Ch. 3 Flashcards
(52 cards)
Genes*
Basic unit of inheritance
Transcription facotrs
turn genes on and off
Chromosomes*
long strands of DNA plus associated proteins.
Homologs*
pairs of chromosomes
Locus*
denotes the site of a particular gene on a chromosomes
Alleles*
alternate forms of these genes
multiple alleles*`
more than twp possible alleles at a locus. ex. coat color in dogs
homozygous*
if both genes at a given locus are functionally the same
Heterozygous*
If the genes at a given locus are functionally different
Gregor Mendel (1822-1884)
Father of Modern Genetics. Performed genetic experiments on peas. Called genes “factors”
Law of segregation*
During gamete formation, the alleles for each gene segregate from each other so that each gamete carries only one allele for each gene.
Law of Independent Assortment*
Genes for different traits can segregate independently during the formation of gametes.
Law of Dominance *
Some alleles are dominant while others are recessive; an organism w/at least one dominant allele will display the effect of the dominant allele.
meiosis*
the process of germ cell formation
Independent Assortment
During metaphase, chromosomes line up in Pairs, but they line up randomly
Linkage*
the occurrence of two or more loci of interest on the same chromosome
Crossing over*
A reciprocal exchange of chromosome segments between homologs. Occurs during prophase 1 prior to the time homologous chromosomes are separated to form gametes. Exchanges genetic info which increases genetic variability
Genetic recombination*
The formation of a new combination of genes on a chromosome as a result of crossing over
Zygote*
the result of the fusion starting embryonic development
Punnett Square
A device for determining genotypes of possible zygots obtainable from a mating
Rule #1 of Probability w/Punnet Squares
The Probability of two independent events occuring together is the product of the probabilities of their individual occurrences (chance of getting homozygous)
Rule #2 of Probability w/Punnet Squares
The probability of one of the other of two mutually exclusive events occuring is equal to the sum of the probabilities of their individual occurences (chance of getting heterozygous)
Blending Theory
Before Mendel, scientists thought blending of fluids determined genetic make-up (% blood)
Medelian Inheritance allows for
extreme genetic variability and thus randomness