor/ligand binds to external receptors or an intracellular receptor. The role of protein modification in signal transduction -pathways is to cause a conformational shape change due to the ligand binding. This change elicits an intracellular response, which causes a second messenger to be activated. A phosphorylation cascade is a signaling pathway where one enzyme phosphorylates another, causing an amplification of the reaction, leading to the phosphorylation of thousands of proteins.
How ATP is Made
ATP can be produced by a number of distinct cellular processes; the three main pathways in eukaryotes are glycolysis, the citric acid cycle/oxidative phosphorylation, and beta-oxidation.
ATP (Adenosine Triphosphate)
ATP is an organic compound and hydrotropic (small molecules that solubilize hydrophobic molecules in aqueous solutions) that provides energy to drive many processes in living cells. These include: -Muscle contraction -Nerve impulse propagations -Condensate dissolution -Chemical syntheses Found in all known forms of life Known as the "molecular unit of currency" for intracellular energy transfer. When consumed in metabolic processes, it converts to either ADP (adenosine diphosphate) or to AMP (adenosine monophosphate) Other processes regenerate ATP so that the human body recycles its own body weight equivalent in ATP each day It is also a precursor to DNA and RNA, and is used as a coenzyme. Made up of three components: adenine as the nitrogenous base, sugar ribose (sugar and carbohydrate), and triphosphate (three phosphates, duh).
Unit 3.6 Cellular Respiration
All living things use fermentation and cellular respiration to produce ATP. Eukaryotes coordinate cellular respiration in three metabolic stages which are glycolysis, pyruvate oxidation and Krebs cycle, and oxidative phosphorylation. NADH and FADH₂ deliver electrons to ETC which uses the electron energy to create an electrochemical gradient of protons. The electron transport chain allows for the efficient transfer of energy from electrons to a proton gradient. NDAH and FADH₂ donate high energy electrons to the electron transport chain. The electrochemical gradient provides stored energy that is transformed into energy of chemiosmosis used by ATP synthase to synthesize ATP Oxidative phosphorylation is the pathway utilizing electron transport chains, chemiosmosis and ATP synthase to make ATP. When decoupling occurs during cell respiration, heat is released and can be used for thermoregulation. Glycolysis releases energy in glucose to form ATP and NADH Pyruvate is transported to the mitochondria where it is oxidized. During the Krebs cycle (The Citric Acid Cycle) carbon dioxide is released, ATP is synthesized, and NADH and FADH₂ are produced. The electrons extracted in glycolysis and krebs cycle are transferred by NADH and FADH₂ to the electron transport chain. Fermentation allows Glycolysis to olatpur without oxygen and produces ethanol and lactic acid. Energy Released when the third phosphate is broken off of ATP resulting in ADP.
Unit 1.3 Intro to Biological Macromolocules
All monomers contain carbon and are used to build biological macromolecules. Covalent bonds are used to connect monomers together. Dehydration synthesis reactions are used to create biological macromolecules and water is an additional product. Hydrolysis reactions use water to break down biological macromolecules.
Unit 1.5 Structure and Function of Biological Macromolecules Part 2
Amino acids have directionality with an amino terminus (NH2) and a carboxyl terminus (COOH) on the other. Amino acids are added to the carboxyl terminus of a growing peptide chain by the formation of covalent bonds. There are 4 elements of protein structure: primary, secondary (alpha helices & beta sheets), tertiary, and quaternary. Levels of structure beyond the primary linear sequence of amino acids arise through local folding and other chemical interactions among amino acids. The resulting 3D shape gives rise to the protein's specific function. A change in an amino acid subunit at the primary level of structure may lead to a change in the structure and function of the protein at subsequent levels.
Unit 8.7 Disruptions to Ecosystems
An adaptation is a genetic variation that is favored by selection and is manifested as a trait that provides an advantage to an organism in a particular environment. The intentional or unintentional introduction of an invasive species can allow the species to exploit a new niche free of predators of competitors or to outcompete other organisms for resources. The introduction of new diseases can devastate native species. Habitat change can occur because of human activity. Geological and meteorological events affect habitat change and ecosystem distribution.
Unit 1.6 Nucleic Acids
Both DNA and RNA are formed from nucleotide subunits connected by covalent bonds to form linear molecules with 5' and 3' ends. Each nucleotide is comprised of a sugar, phosphate group, and nitrogenous base. Differences include the type of sugar, one of the nitrogenous bases (RNA contains uracil whereas DNA contains thymine), and number of strands. DNA has two nucleotide strands that are antiparallel.
Unit 2.11 Origins of Cell Compartmentalization
Both prokaryotic and eukaryotic cells have external plasma membranes. However, whereas prokaryotes only have internal regions where specialized structures and functions can occur, eukaryotic cells have additional internal membrane-bound organelles that compartmentalize the cells. According to the theory of endosymbiosis, a previously free-living prokaryote (bacteria) was engulfed by another cell through endocytosis. After living together symbiotically for some time, the once free-living prokaryotic lost its independent functionality and gave rise to either the mitochondria or the chloroplasts. Evidence supporting the evolution of mitochondria and chloroplasts by endosymbiosis includes the presence of double membranes, circular DNA, and ribosomes in both these organelles.
