Chapter 12 Intro to Genetics Biology

2/4/25

Chapter 12: Introduction to Genetics

• 12.4, 12.1, 12.2, 12.3

• 30 term crossword puzzle…… YIPEEE!!!! Kai yeah!

Homologous - term used to refer to chromosomes in which one set from the male parent and one set comes from the female parent

Diploid - term used to refer to a cell that contains two sets of homologous chromosomes 

Haploid - terms used to refer to a cell that contains only a single set of genes

Meiosis - process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

Tetrad - structure containing four chromatids that forms during meiosis

Crossing-over - process in which homologous chromosomes exchange portions of their chromatids during meiosis

Genetics - scientific study of heredity 

Fertilization - process in sexual reproduction in which male and female reproductive cells join to form a new cell

Trait - specific characteristics of an individual 

Hybrid - offspring of crosses between parents with different traits

Gene - sequence of DNA that codes for a protein and thus determine a trait; factor that is passed from parent to offspring

Allele - one of a number of different forms of a gene

Principle-of-dominance - Mendel’s second conclusion, which states that some alles are dominant and other recessive

Segregation - separation of alles during gamete formation

Gamate - sex cell

Probability - likelihood that particular event will occur

Homozygous - having two identical alles for a particular gene

Heterozygous - having two different alles for a particular gene

Phenotype - physical characteristics of an organism

Genotype - genetics makeup of an organism

Punnett-square - diagram that can be used to predict the genotype and phenotype combinations of a genetic cross

Independent assortment - one of Mendel’s principles that state that genes for different traits can be segregate independently during the formation of gamates

Incomplete-dominance - situation in which one allele is not completely dominant over another allele

Codominance - situation in which the phenotypes produced by both alleles are completely expressed

Multiple-alleles - a gene that has more than two alleles

Polygenic-trait - trait controlled by two or more genes

2/10/25

• New Seats

-Assessments

• Ch 11.1-11.3 Test

  • Returned Today

  • Will be entered into Blackboard tonight(?)

• 11.4 Quiz

  • Returned tomorrow

  • Entered tonight (?)

  • Now

    • 2 minutes consultation with partner

    • 10 points total….. Discuss the appropriate split…… no 5/5 and  5.1 / 4.9

-Ch 12 TEST - FRIDAY, 2/14/25

• 12.4 Thursday, 2/13^th

-MEIOSIS

• Purpose?

  • Sexual Reproduction 

    • Production of sex cells/gametes

      • Requires two ‘parental’ organisms

        • Fertilization = combination of egg & sperm

          • Haploid Egg(23) + Haploid Sperm(23) → Diploid Fertilized Egg (46) → Zygote → Blastocyst → Embryo → Fetus → Newborn

      • Not genetically identical - favors genetic diversity → adaptation(individual organisms) → (population) → evolution (species) 

      • Results in the formation of FOUR genetically unique cells

      • Each gamete contains ½ of the chromosomes #

      • Eggs - Oogenesis

      • Sperm - Spermatogenesis 

  • Multicellular organisms…… ALL (???)

  • Phases of MEIOSIS

    • PMAT(PMAT2)

      • Technically 8 phases – those phase that deal with nuclear contents/DNA/Chromosomes

    • (I)PMAT(C){PMAT2}(C)

      • Conceptual discussion……… 11 “phases”

      • Why only ONE (I)?

        • A 2nd (I) would negate the purpose of the process…. Reducing chromosome  # by 50%

    • Amoeba Sister Video

    • HW 

      • Re-read 12.4 & 12.1

      • Get tests signed by Parental Units(s)

2/11/25

-Hw Check

- 12.4,12.1,12.2,12.3

-Questions???

- Meiosis - Gametogenesis

• Process of creating gametes/sex cells

  • Egg-female - oogenesis

  • Sperm-male - spermatogenesis

• Reduce the genetic material by ½ 

  • Produces 4 haploid sex cells

    • Each is Genetically unique

      • Increases genetic diversity 

• Female genotype (genetic info related to a characteristic - sex)

  • XX

  • Secondary sex characteristics

    • Hormones - estrogen, progesterone, _testosterone

    • Period/Menstrual Cycle

      • The monthly release of 1 egg - ovary 

      • Are born with all the eggs they might need in life - “suspended” 

    • Body hair

    • Breasts development

    • Hips widens

• Male genotype

  • XY

• Secondary Sex Characteristics

  • Hormones - Testostrone, _{estrogen, progesterone}

  • Semen Production 

  • Body/Facial Hair 

  • Limited breast development 

  • Deep voice

  • More muscle development

  • Chest/shoulder widens

  • Testicles (aka “Balls”)