1. Fundamental life processes of plants and animals depend on a variety of chemical reactions that are carried out in specialized areas of the organism's cells. As a basis for understanding this concept, students know

• cells are enclosed within semi-permeable membranes that regulate their interaction with their surroundings
  
• enzymes are proteins and catalyze biochemical reactions without altering the reaction equilibrium. The activity of enzymes depends on the temperature, ionic conditions and pH of the surroundings
  
• how prokaryotic cells, eukaryotic cells (including those from plants and animals), and viruses differ incomplexity and general structure
  
• the Central Dogma of molecular biology outlines the flow of information from transcription of RNA in the nucleus to translation of proteins on ribosomes in the cytoplasm
  
• usable energy is captured from sunlight by chloroplasts, and stored via the synthesis of sugar from carbon dioxide.
  
• most macromolecules (polysaccharides, nucleic acids, proteins, lipids) in cells and organisms are synthesized from a small collection of simple precursors.

2. Mutation and sexual reproduction lead to genetic variation in a population. As a basis for understanding this concept, students know

• meiosis is an early step in sexual reproduction in which the pairs of chromosomes separate and segregate randomly during cell division to produce gametes containing one chromosome of each type
  
• only certain cells in a multicellular organism undergo meiosis
  
• how random chromosome segregation explains the probability that a particular allele will be in a gamete
  
• new combinations of alleles may be generated in a zygote through fusion of male and female gametes (fertilization).
  
• why approximately half of an individual's DNA sequence comes from each parent
  
• the role of chromosomes in determining an individual's sex
  
• how to predict possible combinations of alleles in a zygote from the genetic makeup of the parents.

3. A multicellular organism develops from a single zygote, and its phenotype depends on its genotype, which is established at fertilization. As a basis for understanding this concept, students know

• how to predict the probable outcome of phenotypes in a genetic cross from the genotypes of the parents and mode of inheritance (autosomal or X-linked, dominant or race
  
• the genetic basis for Mendel's laws of segregation and independent assortment.

4. Genes are a set of instructions, encoded in the DNA sequence of each organism that specify the sequence of amino acids in proteins characteristic of that organism. As a basis for understanding this concept, students know

• the general pathway by which ribosomes synthesize proteins, using the tRNAs to translate genetic information in mRNA
  
• how to apply the genetic coding rules to predict the sequence of amino acids from a sequence of codons in mRNA
  
• proteins can differ from one another in the number and sequence of amino acids.

5. The genetic composition of cells can be altered by incorporation of exogenous DNA into the cells. As a basis for understanding this concept, students know

• the general structures and functions of DNA, RNA, and protein.

6. Stability in an ecosystem is a balance between competing effects. As a basis for understanding this concept, students know:

• biodiversity is the sum total of different kinds of organisms, and is affected by alterations of habitats
  
• how water, carbon, and nitrogen cycle between abiotic resources and organic matter in the ecosystem and how oxygen cycles via photosynthesis and respiration
  
• a vital part of an ecosystem is the stability of its producers and decomposers
  
• at each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat and this can be represented in a food pyramid.

7. The frequency of an allele in a gene pool of a population depends on many factors, and may be stable or unstable over time. As a basis for understanding this concept, students know

• why natural selection acts on the phenotype rather than the genotype of an organism
  
• Variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions.

8. Evolution is the result of genetic changes that occur in constantly changing environments. As a basis for understanding this concept, students know

• how natural selection determines the differential survival of groups of organisms
  
• a great diversity of species increases the chance that at least some organisms survive large changes in the environment
  
• reproductive or geographic isolation affects speciation.

9. As a result of the coordinated structures and functions of organ systems, the internal environment of the human body and other living systems remains relatively stable (homeostatic), despite changes in the outside environment. As a basis for understanding this concept, students know

• how the complementary activity of major body systems provides cells with oxygen and nutrients, and removes toxic waste products such as carbon dioxide
  
• how the nervous system mediates communication between different parts of the body and interactions with the environment
  
• how feedback loops in the nervous and endocrine systems regulate conditions within the body.
  
• the functions of the nervous system, and the role of neurons in transmitting electrochemical impulses
  
• the roles of sensory neurons, interneurons, and motor neurons in sensation, thought, and response.

10. Organisms have a variety of mechanisms to combat disease. As a basis for understanding the human immune response, students know

• the role of the skin in providing nonspecific defenses against infection
  
• the role of antibodies in the body's response to infection
  
• how vaccination protects an individual from infectious diseases.