Unit 1.5 Structure and Function of Biological Macromolecules Part 3
Carbohydrates comprise linear chains of sugar monomers connected by covalent bonds. Sugar monomers may vary in the direction of some of their components, such as the bond orientation of -OH groups linked to the carbon chain. Depending on the type of sugar monomer used in its formation, a carbohydrate polymer may have a linear or branched structure and can differ in function.
Unit 4.1 Cell Communication
Cells use local regulators to communicate across short distances. Cells can release chemical signals with the ability to travel over long distances to target cells of other types. Structural modifications of the cell membrane and cell wall allow cells to send chemical signals directly into adjacent cells.
Unit 4.7 Regulation of Cell Cycle
Checkpoints are regulatory events in the cell cycle. Checkpoints help determine whether the cell is ready to progress through the cell cycle. Proteins are used to activate or inhibit cell cycle activities. Apoptosis and/or cancer occur when the cell cycle is disrupted.
Unit 5.6 Chromosomal Inheritance Part 2
Chromosomes are inherited as full units and passed from parents to offspring. Patterns of inheritance of traits, diseases, or disorders can be analyzed to determine how chromosomes were inherited. Visual representation such as pedigrees can be used to help us predict the causes or effects of changes in chromosomal inheritance from parents to offspring.
Unit 5.2 Meiosis and Genetic Diversity
Crossing over in prophase I occurs when nonsister chromatids exchange segments. This results in recombinant chromosomes. Random assortment of chromosomes in metaphase I can result in different combinations of chromosomes in gametes. During sexual reproduction, any gamete from one parent can combine with any gamete from another parent, resulting in genetically different offspring. This increases the genetic diversity within a population of organisms.
Unit 4.6 Cell Cycle Part 2
DNA becomes visible and the nuclear envelope disappears during prophase. Chromosomes are aligned across the center of the cell. Double chromosomes are separated into single chromosomes and single chromosomes migrate to opposite sides of the cell. DNA uncoils and nuclear envelopes reappear. Two new nuclei form and each nucleus contains a complete genome. Cytokinesis begins at the end of mitosis and separates the cell into two daughter cells.
Unit 6.2 Replication
DNA replication ensures the continuity of hereditary information, allowing transmission of genetic information between generations DNA replication is semiconservative. One strand acts as a template for a new complimentary strand of DNA. DNA is synthesized in the 5' to 3' direction. DNA is synthesized continuously on the leading strand and discontinuously on the lagging strand. Enzymes are involved in DNA replication Helicase - unwinds DNA strands Topoisomerase - relaxes the supercoil ahead of the replication fork DNA polymerase - synthesizes new DNA strands.
Unit 6.1 DNA and RNA Structure
DNA, and in some cases RNA, is the primary source of heritable information DNA and RNA store information as nitrogen base sequences. Base pairing occurs with specific pyrimidines always pairing with specific purines. This base pairing is conserved through evolution Prokaryotes typically have circular chromosomes while eukaryotes have linear chromosomes. Prokaryotic genomes are typically smaller than eukaryotic genomes. Prokaryotic plasmids are found in the cytosol while eukaryotic plasmids are found in the nucleus.
Unit 3.3 Environmental Impacts on Enzyme Function
Denaturation of an enzyme occurs when the conformation protein structure is disrupted, eliminating the ability to catalyse reactions. Denaturation: to take away something's original purpose This applies to the enzymes when they break apart removing their purpose of inhibiting the protein. Changes in pH outside of optimum pH range in either direction, will result in decreased enzyme activity and eventually enzyme denaturation. pH measures the acidic or alkalinic, the scale goes from 0 to 14. Seven is a neutral like water. It's near impossible to have a truly neutral substance so most things have a range in which they are comfortable. Increasing temperature, outside of the temperature range, will initially cause increased reaction rates with continued increases resulting in denaturation. Decreasing temperature outside the optimum range will result in slowed reaction rates but not denaturing of the enzyme. Temperature is how hot something is. I hope you know this... There is Kalvin [k], Celsius [c], and liberty (freedom) units (Fahrenheit [f]). Increased enzyme concentration will increase reaction rate. Decreased enzyme concentration will decrease reaction rate. Common sense really... Increasing substrate concentration will initially increase reaction rate. Substrate saturation will not result in continued increase in reaction rate. Reaction rate will remain constant if substance saturation levels are maintained. Competitive inhibitors can bind reversibly/irreversibly active sites, potentially altering reaction rate. Noncompetitive inhibitors can bind allosteric sites, decreasing the catalytic capability of enzymes.
Unit 5.1 Meiosis
Diploid cells have pairs of chromosomes (a full set), one from each parent, and are represented by 2n. Haploid cells have a single set of chromosomes, represented by n. The purpose of meiosis is to produce haploid gametes. Meiosis involves two rounds of cell division. In meiosis I, pairs of chromosomes separate, resulting in two haploid cells containing only one of the double chromosomes from each pair. In meiosis II, double chromosomes separate, resulting in four haploid cells, each with single chromosomes. Mitosis and meiosis are similar in the overall process (PMAT) of how genetic information is passed onto daughter cells. However, mitosis produces two genetically identical cells and meiosis produces four haploid genetically varied cells.
