Chapter 16 Flashcards
Blending hypothesis
The idea that genetic material from the two parents blend together (blue and yellow paint becoming green)
Particulate hypothesis
the idea that parents pass on discrete heritable units (genes)
Character
A heritable feature that varies among individuals (flower color)
Trait
Each variant of character, such as purple or white color for flowers
True-breeding
organism that produce offspring of the same variety when they self-pollinate
hybridization
the mating of two contrasting, true-breeding varieties
P generation
the true-breeding parents
F₁ generation
The hybrid offspring of the P generation
F₂ generation
The offspring produced when F₁ individuals self-pollinate or cross pollinate with other F₁ hybrids
alleles
the alternative versions of a gene
Mendel’s model first concept
Alternative versions of genes account for variations in inherited characters
Mendel’s model second concept
For each character, an organism inherits two alleles, one from each parent
Mendel’s model third concept
If the two alleles at a locus differ, then one (the dominant allele) determines the organism’s phenotype, and the other (the recessive allele) has no noticeable effect on the phenotype
Mendel’s model fourth concept
The law of segregation; the two alleles for a heritable character separate during gamete formation and end up in different gametes
Homozygote
An organism with two identical alleles for a character
Heterozygote
An organism with two different alleles for a gene
Phenotype
physical appearance
Genotype
genetic makeup
testcross
breeding the mystery individual with a homozygous recessive individual
law of independent assortment
Each pair of alleles segregates independently of any other pair of alleles during gamete formation
multiplication rule
the probability that two or more independent events will occur together is the product of their individual probabilities
addition rule
the probability that any one or two or more mutually exclusive events will occur is calculated by adding together their individual probabilities
Watson and Crick
Introduced the double-helical model for DNA
T. H. Morgan
Showed that genes were located on chromosomes; this spurred on the search for the true genetic material: DNA or proteins
bacteriophages
Or phages, viruses widely used in molecular genetic research
Virus
A DNA (sometimes RNA) enclosed by a protective coat, often simply protein
Hershey and Chase
Discovered that DNA is the genetic material using phages and radioactivity
antiparallel
DNA’s subunits run in opposite directions
Watson and Crick believed that based pairs paired with _________ pairs (A with __)
like; A
A purine (A or G) pairs with a _______
pyrimidine (C or T)
DNA replication is ________
Semi-conservative
Semiconservative model
When DNA replicates, each daughter molecule will have one old strand and one newly made strand
Meselson and Stahl
Proved the semi-conservative model of DNA replication by culturing bacteria with a heavy isotope, letting it replicate, and then culturing it in a lighter isotope. When centrifuged, two bands of DNA occurred
Origins of replication
The particular site where replications begins, where the two NA strands are separated, opening up a replication bubble
DNA is made in the _______ direction
5’-to-3’
Primer
the initial nucleotide strand (RNA) that is 5-10 nucleotides long
primase
an enzyme that synthesizes primers
DNA polymerase
enzymes that catalyze the synthesis of new DNA at a replication fork
Each nucleotide that is added to a growing DNA strand is a ____________
nucleoside triphosphate
______ supplies adenine to DNA
dATP
Leading strand
moves toward the replication fork
lagging strand
works in the direction away from the replication fork
Okazaki fragments
The name for the fragments which make up the lagging strand
DNA ligase
Join together the Okazaki fragments
