Genes and Genetic Disease Flashcards
Allele
Different version of a paired gene
Mutagen
Substance that alters genetic material (DNA)
Autosome
Chromosome that is not a sex chromosome
Gene
Segment of DNA that is the basic unit of inheritance
Codon
Sequence of three nitrogenous bases that specifies a particular amino acid
Intron
Noncoding segment spliced out of mRNA
Mutation
Alteration of DNA capable of being passed to offspring
Exon
Segment of mRNA that codes for proteins
Chromosome
Strand of condensed chromatin visible right before cell division
Karotype
A display of chromosomes ordered according to length and centromere location
A ________ cell has ___ pairs of chromosomes
23
Frame shift mutation of DNA
Involves addition or deletion of a number of base pairs that is not a multiple of three and thus alters all of the codons downstream from the site of insertion or deletion
A ________ gene will be expressed only if it is present in two copies
Recessive
People with Down’s Syndrome have high risk for developing ___________ disease because of involvement of chromosome 21
Alzheimer
Persons who have the 47,XXY karyotype have _______
Klinefelter syndrome
Translocation
Interchanging of genetic material between nonhomologous chromosomes
Difference between heterozygous and homozygous
Heterozygous means that the two genes at the same locus on both chromosomes are not identical, but homozygous means that the two genes are identical
Difference between monosomy and trisomy
Monosomy means that one of the chromosomes in somatic cells has only one copy instead of the normal two copies but trisomy means that one of the chromosomes in somatic cells have three copies
Difference between genotype and phenotype
A genotype is an individual’s genetic makeup, but a phenotype is the outward appearance of an individual
Difference between mitosis and meiosis
In mitosis, a diploid cell makes a copy of itself, but in meiosis, a haploid cell is created from a diploid
Synthesis of a protein
RNA polymerase binds to DNA promoter region
Transcription
mRNA is spliced to remove noncoding sections
mRNA leaves the nucleus
Translation
What type of genetic disorder is Huntington Disease
Single-gene disorder
What type of gene disorder is Turner Syndrome
Chromosomal Disorder
What type of gene disorder is Down Syndrome
Chromosomal Disorder
What type of gene disorder is Fragile X syndrome
Chromosomal Disorder
What type of gene disorder is Cystic Fibrosis
Single-gene Disorder
What type of gene disorder is Klinefelter syndrome
Chromosomal Disorder
What type of gene disorder is Duchenne muscular Distrophy
Single-gene Disorder
Diploid Cell
A somatic cell that has 46 chromosomes in its nucleus
Genetic diseases caused by __________ usually are autosomal dominant, autosomal recessive, or X-lined recessive
Single genes
X-linked recessive diseases are seen much more often in _____ than in _____
males, females
The structure of _____ is a double helix
DNA
Proteins are made of a sequence of
amino acids
If cells have three copies of each chromosome, ______ is present
Triploidy
______ of chromosomal material has more serious consequences than ________ of chromosomal material
Loss, duplication
Barr body
An inactivated X chromosome that is seen in normal female cells
Haploid Cell
A cell that has only 23 chromosomes; a gamete (sperm or egg)
Homologous chromosomes
A pair of identical chromosomes
Polyploidy
Condition in which cells have more than two copies of each chromosome
Nondisjunction
An error during meiosis or mitosis in which homologous chromosomes or sister chromatids fail to separate normally
Carrier
An individual who has a disease-causing allele but is phenotypically normal, often because the allele is recessive and the individual is a heterozygote