Unit 6.8 Biotechnology
Electrophoresis, PCR, bacterial transformation, and DNA sequencing are used to analyze of manipulate DNA and RNA Genetic engineering techniques can be used to amplify, modify, and compare samples of DNA and RNA
Unit 8.2 Energy Flow Through Ecosystems
Endotherms and ectotherms use different strategies to regulate body temperature and metabolism. Different organisms use various reproductive strategies in response to energy availability. There is a relationship between the metabolic rate per unit body mass and size of multicellular organisms, with generally the smaller the organism, the higher the metabolic rate. A net gain in energy results in energy storage or growth for an organism, while a net loss of energy results in loss of mass and ultimately the death of an organism. Changes in energy availability can result in changes in population size and disruption to an ecosystem. Autotrophs such as photosynthetic and chemosynthetic organisms capture energy from physical or chemical sources in the environment. Heterotrophs capture energy present in the carbon compounds produced by other organisms.
Unit 3.1 Enzyme Structure
Enzymes speed up biochemical reactions by lowering activation energy requirements. The structural characteristics of an enzyme make the enzyme very reaction specific. See above they all have a different shape like a key to a lock The shape and charge of the substrate must be compatible with the active site of the enzyme for a reaction to occur. Enzymes are not consumed by the reaction. Enzymes are reused
Unit 2.10 Cell Compartmentalization
Eukaryotic cells contain various membrane-bound organelles including, but not limited to; the ER, Golgi complex, lysosomes, mitochondria, and chloroplasts. These structures compartmentalize intracellular processes and enzymatic reactions increasing the efficiency of cellular function. Internal membranes facilitate cellular processes by minimizing competing interactions and by increasing surface areas where reactions can occur. Loss of these intracellular compartments or changes to the unique internal surfaces and environments within membrane-bound organelles may hinder proper cell function.
Unit 7.8 Continuing Evolution
Evidence of genomic changes within a population over time provides evidence that all life has evolved and continues to evolve The evolution of resistance to antibiotics, pesticides, herbicides, and chemotherapy drugs leads to a species' evolution As pathogens evolve, the phenotypes selected for and against in host populations can change over time.
Unit 7.11 Extinction
Evolution can be rapid during periods of ecological stress Extinction rates can be rapid during times of ecological stress Speciation and extinction rates can increase or decrease species diversity Extinction creates open niches for other species to exploit
Unit 7.4 Population Genetics
Evolution is driven by random occurrences. Mutation is a random process that results in genetic variation, which provides phenotypes on which natural selection acts and contributes to evolution Genetic drift is a nonselective process occuring in small populations through bottleneck and founder effects. The reduction of genetic variation within a given population can increase the differences between populations of the same species.
Unit 2.8 Tonicity and Osmoregulation: Part 1
External environments can be hypotonic, hypertonic or isotonic to the internal environment of cells. Water moves by osmosis from areas of low osmolarity/solute concentration to areas of high osmolarity/solute concentration. Growth and homeostasis are maintained by the constant movement of molecules across membranes. Osmoregulation maintains water balance and allows organisms to control their internal solute composition.
Unit 4.5 Feedback
Feedback mechanisms are processes used to main homeostasis by increasing or decreasing a cellular response to an event. Negative feedback mechanisms maintain homeostasis for a particular condition by regulating physiological processes. Positive feedback mechanisms amplify responses and processes in biological organisms.
Unit 3.7 Fitness
Fitness, on an organism level, refers to the ability to survive and reproduce. Variation at the molecular level provides organisms with fitness advantages under changing environment conditions.
