Anchor BIO.B.2.1 Compare Mendelian & non-Mendelian patterns of inheritance.

BIO.B.2.1.1 Describe and/or predict observed patterns of inheritance (i.e., dominant, recessive, co-dominance, incomplete dominance, sex-linked, polygenic, and multiple alleles).

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Complete Dominance – one allele in a gene pair is dominate over the other. Dominant alleles are expressed in a homozygous (TT) or heterozygous (Tt) individual. Recessive alleles are expressed only in homozygous (tt) individuals.

Codominant inheritance results in both of the alleles of the heterozygous condition being expressed equally in offspring.

Incomplete dominance inheritance results of a mixing of alleles in the heterozygous individual. (red flwr + white flwr pink flwr)

Sex-linked traits involve inheritance with the X or Y chromosomes (i.e. red-green colorblindness or hemophillia)

Polygenic traits are controlled by inheritance on many chromosomes and a graph of the population expression results in a “bell shaped curve”. (i.e. human height or skin color)

Multiple Alleles When three or more alleles for a trait exist within a interbreeding population (NOTE: individual can only have two for trait)

Anchor BIO.B.2.1 Compare Mendelian & non-Mendelian patterns of inheritance.

BIO.B.2.1.2 Describe processes that can alter composition or number of chromosomes (i.e., crossing-over, nondisjunction, duplication, translocation, deletion, insertion, & inversion).

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The crossing over of genetic material from one chromosome to its complementary partner of the homologous pair (from daddy’s chromosome to mommy’s) might happen due to synapsis into tetrads during Prophase I of meiosis.

Nondisjunction is the result of a lack of separation between homologous pairs of chromosomes (the tetrad) during meiosis 1 or the pairs of sister chromatids in meiosis 2. The result is gametes being produced without a reduction in chromosome number.

Nondisjunction in Meiosis 1

Nondisjunction in Meiosis 2

Deletion is the removal of a segment of chromosome.

Duplication is the copying of a segment of chromosome.

Inversion is the reversal of a segment of chromosome.

Translocation is the movement of a segment from one chromosome to another nonhomologous chromosome.

Types of DNA Mutations

Anchor BIO.B.2.2 Explain the process of protein synthesis (i.e., transcription,

translation, & protein modification).

BIO.B.2.2.1 Describe how the processes of transcription and translation are similar in all organisms.

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In the nucleus a segment of DNA which codes for a protein (a gene) is transcribed (copied) to form a segment of mRNA.

The transcribed mRNA strand moves to the ribosome where it is translated into a protein chain.

Anchor BIO.B.2.2 Explain the process of protein synthesis (i.e., transcription,

translation, & protein modification).

BIO.B.2.2.2 Describe the role of ribosomes, endoplasmic reticulum, Golgi apparatus, & nucleus in the production of specific types of proteins.

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Protein synthesis begins in the nucleus with the transcription of the DNA code to form a messenger RNA (mRNA) molecule. The mRNA leaves the nucleus and travels to a ribosome located in the cytoplasm. At the ribosome transfer RNA (tRNA) molecules match their triplet base anticodon with a 3 base segment of the mRNA codon. Attached to the tRNA molecules are amino acids, these amino acids are peptide bonded to amino acids on ajoining tRNA molecules forming a polypeptide molecule. The new polypeptide travels along the endoplasmic reticulum where additional polypeptide strands are incorporated into the developing protein molecule. At the Golgi apparatus (body) the protein is coated with lipids to form a vesicle for exocytosis out of the cell (secretion).

Anchor BIO.B.2.3 Explain how genetic information is expressed.

Point Frameshift

BIO.B.2.3.1 Describe how genetic mutations alter the DNA sequence and may or may not affect phenotype (e.g., silent, point, nonsense, frame-shift).

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THE BAD CAT ATE THE SAD RAT

POINT MUTATION: substitution of DNA base only affecting a single codon (may lead to successful “new trait”--evolution)

THE SAD CAT ATE THE MAD RAT

THE BAD CAT ATE THE SAD CAT FRAMESHIT MUTATION: deletion or insertion of DNA base causing

entire sequence of codons to shift ……(total disaster!)

