Chapter 5 Flashcards
A genotype that causes death
lethal
causes death before the individual can reproduce
lethal genotype
t/f lethal genotypes prevents passage of genes to the next gen
t
t/f early-acting lethal alleles causes spontaneous abortion
t
t/f a double dose of dominant allele (lethal) cancels the mutation
f
t/f an indiv has two alleles for any autosomal gene
t
t/f genes cannot have multiple alleles bcz its sequence can deviate in many ways
f
t/f multiple alleles are considered carrier testing for cystic fibrosis
t
one allele is expressed, while the other is not
complete dominance
heterozygous phenotype is between those of the two homozygotes
incomplete dominance
different alleles that are both expressed in a heterozygote
codominance
alkaptonuria - inability to breakdown ___
tyrosine
phenylketonuria - inability to breakdown ____
phenylalanine
t/f the three general phenomena that seen to be exceptions to Mendel’s law, but are really not: gene expression, mitochondrial inheritance, linkage
t
what type of alleles cause spontaneous abortion
early-acting lethal alleles
t/f ABO gene encodes a cell surface protein while ABO blood group is based on the expression of codominant alleles
T
it is determined by the patterns of molecules on the surfaces of red blood cells - these molecules are embedded in the plasma membrane with attached sugars that extend from the cell surface
blood type
a phenomenon where one gene affects the expression of a second gene; the interaction between different genes, not between the alleles of the same gene
epistasis
a gene that affects the expression of another gene
modifier gene
In epistasis, the blocked gene is expressed normally, but the product of the modifier gene (activates or inactivates) it, removes a structure needed for it to contribute to the phenotype, or otherwise
counteracts its effects.
inactivates
refers to all-or-none expression of a genotype
penetrance
refers to the severity or extent
expressivity
Genotype is (incompletely or completely) penetrant if some individuals do not express the phenotype
incompletely
Phenotype is variably (expressive or inexpressive) if symptoms
vary in intensity among different people
expressive
An allele combination that produces a phenotype in everyone who inherits it is (completely or incompletely) penetrant
completely
A genotype is (completely or incompletely) penetrant if some individuals do not express the phenotype.
incompletely
A single-gene disorder with many symptoms, or a gene that controls several functions or has more than one effect
pleiotropy
a part of heme that is routed into the urine instead of being broken down and metabolized in cells
porphyrin ring
a disease that results from deficiencies of any of several enzymes required to make heme
porphyrias
y/n Is Marfan syndrome pleiotropic?
y
when different genes produce the same phenotype
genetic heterogeneity
Genetic heterogeneity can occur when genes encode enzymes that (inhibit or catalyze) the same biochemical pathway, or different proteins that are part of the pathway
catalyze
An environmentally caused trait that appears to be inherited
phenocopy
revealed that complications to mendelian inheritance are more common than originally thought
human genome sequence
revealed that complications to mendelian inheritance are more common than originally thought
human genome sequence
t/f mitochondrion’s mtDNA have 36 genes without noncoding sequences
f
t/f mitochondrion mutation rate is greater than nuclear dna
t
t/f mitochondrial genes can be transmitted from mother and father to all of their offspring
f
t/f mitochondrial genes encode RNA molecules and proteins
t
how many mitochondrial genes encode proteins that function in cellular respiration
13
the process that uses energy from digested nutrients to synthesize ATP
cellular respiration
several mitochondrial disorders result from mutations in ______
mtDNA
a mutation in a mitochondrial gene that encodes a tRNA or rRNA impairs the organelle’s ability to manufacture ______
proteins
this technique enable woman to avoid transmitting a mitochondrial disorder
ooplasmic transfer
condition where the mtDNA sequence is not the same in all copies of the genome
heteroplasmy
provides a powerful forensic tool to link suspects to crimes, identify war dead, and support or challenge historical records
mtDNA
these genes are maternally inherited and mutate rapidly
mitochondrial genes
in this disorder, cells contain mitochondria that have different alleles of a gene
heteroplasmy
genes that are close on the same chromosome are said to be_____
linked
refers to the transmission of genes on the same chromosome
linkage
linked genes (do or do not) assort independently
do not
linked genes (do or do not) produce mendelian ratios for crosses tracking two o more genes
do not
an exchange between homologs that mixes up maternal and paternal gene combinations without disturbing the sequence of genes on the chromosome
crossing over
chromosomes recombine during crossing-over in ________ of meiosis
prophase I
______ chromosomes have the original configuration while the ________ chromosomes have new combination of alleles
parental, recombinant
progeny that exhibit this mixing of maternal and paternal alleles on a single chromosome
recombinant
Two dominant or two recessive alleles are on
each chromosome
cis
One dominant and one recessive allele are on
each chromosome
trans
correlation between crossover frequency and gene distance is used to construct ________
linkage maps
distance is represented using “map units” called ______
centimorgans
t/f 1 centimorgan equals 1 percent recombination
t
frequency of recombination is based on the percentage of (meiotic or mitotic) divisions that break the linkage between two parental alleles
meiotic
DNA sequences that serve as landmarks near
genes of interest; used starting in 1980 in linkage mappings
genetic markers
DNA sequences that serve as landmarks near
genes of interest; used starting in 1980 in linkage mappings
genetic markers
scan the genomes of thousands of individuals who have a particular phenotype for DNA sequences that they share, but are much rarer in people who do not have the trait
genome-wide association studies
tightness of linkage between a marker and a gene of interest
logarithm of the odds
indicates the likelihood that particular crossover frequency data indicate linkage, rather than the inheritance of 2 alleles by chance
LOD score
t/f LOD scores of 3 or lesser signifies linkage
f
set of DNA sequences inherited on one
chromosome due to linkage disequilibrium
haplotype
set of DNA sequences inherited on one
chromosome due to linkage disequilibrium
haplotype
t/f The farther apart two genes are on a chromosome, the more likely they are to cross over.
t
