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Genetics & defects
PHRM 6101
Question | Answer |
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Genetics and Gene | Genetics: the study of biologic heredity .. Gene: basic unit of heredity |
Genomics and Genome | Genomics: The field of genetics concerned with the structural and functional studies of a genome .. Genome: DNA representing all of the genes for a given species |
Genotype Vs Phenotype | Genotype (what they have) genetic makeup of the organism .. Phenotype(what they demonstrate) the observable appearance of the genetics of an organism |
Mitosis vs Meiosis (I & II) | purpose of Mitoses is from 1 cell ---> 2 DIPLOID cells and it produces cells that are genetically identical .... Purpose of Meioses if from 1 Cell ---> 4 HAPLOID cells and it produces cell that are NOT genetically identical |
What are the basic stages of cell cycle? | 1. Interphase : it has G0/G1 (Gap phases), S (DNA synthesis), and G2 phase (accumulation of RNA and proteins necessary for cell division) 2. M phase: have prophase, metaphase, anaphase, and Telophase 3. Cytokinesis : chromosomes seperate and cell divides |
Stages of the M phase (mitotic) | Prophase: DNA condensation and nuclear membrane dissolution .. Metaphase: Microtubules align chromosomes along center of the cell .. Anaphase: Pairs of chromosomes seperate .. Telophase: New nuclear membrane form |
Chromosomes Theory of inheritance 5. during formation of gametes, different types of chromosomes segregate independently 6. Each parent gives 1 set of chromosomes to it's offspring | 1. Chromosomes contains genetic material 2. they are passed from parent to offsprings 3. The nuclei of eukaryotic cells contains chromosomes that are homologous pairs 4.during meiosis, Each homologous segregate into 1 of 2 daughter nuclei |
Are gametes formed by mitosis or meiosis? | Meiosis .. all other cells are formed via mitosis |
What happens in late prohphase I? | Crossing over takes place, and the nuclear membrane breaks down |
What's the difference between Metaphase of Mitosis and Metaphase I of Meiosis? *** homologous pairs of chromosomes line up along the metaphase plate. Sister chromatids aligned on same side of metaphase plate, opposite side of homologous pair | Metaphase of Mitosis: chromosomes line up on the metaphase plate and sister chromatids are on opposite sides of the metaphase plate .......................... go back to the front for Metaphase I of Meiosis: |
What are somatic cells? | diploid cells that have 46 chromosomes |
How many chromosomes do gametes have? | Haploid .. 23 chromosomes |
What is the structure of a chromosome | short arm -p and long arm q |
what is a centromere? | region of attachment of sister chromatids |
what is a Telomere? | region containing multiple base pairs. shortens with each cell division |
What are autosomes | The first 22 of 23 pairs of chromosomes in males and females. the 2 members are identical and said to be homologous |
Define a mutation | any inherited alteration of genetic material |
What is base pair substitution | one base pair substituted for another, may result in changes in amino acids sequence |
What is silent substitution | Does not result in an amino acid change |
TRUE/FALSE: mutation in somatic cells are not transmitted to to offspring? | TRUE |
TRUE/FALSE: mutation in gemetes are transmitted to offsprings | TRUE |
What is a mutagen | an agents known to increase frequency of mutation like radiations and chemicals |
What is point mutation and give an example | A single nucleotide base-pair change in DNA .. example is sickle cell anemia |
What is a silent Mutation | A DNA sequence change that does not change the amino acid sequence of a gene |
what is a Missense mutation | A type of mutation that result in a single amino acid change in the translated gene product |
Nonsense mutation | A type of mutation where mRNA stop codon is produced (resulting in premature termination of the protein sequence) or removed ( resulting in elongated protein sequence) |
Frameshift mutation | An alteration of DNA in which an addition of deletion of a base pair occurs. it results in change in the entire reading frame |
What's the consequence of a mutation | Gain of function: associated with dominant disorder, and production of new protein product .. Loss of function: associated with recessive disorders, and loss of 50% of protein products |
what are Euploid cells | Have multiple of the normal number of chromosomes. Haploids and diploids are euploid forms |
