Genes and Genetic Diseases Flashcards
Information covering the various topics of the "Genes and Genetic Diseases" lecture. (124 cards)
1
Q
The study of biologic heredity
A
Genetics
2
Q
The basic unit of heredity
A
Gene
3
Q
The field of genetics concerned with the structural and functional studies of the genome
A
Genomics
4
Q
DNA representing all of the genes for a given species
A
Genome
5
Q
Name the 3 basic parts of Nucleotide
A
- Deoxyribose (pentose sugar)
- Phosphate molecule
- Nitrogenous base
6
Q
Nucleotide nitrogenous bases can be broken down into 2 basic groups
A
- Purines
2. Pyrimidines
7
Q
Name the Purines associated with DNA
A
- Adenine
2. Guanine
8
Q
Name the Pyrimidines associated with DNA
A
- Cytosine
2. Thymine
9
Q
How does complementary pairing occur (general)?
A
A Purine binds with Pyrimidine:
- A to T
- C to G
10
Q
The basic building block of Proteins
A
Amino Acids
11
Q
The number of Amino Acids associated with human physiology
A
20
12
Q
Nucleic Acid which contains the transcribed instructions for protein synthesis
A
Messenger RNA (mRNA)
13
Q
Site of Transcription
A
Nucleus
14
Q
Nucleic Acid which provides the machinery needed for protein synthesis
A
Ribosomal RNA (rRNA)
15
Q
Nucleic Acid which delivers Amino Acids to the Ribosome
A
Transfer RNA (tRNA)
16
Q
Site of Translation
A
Cytoplasm
17
Q
T/F: DNA never leaves the nucleus
A
TRUE
18
Q
4 ways in which mRNA is process
A
- Removing some parts (Introns)
- Keeping some parts (Extrons, “expressed”)
- Adding some bases
- Cutting and Splicing mRNA
19
Q
_____ acts as a pattern/template telling the cell how to line up Amino Acids for Protein synthesis
A
mRNA
20
Q
Cellular structure that holds mRNA and binds Amino Acids during Protein synthesis
A
Ribosome
21
Q
Process which involves taking the instructions transcribed from DNA to mRNA and using them for Protein synthesis
A
Translation
22
Q
_____ refers to 3 consecutive bases on mRNA
A
Codon
23
Q
_____ refers to 3 consecutive bases on tRNA that are complementary to an mRNA Codon
A
Anticodon
24
Q
Substance that directs the creation of all Proteins and cell
A
DNA
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Sequences of DNA which contain the instructions for making a Protein
Gene
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Chromosomes that are Sex-linked
X and Y chromosomes
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T/F: The X chromosome is Dominant
FALSE
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_____ refers to all chromosomes other than sex-linked
Autosomal
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Human cells containing 46 chromosomes (23 pairs); Diploid cells
Somatic Cells
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Human cells containing 23 chromosomes; Haploid cells
Gametes
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The process which forms Haploid cells from Diploid cells
Meiosis
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Chromosome Structure:
| Notated as "p"
Short arm
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Chromosome Structure:
| Notated as "q"
Long arm
34
Chromosome Structure:
| The region of attachment between sister chromatids
Centromere
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Chromosome Structure:
| End "caps" containing multiple base pairs which shorten with each cell division
Telomere
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A Chromosome pair that are virtually identical are said to be _____
Homologous
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Example of a Nonhomologous pair of Chromosomes
XY
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Any inherited alteration of genetic material
Mutation
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The 2 basic types of Mutation
1. Chromosome aberrations
| 2. Base pair substitutions
40
# Choose: Somatic Cells or Gametes
Mutations in this type of cell can be transmitted to offspring
Gametes
41
An agent known to increase the frequency of mutations
Mutagen
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The 2 basic types of Mutagens
1. Radiation
| 2. Chemicals
43
The 4 basic types of Base Pair Substitution Mutations
1. Silent
2. Missense
3. Nonsense
4. Frameshift
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A DNA sequence change that does not change the Amino Acid sequence of the Gene
Silent Mutation
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A type of Mutation that results in a single Amino Acid change in the translated Gene
Missense Mutation
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A type of Mutation in which an mRNA [STOP] Codon is either produced or removed
Nonsense Mutation
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An alteration of DNA in which an addition or deletion of a Base Pair occurs
Frameshift Mutation
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Examples of consequences of Mutation which result in a gain of function
(Associated with Dominant Disorders)
- Production of new Protein product
| - Overexpression of a Protein product
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Examples of consequences of Mutation which result in a loss of function
(Associated with Recessive Disorders)
Loss of 50% Protein product
| May or may not be adequate for normal function.