Unit 6.5 Regulation of Gene Expression
Gene expression is the process by which instructions in the DNA are transcribed and translated into a functional protein. Gene expression is regulated by interactions between regulatory proteins and regulatory sequences, due to the presence of certain transcription factors, or due to modifications of DNA or histones. Epigenetics are reversible modifications of DNA or histones which help regulate gene expression. The phenotype of a cell or organism is determined by the combination of genes that are expressed Structural proteins with related functions are typically encoded together in the genome Operons are closely linked genes that produce a single mRNA molecule in transcription The lac operon is considered inducible because it is usually turned off
Unit 6.3 Transcription and RNA Processing
Genetic information flows from DNA to RNA to protein. Transcription is the process by which RNA polymerase uses the noncoding strand of DNA as a template to produce an mRNA molecule. RNA polymerase synthesizes mRNA in the 5' to 3' direction while reading DNA in the 3' to 5' direction There are three types of RNA molecules, each with their own structure accounting for the difference in function mRNA - carries copy of gene to ribosomes tRNA - is recruited to the ribosome in order to build the primary amino acid sequence (polypeptide) dictated by the mRNA sequence rRNA - the functional building block of ribosomes responsible for protein assembly Addition of a poly-A tail, addition of a GTP cap, excision of introns, splicing, and retention of exons are examples of enzyme-regulated modifications to mRNA. Alternative splicing is when introns are exercised from a primary mRNA transcript and exons are retained and joined together Different combinations of exons can be retained in a mature mRNA transcript. Different exon combinations encode for different proteins
7.13 Origins of Life on Earth
Geological evidence provides support for models of the origin of life on Earth Models for the origin of life indicate that life was extraterrestrial or early Earth atmospheric conditions were ideal for forming monomers for life. The RNA World Hypothesis proposed that RNA could have been the earliest genetic molecule
Unit 7.5 Hardy-Weinberg Equilibrium
Hardy-Weinberg is a model for describing and predicting allele frequencies in a non-evolving population The conditions for a population to be in Hardy-Weinberg equilibrium are a large population size, absence of migration, no net mutations, random mating and absence of selection The allele and genotype frequencies can be calculated using the Hardy-Weinberg equation where p and q represent the alleles and p^2,2pq, and q^2 represent the genotypes Changes in allele frequencies provide evidence for the occurrences of evolution in a population A population can evolve if the conditions of Hardy-Weinberg are not met with small populations being more susceptible to random environment impact than larger populations
Extra Motivation/Tips
Hit easiest ones first and bs the hard ones. NEVER leave an frq blank, there is always an opportunity for bs´ing (Yeah but BS with all the facts you know) The hard ones are fs gonna be the first two, usually b.) is worth the most points. If it says list two, list best two, and no more Write in essay form!! You can use a) and b) and stuff, but dont bc college board, they can search for the answer. Don't use "proves", and don't treat it like ap lang with using a bunch of fluff (thus, therefore, nevertheless bs) DONT RESTATE QUESTION but only if bs'ing (Restate the question helps) Use DRY MIX Line graph: measuring change over time Bar: comparing individuals with only one data point Scatter: two quantitative data points Pie: comparing percentages Remember Error Bars, if they overlap, no significant change Null hypothesis: basically opposite of hypothesis i think, just saying the experiment didn't work and there were no significant results (The null hypothesis is that the change observed is random) "No experimental difference" "Treatment has no significant difference from control variable" Motivation, Tips, and Taking advantage of at-home testing: Make sure your cat is with you for emotional support Print off the formulas the ap bio graders allow you to have (i think its legal dw) Just remember all that comes from failing this exam is just a bit of saltiness and resentment, it could be a lot worse tbh (And time and money; totally not important) DON'T DAYDREAM "Whilst effort does not always bring success, there is no such thing as wasted effort"- Fujiwara Chika So answering is better than not adding info YOU WILL NOT lose points for giving wrong information *answering Living fully means accepting suffering (oh okay...) We are sacks of electric flesh on a floating rock, sharing the same sky. I'll probably be fine... You don't know everything but you know enough Take 5-10 second brain naps when needed Your gut choice is statistically more likely, so if you're guessing - why would you be guessing - go with the first choice The longest answer is sometimes the right one Also for multiple choice if there are multiple answers with the same varying answer pick the one you think works best. The extraneous is usually wrong.
Unit 2.1 Cell Structure - Subcellular Components
How do ribosomes reflect the common ancestry of all known life? All living cells contain a genome and ribosomes, reflecting the common ancestry of all known life. Structure and function of the following subcellular components and organelles: ribosomes, rough ER, smooth ER, golgi complex, mitochondria, lysosomes, a vacuole, and chloroplasts. Ribosomes synthesize protein according to mRNA sequence and the instructions that are encode in that mRNA sequence originate from the genome of the cell Ribosomes consist of two subunits that are NOT membrane enclosed Ribosomes synthesize protein according to the mRNA sequences Endoplasmic Reticulum (ER) is a network of membrane tubes within the cytoplasm of eukaryotic cells. Rough ER has little dots (ribosomes) attached to its membrane. Smooth ER is smooth. Golgi Complex is a series of flattened membrane-bound sacs found in eukaryotic cells. Involved in correct folding and chemical modification of newly synthesized proteins and packaging for protein trafficking. Mitochondria: has a double membrane. Outer membrane is smooth and inside forms folds called cristae. Lysosomes: Contain hydrolytic enzymes. These can be used to digest a variety of materials such as damaged cell parts or macromolecules. Vacuoles: Membrane-bound sacs found in eukaryotic cells. Store water and other macromolecules and release waste from a cell. Chloroplasts: Similar to mitochondria as they have a double outer membrane. They are specialized for capturing energy from the sun and producing sugar for the organism. Sun to Sugar Factory
Unit 2.2 Cell Structure and Function (A lot of this section is similar to 2.1 just explains more of the structures of the subcellular molecules)
How do subcellular components and organelles interact and contribute to the function of the cell? Chloroplasts: Specialized for photosynthesis and capturing energy from the sun to produce sugar. Within chloroplasts there are distinct compartments: Thylakoid: contain folded membrane compartments called grana. More folds=more efficient light reactions. Stroma: fluid between the inner chloroplast membrane and outside the thylakoids. The Calvin Benson cycle occurs here (carbon fixation). Mitochondria: double membrane provides compartments for different metabolic reactions. Capture energy from macromolecules. The Krebs cycle (citric acid cycle) reactions occur in the matrix (fluid part) of the mitochondria Electron transport and ATP synthesis occur in the inner mitochondrial membrane. (skin part) Folding of the inner membrane increases the surface area, which allows for more ATP to be made. Vacuoles: Play a variety of roles, storage and release of water, macromolecules and waste from a cell. Vacuoles aid in retention of water for turgor pressure. Turgor pressure is what forces water around a plant and is caused by water pushing up against the plasma membrane and cell wall. Lysosomes: Contain hydrolytic enzymes. These can be used to digest a variety of materials such as damaged cell parts or macromolecules. Endoplasmic Reticulum (ER) is a network of membrane tubes within the cytoplasm of eukaryotic cells. Provides mechanical support. Plays a role in intracellular transport. Rough ER has little dots (ribosomes) attached to its membrane. Carries out protein synthesis on ribosomes that are bound to its membrane. Smooth ER is smooth Amino acids are the building blocks of proteins!
