Unit 3

Unit 3

1. CH 11: Sexual Reproduction and Meiosis

   • SEXUAL LIFE CYCLES
     • HAPLOID
       • HAPLOID CELLS
         • 1 copy of each chromosome
         • GAMETES
     • DIPLOID
       • DIPLOID CELLS
         • 2 copies of each chromosome
         • GERMLINE CELLS
           • undergo meiosis and reduce chromosome from 2n to 1n into gametes
         • ZYGOTE
           • undergoes mitosis to continue to produce diploid cell
           • to become a viable organism/offspring; needs to get bigger thru mitosis (growth)
       • in most animals diploid dominates
   • SEXUAL REPRODUCTION
     • meiosis and fertilization constitute a cycle of reproduction
     • inherit 23 chromosomes from both parents
       • MOTHER
         • MATERNAL HOMOLOGUE
         • EGG
         • XX
       • FATHER
         • PATERNAL HOMOLOGUE
         • SPERM
         • XY
           • male sperm determines gender of offspring
     • sperm and egg fuse for fertilization to take place resulting in a zygote
       • FERTILIZATION restores diploid # (1n plus 1n equals 2n)
   • MEIOSIS
     • 2 ROUNDS OF DIVISION
       • MEIOSIS I
         • PROPHASE I
           • chromosomes condense, nuclear envelope disappears, spindle apparatus forms, synapsis, crossing over
             • SYNAPIS
               • homologous chromosomes become closely associated
             • CROSSING OVER
               • genetic material exchange
                 • allows for genetic variety
         • METAPHASE I
           • chiasmata hold homologues together, homologues align at metaphase plate, spindles attach to homologues
         • ANAPHASE I
           • chiasmata break, chromosomes pulled to opposite poles (each pole has complete haploid), separates homologues
         • TELOPHASE I
           • nuclear envelope reforms, sister chromatids not identical (diversity)
       • MEIOSIS II
         • PROPHASE II
           • chromosomes
         • METAPHASE II
         • ANAPHASE II
         • TELOPHASE II
           • 4 daughter cells (1 copy of each chromosome)
     • ERRORS OF MEIOSIS
       • ANEUPLOID GAMETES
         • missing or extra chromosomes in gametes
       • NONDISJUNCTION
         • genetic disorder, too many or too less chromosomes
     • MEIOSIS FUNCTION
       • production of gametes
       • mitosis function is growth and repair
     • MEIOSIS FEATURES
       • (compare mitosis and meiosis)
       • synapsis + crossing over
       • sister chromatids joined in meiosis I
       • kinetochores of sister chromatids attach to same pole
       • DNA replicating suppressed
       • independent assortment
       • 2n to 1n
     • also referred to as REDUCTION DIVISION
       • chromosome #s reduce, divides cell into four daughter cells

2. CH 12: Patterns of Inheritance

   • PRINCIPLE OF INDEPENDENT ASSORTMENT
     • PRINCIPLE OF SEGREGATION
       • 2 alleles for a gene segregate during gamete formation (meiosis)
         • rejoined at random, one from each parent, during fertilization
     • in dihybrid cross, alleles for each gene assort differently
       • traits separate independently in gamete formation
   • EPIGENTICS
     • EPISTASIS
       • behaviour of gene products change ratio
     • how genes react w/ other molecules
   • POLYGENIC INHERITANCE
     • PLEIOTROPHY
       • GENE
         • ALLELE
           • DIHYBRID CROSS
             • MONOHYBRID CROSS
               • *punnet square
               • F1 GENERATION
                 • F2 GENERATION
                   • breed F1 offspring
                 • offspring in first cross
             • two traits; four outcomes ---> 16 outcomes
           • different forms of the same gene
         • segment of DNA found on chromosome, codes for protein
     • DOMINANT
       • INCOMPLETE DOMINANCE
         • CODOMINANCE
           • heterozygote shows both traits (co means with)
           • RECESSIVE
             • masked by dominant allele
             • HOMOZYGOUS RECESSIVE
               • HOMOZYGOUS DOMINANT
                 • HETEROZYGOUS
                   • GENOTYPE
                     • PHENOTYPE
                       • physical characteristic
                     • genetic makeup
         • blend, alleles do not mask eachother
       • dominant allele masks recessive allele

3. CH 13: Chromosomes, Mapping, and the Meiosis-Inheritance Connection

   • SEX LINKAGES
     • sex linked conditions reside on X or Y chromosome
     • certain genetic disease affect males to a greater degree than females
   • X CHROMOSOME
     • is larger than Y chromosome
     • more sex linked conditions because it's bigger
     • in FEMALES, one X chromosome is inactivated
     • carries essential genes
   • GENETIC MOSAICS
   • Y CHROMOSOME
     • smaller than X chromosome, not a lot of info
   • CHROMOSOME THEORY EXCEPTIONS
   • GENOMIC IMPRINTING
     • "Which parent contributed the alleles?"