50
A Mutation that occurs in absence of exposure to known Mutagens
Spontaneous Mutation
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Areas of the Chromosomes that have high Mutation rates
Mutational Hotspots
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Example of a Mutational Hotspot in Humans
Cytosine base followed by a Guanine base
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A specific position of a Gene along a Chromosome
Locus
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A different form of a particular Gene at a given Locus
Allele
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A Locus that has two or more Alleles that occur with appreciable frequency
Polymorphism
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The genetic makeup of an organism
Genotype
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The observable, detectable, or outward appearance of the Genetics of an organism
Phenotype
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When all copies of a Gene/Loci (between Chromosomes) are alike, they are said to be _____
Homozygous
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When all copies of a Gene/Loci (between Chromosomes) are different, they are said to be _____
Heterozygous
60
When only one copy of a Gene exists, it is said to be _____
Hemizygous
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In studying Pedigrees, the person with whom the disorder begins is referred to as the _____
Proband
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Process of turning a Gene "ON"
| Promoted by external influence.
Induction
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Process of turning a Gene "OFF"
Repression
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The ability of a Gene to express its function
Penetrance
65
When many Genes can affect one Trait
Polygenic
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When both multiple Genes and the environment can affect one Trait
Multifactorial
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When one Gene can mask the effect of another
Epistasis
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When one Gene might depend on another Gene
Complementary
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When two Genes together might create a new Phenotype
Collaborative
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The probability that parents of a child with a genetic disease will have yet another child with the same disease
Recurrence Risk
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When one parent is affected by an Autosomal Dominant disease and the other is normal, the occurrence and recurrence risks for each child are _____
50%
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When inheriting a dominant mutant gene fails to be expressed, the trait is said to have _____
Reduced Penetrance
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Disorders that can be expressed differently among individuals are said to have _____
Variable Expressivity
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The percentage of individuals with a specific Genotype who also express the expected Phenotype
Penetrance
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The variation in a Phenotype associated with a particular Genotype
Expressivity
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Disorder type that is manifested only when both members of the gene pair (Homozygous) are affected
Autosomal Recessive Disorders
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The mating of two related individuals
Consanguinity
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X chromosome or Y chromosome:
Location of most Sex-linked Disorders
X chromosome
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Presence in one individual of two or more cell lines characterized by distinctive karyotypes
Mosaicism
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A change in chromosome number
Aneuploidy
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The presence of only one member of a chromosome pair
| Severe; often causes abortion.
