genetics Flashcards
speciation
the formation of a new species, which can cause populations to become reproductively isolated
reproductive isolation
members of two populations cannot interbreed & produce fertile offspring - Behavioral, geographic, and temporal isolation
behavioral isolation
organisms have differences in dating rituals
geographic isolation
organism are separated by geo barriers such as rivers, mountains, bodies of water
temporal isolation
species reproduce at different times of the year
cell differentiation
the process when an unspecialized (blank) cell develops into a mature specialized cell
what controls the process of cell differentiation
DNA
how do unspecialized cells become specialized cells
DNA is expressed differently in different specialized cells [called gene expression]
gene expression
the turning on or off of genes in DNA
what causes gene expression
external factors such as temperature, presence of drugs & chemicals, and light & internal factors such as hormones & nutrients
genetics
the field of biology that studies how traits are passed on from parent to child
law of segregation
states that organisms inherit two copies of each gene, one from each parent
law of independent assortment
states that genes segregate independently & don’t influence each other’s inheritance
gene
a piece of DNA that directs a cell to make a certain protein
allele
a variant form of a gene
genotype
refers to the makeup of a specific set of genes
phenotype
the physical expression of a trait
codominance
both alleles are expressed {Black Chicken + White Chicken = Speckled Chicken (Black and white chicken)]
incomplete dominance
mixed of both traits [red + white flower = pink flower]
multiple alleles
Multiple alleles are seen in one gene. Normally one gene has two possible alleles, an uppercase letter, and a lowercase letter. But in multiple alleles, there are more than two possible alleles to pick from. HOWEVER, the offspring will only get 2 alleles for each gene, one from each parent. Example: blood types
polygenic inheritance
occurs when a trait is controlled by 2+ genes (ex: eye, skin color, height)
sex chromosomes [what number]
23rd pair of chromosomes
female sex chromosomes
XX
male sex chromosomes
YY
