Chapter 5.1 Flashcards
Morphs
genetic varieties of the same species
Inheritance patterns
the predictable patterns seen in the transmission of traits from one generation to the next
Hereditary traits
inherited traits
True-breeding plant
self-fertilized plant that produces offspring identical in appearance to itself generation after generation
Cross-fertilization
sperm from the pollen of one plant fertilizes the eggs in a flower of a different plant
“F” stands for
filius and filia, Latin words for son and daughter
Hybrids
offspring that results from crossing two true-breeding varieties of the same species
Monohybrid
type of hybrid offspring in which the parents differ in just one trait
Monohybrid cross
hybrids with parents that differ in one trait are crossed
Allele
alternative version of a gene
Homozygous
when the two alleles are the same for an individual’s gene
Heterozygous
when two alleles are different for an individual’s gene
Dominant allele
determines the trait that a heterozygous individual expresses
Recessive allele
not expressed in a heterozygous individual
Law of segregation
two alleles for a trait/gene segregate during meiosis
Heritable
the ability to be inherited
Genotype
the genetic makeup/combination of alleles for an individual
Phenotype
an individual’s expressed traits (physical appearance)
Probability
the likelihood that a particular event will occur
Punnett square
diagram that shows the expected proportions of all possible outcomes of a genetic cross
Phenotypic ratio
ratio of the phenotypes
Test-cross
breeds an individual of unknown genotype but dominant phenotype with a homozygous recessive individual
Dihybrid
type of hybrid offspring with parents differing in two traits
Dihybrid cross
hybrids with parents differing in two traits are crossed
Law of independent assortment
genes that segregate independently during meiosis do not influence each other’s inheritance
Fruit fly scientific name
drosophila melanogaster
What is the highly sought out snake with exotic traits called?
leucistic ball python
Gregor Mendel (1822-1884)
- autrian monk
- did series of experiments in 1850s
- 7 years he bred pea plants
What did Mendel hypothesize?
that parents pass down separate factors that are responsible for hereditary traits, and that they retain identity generation after generation
What are parental plants in a genetic cross known as?
P
What is the first generation of offspring called?
First filial generation
How does cross-fertilization work?
- remove pollen carrying structures from one plant
- brush pollen from second flower to first
What did Mendel observe in hybrids?
there must be 2 factors of stem length
Mendel used monohybrid cross to study 7 categories of plants that include:
- seed colour
- seed shape
- seed coat colour
- pod shape
- pod colour
- stem length
- flower position
What did Mendel observe after studying inheritance patterns?
that one of the two parent traits were gone in F1, came back but only 1/4 in F2
Mendel’s Model of Inheritance 1
genes exist in different forms
Mendel’s Model of Inheritance 2
for each gene, an individual organism inherits two alleles, one from each parent
Mendel’s Model of Inheritance 3
an allele may be expressed as a trait/hidden in a heterozygous individual
Mendel’s Model of Inheritance 4
each gamete carries one allele for each hereditary trait due to the separation of allele pairs when gametes form. they are then reformed during fertilization
Describe Mendel’s Law of Segregation
- alleles are within a chromosome
- chromosomes become sister chromatids
- they branch off and alleles separate
- chromosomes get fertilized and alleles get paired up (makes offspring)
The probability of a particular outcome is equal to
the product of the individual properties
Who was the Punnett square made by?
Reginald C. Punnett (1875-1967)
When the genotype of an organism that displays a dominant phenotype not known
- test cross
- phenotype will reveal genotype
- homozygous recessive only contributes recessive allele, which will reveal the allele from other parent
Why did Mendel follow the inheritance of 2 categories of traits
wanted to know of inheritance of seed colour affects seed shape
Mendel’s experiment used 556 seeds
- 315 round/yellow
- 32 wrinkled/green
- 108 round/green
- 101 wrinkled/yellow
In 1931, who made the discovery of taste after spilling PTC in a lab?
Chemist named Arthur Fox
Why did Thomas Hunt Morgan use fruit flies to model genetics?
they produce a large number of offspring quickly
