CYTO Flashcards
one alternative of a pair or group of genes that could occupy a specific position of
chromosome
Allele
Is the cause of similarities between individuals
Heredity
Is the cause of differences between individuals
Variation
Variant of a gene for a trait
Allele
Linear strand of DNA harboring many genes
Chromosome
molecule in which genetic information is encoded
DNA
- that produces the same phenotypic effect whether inherited heterozygously or homozygously
Dominant Allele
- an allele that “masks” a recessive allele
Dominant Allele
unit of genetic information that occupies a specific position on a chromosome &
comes in multiple version aka the allele
Gene
genetic constitution of an organization
Genotype
having a genotype with two different and distinct alleles for the same trait
Heterozygous
having a genotype with two of the same allele for a trait
Homozygous
the physical observable characteristic of an organism
Phenotype
produces no phenotypic effect when inherited heterozygously and only
affecting the phenotype when inherited homozygously
Recessive Allele
- an allele “masked” by a dominant allele
Recessive Allele
Gregor Mendel was born on _____________________ (place) in ___________ (year)
Czech Republic 1822
Mendel went to the ________________, where he studied botany and learned the Scientific Method
and Worked with pure lines of peas for ______ years
university of Vienna, eight
Prior to Mendel, heredity was regarded as “___________” process and the offspring were
essentially a “_____________” of the different parental characteristics
blending, dilution
3 Principles of Mendelian Genetics
- Law of Dominance
- Law of Segregation
- Law of Independent Assortment
Dominant trait is always expressed in F1, while the recessive trait is masked only to
reappear in F2
Law of Dominance
2 alleles for a heritable character separate or segregate during gamete formation, and end
up in different gametes.
- In the monohybrid cross
- Known as the law of purity of gametes
Law of Segregation
Each pair of allele segregate independently of other pairs of alleles durinn gamete
information
- In the dihybrid cross
- Describes how different genes independently separate from one another when
reproductive cells develop (searched)
Law of Independent Assortment
a genetic mix between 2 individuals who have a homozygous genotypes that have
completely dominant or completely recessive alleles, which results in opposite
phenotypes of certain genetic trait
- parents differ by a single trait
- 3:1 phenotypic ratio
Monohybrid Cross
- has 16 punnett square
- combine randomly
- two different genes that differ in two observable traits
- cross that shows the possible offspring for two traits
- studying the inheritance of two characters simultaneously
- 9:3:3:1 phenotypic ratio
- two characters are inherited independently
Dihybrid Cross
- no trait is dominating
- one allele of a pair is not fully dominant over its partner
- third phenotype appears
ex: white x red = pink
Incomplete Dominance
one allele of a pair is not fully dominant over its partner, so a heterozygous phenotype somewhere in between the two homozygous
phenotypes emerges. An example is the case of snapdragons (starr et al., 160p)
b. When an organism is heterozygous for a trait, it will show a third phenotype; the
third phenotype is a blend of the other two
c. Example: cross between white and red flower the offspring becomes pink
Incomplete Dominance
- pair of non-identical alleles specific to two phenotypes which are both expressed at the
same time in heterozygous
ex: AB blood group
Codominance/Multiple Alleles
- means stopping
- a gene at one locus alters the phenotypic expression of the gene at a second locus
- a circumstance where the expression of one gene is modified by the expression of one or
more other genes (searched)
ex: albinism
Epistasis
pleion = more, greek word
- most genes have multiple phenotypic effects
- the phenomenon of one gene or one mutation affecting multiple traits (searched)
ex: cystic fibrosis & sickle cell disease - its alleles is responsible for the multiple
symptoms happening
. Pleiotropy
classified on an either-or-basis
- called quantitative variations usually indicate polygenic inheritance, an additive effect of
two or more genes on a single trait
ex: skin color
Polygenic Inheritance
segregate into the gametes independently of one another
Unlinked gene
- don’t segregate independently of each other and thus don’t give the phenotypic ratio of the F2 offspring
Linked gene
____________ is the genetic material
while a _________ is the basic physical and functional unit of heredity
DNA, gene
The Human Genome Project has estimated that humans have between ________________________ genes
20,000-25,000
The 3-Dimensional structure of DNA was discovered in 1953 by ____________________ in Cambridge,
using the experimental data of Wilkins and Franklin in London, for which they won a Nobel prize.
Watson & Crick
is polymeric nucleic acid of four monomeric robotids or ribonucleotids.
RNA
Each ____________________ contains a pentose sugar
ribonucleotide
DNA and RNA contains what elements
Carbon, Oxygen, Hydrogen, Nitrogen and Phosphorous.
The information content of DNA is in the form of specific sequences of ________________________
nucleotides
The DNA inherited by an organism leads to specific traits by dictating the synthesis of
______________
proteins
______________ are the links between genotype and phenotype
Proteins
the process by which DNA directs protein synthesis,
Gene Expression
Two stages of Gene Expression
Transcription and Translation
In 1909, British physician ___________________ first suggested that genes dictate phenotypes
through enzymes that catalyze specific chemical reactions
Archibald Garrod
___________________ and ____________ exposed bread mold to X-rays, creating mutants that
were unable to survive on minimal medium as a result of inability to synthesize certain
molecules
George Beadle, Edward Tatum
states that each gene
dictates production of a specific enzyme
one gene–one enzyme hypothesis
Who developed the one gene–one enzyme hypothesis
George Beadle, Edward Tatum
Some proteins aren’t enzymes, so researchers later revised the hypothesis: one gene– one enzyme to _____________________
one gene– one protein
Introduced the Central Dogma of Molecular Biology
Francis Crick