4. CH 14: DNA: The Genetic Material

   • DNA STRUCTURE
     • DNA is a nucleic acid
       • nucleic acid is made up of NUCLEOTIDES
         • NUCLEOTIDES
           • are made up of:
             • DEOXYRIBOSE
             • PHOSPHATE GROUP
             • NITROGENOUS BASE
               • PURINES
                 • Adenine and Guanine
               • PYRIMIDINES
                 • Thymine and Cytosine
                 • Uracil (RNA)
               • COMPLEMENTARY BASE PAIRING
                 • A to T
                   • AMOUNT OF A = AMOUNT OF T
                 • G to C
                   • AMOUNT OF G = AMOUNT OF C
               • HYDROGEN BONDS joins nitrogenous bases
                 • "easy to make, easy to break"
         • PHOSPHODIESTER BONDS
           • joins two nucleotides
     • DNA is a double stranded molecule
       • "COOLING STRAND"
       • "TEMPLATE STRAND"
         • *template means pattern
         • used to make mRNA
   • CELLS REPLICATE DNA TO REPRODUCE
     • DNA is replicated during SYNTHESIS
   • DNA is made in 5 PRIME TO 3 PRIME direction
   • DNA POLYMERASE
     • ENZYMES RESPONSIBLE FOR MAKING DNA

5. CH 15: Genes and How They Work

   • CENTRAL DOGMA OF BIOLOGY
     • information flows in one direction
       • DNA ---> RNA
       • RNA ---> PROTEIN
     • EXCEPTION:
       • RETROVIRUSES use the enzyme, REVERSE TRANSCRIPTASE to convert RNA to DNA
   • PROTEIN SYNTHESIS
     • TRANSCRIPTION
       • RNA POLYMERASE
         • used to make RNA
           • NOT a good proofreader
     • TRANSLATION
       • tRNA, TRANSFER RNA, transfers amino acids to ribosomes
         • RIBOSOMES: site of protein synthesis
           • ribosomes are made of two subunits
         • peptide bond forms between amino acids on protein
     • IMPORTANT FOR PROTEIN SYNTHESIS:
       • mRNA
       • tRNA
       • rRNA
   • DIFFERENCES IN RNA AND DNA
     • RNA
       • single stranded
         • A-U
           • ribose
     • DNA
       • double stranded
         • A-T
           • deoxyribose
   • CODONS
     • STOP CODONS
       • terminates translation; stops process
         • UUA, UGA, UAG
     • START CODONS
       • start of translation
         • AUG
     • a codon is 3 NUCLEOTIDES in a row
       • code is degenerate; multiple codons code for the same amino acid
     • "WOBBLE EFFECT"
       • mutation of the third nucleotide does not affect amino acid
   • MUTATIONS
     • POINT MUTATION
       • alters a single base, can be SPONTANEOUS or INDUCED
         • SPONTANEOUS MUTATIONS
           • cause: DNA polymerase proofreads incorrectly
         • INDUCED MUTATIONS
           • cause: radiation, chemicals
     • FRAMESHIFT MUTATION
       • more profound effects than point mutation
         • changes reading frame
           • the addition or deletion of a base
       • TRIPLET REPEAT EXPANSION MUTATION
     • CHROMOSOMAL MUTATIONS
       • changes structure
         • DELETION
           • genes deleted from chromosome, chromosome lacks gene
           • DUPLICATION
             • INVERSION
               • genes become inverted (flip-flopped)
               • RECIPROCAL TRANSLOCATION
                 • moving genes from one place to another
             • genes duplicated, multiple copies of genes on chromosome

6. EUKARYOTES

   • DNA in EUKARYOTES is LINEAR
   • PLANTS, ANIMALS, FUNGI, AND PROTISTS

7. PROKARYOTES

   • DNA in PROKARYOTES is CIRCULAR
   • BACTERIA and ARCHEA

8. SICKLE CELL DISEASE

   • single point mutation of one base
     • causes red blood cell to take on a sickle shape
       • spleen filters out sickle shaped red blood cells
         • person does not have enough red blood cells to carry oxygen to cells
           • person gets anemia, anemic people are tired

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