Notebook Check #8

Section 1 Vocabulary

Genetics: field of biology for understanding how characteristics from parents are in their offspring

Heredity: transmission of characteristics from parents to offspring

Trait: genetically determined variant of a characteristic

Pollination: pollen grains made in the male reproductive part of a flower is moved to the female reproductive part

Self-pollination: when pollen is transferred from a flower to another flower that’s on the same plant

Cross-pollination: when pollen is transferred from a flower to a flower of another plant

True-breeding: pure, traits they have when they self-pollenate

P generation: True breeding parents

F1 generation: offspring of P generation through cross

F2 generation: offspring of F1 generation through self-pollinating

Dominant: dominates the factor of the other trait in a pair

Recessive: a trait with no observable effect on an organism’s appearance when it is paired with a dominant trait

Law of Segregation: a pair of factors is separated during the formation of gametes

Law of Independent Assortment: factors separate independently of one another during the formation of gametes

Molecular Genetics: study of the structure and function of chromosomes and genes

Allele: two or more alternative forms of a gene

Section 2 Vocabulary

Genotype: organism’s genetic makeup

Phenotype: organism’s physical appearance

Homozygous: when both alleles of a pair are alike

Heterozygous: when both alleles of a pair are different

Probability: the likelihood that a specific event will occur

Monohybrid Cross: when one characteristic is tracked when crossing

Punnett Square: diagram used to predict the distribution of inherited traits

Genotypic Ratio: ratio of genotypes that appear in offspring

Phenotypic Ratio: ratio of phenotypes of offspring

Testcross: where an individual with an unknown genotype is crossed with a homozygous recessive individual

Complete Dominance: when one allele is completely dominant over the other

Incomplete Dominance: when the phenotype of a heterozygote is intermediate between phenotypes determined by the dominant and recessive traits

Codominance: both alleles are expressed in a heterozygous offspring

Dihybrid Cross: a cross in which two characteristics are tracked

Notes

Mendel saw a pattern when breeding the pea plants. When he breeded the P generation that was true breeded he saw that the F1 generation all had the dominant green color. When he breeded the F2 generation he saw that 3/4 of the generation had the dominant green gene and 1/4 had the recessive yellow gene.

The factors Mendel was referring to are now called alleles

Chromosome → threadlike structure made of DNA

Gene → segment of DNA on a chromosome that controls specific hereditary traits

Chromosomes come in 2 pairs = Genes come in 2 pairs

Capital letters= Dominant alleles

Lowercase letters= Recessive alleles

Genotype has alleles that the organism gets from its parents

Phenotype doesn’t always identify the genotype

Certain environmental factors can affect the phenotype

An organism can be homozygous dominant or recessive

Offsprings of a monohybrid cross are called monohybrids

With codominance, neither allele is dominant or recessive and they don’t blend into the phenotype

Predicting the results of a dihybrid is harder than predicting the results of a monohybrid because there are many possibilities

Powerpoint Notes

Genes are inherited from parent to offspring, not physical traits

Genes are passed to the next generation through reproductive cells

Genes have specific locations on a certain chromosome called locus

Asexual Reproduction: 1 parent, genetically identical

Sexual Reproduction: 2 parents, unique combination of genes from each parent

Somatic cells: any cell other than the gametes, has 23 pairs of chromosomes

Sex chromosomes are X and Y

Females: homologous pair (XX)

Males: heterologous pair (XY)

Only the 23rd chromosome determines sex

The other 22 chromosome pairs are called autosomes

The zygote makes somatic cells by mitosis and develops into an adult

At sexual maturity, ovaries and testes make haploid gametes

Gametes are the only human cells made by meiosis

Gametes are also the only haploid cells in animals

Gametes fuse to form a diploid zygote that divides bu mitosis to develop into a multicellular organism