THE ADC ATA TET HES ADR AT (deletion of “B”)

THE BTA DCA TAT ETH ESA DRA T (insertion of “T”)

A single substitution mutation (adenine is substituted for thymine) results in the substitution of the amino acid valanine for glutamine and a resulting defective mutant hemoglobin molecule.

Mutant cat

Anchor BIO.B.2.4 Apply scientific thinking,processes, tools, and technologies in the study of

genetics. BIO.B.2.4.1 Explain how

genetic engineering has impacted the fields of medicine, forensics, and agriculture (e.g., selective breeding, gene splicing, cloning, genetically modified organisms, gene therapy).

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Selective breeding is allowing individuals with the desired traits to breed. The desired traits change the phenotype (appearance) of the offspring over many generations of selection.

The processes of gene splicing, cloning, genetically modified organisms and gene therapy all involve the manipulation of a DNA sequence on the molecular level

Female

Cloning is used to make more transgenic animals exactly like the original. Clones are used in research because there are less variables to control—all individuals are genetically the same!

Anchor BIO.B.3.1 Explain the mechanisms ofevolution.

BIO.B.3.1.1 Explain how natural selection can impact allele frequencies of a population.

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Directional selection for an extreme phenotype (darker mice). The population becomes darker over time.

Disruptive selection against the medium phenotype (brown mice). Two populations of the extreme phenotype develop over time.

Stabilizing selection for the medium phenotype (brown mice survive).The population stays the same over time.

Anchor BIO.B.3.1 Explain the mechanisms ofevolution.

BIO.B.3.1.2 Describe the factors that can contribute to the development of new species (e.g., isolating mechanisms, genetic drift, founder effect, migration).

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Genetic Drift is the random selection of a set of alleles. Above the green bugs have been selected against by random walking in the grass and more brown bugs are left to pass on their brown alleles. The population has gone through a “genetic bottleneck” because there are less individuals left and less genetic diversity in the bug gene pool.

Migration of individuals from one population to another allows for new alleles to enter the population. If the new alleles are selected for (favored) then the allele frequency in the population will change over time and the population will be said to have evolved.

Anchor BIO.B.3.1 Explain the mechanisms ofevolution.

BIO.B.3.1.3 Explain how genetic mutations may result in genotypic and phenotypic variations within a population

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Before the pollution of the industrial revolution darkened the bark of trees, peppered moths with a light colored phenotype were camouflaged and had a selective advantage (photo on the left). After the bark was darkened by soot, the light moths were at a disadvantage and the dark moths survived to reproduce. The population of peppered moths became more dark.

Pre-Industrial (Light tree bark) Post-Industrial (Dark tree bark)

Anchor BIO.B.3.2 Analyze the sources ofevidence for biological evolution.

BIO.B.3.2.1 Interpret evidence supporting the theory of evolution (i.e., fossil, anatomical, physiological, embryological, biochemical, and universal genetic code).

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Volcanic activity, Plate tectonics, water/wind action

Erosion & Sediment Build up

Sedentary rock layers --build up & erosion(requires millions of yrs)

The Fossil Record --By comparing fossils from older rock layers with fossils from younger layers, scientists can see that life forms have changed over time.

Darwin decided that all Galápagos finches found on the different islands could have “descended with modification” from a common mainland ancestor based on anatomical similarities to each other. (also called Adaptive Radiation)

Homologous Body StructuresStructures that have different mature forms but develop from the same embryonic tissues are called homologous structures.

Body parts derived from common ancestry and have same basic structural shape

However, different environments caused functional changes in these body parts.

Results from Divergent Evolution

Different job, structurally similar

Comparative Anatomy of Homologous Body Parts

Comparative Anatomy of Analogous Body Parts

Body parts that have same basic functional shape due to similar environment

However, structurally different since organisms have no recent common ancestor.

Results from Convergent Evolution

Same job, structurally different

Similarities in EmbryologyThe early stages, or embryos, of many animals with backbones are very similar. The same groups of embryonic cells develop in the same order and in similar patterns to produce the tissues and organs of all vertebrates.

Molecular Comparison

• Genetic Code (based on mRNA) for protein synthesis is universal among all life

Molecular Comparison

• Amino acid sequences of a protein --fewer differences imply more recent ancestry (less mutations to gene have accumulated)

Examples: cytochrome C, hemoglobin, cilia