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- THE BIG PICTURE OF BIOLOGY
- BIG IDEA 1: EVOLUTION
- 1A: Evolution - Change in Genetic Makeup
- 1B: Evolution by Common Descent
- 1C: Life Continues to Evolve
- 1D: Theories of the History of Life
- BIG IDEA 2: ORGANISMS USE ENERGY AND MOLECULES TO GROW, REPRODUCE, AND MAINTAIN HOMEOSTASIS
- 2A: PHOTOSYNTHESIS, CELLULAR RESPIRATION, AND ENERGY
- 2B: CELL HOMEOSTASIS - CELL MEMBRANE PROCESSES
- 2.C: HOMEOSTASIS - POSITIVE AND NEGATIVE FEEDBACK
- 2.D: Growth and dynamic homeostasis of a biological system are influenced by changes in the system’s environment.
- 2.E: Many biological processes involved in growth, reproduction and dynamic homeostasis include temporal regulation and coordination.
- BIG IDEA 3: LIVING SYSTEMS STORE, RETRIEVE, TRANSMIT, AND RESPOND TO INFORMATION
- 3.A: DNA TRANSCRIPTION AND TRANSLATION
- 3.B: GENE REGULATION - TRANSCRIPTION AND TRANSLATION
- 3C: GENETIC MUTATIONS AND VIRUSES
- 3D: CELL COMMUNICATION AND SIGNAL TRANSDUCTION
- 3E: ANIMAL BEHAVIOR AND NERVOUS SYSTEM
- BIG IDEA 4: BIOLOGICAL SYSTEMS INTERACT IN COMPLEX WAYS
- 4A: BIOCHEMISTRY AND CELL BIOLOGY
- 4.B: Competition and cooperation are important aspects of biological systems.
- 4.C: Naturally occurring diversity among and between components within biological systems affects interactions with the environment.
- RESULTS AND RESOURCES
- AP BIO LABS: BIG IDEA 1 - EVOLUTION
- AP BIO LABS: BIG IDEA 2 -
- AP BIO LABS: BIG IDEA 3
- AP BIO LABS: BIG IDEA 4
Essential knowledge 3.A.1: DNA, and in some cases RNA, is the primary source of heritable information.
Genetic information is transmitted from one generation to the next through DNA or RNA.
Evidence of student learning is a demonstrated understanding of each of the following:
1. Genetic information is stored in and passed to subsequent generations through DNA molecules and, in some cases, RNA molecules.
2. Noneukaryotic organisms have circular chromosomes, while eukaryotic organisms have multiple linear chromosomes, although in biology there are exceptions to this rule.
3. Prokaryotes, viruses and eukaryotes can contain plasmids, which are small extra-chromosomal, double-stranded circular DNA molecules.
4. The proof that DNA is the carrier of genetic information involved a number of important historical experiments. These include:
i. Contributions of Watson, Crick, Wilkins, and Franklin on the structure of DNA
ii. Avery-MacLeod-McCarty experiments
iii. Hershey-Chase experiment
5. DNA replication ensures continuity of hereditary information.
i. Replication is a semiconservative process; that is, one strand serves as the template for a new, complementary strand.
ii. Replication requires DNA polymerase plus many other essential cellular enzymes, occurs bidirectionally, and differs in the production of the leading and lagging strands.
6. Genetic information in retroviruses is a special case and has an alternate flow of information: from RNA to DNA, made possible by reverse transcriptase, an enzyme that copies the viral RNA genome into DNA. This DNA integrates into the host genome and becomes transcribed and translated for the assembly of new viral progeny. [See also 3.C.3]
b. DNA and RNA molecules have structural similarities and differences that define function. [See also 4.A.1]
Evidence of student learning is a demonstrated understanding of each of the following:
1. Both have three components — sugar, phosphate and a nitrogenous base — which form nucleotide units that are connected by covalent bonds to form a linear molecule with 3' and 5' ends, with the nitrogenous bases perpendicular to the sugar-phosphate backbone.
2. The basic structural differences include:
i. DNA contains deoxyribose (RNA contains ribose).
ii. RNA contains uracil in lieu of thymine in DNA.
iii. DNA is usually double stranded, RNA is usually single stranded.
iv. The two DNA strands in double-stranded DNA are antiparallel in directionality.
3. Both DNA and RNA exhibit specific nucleotide base pairing that is conserved through evolution: adenine pairs with thymine or uracil (A-T or A-U) and cytosine pairs with guanine (C-G).
i. Purines (G and A) have a double ring structure.
ii. Pyrimidines (C, T and U) have a single ring structure.
