Genetics Flashcards
Filial generation
Offspring of Parent generation
Parent generation
creator of offspring or starting point of experiment
Genes
unit of heredity passed to offspring. Contain alleles
True breeding
parents produce offspring that carry the same phenotype.
Purebred
all ancestors of the offspring will have the same phenotype
Hybrid
offspring of 2 different varieties
Alleles
alternative forms of a gene (Ex: AA and aa)
Multiple alleles
more than one allele for a trait (Ex: blood; I^A and i and I^B)
Codominance
neither allele masks the other (both traits visible) Ex: speckled chickens
Incomplete dominance
neither trait is dominant, resulting in a blend (Ex: pink flowers from red and white ones because both allele is equally present)
Complete dominance
one allele completely masks the other
Law of Independent Assortment
The inheritance of alleles for one trait does not affect the inheritance of another trait
Dihybrid cross
a cross between the alleles of 2 different traits (16 squares instead of 4)
Recessive
overpowered, latent trait
Inheritance
the transmission of traits from parents to offspring
Monohybrid cross
A cross studying one trait (4 squares)
Genotype
allele combinations for offspring – genetic makeup
Phenotype
Physical representation of alleles
Punnett Square
Used to determine the outcomes of monohybrid and dihybrid crosses
Homozygous
the same gene in an allele (Ex: ii and AA)
Heterozygous
Different genes in an allele (Ex: Aa and Gg)
Law of Segregation
Inherited traits are determined by pairs of factors, which segregate in the gametes, with one in each gamete.
Principle of Dominance
When individuals with contrasting traits are crossed, the offspring will express only the dominant traits
Mendelian ratio
3:1 ratio of F2 generation. 9:3:3:1 for the dihybrid cross
Traits
distinct characteristics that make up an individual
Gametes
sex cells
Blending Theory of Inheritance
offspring were a blend of parental characteristics (19th century thought)
Charles Darwin
theorized offspring had variations of parental characteristics but could not explain heredity.
Gregor Mendel
Experimented with pea plants and found answers to how traits were inherited.
Latent characteristic
dormant characteristic
Homologous pair
2 sister chromatids
tetrad
2 homologous pairs (four chromosomes)
Microtubules
tiny hollow rods that make spindle fibres and centrioles
diploid
number of chromosomes in body cells (46)
haploid
number of chromosomes in a gamete (23)
Somatic cells
body cells
G1 phase
metabolic processes to prepare for synthesis
S phase
Synthesis. Duplication of DNA
G2 phase
cells prepare for division
G0 phase
rest phase that follows G1. Some cells do not replicate.
Interphase
Growth stage (G1, S, G2)
Cell cycle
Interphase and mitosis
Daughter cell
cell created through mitosis
spindle fibre
things that pull chromosomes during anaphase
Centriole
Where the spindle fibres come from during metaphase
Chromosome
sister chromatids or singular chromosome
Chromatid
Singular half of a sister chromosome
Cytokinesis
cytoplasm pinches in half after mitosis
Telophase 1 & 2
membranes are formed and division is complete
Anaphase 1 & 2
breaking apart and going to opposite poles (a for away)
Metaphase 1& 2
homologous pairs attach to spindle fibres and line up on the equatorial plate
Prophase 1
Chromatids pair up in their homologous pairs and perform crossing over. Nuclear membranes dissolve and spindle fibres form.
Prophase 2
Nuclear membranes dissolve and spindle fibres form
Prophase (Mitosis)
Chromatin condenses; nuclear membrane dissolves; centrioles migrate to opposite poles; spindle fibres start to form.
Mitosis
Prophase
Metaphase
Anaphase
Telophase