Polyploid | When a euploid cell have more than the diploid number. Ex, Triploidy: a zygotes having 69 chromosomes .. and tetrapolidy: 4 copies of each 92 total. Fetuses of tri and tetra don't survive |
Disnjunction | Normal seperation of chromosomes during cell division |
Nondisjuction | Usually the cause of aneuploidy, it is defined as the failure of homologous chromosomes or sister chromatids to seperate normally during meiosis or mitosis |
Aneuploidy | opposite of euploidy .. a somatic cell that does not contain multiple of 23 chromosomes |
What is Trisomic (trisomy) | A cell containing 3 copies of chromosomes |
What is Monosomy | the presence of only one copy of any chromosome .. it's often fatal .. infants can survive with trisomy .. better have extra than less |
Down syndrome is an example of which type of chromosome abnormality? Euploid or aneuploidy? | Aneuploidy |
Describe people with down syndrom? | Mentally retarded, lower nasal bridge, epicanthal folds, protruding tongue, poor muscle tone |
Partial Trisomy | Only an extra portion of a chromosome is present in each cell |
Chromosome moasics | Trisomies occurring only in some cells of the body |
Trisomy X, and symptoms | is a females with 3 X chromosomes termed Metafemale. Symptoms: Sterility, Menstrual irregularity and mental retardation .. symptoms worsen with each addition of X |
Turner syndrome | Females with 1 X |
Characteristics of Turner syndrom | Absence of ovaries .. short stature .. webbing of the neck .. edema .. underdeveloped breast, wide nipples .. usually inherited from the Mother. |
Klinefelter syndrom | individuals with at least 2 Xs and 1 Y chromosomes |
Klinefelter syndrom characteristics | Male appearance .. develop females like breasts .. small testes .. long limbs .. spares body hair ... abnormalities increase with addition of each X |
What are alteration in chromosomes structure | Deletion .. Inversion .. Translocation .. Ring chromosomes .. Chromosomes breakage |
What is Deletion of chromosomes: | Loss of DNA sequence of DNA from a chromosome |
What is inversion of chromosomes | chromosomes rearrangement in which a segment of a chromosome is reversed end to end .. ex abCDEfg becomes abEDCfg |
what is translocation of chromosomes | Transfer of one chromosomes segment to another |
Ring chromosome | structurally abnormal chromosome in which the telomere is deleted and broken arm has joined |
Chromosome breakage | when a chromosome break, a physiologic mechanism usually repair the break. but it heals in a way that alters the structure of the chromosomes ,, agents of chromosome breakage are ionization agents and chemicals and viruses |
What are fragile sites | areas on chromosomes that develop distinctive breaks or gaps when cells are cultured. Has no apparent relationship to disease |
Fragile X syndrom | site on long arm of X chromosome associated with mental retardation .. second in occurrence to down syndrom .. higher in males because they only have 1 X |
What is Locus | Location occupied by a gene or chromosome |
What is an Allele? | Alternate version of gene at a locus |
What is Polymorphism | Locus that has 2 or more alleles |
Can alleles be codominants? | Yes |
What is a carrier | It has the disease gene but phenotypically normal .. ex sickle disease Ss = Carrier .. ss = has the disease |
What is Recurrence risk | the probability that parents of a child with a genetic disease will have yet another with the same disease |
What is autosomal dominant disorder | abnormal allele is dominant, normal allele is recessive, and the gene exist on pairs of autosomes |
What are the characteristics of autosomal dominant disorder | 1. condition is expressed equally in males and females 2. about 1/2 of children of an affected heterzygous individual will express the condition 3. no generation skipping |
What is expressivity | It's the variation in a phenotype associated with a particular genotype. can be caused by modifier genes .. example: Von Recklinghausen disease |
What are the characteristics of autosomal recessive disorder | 1. Abnormal allele is recessive and a person must be homozygous to express the disease 2. The treat usually appears in the children, not the parents, and it effects the genders = 3. Generation skipping may be present 4. Consanguinity may be present |
X-linked disorders usually expressed by _____ because _____ have another X chromosomes to mask the abnormal allele | Male, Female |
X linked recessive disorder characteristics | 1. male most common effected 2. Unaffected carrier females 3. Pedigree analysis : generation skipping often present and no father-son transmission |
What is Hemophilia | Bleeding disorder resulting from congenital deficiency of coagulation factors |