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Genetics Unit


Genetics Unit Cell Reproduction Asexual reproduction Binary fission Mitosis Sexual reproduction Meiosis Meiosis I, meiosis II gametes – PowerPoint PPT presentation

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Title: Genetics Unit

Genetics Unit Cell Reproduction
  • Asexual reproduction
  • Binary fission
  • Mitosis
  • Sexual reproduction
  • Meiosis
  • Meiosis I, meiosis II
  • gametes

Genetics Unit Chpt. 9Punnett Squares
  • Probability
  • Punnett square
  • Monohybrid, dihybrid
  • Dominant, recessive, homozygous, heterozygous
  • Incomplete, Co-dominant and x-linked traits

Genetics Unit Gregor Mendel
  • Father of modern genetics
  • 1st to apply mathematics of statistics to
    crosses, 1840s, Austria, monastery gardens
  • Genetics ? field of biology devoted to
    understanding HOW characteristics are transmitted
    from parents to offspring
  • Heredity ? the transmission of characteristics
    from parents to offspring

Mendels Laws
  1. Law of Segregation pair of factors is separated
    during the formation of gametes
  2. Law of Independent Assortment factors for
    different traits are distributed to gametes

Molecular Genetics
  • Molecular genetics ? is the study of the
    structure and the function of the chromosomes and
    the genes.
  • This would include mapping the genome, locating
    markers for diseases, making proteins and
    technology like cloning, genetic engineering and
    DNA fingerprinting.

Genetics Unit- Nucleic acids and protein
  • DNA organic compound made of repeating subunits
    called nucleotides.
  • A DNA nucleotide has three parts
  • Sugar (deoxyribose)
  • Phosphate group (PO4)
  • Nitrogen containing base (A,T,C,G)
  • Adenine, thymine, cytosine and guanine

Watson and Crick
  • James Watson and Francis Crick are the
    discoverers of the DNA double helix
  • 1953, Cambridge, England
  • Built a wooden model based on other research ,
    including x-ray crystallography
  • Other scientists involved where Rosalind
    Franklin, Linus Pauling, Maurice Wilkins

Complementary Base Pairing
  • Because of the exact shape and size of the DNA,
    the sugars and phosphates make the sides of the
    ladder and the nitogenous bases make the rungs.
  • A and G (purines) are larger than C and T
  • MUST PAIR UP with A-T and C-G so all rungs are
    the same length.
  • A-T and C-G are hydrogen bonds.

DNA Replication
  • During the S portion of interphase
  • All DNA is copied so there are 2 complete sets,
    one set for each new cell
  • p.188
  • DNA helix is untwisted by helicase enzyme
  • DNA polymerase enzymes add new bases
  • Get two identical strands of double helix

  • Change in the nucleotide sequence
  • 1 error per 100,000 bases, VERY accurate
  • Proof reading enzymes correct allowing for 1
    per billion nucleotide average
  • Changes can also be caused by mutagens like
    chemicals and radiation

  • Single stranded
  • Copies of DNA
  • Can leave nucleus
  • Takes DNA code to the ribosomes so that proteins
    can be manufactured
  • Contains the sugar ribose, and the bases A, C, G
    and U (uracil). There is no T in RNA

RNA Transcription
  • DNA is opened, only at the gene/region of
  • A copy is made by matching A-U and C-G
  • The mRNA (leaves) and the DNA reseals. Original
    DNA is intact, undiluted, unchanged and in the
  • RNA strand is EDITTED to delete unnecessary
    regions called introns and the good regions are
    spliced together (exons) and make the final mRNA

Types of RNA
  • mRNA messenger, carries DNA info from the
    nucleus to the cytoplasm
  • tRNA transfer (transport), short chain, highly
    folded, binds specific amino acids to the mRNA
  • rRNA ribosomal, most abundant version,
    ribosomes are made of protein and rRNA.

Translation of RNA into protein
  • protein synthesis
  • mRNA is read by the ribosome in chunks
  • Each region of 3 bases on the mRNA is called a
    codon (p.194)
  • Each codon signals a specific amino acid
  • If you put the right amino acids in the right
    order you have .. A protein.

  • Every thing, in every cell, is either made of a
    protein or run by a protein.
  • Functions of proteins include
  • muscle, structure, storage, immunity,
    identification, communication, and transport

Genetics Unit Chpt 11Gene Expression
  • Gene expression all genes are not on all the
    time. The process of turning on the right genes
    at the right time is gene expression
  • Genome complete set of genetic material for an

  • Found in bacteria cells very different
    machinery from our cells
  • Jacob and Monad
  • Operon structural genes promoter operater
  • Operons can
  • 1. repress protein production (repressor)
  • 2. activate protein production (inducer)

More Chpt. 11 vocabulary
  • Cell differentiation the development of cells
    that have specialized functions ( muscle, nerve,
    skin, etc.)
  • Morphogenesis the formation of an organism,
    getting the tissues and organs in the right
  • Homeotic genes regulatory genes that determine
    where anatomical features go

  • Malignant tumors are usually called cancer.
  • Tumor abnormal proliferation of cells,
    uncontrolled cell division
  • Benign tumor mass of cells
  • Malignant tumor uncontrolled cell division that
    invades and destroys healthy tissue
  • Metastasis spread of cancer to new sites

Cancer continued
  • Oncogenes genes that cause cancer, code for
    uncontrolled cell growth
  • Tumor suppressor genes code for proteins that
    prevented uncontrolled cell division.
  • Mutation of tumor suppressor genes cause a
    predisposition to cancers
  • Some cancers are now directly linked to viruses
    as their cause .
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