AP Biology Exam Review

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AP Biology Exam Review

• Heredity and Evolution 25

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Heredity and Evolution

• Heredity 8
• Molecular Genetics 9
• Evolutionary Biology 8

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Heredity

• Meiosis and gametogenesis
• Eukaryotic chromosomes
• Inheritance patterns

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Asexual vs. Sexual Reproduction

• Asexual reproduction binary fission,
  regeneration, vegetative propagation, budding
• Sexual reproduction result of gametic fusion,
  gametes formed from meiosis, promotes genetic
  recombination (variety)
• Meiosis process of gametic nuclear transfer

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Sexual life cycles

• Remember Asexual life cycles do not require the
  fusion (fertilization) of sperm and egg.

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Meiosis overview

• Each normal 2N (diploid) cell has 2 sets of
  chromosomes, one from each gamete.
• Gametogenesis specialized cells (spermatocyte,
  oocyte) undergoing meiosis to produce gametes
  with some combination of the 2 chromosome sets

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Important vocabulary

• Homologous chromosomes pair of like chromosomes,
  having similar length, centromere position, gene
  loci
• Linkage group genes that are linked on the same
  chromosome (linked loci)
• Locus (pl. loci) site on chromosome where gene
  is located on the chromosome

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Meiosis
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Meiosis
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Crossing over

• Genetic variation in meiosis result of crossing
  over when chromosomes aligned in tetrad formation
• Breaks linkage groups (genes found on the same
  chromosome)

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Oogenesis
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Spermatogenesis
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Pine life cycle
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Eukaryotic chromosome
Allele alternative form of the same
genes Chromosome condensed double helix (DNA)
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EukaryoticDNA packing

• Nucleosomes beads on a string (beads
  histones)
• Chromatin condensed nucleosomes
• Looped chromatin on protein scaffolding
• Chromosomes

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Mendels work

• Law of independent assortment
• Law of segregation
• Dominant vs. recessive phenotype
• Used peas because of fast generations, easily
  recognizable characteristics, two alleles

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Inheritance patterns

• Mendelian inheritance AA Aa dominant
  phenotype aa recessive phenotype
• Codominance Aa shows both A and a equally

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Incomplete dominance

• Intermediate inheritance
• AA dominant
• Aa half way between AA and aa
• aa recessive phenotype

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Inheritance patterns

• Hybrid mixed genes between two species
• Pleiotropy ability of one gene to affect many
  different genes

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Epistasis

• Expression of one gene determines the expression
  of another gene

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Polygenic inheritance

• Many genes affecting a phenotype
• Leading to many possible phenotypes of a trait

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Multiple alleles
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Test cross

• If Mendelian inheritance, AA and Aa genotypes are
  indistinguishable.
• Crossing dominant phenotype with aa. 100
  dominant PP 11 Pp

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Sex-linked

• Sex-linked gene loci on sex chromosome (X or
  Y)Ex hemophilia, color blindness
• First discovered in 1910 by Thomas Hunt Morgan
• Autosomal gene loci on non-sex chromosome

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Sex linkage

• Look for inheritance patterns that deviate from
  31 or 11.
• Also look for disorders affecting mostly males.

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Recombination frequencies
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X-inactivation Barr bodies
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Nondisjunction
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Nondisjunction disorders
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Human pedigrees

• Square male
• Circle female
• Colored in affected

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Molecular Genetics 9

• RNA and DNA structure and function
• Gene regulation
• Mutation
• Viral structure and replication
• Nucleic acid technology and application

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DNA structure

• Nucleotide nitrogen base, deoxyribose sugar,
  phosphate group
• Nitrogen bases adenine, thymine, cytosine,
  guanine
• Joined 5 3 (phosphodiester bonds)
• Sugar-phosphate backbone

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RNA structure

• Nucleotide nitrogen base, ribose, phosphate
  group
• Nitrogen bases uracil, adenine, guanine,
  cytosine
• Single stranded
• Joined 5-3
• In eukaryotes RNA produced in nucleolus of
  nucleus.
• tRNA, rRNA, mRNA

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Griffith experiment
Avery did a follow-up experiment and coined
transformation.
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Phage
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Hershey and Chase
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DNA replication models
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Meselson and Stahl
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Origin of replication
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DNA elongation
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DNA synthesis

• Leading strand made continuously
• Lagging strand Okazaki fragments

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DNA priming

• Necessary for starting DNA synthesis

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Okazaki fragments
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Telomeres

• Necessary to preserve DNA through successive
  rounds of DNA replication

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Controlling gene expression

• Gene expression transcription
• RNA transcript is translated into amino acid
  polymer.
• Operons are examples of prokaryotic gene
  expression control.
• Methylation is an example of eukaryotic gene
  expression control.

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One enzyme, one protein (controlling gene
expression)

• Beadle and Tatum

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Overview

• Transcription DNA ? RNA
• Translation RNA ? amino acid polymer (peptide)

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Transcription

• Initiation
• Elongation
• Termination

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DNA ? RNA

• A ? U
• T ? A
• C ? G
• G ? C

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RNA processing

• Removing introns that interrupt the express-able
  code (exons)
• Also adding poly-A tail and 5-CAP

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tRNA

• tRNA charged with amino acid
• assists ribosomes with protein synthesis

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Translation - initiation
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Translation - elongation
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Translation - termination
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Point mutation

• Codon can be mutate due to substitution.

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Insertion deletion

• Frameshift mutation
• Mutation spontaneously occurs basis of
  variation in populations

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Viral reproduction

• Lytic vs. lysogenic life cycle
• Viruses are not cells.
• Viruses are particles of nucleic material and
  protein that requires host cells for
  reproduction.
• Bacteriophage viruses that infect bacteria

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Lytic life cycle
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Lysogenic life cycle
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HIV

• Retrovirus
• RNA nucleic acid
• Requires reverse transcriptase enzyme (RNA ? DNA)

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Bacterialreplication
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Using recombinant bacteria
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Transduction
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Plasmid biotechnology
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RecombinantDNA

• Restriction enzymes cut host DNA and gene of
  interest
• Sticky ends complementary (match), enabling
  recombination

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Genomiclibrary

• Having multiple copies of DNA or phage

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PCR

• Polymerase chain reaction heat, cool, add primer
  
• Forms cDNA (clonal DNA) library

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Gel electrophoresis
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RFLP cut sites in junk DNA

• Restriction fragment length polymorphism

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Southern blotting
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Sanger

• Method to deduce the DNA sequence that is unknown

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Gene therapy
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Phage as a vector
Transduction using virus as a means to transport
eukaryotic gene into bacteria