Chapter 4: Genes, Gene-environment Interaction, And Epigenetics Flashcards
The basic unit of inheritance
Genes
Name the four nitrogenous bases
Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)
Each DNA subunit—consisting of one deoxyribose molecule, one phosphate group, and one base
Nucleotide
This consists of the breaking of the weak hydrogen bonds between the bases, leaving a single stand with each base unpaired
DNA replication
This enzyme travels along the subtle DNA strand, adding the correct nucleotides to the free end of the new strand
DNA polymerase
Any inherited alteration of genetic material
Mutation
A large number of agents that can increase the frequency of mutations
Mutagens
The transport of the DNA code from nucleus to cytoplasm and the subsequent protein formation involves these two processes
Transcription
Translation
The process by which RNA is synthesized from a DNA template
Transcription
The result of transcription is the formation of:
messenger RNA (mRNA)
How does RNA differ from DNA?
RNA uses uracil (U) as a base amino acid rather than thiamine (T)
Transcription continues until a DNA sequence called _______ ________ is reached
Termination sequence
The process by which RNA directs the synthesis of a polypeptide
Translation
Translation utilizes this which is a clover shaped strand it about 80 nucleotides
Transfer RNA (tRNA)
Human cells can be categorized into two types:
Germline (sperm and egg, or gametes)
Somatic cells (including all other cells)
Gametes are ________ cells, so only 1 member of each chromosome pair
Haploid
The process by which these haploid cells are formed from diploid cells is called
Meiosis
The most well known form of aneuploidy is
Trisomy 21
Broken chromosomes and loss of DNA cause
Deletions
The occurrence of two breaks in a chromosome, followed by the reinsertion its missing fragment at its original site, but in inverted order
Inversion
The interchange of genetic material between nonhomologous chromosomes
Translocation
Each gene occupies a position along a chromosome known as a
Locus
Genes at a particular locus can take different forms, known as
Alleles
When two alleles are identical, the individual is __________. When the alleles are different, they are _____________.
Homozygous
Heterozygous
The composition of genes at a given locus is known as
Genotype
The outward appearance of an individual
Phenotype
The ___________ of a trait is the percentage of individuals with a specific genotype who also exhibit the expected phenotype
Penetrance
The most common lethal recessive disease in white children
CF
___________ refers to the mating of two related individuals and their offspring are said to be _________
Consanguinity
Inbred
A trait that occurs much more often in one sex than the other
Sex-Influenced trait
Different version of a paired gene
Allele
Substance that alters genetic material
Mutagen
Chromosome that is not a sex chromosome
Autosome
Segment of DNA that is the basic unit of inheritance
Gene
Sequence it three nitrogenous bases that specifies a particular amino acid
Codon
No coding segment spliced out of mRNA
Intron
Alteration of DNA capable of being passed off to offspring
Mutation
Segment of mRNA that codes for proteins
Exon
Strand of condensed chromatin visible right before cell division
Chromosome
A display of chromosomes ordered according to length and centeomere location is called
Karyotyoe
A somatic cell has how many pairs of chromosomes
23
A _________ mutation of DNA involves addition or deletion of a number of base pairs that is not a multiple of three and thus alters all the codons downstream from the site of insertion or deletion
Frameshift
A ______ gene will only be displayed if two copies are present
Recessive
Person who has Down syndrome has a high risk of developing _________ disease because of involvement with chromosome 21
Alzheimer’s
Person with the 47,XXY karyotyoe have ______ syndrome
Klinefelters
X-linked recessive diseases are seen much more often in ——- rather than _______
Males more than females
An error during mitosis or meiosis where homologous chromosomes fail to separate normally
Nondisjunction