DNA AND HEREDITY

• Genetics

  • Is the study of heredity and genes.
• Heredity

  •The passing of genes from parents to offspring
• DNA

  carries the genetic information of an organism.
• DNA

  plays a vital role in the transfer of genetic materials from parents to offspring.
• DNA is made from NUCLEOTIDES that have 3 parts:

  • 5 CARBON SUGAR (DEOXYRIBOSE)
  • PHOSPHATE GROUP
  • NITROGEN BASE
• 3 parts of a nucleotide:

  • phosphate
  • base
  • deoxyribose sugar
• DEOXYRIBOSE SUGAR

  • sugar comes from a ribose when it loses an oxygen atom
• PHOSPHATE GROUP

  • backbone of the DNA molecule
• NITROGEN BASE PAIRS

  • Consists of purines and pyrimidines
• PURINES

  • Guanine and Adenine
• PYRIMIDINES

  • Cytosine and Thymine
• CHROMOSOME

  • strand of DNA
• Genes

  • building blocks of heredity
  • chromosomes
  • units of info about heritable traits
  • segment of chromosomes
• Allele

  •Any alternative form of gene

  •Represents in Capital or lower case letter

  •Can be identical or non-identical
• Each strand has a complementary sequence of bases, with adenine always pairing with thymine and guanine always pairing with cytosine.
• DOMINANT

  •Trait that masks the presence of the other trait. (Capital letter)
• RECESSIVE

  •Traits that are being masked by the presence of other traits. (lower case letter)
• GENOTYPE

  •Refers to the particular alleles of an organism
• PHENOTYPE

  •Refers to the observable traits of an organism
• MENDELIAN GENETICS

  Law of dominance

  • This law means that one allele masks the effect or expression of the other allele.
• Law of Segregation

  •A parent who has TWO alleles for a gene can only pass on ONE allele or the other to each offspring
• Law of Independent Assortment

  •Two or more traits are inherited SEPARATELY from each other; they don’t always occur together.
• •Non-Mendelian genetics are basically any inheritance patterns that don’t follow one or more laws of Mendelian genetics. (not inheritance)
• NON-MENDELIAN INHERITANCE

  INCOMPLETE DOMINANCE

  •When two alleles are equally dominant, they interact to produce a NEW PHENOTYPE.
• INTERMEDIATE INHERITANCE

  Type of inheritance in which traits are passed from parent to offspring.
• CODOMINANCE

  is a form of dominance wherein the alleles of a gene pair in a HETEROZYGOTE are fully expressed
• Two types of chromosome

  • AUTOSOME
  • SEX CHROMOSOME
• sex-linked traits

  A gene present on one of the sex chromosomes (X or Y in mammals) is (blank) because its EXPRESSION DEPENDS ON THE SEXof the individual
• Color blindness and Hemophilia are linked to the X chromosome, Most common to male
• MULTIPLE ALLELES

  Are the DIFFERENT version of a trait that exist within a population.