Monosomy
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The presence of more than 2 chromosomes to a set
Polysomy
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The presence of three chromosomes to a set
Trisomy
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Most common trisomy disorder (and most common chromosome disorder)
Down Syndrome (Trisomy 21)
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The normal separation of chromosomes during cell division
Disjunction
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The failure of homologous chromosomes or sister chromatids to separate normally during Mitosis or Meiosis
Nondisjunction
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Type of Chromosome Aberration that usually the cause of Aneuploidy
Nondisjunction
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Autosomal Aneuploidy in which only an extra portion of a chromosome is present
Partial Trisomy
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Trisomies occurring only in some cells of the body
Chromosome Mosaics
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The best known example of Aneuploidy
Down Syndrome (Trisomy 21)
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Aneuploidy whose signs/symptoms include:
- Mental retardation
- Low nasal bridge
- Epicanthal folds
- Protruding tongue
- Poor muscle tone
Down Syndrome (Trisomy 21)
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T/F: The risk of offspring with Trisomy 21 increases with maternal age
TRUE
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Aneuploidy resulting in a female that is XXX
Trisomy X
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Aneuploidy termed "Metafemales"
Trisomy X
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Autosomal Aneuploidy or Sex-linked Aneuploidy:
Down Syndrome (Trisomy 21)
Autosomal Aneuploidy
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Aneuploidy whose signs/symptoms (variable) include:
- Sterility
- Menstrual irregularity
- Mental retardation
Trisomy X ("Metafemales")
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Aneuploidy resulting in a female with that is X_
Turner Syndrome
98
Aneuploidy whose signs/symptoms include:
- Sterility (absence of ovaries)
- Short stature
- Webbing of the neck
- Edema
- Underdeveloped breasts and wide nipples
- High number of aborted fetuses
Turner Syndrome
99
Aneuploidy resulting in an individual with at least 2 X chromosomes and 1 Y chromosome
Klinefelter Syndrome
100
Increase or Decrease:
Generally, in Aneuploidy disorders, additional X chromosomes will _____ abnormalities.
Increase
101
Aneuploidy whose signs/symptoms include:
- Male appearance
- Development of female-like breasts
- Small testes
- Sparse body hair
- Long limbs
Klinefelter Syndrome
102
3 Agents of Chromosomal Breakage
1. Ionizing Radiation
2. Chemicals
3. Viruses
103
5 Types of Chromosomal Damage involving Breakage and Rearrangement
1. Deletion
2. Inversion
3. Isochromosome Formation
4. Ring Formation
5. Translocation
104
Chromosomal Breakage and Rearrangement:
Disorder resulting from the deletion of a short arm of Chromosome 5
Cri du Chat Syndrome
105
Chromosomal Breakage and Rearrangement:
The presence of a repeated gene or gene sequence
Duplication
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Chromosomal Breakage and Rearrangement:
Duplication in the same region as _____ causes mental retardation but no physical abnormalities
Cri du Chat Syndrome
107
Chromosomal Breakage and Rearrangement:
Reversal of gene order; usually occurring from a breakage that is reversed during reattachment
Inversion
108
Chromosomal Breakage and Rearrangement:
2 Types of Inversion
1. Pericentric
| 2. Paracentric
109
Chromosomal Breakage and Rearrangement:
Inversion resulting in genes moved to the opposite side of the Centromere
Pericentric Inversion
110
Chromosomal Breakage and Rearrangement:
Inversion involving a break on the same arm of the chromosome
Paracentric Inversion
111
The interchanging of material between nonhomologous chromosomes
Translocations
112
A Translocation at the point of the Centromere
Robertsonian Translocation
113
Areas on chromosomes that develop distinctive breaks or gaps when cells are cultured
Fragile Sites
114
Disorder involving a weakened site on the long arm of the X chromosome
Fragile X Syndrome
115
The second most common cause of mental retardation
Fragile X Syndrome
116
Disorder in which a small region of a sex chromosome gene undergoes repeated duplication, resulting in a longer gene which is susceptible to methylation
Fragile X Syndrome
117
Many genes act together to influence an expressed trait
Multifactorial Inheritance
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When expression of a disease existed in two related family members
Concordance
119
When expression of a disease exists in on family member but not a second
Discordance
120
An environmental agent that produces abnormalities during embryonic or fetal development
Teratogenic Agent
121
3 Types of Teratogenic Agents
1. Radiation
2. Chemicals and Drugs
3. Infectious Agents
4. Folic acid Deficiency
122
Why is Mitochondrial DNA subject to mutations at a higher rate than Nuclear DNA?
Lack of repair mechanisms
123
Where does all of an offspring's Mitochondrial DNA come from?
The Mother
124
Mitochondrial DNA codes for the proteins needed for _____
Aerobic Metabolism