Unit 7.3 Artificial Selection
Humans affect diversity within a population by breeding plants and animals and selecting for desirable traits. Convergent evolution is the process by which smaller environmental conditions select for similar traits in different populations or different species over time. Environmental changes can lead to similar evolutionary changes across different populations or species due to similar selective pressures.
Glycolysis
In glycolysis, glucose and glycerol are metabolized to pyruvate. Glycolysis generates two equivalents of ATP through substrate phosphorylation catalyzed by two enzymes, PGK and pyruvate kinase. Two equivalents of NADH are also produced, which can be oxidized via the electron transport chain and result in the generation of additional ATP by ATP synthase. The pyruvate generated as an end-product of glycolysis is a substrate for the Krebs Cycle.
Beta-Oxidation
In the presence of air and various cofactors and enzymes, fatty acids are converted to acetyl-CoA. The pathway is called beta-oxidation. Each cycle of beta-oxidation shortens the fatty acid chain by two carbon atoms and produces one equivalent each of acetyl-CoA, NADH, and FADH2. The acetyl-CoA is metabolized by the citric acid cycle to generate ATP, while the NADH and FADH2 are used by oxidative phosphorylation to generate ATP. Dozens of ATP equivalents are generated by the beta-oxidation of a single long acyl chain.
Unit 5.4 Non-Mendelian Genetics Part 2
Inheritance determined by multiple genes has a larger number of possible genotypes and a larger range of phenotypes possible compared to inheritance determined by a single gene. These traits do not segregate in Mendelian patterns. Non-nuclear inheritance seen in chloroplasts and mitochondria is maternally inherited. These traits do not segregate in Mendelian patterns.
Unit 5.4 Non-Mendelian Genetics Part 1
Linked genes are genes located on the same chromosome that are typically inherited together. Map distance tells you how close together a pair of linked genes is. The smaller the map distance, the closer together the genes are on the chromosome and the more likely those genes will be inherited together. Sex-linked traits are determined by genes located on sex chromosomes. Sex-linked traits differ from Mendelian traits because each parent does not contribute sex-linked alleles to every biological offspring, like with Mendelian inheritance; biological sex determine which sex-linked alles are inherited.
Unit 1.2 Elements of Life
Living systems need a constant input of energy to grow, reproduce and maintain organization. Atoms and molecules from the environment are necessary to build new molecules. Carbon is used to build all macromolecules, store energy and from cells. Nitrogen is used to build proteins and nucleic acids. Phosphorus is used to build nucleic acids and certain lipids.
Unit 3.4 Cellular Energy
Living things use the chemical energy stored in molecular bonds of macromolecules and ATP to perform necessary life functions. Pathways in biological systems are sequential to allow for a more controlled and efficient transfer of energy.
Unit 2.7 Facilitated Diffusion
Membrane proteins are required for facilitated diffusion of charged and large polar molecules through a membrane Large quantities of water pass through aquaporins. Membranes become polarized by movement of ions across the membrane Membrane proteins are necessary for active transport. Metabolic energy (such as from ATP) is required for active transport of molecules and/or ions across the membrane and to establish and maintain concentration gradients. The NA+/K+ ATPase contributes to the maintenance of the membrane potential.
Unit 7.7 Common Ancestry
Membrane-bound organelles, linear chromosomes, and introns provide evidence of common ancestry of all eukaryotes.
Unit 5.3 Mendelian Genetics Part 2
Mendel's law of segregation states that alleles are segregated into separate gametes during meiosis. Mendel's law of independent assortment states that genes are not linked. A monohybrid cross examines the inheritance of one trait and a dihybrid cross examines the inheritance of two traits. Understanding Mendel's laws allows for the application of mathematical calculations and laws of probability to predict genetic events. Pedigrees show inheritance patterns within families and can be used to predict inheritance of traits in subsequent generations.
