4.4 Flashcards
___ is the transmission of genetic characteristics from parent to offspring
heredity
1 member of each ___ of chromosomes is inherited from the individual’s mother and the other from the father
homologous pair
a female normally has ___ chromosomes
2 X
which chromosomes do not determine the sex of an individual?
autosomes
allele (def)
alternative forms of a gene are known as alleles
cells contain pairs of chromosomes. Since they are the same size and shape and also code fo the same information, each pair of chromosomes is called which of the following?
homologous chromosomes
what is true of recessive alleles?
their expression is masked in the presence of a dominant allele
they are expressed only when present on both of the homologous chromosomes
the X and Y chromosomes are referred to as ___ chromosomes
sex chromosomes
phenotype (def)
expression of genes as an observable trait (such as eye color)
chromosomes X and Y are called the sex chromosomes because they determine the sex of an individual; all others are called ___
autosomes
homozygous (def)
individuals w/ 2 identical alleles for a particular trait
which term refers to a type of inheritance in which 3 or more alleles exist for the same gene?
multiple allele inheritance
when both alleles of a heterozygote are expressed, that trait is described as a ___ trait
codominant
codominance (def)
equally dominant alleles
both alleles of a heterozygote are expressed
both phenotypes are expressed
ex. red flower + white flower == red and white flower
incomplete dominance (def)
describes the inheritance of a trait in which the heterozygote has an intermediate expression b/n either allele
ex. red flower + white flower == pink flower
eye color and skin color are traits determined by genes at multiple loci. They are examples of which type of inheritance?
polygenic (multiple-gene) inheritance
polygenic (multiple-gene) inheritance
genes at 2 or more loci, or even on different chromosomes, contribute to a single phenotypic trait
ABO blood type is a trait that demonstrates which type of inheritance?
multiple allele
which term refers to a phenomenon in which 1 gene produces multiple phenotypic effects (i.e. Alkaptonuria)?
polygenic inheritance
pleiotropy (def)
when 1 gene produces multiple phenotypic effects
ex. Alkaptonuria
males are more likely than females to inherit a genetic disease if the gene for it is which of the following?
X-linked
men only have 1 X chromosome –> if it’s recessive, it is expressed
women have 2 X chromosomes –> if 1 of them is recessive, the other could still be dominant –> no expression
sex-linked traits (def)
are carried on the X or Y chromosome and tend to be inherited by one sex more than the other
an individual w/ type AB blood has both blood type alleles IA and IB, and therefore expresses both A and B proteins on the surface of their erythrocytes. Why does this occur?
the alleles are codominant
epigenetic effects alter ___
gene expression
what happens when red flower + white flower == pink flower?
incomplete dominance
what type of inheritance:
2+ genes contribute to a single phenotypic trait
polygenic
alkaptonuria is a phenomenon in which 1 gene can have many phenotypic effects. Based on this information, which type of inheritance does alkaptonuria demonstration?
pleiotropy
epigenetic effects can alter ___
gene expression – reversibly activating or silencing genes w/o changes in base sequence
epigenetic inheritance
we can pass on changes in gene expression to the next generation w/o changes in the structure of the genes themselves
epigenetic effects ___
can cause cancer
cause a stem cell to become a liver cell
can cause obesity
which term refers to a phenomenon in which 1 gene produces multiple phenotypic effects (i.e. Alkaptonuria)?
pleiotropy
epigenetic effects alter
gene expression