4. The sequence of the RNA bases, together with the structure of the RNA molecule, determines RNA function.
i. mRNA carries information from the DNA to the ribosome.
ii. tRNA molecules bind specific amino acids and allow information in the mRNA to be translated to a linear peptide sequence.
iii. rRNA molecules are functional building blocks of ribosomes.
iv. The role of RNAi includes regulation of gene expression at the level of mRNA transcription.
c. Genetic information flows from a sequence of nucleotides in a gene to a sequence of amino acids in a protein.
Evidence of student learning is a demonstrated understanding of each of the following:
•Addition of a GTP cap
•Addition of a poly-A tail
•Excision of introns
3. Translation of the mRNA occurs in the cytoplasm on the ribosome.
4. In prokaryotic organisms, transcription is coupled to translation of the message. Translation involves energy and many steps, including initiation, elongation and termination.
The salient features include:
i. The mRNA interacts with the rRNA of the ribosome to initiate translation at the (start) codon.
ii. The sequence of nucleotides on the mRNA is read in triplets called codons.
iii. Each codon encodes a specific amino acid, which can be deduced by using a genetic code chart. Many amino acids have more than one codon.
4^3 = 64 COMBINATIONS of CODONS
iv. tRNA brings the correct amino acid to the correct place on the mRNA.
v. The amino acid is transferred to the growing peptide chain.
vi. The process continues along the mRNA until a “stop” codon is reached.
vii. The process terminates by release of the newly synthesized peptide/protein.
d. Phenotypes are determined through protein activities.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Enzymatic reactions
• Transport by proteins
• Synthesis
• Degradation
e. Genetic engineering techniques can manipulate the heritable information of DNA and, in special cases, RNA.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Electrophoresis
• Plasmid-based transformation
• Restriction enzyme analysis of DNA
• Polymerase Chain Reaction (PCR)
Illustrative examples of products of genetic engineering include:
• Genetically modified foods
• Transgenic animals
• Cloned animals
• Pharmaceuticals, such as human insulin or factor X
Evidence of student learning is a demonstrated understanding of each of the following:
1. Genetic information is stored in and passed to subsequent generations through DNA molecules and, in some cases, RNA molecules.
2. Noneukaryotic organisms have circular chromosomes, while eukaryotic organisms have multiple linear chromosomes, although in biology there are exceptions to this rule.
3. Prokaryotes, viruses and eukaryotes can contain plasmids, which are small extra-chromosomal, double-stranded circular DNA molecules.
4. The proof that DNA is the carrier of genetic information involved a number of important historical experiments. These include:
i. Contributions of Watson, Crick, Wilkins, and Franklin on the structure of DNA
ii. Avery-MacLeod-McCarty experiments
iii. Hershey-Chase experiment
5. DNA replication ensures continuity of hereditary information.
i. Replication is a semiconservative process; that is, one strand serves as the template for a new, complementary strand.
ii. Replication requires DNA polymerase plus many other essential cellular enzymes, occurs bidirectionally, and differs in the production of the leading and lagging strands.
6. Genetic information in retroviruses is a special case and has an alternate flow of information: from RNA to DNA, made possible by reverse transcriptase, an enzyme that copies the viral RNA genome into DNA. This DNA integrates into the host genome and becomes transcribed and translated for the assembly of new viral progeny. [See also 3.C.3]
b. DNA and RNA molecules have structural similarities and differences that define function. [See also 4.A.1]
Evidence of student learning is a demonstrated understanding of each of the following:
1. Both have three components — sugar, phosphate and a nitrogenous base — which form nucleotide units that are connected by covalent bonds to form a linear molecule with 3' and 5' ends, with the nitrogenous bases perpendicular to the sugar-phosphate backbone.
2. The basic structural differences include:
i. DNA contains deoxyribose (RNA contains ribose).
ii. RNA contains uracil in lieu of thymine in DNA.
iii. DNA is usually double stranded, RNA is usually single stranded.
iv. The two DNA strands in double-stranded DNA are antiparallel in directionality.
3. Both DNA and RNA exhibit specific nucleotide base pairing that is conserved through evolution: adenine pairs with thymine or uracil (A-T or A-U) and cytosine pairs with guanine (C-G).
i. Purines (G and A) have a double ring structure.
ii. Pyrimidines (C, T and U) have a single ring structure.
4. The sequence of the RNA bases, together with the structure of the RNA molecule, determines RNA function.
i. mRNA carries information from the DNA to the ribosome.
ii. tRNA molecules bind specific amino acids and allow information in the mRNA to be translated to a linear peptide sequence.
iii. rRNA molecules are functional building blocks of ribosomes.
iv. The role of RNAi includes regulation of gene expression at the level of mRNA transcription.
c. Genetic information flows from a sequence of nucleotides in a gene to a sequence of amino acids in a protein.
Evidence of student learning is a demonstrated understanding of each of the following:
- The enzyme RNA-polymerase reads the DNA molecule in the 3' to 5' direction and synthesizes complementary mRNA molecules that determine the order of amino acids in the polypeptide.