Unit 7.6 Evidence for Evolution
Molecular, morphological, and genetic evidence from extant and extinct organisms add to the understanding of evolution Fossils can be dated by a variety of methods to prove evidence of evolution. For example, relative and radioactive dating techniques Morphological homologies provide evidence of shared common ancestry Many fundamental molecular and cellular features and processes are conserved across organisms. For example, similar genetic codes and processes that synthesize ATP. Structural and function evidence supports relatedness of organisms in all domains.
Unit 8.6 Biodiversity
Natural and artificial ecosystems with fewer component parts and with little diversity among the parts are often less resilient to changes in the environment. The long-term structure of an ecosystem can be stabilized with more diversity. Changes in diversity can cause short-term and long-term structural changes in a community. Keystone species, producers, and essential abiotic and biotic factors contribute to maintaining the diversity of an ecosystem. The effects of keystone species on the ecosystem are disproportionate relative to their abundance in the ecosystem, and when they are removed from the ecosystem, the ecosystem often collapses.
Unit 7.1 Introduction to Natural Selection
Natural selection is the process whereby organisms with adaptations suited for a particular environment will have a higher chance of survival. Natural selection is influenced by environment stability, genetic variation, adaptations, and fitness. Natural selection can result in an increase or decrease of a specific phenotypes within a population over time
Unit 1.4 Properties of Biological Macromolecules
Nucleotides can vary in the sugar and base components resulting in nucleic acids with different structure and function. The amino terminus and carboxyl terminus give amino acids directionally and determine how amino acids assemble into protein polymers. R group properties determine how amino acids interact within the polypeptide and determine the structure and function of the protein. Differences in the components of carbohydrate monomers determine how the monomers assemble into complex carbohydrates and determine function. Lipids are nonpolar macromolecules and differences in saturation determine the structure and function of lipids. Phospholipids contain polar regions that interact with other polar molecules and nonpolar regions.
Unit 8.1 Responses to the Environment
Organisms respond to changes in their environment to maintain homeostasis, which increases survivability. Organisms exchange information about changes in the environment with one another by using various communication mechanisms. Organisms have a variety of signaling behaviors that can help increase the survival chance of other members in the population, resulting in differential reproductive success. Animals use visual, audible, tactile, electrical, and chemical signals to indicate dominance, find food, establish territory, and ensure reproductive success. Natural selection favors innate and learned behaviors that increase survival and reproductive fitness. Cooperative behavior tends to increase the fitness of the individual and the survival of the population.
Unit 2.9 Mechanisms of Transport
Passive transport is the net movement of molecules from high concentration to low concentration without direct input of metabolic energy. Water is transported in small amounts across the membrane by simple diffusion and in large amounts via facilitated diffusion through aquaporins embedded in the membrane. Active transport requires the direct input of energy to move molecules form regions of low concentration to regions of high concentration Large molecules and large amounts of molecules are moved into the cell by endocytosis and out of the cell by exocytosis
Unit 2.6 Membrane Transport
Passive transport is the net movement of molecules from high concentration to low concentration without the direct input of metabolic energy Active transport requires the direct input of energy to move molecules for regions of low concentration to regions of high concentration The selective permeability of membranes allows for the formation of concentration gradients of solutes across the membrane In exocytosis the internal vesicles use energy to fuse with the plasma membrane and secrete large macromolecules out of the cell In endocytosis, the cell uses energy to take in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane.
Unit 5.5 Environmental Effects on Phenotype
Phenotypic plasticity is the ability of one genotype to produce more than one phenotype. The same genotype can result in multiple phenotypes due to changes in environmental conditions. Environmental factors can influence how genes are expressed. This leads to phenotypic plasticity.
Unit 7.2 Natural Selection
Phenotypic variation increases the probability a population will continue in unstable environments. Natural selection acts on phenotypic variation by selecting individuals with the most advantageous traits based on certain environmental conditions. Changes in environmental conditions can change which individuals in a population will be selected for or selected against Any phenotype that increases an organism's chances of survival and reproduction will significantly increase an organism's fitness and ultimately increase the fitness of the entire population.
Unit 2.4 Plasma Membrane
Phospholipids spontaneously form a bi-layer in an aqueous environment with hydrophilic phosphate regions oriented toward the aqueous external or internal environment and the hydrophobic fatty acid regions face each other within the interior of the membrane. Embedded proteins can be hydrophilic, with charge and polar side groups, and/or hydrophobic with nonpolar side groups. Embedded proteins have a variety of functions including transport, cell-to-cell recognition, enzyme activity, signal transduction, intercellular joining, and attachment to cytoskeleton and extracellular matrix. The Fluid Mosaic Model consists of a structural framework of phospholipid molecules that are embedded with proteins, steroids (such as cholesterol in eukaryotes), glycoproteins, and glycolipids that can flow around the surface of the cell within the membrane.
