Bio 422 Flashcards
Phenotype
outward appearance of an organism
ex: tall, P
Genotype
genetic makeup of an organism
ex: TT or Tt
Dominant
Describes a trait that covers over, or dominates, another form of that trait
Recessive
An allele that is masked when a dominant allele is present
Heterozygous
having two different alleles for a trait
Homozygous
having two identical alleles for a trait
Gene
equivalents of mendel’s trait
Allele
form of a gene
important phenotypic ratios
3:1
1:1
9:3:3:1
1:1:1:1
mendel seven visble features
seed shape, seed color, pod shape, flower color
pod color, flower postion, stem height
true-breeding
term used to describe organisms that produce offspring identical to themselves if allowed to self-pollinate
P1 generation
parental generation
F1 generation
offspring of the P generation
F2 generation
Offspring resulting from interbreeding of the hybrid F1 generation.
Mendel’s experiment
Gregor Mendel cross-pollinated plants that had different traits, and found that they were heritable
Mendel model organism Peas
easy to grow
true breedding strains
controlled matings (self ferlilzation)
observed characteristics with two different forms
grow maturity in one season
Simple Mendelian Inheritance
A single gene with two different alleles
Alleles display a simple dominant/recessive relationship
True (pure) breeding
an organism that always passes on a specific trait to its offspring, which means the trait is homozygous.
reciprocal crosses
a pair of crosses between a male of one strain and a female of another, and vice versa
Mendel three laws
Dominance/recessiveness
Segregation
Independent Assortment
Law of Dominance
When there are two different alleles, one is dominant and other recessive
Law of Segregation
two alleles for each gene are placed in different gametes
Law of Independent Assortment
the inheritance of one gene does not affect the inheritance of another gene.
complete dominance
a relationship in which one allele is completely dominant over another
autosomal
the sex of the parent giving a particular allele doesn’t matter
monohybrid cross
A cross between two individuals, concentrating on only one definable trait
dihybrid test cross
Crossing an unknown genotype dominant individual with a known recessive to find out its genotypic makeup. 1:1:1:1
trihybrid cross
a cross involving three traits with 64 boxes
product law
calculates probability of outcomes occurring together
sum law
calculates probability of outcomes independent of each other
Binomial Theorem
calculates probability of alternative ways to achieve combination of events
Chi-square analysis
Evaluates influence of chance on genetic data
chance deviation
chance events subject to random fluctuations
null hypothesis
assume data will fit given ratio
Chi-square
goodness of fit of null hypothesis, analysis used to test how well the data fit the null hypothesis
Pedigrees
family trees that show the occurrence of inherited phenotypes in several generations of related individuals
Inheritance of a Recessive Trait
Recessive traits may occur in individuals whose parents are not affected.
Rare recessive traits are most likely to appear in a pedigree when spouses are related to each other.
Inheritance of a dominant trait
Every affected individual is expected to have at least one affected parent
individual who carries the dominant allele manifests the trait
Mendel’s wrinkled peas
molecular explanation
SBEI: starch-branching enzyme
catalyzes formation of branched starch molecules as seed matures
wrinkled peas lack this enzyme
osmotic pressure rises= wrinkled peas
Tay-Sachs disease
destroys nerve cells in the brain and spinal cord
What lysosomal enzyme is deficient in • Tay-Sachs disease?
Hexosaminidase A
Meiosis
a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.
Mitosis
cell division in which the nucleus divides into nuclei containing the same number of chromosomes
homologous chromosomes
Chromosomes that have the same sequence of genes and the same structure (46)
Metracentric
centromere in middle
Submetracentric Chromosome
Unequal arms. L-Shape
acrometric
off center
telocentric
centromere at end
Karyotype
A display of the chromosome pairs of a cell arranged by size and shape.
Mitosis phases
prophase, metaphase, anaphase, telophase
Meisosis Phases
Interphase (G1, S, G2), Meiosis 1, Meiosis 2, cytokinesis 2. Creates 4 haploid cells.
meiosis 1
reduction division
Meiosis II
the second phase of meiosis consisting of chromatids separating, along with the two diploid cells splitting in two
Central Dogma
DNA-transcription-RNA-translation-protein
nitrogenous base
An organic base that contains nitrogen, such as a purine or pyrimidine; a subunit of a nucleotide in DNA and RNA
nucleosides
base + sugar
nucleotides
Basic units of DNA molecule, composed of a sugar, a phosphate, and one of 4 DNA bases
phosphodiester bond
a chemical bond of the kind joining successive sugar molecules in a polynucleotide.
Chargaff’s Rule
A=T and C=G
double helix
two strands of nucleotides wound about each other; structure of DNA
3 classes of RNA
messenger RNA, ribosomal RNA, and transfer RNA
telomerase RNA and RNA primers
invloved in dna replication
antisense RNA, microRNA, siRNA
gene regulation
snRNA
process m rna
Promoters
regions of DNA that have specific base sequences
