unit 5: Heredity

Genes

• segments of DNA that code for the basic units of heredity and are transmitted from one generation to the next

• gametes

• reproductive cells that pass genes from one generation to the next

locus

• spot of the gene on a chromosome

asexual reproduction

• a single parent passes copies of all its genes to its offspring

• new offspring arise by mitosis and have copies of parents genome

• eventually becomes a clone

somatic cells

• regular cells that are part of the body

• Not sex cells

homologous chromosomes

• pairs of similar (not identical) chromosomes

• like yk how theres 2 sticks in chromosome 1 space

• one from mom, one from dad

• both chromosomes code for the same thing but the actual genes can be different

autosomes

• non sex chromosomes

sex chromosomes

• x and y

meiosis

• make gametes from a somatic cell

• Interphase

• Meiosis I - chromosome number split in half

  • Prophase I

    • Chromosomes condense, sister chromatids attached at centromeres

    • snapsis occurs

      • Joining of homologous chromosomes along their length

      • This allows for crossing over to occur

      • Ciasmata

        • crisscrossed regions`

  • Metaphase I

    • homologous chromosomes line up on the metaphase plate

  • Anaphase I

    • Homologous pairs separate ad move torwords poles

  • Telophase I

    • Homologous chromosomes reach opposite poles and cytokinesis takes place

• Meiosis II

  • Propahase II

    • Sister chromatids go to metaphase plate

  • Metaphase II

    • On metaphase plate

  • Anaphase

    • Split

  • Telopjase

    • Reachs opposite ends and cytokinesis takes place

genetic variation in sexual life cycles is due to what?

• Crossing over

• Random fertilization

• Random/independent assortment

rule of multiplication

• when calculating the probability that two or more independent events will occur toegther in a specific combination, multiply the probabilities

Rule of addition

• WHen calculating the probability of any of two or more mutally exculusive events you add for probability

Complete dominance

• dominance in which the hetrozygote and homozygote for the dominant allele are indistinguishable

Incomplete dominance

• Where they look in between two parents

• white + red = pink

Codominance

• Spots or shared

• Blood

multiple alleles

• blood type

• genes can be in more than 2 alleles

polygenic inheritance

• Two or more genes have an additive effect on a single phenotype

Chromosome theory of inheritance

• states that genes have specific locations on chromosomes and that it is chromosomes that segregate and assort independently