7.9 Phylogeny
Phylogenetic trees and cladograms are branching diagrams showing evolutionary relationships among species Phylogenetic trees and cladograms both show relationships between lineages, with phylogenetic trees showing the amount of change over time Traits that are gained or lost during evolution can be used to construct a phylogenetic tree or cladogram Shared, derived characteristics indicate common ancestry The out-group is a distantly related group that is used to show how the main group falls in the main tree of evolution Molecular data typically provide more accurate and reliable evidence than morphological traits when constructing phylogenetic trees and cladograms Phylogenetic trees and cladograms can be used to illustrate speciation that has occurred Phylogenetic trees and cladograms represent hypotheses that are constantly being revised based on evidence.
Unit 3.5 Photosynthesis
Plants and other autotrophs use pigments to trap light energy to make organic molecules. The pigments used in the light-dependent reactions help transform light energy into chemical energy. Is temporarily stored in the chemical bonds of carrier molecules called NADPH. The products of the light-dependent reactions are ATP and NADPH. ATP and NADPH are products that will be used in the Calvin cycle to produce carbohydrates.
Unit 8.3 Population Ecology
Populations comprise individual organisms of the same species that interact with one another and with the environment in complex ways. Population growth dynamics depend on several factors, including time, birth rate, death rate, and population size. Reproduction without constraints results in the exponential growth of a population.
Unit 7.12 Variations in Population
Populations with little genetic diversity are at risk of extinction Genetically diverse populations are more resilient to environmental perturbation because they are more likely to contain individuals who can withstand the environmental pressure. The selective pressures of the environment determine the individual's chance for survival
Unit 6.6 Gene Expression and Cell Specialization
Promoters are sequences upstream of the transcription start site where RNA polymerase and transcription factors bind to initiate transcription The interaction of promoters and other transcription factors helps determine phenotypic differences between tissues within an organism or between individual organisms Phenotypic differences in cells and organisms are due to the combination of genes that are expressed Negative regulatory molecules inhibit gene expression by binding to DNA and blocking transcription. Small RNA molecules can regulate gene expression post transcription by either blocking transcription or by breaking down mRNA
Unit 5.3 Mendelian Genetics Part 3
Scientists use hypothesis testing to determine if investigative results are due to the independent variable or due to chance. A chi-square goodness-of-fit test evaluates numerical data from two groups to determine if the observed results are significantly varied from the expected results. The steps of a chi-square goodness-of-fit test include establishing a question and hypothesis, determining the observed and expected values, calculating the chi-square value, identifying the critical value, and drawing a conclusion determining whether the null hypothesis should be rejected or if the data failed to reject the null.
Unit 5.3 Mendelian Genetics Part 1
Shared and conserved processes support the concept of common ancestry because fundamental features link organisms by lines of descent. Processes like cellular respiration and transmission of genetic information allow life to continue through generations.
Unit 7.10 Speciation
Speciation may occur when two populations become reproductively isolated from each other The biological species concept states that species can be defined as a group capable of interbreeding and exchanging genetic information to produce viable, fertile offspring. Punctuated equilibrium is when evolution occurs after a long period of stasis Gradualism is when evolution occurs when adaptations to new habitats result in phenotypic diversification, with the possibility of specification rates being rapid. Divergent evolution occurs when adaptations to new habitats result in phenotypic diversification, with the possibility of speciation rates being rapid Speciation may be sympatric, which occurs without geographic isolation, or allopatric, which occurs with geographic isolation. Both result in the diversity of life forms. Prezygotic and postzygotic mechanisms can maintain reproductive isolation and prevent gene flow between populations. This leads to speciation.
Unit 2.8 Tonicity and Osmoregulation: Part 2
The components of a graph include a title, correctly labeled axis with units, uniformed intervals, identifiable lines or bars, and trend lines. The graph type used is based on the type of data collected Graphs can be used to show trends over time, comparisons, distributions, correlations, variability in samples and relationships between variables.
Unit 4.3 Signal Transduction
The environment is not static and organisms need to respond to changes in the environment. The ability to respond to stimuli is characteristic of life and necessary for survival. Signal transduction pathways are used to influence cellular responses when the environment changes. Transduction pathways can regulate gene expression in response to changes in the environment or lead to apoptosis.
Unit 1.5 Structure and Function of Biological Macromolecules Part 1
The linear sequence of all nucleic acids is defined by the 3' hydroxyl and 5' phosphate of the sugar in the nucleotide. DNA is structured as an antiparallel double helix with two strands running in opposite 5'-3' directions. This allows for the two strands of DNA to be held together by hydrogen bonds between the base pairs. A-T held together by 2 hydrogen bonds; G-C held by 3. During DNA and RNA synthesis, nucleotides can only be covalently added to the 3' end of a growing nucleotide strand. Changes in the linear sequences of the nucleotide bases may lead to differences in the encoded biological information or the structural stability of the molecule.
Unit 4.6 Cell Cycle Part 1
The role of interphase is to allow newly divided cells the opportunity to grow, maintain normal cell function, and prepare for division. During interphase cells grow, replicate DNA, and prepare for division. Mitosis plays a role in growth, tissue repair, and asexual reproduction. During mitosis, genetic information is transferred. Cytokinesis ensures equal distribution of cytoplasm to daughter cells.
