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46 Cards in this Set

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  • Back
Diploid number of chromosomes are found in all cells except?
gametes
Genetics is the study of what?
mechanism of heredity
Karyotype
diploid chromosomal complement displayed in homologous pairs
Genome
genetic dna makeup two sets of genetic instructions maternal and paternal
Alleles
alternate forms of the same gene
Homozygous alleles
alleles controlling a single trait are the same
Example~ EE or ee
Heterozygous alleles
alleles for a trait are different
Example~ Ee
Dominant alleles
an allele that masks or suppresses its recessive partner
or
an allele that is expressed whether in single or double dose
Genotype
the genetic make up
What our genes are
Phenotype
the way the genotype is expressed
the way we look
Cross over of homologues creates?
genetic variability
Because of independent assortment and random fertilization an offspring represents one out of how many zygote possibilities?
72 trillion
8.5 millionx8.5 million
Punnett square
predicts the possible gene combination's resulting from the mating of parents of known genotypes
TT and tt are what type of allele?
homozygous
Tt is what type of allele?
heterozygous
With dominant recessive inheritance what is the likelihood of the percentages of the offspring using TT and tt?
What percent TT
What percent Tt
what percent tt
25% TT
50% Tt
25%tt
Heterozygotes?
are carries of a trait that do not express it but can pass it on to their offspring
Multiple-allele inheritance
genes that exhibit more than two allele forms
example~ ABO blood grouping, height
X chromosomes bear how many genes?
over 2500
Y chromosomes bear how many genes?
78
X linked genes are found where?
They are passed from who to two?
Found only on the X chromosome
typically passed from mothers to sons
Polygene Inheritance
depends on several different gene pairs at different locations acting in tandem
Examples of this are skin color, eye color, and height
If a person carries this then their skin would be blotchy not dark skin or fair skin.. they would show both.
Phenocopies
environmentally produced phenotypes that mimic conditions caused by genetic mutation
What are Epigentic Marks?
Information stored in the proteins and chemical groups bound to DNA
Determine whether DNA is available for transcription or silenced
May predispose a cell to cancer or other devastating illness
What is Genomic imprinting?
tags genes as maternal or paternal and is essential for normal development
allows the embryo to express only the mothers gene or the fathers gene
What is genomic imprinting?
tags genes at maternal or paternal and is essential for normal development
allows the embryo to express only the mother's or fathers's gene
What are two major avenues for identifying carries of genes?
pedigrees and blood tests
Amniocentesis
amniotic fluid is withdrawn after the 14th week and fluid and cells are examined for genetic abnormalities
Human Gene Therapy
genetic engineering has the potential to replace a defective gene
the patients cells can be directly injected with corrected DNA
What term is given to chromosomes other than our sex chromosomes?
Autonomes
An allele represented by a capital letter is presumed to be dominant or recessive?
Dominant
Harold is homozygous for the dominant alleles HH,CC, and LL and heterozygous for Bb and Kk. He is blond and blue eyed and hair a very hair chest. Which of these descriptions refer to his phenotype?
Blond, Blue eyed, and hairy chest
Independent assortment occurs during which stage of meiosis?
Meiosis I
Recombinant chromosomes
mixed contributions from each parent caused when chromosomes break and exchange gene segments with their homologous counterparts during meiosis
What at the sex linked traits determined by?
genes on the sex chromosomes
Which of the following factors may alter gene expression?
Other genes, measles in a pregnant woman, lack of key nutrients in the diet
All three would alter gene expression
Protein coding genes account for what percent of the DNA of a human cell?
less than 2%
what is a pedigree?
traces a genetic trait through several generations and helps predict the future
Blood chemistry tests and DNA probes detect what?
the presence of unexpressed recessive genes
What are the three sources of genetic variation?
chromosome segregation and independent assortment
crossover of homologues and gene recombination
random fertilization of eggs by sperm
autosomes
chromosomes that dictate most body characteristics
recessive allele
an allele that must be present in double dose to be expressed
What type of inheritance do only sons show the trait?
sex liked
What type of inheritance do homozygotes and heterozygotes have the same phenotype?
dominant-recessive
in what type of inheritance do heterozygotes exhibit a phenotype intermediate between those of the homozygotes?
incomplete dominance
In which type of inheritance reflects the activity of the mitochondrial DNA?
extranuclear