Mendelian Gentics And Beyond Flashcards
Phenotype
Expression of genotype; physical appearance (tall or short)
Inheritance
How traits are passed from parents to offspring
Blending model
Idea that genetic material from two parents blends together; leads to loss of variation; incorrect model
Particulate model
Idea that parents pass on discrete heritable units called genes; correct model
True breeding
Plants that produce offspring of the same variety when they self-pollinate
F1 generation
All plants were purple (heterozygous); showed that the blending model was not correct
F2 generation
3 purple : 1 white; factor for white flowers (recessive gene) was not diluted or destroyed because it reappeared in the F2 generation; consistent w/ particulate model
Genes
Discrete heritable units on chromosomes
What were the six characters of plants that Mendel observed?
Flower color (purple or white), seed color (yellow or green), seed shape (round or wrinkled), pod color (green or yellow), pod shape (inflated or constricted), flower position (axial or terminal), and stem length (tall or dwarf)
The particulate model currently recognizes that ___ are the hereditable units
Genes
Alleles
Alternative versions of genes (dominant or recessive)
Which allele is expressed over the other?
Dominant
Homozygous dominant and heterozygous will express the dominant trait
Genotype
Organism’s genetic makeup (RR or rr)
Diploid
Organisms w/ two copies of each chromosome
Homozygote
Organism w/ two identical alleles
Heterozygous
Organism w/ two different alleles
Mendel’s law of segregation
The two alleles for each character segregate (separate) during gamete production such that 50% of gametes receive one allele and 50% receive the other allele
Gamete
A haploid reproductive cell, such as an egg or sperm, that is formed by meiosis
Mendel used true breeding plants as the parents in his experiments. Which of the following characteristics describe true breeding plants:
They have dominant traits
They have recessive traits
They are heterozygous
They are homozygous
Both A and D
They are homozygous
What are the two laws of probability Mendel used?
Multiplication Rule and Addition Rule
Multiplication Rule
The probability that both of two independent events will occur is the product of the probability of their separate occurrences; look for “AND”
What is the probability of rolling a 1 AND then a 4 on two subsequent die rolls?
1/6 x 1/6 = 1/36
Addition Rule
The probability of an event that can occur in two or more mutually exclusive ways is the sum of the probability of their separate occurrences; look for “OR”
What is the probability of drawing a king OR queen from a deck of cards?
1/13 + 1/13 = 2/13 (15%)