Unit 5.6 Chromosomal Inheritance Part 1
The segregation of parental alleles into gametes provides opportunity for more varied combinations of alleles when fertilization occurs. The assortment of genes independently into gametes provides more possible gene combinations when fertilization occurs. Nondisjunction if the failure of chromosomes to fully separate during the formation of gametes. This results in too many or too few chromosomes in the sex cells. Random fertilization leads to genetic variation in offspring of sexually reproducing organisms. Certain human genetic disorders can be attributed to chromosomal inheritance and can result in genetically varied offspring.
Unit 8.5 Community Ecology
The structure of a community is measured and described in terms of species composition and species diversity. Communities change over time depending on interactions between populations. Interactions among populations determine how they access energy and matter within a community. Relationships among interaction populations can be characterized by positive and negative effects and can be modeled. Competition, predation, and symbiosis, including parasitism, mutualism, and commensalism, can drive population dynamics. Cooperation or coordination between organisms, populations, and species can result in enhanced movement of, or access to, matter and energy.
Unit 2.5 Membrane Permeability
The structure of cell membranes results in selective permeability. Cell membranes separate the internal environment of the cell from the external environment Selective permeability is a direct consequence of membrane structure, as described by the fluid mosaic model. Small nonpolar molecules, including N2, O2, and CO2, freely pass across the membrane Hydrophilic substances, such as large polar molecules and ions, move across the membrane through embedded channels and transport proteins. Polar unchanged molecules, including H2O pass through the membrane in small amounts. Cell walls provide a structural boundary, as well as a permeability barrier for some substances to the internal environments. Cell walls of plants, prokaryotes, and fungi are composed of complex carbohydrates
Unit 3.2 Enzyme Catalysis
The two types of control groups are negative and positive control groups. Positive control groups are mainly used to confirm a known effect. Negative control groups are mainly used to confirm results in the absence of any kind of treatment. Results from control tests are used as a baseline data
Unit 6.4 Translation
Translation is the process of generating polypeptides using the information carried on an mRNA molecule. Translation occurs in three main steps: initiation, elongation, and termination. In prokaryotes, translation occurs while the mRNA is being transcribed For a retrovirus genome to be translated, viral RNA must be converted into viral DNA and then the viral DNA is integrated into the host genome. Reverse transcriptase is the viral enzyme that converts viral RNA into viral DNA The fact that nearly all organisms use the same genetic code is evidence of common ancestry of all living organisms. The salient features of translation include: rRNA in the ribosome interacts with a start codon of mRNA tRNA brings the correct amino acid to the correct place, as specified by the mRNA sequence. Each subsequent amino acid is added to the growing polypeptide chain until a stop codon is reached on the mRNA The polypeptide is released The primary molecules involved in translation are -mRNA -tRNA -rRNA -Amino acids
Unit 1.1 Properties of water and hydrogen bonding
Water contains 1 oxygen atom covalently bonded to 2 hydrogen atoms. Oxygen has a higher electronegativity compared to hydrogen resulting in a water molecule having polarity. Polarity allows molecules to form hydrogen bonds when oppositely charged regions of two molecules interact. The term cohesion refers to molecules of the same type forming hydrogen bonds with one another and adhesion refers to different types of molecules forming hydrogen bonds with one another. Living systems depend upon water's properties, like surface tension.
Unit 2.8 Tonicity and Osmoregulation: Part 3
Water moves by osmosis from areas of high water potential to areas of low water potential. Water moves by osmosis from areas of low solute potential to areas of high solute potential. Osmoregulation maintains water balance and allows organisms to control their internal solute composition/water potential.
Unit 2.3 Cell Size
Why are cells typically small? The larger the cell is the harder it is to move nutrients and waste in and out of them. Smaller cells typically have a higher surface area to volume ratio and are more efficient at exchanging materials with the environment. (Area is squared and volume is cubed) As cells increase in volume the relative surface area decreases making it difficult for larger cells to meet the demand for internal resources and remove waste sufficiently These limitations can restrict cell size and shape Surface area-to-volume ratio affects the ability of a biological system to obtain necessary resources, eliminate waste products, acquire and dissipate heat, and otherwise exchange chemicals and energy with the environment. How is the surface area to volume ratio calculated? (Area is squared and volume is cubed) Formulas can be found on the formula sheet. What are some examples of structural modifications of cells that increase surface area? The surface area of the plasma membrane must be large enough to adequately exchange materials. The larger a cell is the more complex the structures will have to be to adequately exchange materials with the environment. How does the surface area to volume ratio affect the ratio of heat exchange with the environment? How are specialized structures and strategies used by cells and organisms for the efficient exchange of molecules with the environment? Membrane folding is used to increase the surface area. Membrane folding increases the surface area, for example our digestion system. Villi are folds and microvilli are smaller folds. As cell volume increases or a cell becomes specialized for transport across its surface, structural modifications such as membrane folds are necessary to adequately exchange molecules form or into the environment As organisms increase in size, their surface area to volume ratio decreases making it harder to release heat energy and adaptations may improve an organism's efficiency in doing so Cells and organisms use specialized exchange surfaces.