- In eukaryotic cells the mRNA transcript undergoes a series of enzyme-regulated modifications.
•Addition of a GTP cap
•Addition of a poly-A tail
•Excision of introns
3. Translation of the mRNA occurs in the cytoplasm on the ribosome.
4. In prokaryotic organisms, transcription is coupled to translation of the message. Translation involves energy and many steps, including initiation, elongation and termination.
The salient features include:
i. The mRNA interacts with the rRNA of the ribosome to initiate translation at the (start) codon.
ii. The sequence of nucleotides on the mRNA is read in triplets called codons.
iii. Each codon encodes a specific amino acid, which can be deduced by using a genetic code chart. Many amino acids have more than one codon.
4^3 = 64 COMBINATIONS of CODONS
iv. tRNA brings the correct amino acid to the correct place on the mRNA.
v. The amino acid is transferred to the growing peptide chain.
vi. The process continues along the mRNA until a “stop” codon is reached.
vii. The process terminates by release of the newly synthesized peptide/protein.
d. Phenotypes are determined through protein activities.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Enzymatic reactions
• Transport by proteins
• Synthesis
• Degradation
e. Genetic engineering techniques can manipulate the heritable information of DNA and, in special cases, RNA.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Electrophoresis
• Plasmid-based transformation
• Restriction enzyme analysis of DNA
• Polymerase Chain Reaction (PCR)
Illustrative examples of products of genetic engineering include:
• Genetically modified foods
• Transgenic animals
• Cloned animals
• Pharmaceuticals, such as human insulin or factor X
Essential knowledge 3.A.2: In eukaryotes, heritable information is passed to the next generation via processes that include the cell cycle and mitosis or meiosis plus fertilization.
A. The cell cycle is a complex set of stages that is highly regulated with checkpoints, which determine the ultimate fate of the cell.
Evidence of student learning is a demonstrated understanding of each of the following:
1. Interphase consists of three phases: growth (G1), synthesis of DNA (S), preparation for mitosis (G2).
2. The cell cycle is directed by internal controls or checkpoints. Internal and external signals provide stop-and-go signs at the checkpoints.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
3. Cyclins and cyclin-dependent kinases control the cell cycle.
4. Mitosis alternates with interphase in the cell cycle.
5. When a cell specializes, it often enters into a stage where it no longer divides, but it can reenter the cell cycle when given appropriate cues. Nondividing cells may exit the cell cycle; or hold at a particular stage in the cell cycle.
b. Mitosis passes a complete genome from the parent cell to daughter cells.
Evidence of student learning is a demonstrated understanding of each of the following:
c. Meiosis, a reduction division, followed by fertilization ensures genetic diversity in sexually reproducing organisms.
Evidence of student learning is a demonstrated understanding of each of the following:
5. Fertilization involves the fusion of two gametes, increases genetic variation in populations by providing for new combinations of genetic information in the zygote, and restores the diploid number of chromosomes.
Evidence of student learning is a demonstrated understanding of each of the following:
1. Interphase consists of three phases: growth (G1), synthesis of DNA (S), preparation for mitosis (G2).
2. The cell cycle is directed by internal controls or checkpoints. Internal and external signals provide stop-and-go signs at the checkpoints.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
- Mitosis-promoting factor (MPF)
- Action of platelet-derived growth factor (PDGF)
- Cancer results from disruptions in cell cycle control
3. Cyclins and cyclin-dependent kinases control the cell cycle.
4. Mitosis alternates with interphase in the cell cycle.
5. When a cell specializes, it often enters into a stage where it no longer divides, but it can reenter the cell cycle when given appropriate cues. Nondividing cells may exit the cell cycle; or hold at a particular stage in the cell cycle.
b. Mitosis passes a complete genome from the parent cell to daughter cells.
Evidence of student learning is a demonstrated understanding of each of the following:
- Mitosis occurs after DNA replication.
- Mitosis followed by cytokinesis produces two genetically identical daughter cells.
- Mitosis plays a role in growth, repair, and asexual reproduction
- Mitosis is a continuous process with observable structural features along the mitotic process. Evidence of student learning is demonstrated by knowing the order of the processes (replication, alignment, separation).
c. Meiosis, a reduction division, followed by fertilization ensures genetic diversity in sexually reproducing organisms.
Evidence of student learning is a demonstrated understanding of each of the following:
- Meiosis ensures that each gamete receives one complete haploid (1n) set of chromosomes.
- During meiosis, homologous chromosomes are paired, with one homologue originating from the maternal parent and the other from the paternal parent. Orientation of the chromosome pairs is random with respect to the cell poles.
- Separation of the homologous chromosomes ensures that each gamete receives a haploid (1n) set of chromosomes composed of both maternal and paternal chromosomes.
