QUARTERLY # 3 - CHECK LIST
DNA
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Describe the 3 components of a nucleotide = deoxyribose sugar + phosphate + nitrogen base
Describe the structure of the DNA model  helix
Evaluate the contributions of:
Chargaff (N-base pairing rules_
Franklin & Wilkins (X-Ray photograph)
In helping Watson & Crick determine the double helix structure of DNA.
Relate the role of the complementary base-pairing rules to the structure of DNA = (C-G) and
(A-T) -- Purines(A/G) vs Pyrimidines (T/C)
Summarize the process the DNA Replication
1 - The 2 original strands separate with DNA Helicase at Replication Fork
2 - DNA Polymerase adds complementary nucleotides to each strand
3 - The 2 DNA molecules that form are identical to the original DNA
Describe how errors are corrected during DNA replication
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RNA - PROTEIN SYNTHESIS
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Proteins are made by decoding information on the DNA molecule/gene
Gene Expression  Genetic Code is nearly universal
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Compare the structure of RNA with DNA
Single Strand instead of double strand
Uracil (U) instead of T
- Transcription: transfers information from DNA  RNA
Summarize the process of Transcription (in Nucleus)
1 - RNA Polymerase binds and the 2 DNA strands unwind and separate
2 - Complementary RNA nucleotides are added  form mRNA strand
 mRNA carries instructions for making proteins from gene(Nucleus)
and delivers it to the site of translation (Ribosome)
- Translation: correct amino acids are joined to form a protein
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Relate the role of Triplet Codons/Anti Codons to the
sequence of Amino Acids that result after Translation
Summarize the process of Translation (at the Ribosome)
1 - The mRNA and tRNA bind together....methionine is start codon
2 - tRNA carrying the Amino Acids specified by codon /anticodon arrives
3 - Peptide bond forms between adjacent Amino Acids
4 - tRNA detaches and leaves Amino Acid behind
5 - Process is repeated until stop codon is reached
6 - Ribosome complex falls apart.....newly made Protein is released FOLDED  FUNCTION
DIAGRAMS
TRIPLET CODON CHART - EXAMPLE
- Prokaryotic and Eukaryotic cells are able to control which genes are
expressed and which are not....depending on the cell’s needs.
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Prokaryotes- Gene expression regulated by OPERONS.
Switched off when REPRESSOR Proteins block RNA polymerase from transcribing a gene.
- Eukaryotes - An ENHANCER must be activated for gene expression.
Transcription factors initiate transcription by binding Enhancers to RNA Polymerase
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Eukaryotic Genes - interrupted by:
segments of DNA that do not code for protein  INTRONS (cut out)
- segments of DNA that are expressed  EXONS (joinedtranslated)
- MUTATIONS - changes in DNA  AA sequence  Protein function
POINT MUTATIONS Substitution of a 1 /few nucleotide(s)
FRAMESHIFT MUTATION - Insertion/Deletion of a 1/more nucleotide(s) Gene read in wrong codon sequence
HEREDITY
-Heredity vs Genetics
- Mendel’s Experiments - contrasting traits in pea plants (P= parental generation)
1 trait shown in F1 generation  other trait appeared in F2 generation (3:1)
- Mendel’s Theory – 2 alleles/gene -- inherited from parents
Dominant = trait expressed (T) Recessive = not expressed (t)
Homozygous = (tt or TT)
Heterozygous = (Tt)
-Law of Segregation - 2 alleles for trait separate with gamete (egg/sperm) formation
-Law of Independent Assortment - 2 or more pairs of alleles separate independently
of one another during gamete formation
-Punnett Squares & Probabilities  Genetic crosses - prediction tools
Test Cross: To determine if dominant trait is heterozygous or homozygous
Monohybrid Cross (1 pair contrasting traits - Ex: Tt x TT)
Dihybrid Cross (2 pairs of contrasting traits - Ex: TtYy x TTYY)
Genotype = set of alleles/ gene combination (Tt)
Phenotype = observable expression of genotype - physical appearance of trait (Tall)
Pedigrees –– family history - inherited traits over many generations
O = female [] = male
- interpretation- trace genetic disorders
- Sex-Linked: Trait for gene carried by either male or female - usually X chromosome most recessive - (Ex: Hemophilia)
[Male= XY Female=XX]
-Patterns of Heredity - Phenotype influenced.
Polygenic Trait - Several genes on different chromosomes influence trait (Ex: Eye Color)
Incomplete Dominance - Display of intermediate trait (Ex: Pink Flowers)
Co-dominance - 2 dominant alleles expressed at same time (Ex: Roan Horse)
Multiple Alleles - 3 or more alleles control traits - individual can only have 2 alleles
(Ex: Blood Types: AO - BO - OO - AB)
(Rh+/Rh-)
Antigens vs Antibodies
Environmental Influence: temperature/pH (Ex: Artic Fox/ Hydrangea)
-Genetic Disorders: Sickle Cell - Tay Sachs - Cystic Fibrosis  Genetic Counseling
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GENE TECHNOLOGY
-Biotechnology:
-Genetic engineering (Ex: Insulin)
4 steps: 1 - DNA cut  restriction enzymes (“scissors”)  vector carries genes into new cell
 plasmids (circular DNA in bacteria)
2 - Gene Splicing/Recombinant DNA is produced DNA ligase (“glue”)
3 - Gene is cloned
4 - Cells screened  transcription/translation of gene  protein
-Electrophoresis: separation of DNA fragments  PCR  use in forensics  DNA Fingerprint
-Medicines - Vaccines - Gene Therapy - Agriculture (Genetically Modified Organism)
-Human Genome Project -map location of every gene on each chromosome
-Transgenic Animals - human proteins in milk of animals
- Cloning: Differentiated cells used  nucleus removed  next to mammary cell  electric shock  cell
division triggered  embryo implanted into surrogate mother  exact genetic copy (Ex: Dolly -sheep 1997)
[STEM cells= undifferentiated embryonic cells]