Genetic Terms Flashcards
Tetrads
2 homologous pairs joined together (4 chromatids, 2 centromeres)
Crossing Over
Chromosomes of the same type are lined up in Meiosis
Independent Assortment
The alleles of two (or more) different genes get sorted into gametes
independently of one another.
Nondisjunction
The failing of homologous chromosome or sister chromatids to separate
correctly in cell division.
Haploid Chromosome Number
The chromosome number of the gametes of a given species (every breed of a species has the same) Half the species diploid number
Diploid Chromosome Number
The chromosome number of somatic cells of a given species (every breed of a species has the same) is Twice the species haploid number.
Twisted Double Helix
Term used to describe DNA. The top and bottom are twisted in different directions
James Watson and Frances Crick
Scientists that discovered the Twisted Double Helix
Sugar-phosphate backbone
Forms the structural framework of nucleic acids like DNA and RNA
Nucleotides that comprise DNA
Adenine, Thymine, Guanine, Cytosine
Nucleotide base-pairing in DNA
A and T and G and C
Genotype
The letter combination that shows which alleles are present in a
organism
Phenotype
The actual appearance of an expressed trait.
Dominant
The gene that codes for a trait that is visible or always expressed
Recessive
The gene that codes for a trait that’s invisible or expressed only when
2 recessive alleles are present.
Allele
Variation of the same sequence of nucleotides at the same place on a
long DNA molecule
Homozygous
A genotype showing 2 identical alleles, AA or aa
Heterozygous
A genotype showing 2 different alleles, Aa
Punnett Square
A square diagram to predict the genotypes of a particular cross
breeding
Pure-bred
Not mixed types in the breeding, the offspring is the same as both parents
Hybrid
Off spring of 2 animals or plants of different subspecies, breeds or
varieties
Heredity
Traits passed down from parents to there offspring
Probability
A calculated chance of something occurring or not occurring.
Gametes in plants
Male gametes are in the tiny pollen grains on the anthers of the flower.
Female gametes are found in the ovules of the flower.
Gametes in animals
Female gametes are egg cells and male gametes are called sperm
Meiosis
Does PMAT twice and only for gametes (Sex cells). Ends with 4 different genetically cells
Mitosis
Does PMAT once and only for somatic cells (Body cells). Ends with 2 identical daughter cells.
Budding
Asexual reproduction in which new organisms develops from an
outgrowth or bud due to cell division happening once (Mitosis)
Tubers
Large structure in plants used as storage organs in plants to store nutrients
Runners
A side stem that grows horizontally along the ground, giving rise to the
roots
Plantlets
A very small or young plant.
Cuttings
A plant section from the stem, leaf or root and is able of developing a
new plant
Fragmentation
Organism divided into minor fragments.
Regeneration
Regrowing either a damaged or removed body part in certain animals
Binary Fission
Separation of Bacteria into 2 new bodies.
Internal fertilization
Union of a egg and sperm during sexual reproduction inside the females
body
External fertilization
Union of a egg and sperm during sexual reproduction outside the females body