- During meiosis, homologous chromatids exchange genetic material via a process called “crossing over,” which increases genetic variation in the resultant gametes. [See also 3.C.2]
5. Fertilization involves the fusion of two gametes, increases genetic variation in populations by providing for new combinations of genetic information in the zygote, and restores the diploid number of chromosomes.
Essential knowledge 3.A.3:The chromosomal basis of inheritance provides an understanding of the pattern of passage (transmission) of genes from parent to offspring
a. Rules of probability can be applied to analyze passage of single gene traits from parent to offspring.
b. Segregation and independent assortment of chromosomes result in genetic variation.
Evidence of student learning is a demonstrated understanding of each of the following:
1. Segregation and independent assortment can be applied to genes that are on different chromosomes.
2. Genes that are adjacent and close to each other on the same chromosome tend to move as a unit; the probability that they will segregate as a unit is a function of the distance between them.
3. The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genes linked on the same homologous chromosome) can often be predicted from data that gives the parent genotype/ phenotype and/or the offspring phenotypes/genotypes.
c. Certain human genetic disorders can be attributed to the inheritance of single gene traits or specific chromosomal changes, such as nondisjunction.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Sickle cell anemia (heterozygote advantage)
• Tay-Sachs disease (brain protein formation)
• Huntington’s disease (autosomal dominant disorders)
• X-linked color blindness (X^n Y)
• Trisomy 21/Down syndrome (3 chromosomes)
• Klinefelter’s syndrome (XXY)
Many ethical, social and medical issues surround human genetic disorders.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Reproduction issues
• Civic issues such as ownership of genetic information, privacy, historical contexts, etc.
b. Segregation and independent assortment of chromosomes result in genetic variation.
Evidence of student learning is a demonstrated understanding of each of the following:
1. Segregation and independent assortment can be applied to genes that are on different chromosomes.
2. Genes that are adjacent and close to each other on the same chromosome tend to move as a unit; the probability that they will segregate as a unit is a function of the distance between them.
3. The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genes linked on the same homologous chromosome) can often be predicted from data that gives the parent genotype/ phenotype and/or the offspring phenotypes/genotypes.
c. Certain human genetic disorders can be attributed to the inheritance of single gene traits or specific chromosomal changes, such as nondisjunction.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Sickle cell anemia (heterozygote advantage)
• Tay-Sachs disease (brain protein formation)
• Huntington’s disease (autosomal dominant disorders)
• X-linked color blindness (X^n Y)
• Trisomy 21/Down syndrome (3 chromosomes)
• Klinefelter’s syndrome (XXY)
Many ethical, social and medical issues surround human genetic disorders.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Reproduction issues
• Civic issues such as ownership of genetic information, privacy, historical contexts, etc.
Essential knowledge 3.A.4:The inheritance pattern of many traits cannot be explained by simple Mendelian genetics.
a. Many traits are the product of multiple genes and/or physiological processes.
Evidence of student learning is a demonstrated understanding of the following:
1. Patterns of inheritance of many traits do not follow ratios predicted by Mendel’s laws and can be identified by quantitative analysis, where observed phenotypic ratios statistically differ from the predicted ratios.
b. Some traits are determined by genes on sex chromosomes.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Sex-linked genes reside on sex chromosomes (X in humans).
• In mammals and flies, the Y chromosome is very small and carries few genes.
• In mammals and flies, females are XX and males are XY; as such, X-linked recessive traits are always expressed in males.
• Some traits are sex limited, and expression depends on the sex of the individual, such as milk production in female mammals and pattern baldness in males.
c. Some traits result from nonnuclear inheritance.
Evidence of student learning is a demonstrated understanding of each of the following:
Evidence of student learning is a demonstrated understanding of the following:
1. Patterns of inheritance of many traits do not follow ratios predicted by Mendel’s laws and can be identified by quantitative analysis, where observed phenotypic ratios statistically differ from the predicted ratios.
b. Some traits are determined by genes on sex chromosomes.
To foster student understanding of this concept, instructors can choose an illustrative example such as:
• Sex-linked genes reside on sex chromosomes (X in humans).
• In mammals and flies, the Y chromosome is very small and carries few genes.
• In mammals and flies, females are XX and males are XY; as such, X-linked recessive traits are always expressed in males.
• Some traits are sex limited, and expression depends on the sex of the individual, such as milk production in female mammals and pattern baldness in males.
c. Some traits result from nonnuclear inheritance.
Evidence of student learning is a demonstrated understanding of each of the following:
- Chloroplasts and mitochondria are randomly assorted to gametes and daughter cells; thus, traits determined by chloroplast and mitochondrial DNA do not follow simple Mendelian rules.
- In animals, mitochondrial DNA is transmitted by the egg and not by sperm; as such, mitochondrial-determined traits are maternally (MOM) inherited.
