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121 Cards in this Set
- Front
- Back
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what is human genetics
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study of inheritance as it occurs in humans
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father of biochemical genetics
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archibald garrod
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came up with laws of inheritance
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gregor mendel
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law stating that when two homozygous plants with different alleles are crossed, all offspring in F1 are identical and heterozygous
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law of uniformity
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law stating that only one factor from each parent can be transmitted at any one time
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law of segregation
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law stating that factors controlling different pairs of characteristics segregate independently of each other
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law of independent assortment
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hereditary unit
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gene
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alternate forms of a gene
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alleles
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refers to precise allelic composition of a cell
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genotype
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refers to observed characteristics of a trait or individual
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phenotype
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first person to apply mendel's laws to human disease
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archibald garrod
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alkaptonuria caused when parents are this
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first cousins
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Garrod coined this term to explain alkaptonuria
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Inborn Errors of Metabolism
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children affected with alkaptonuria have this, while carriers have this
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affected have zero copies of gene
carriers have one copy of gene wild type has both copies of gene |
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in alkaptonuria, this part of the pathway is blocked
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HGA (homogentisic acid) to maleylacetoacetic acid, resulting in accumulations of its oxidation products benzoquinones in collagenous tissues
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alkapturic heart disease has these clinical manifestations
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calcification of aortic valve, may involve mitral valve, endocardium, pericardium, and coronary arteries
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is alkaptonuria a benign disease
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no, alkaptonuria is not a benign disease
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the concept that the invisible and hypothetical entities called genes are parts of the visible structures called chromosomes
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chromosome theory of heredity
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three parts of dna
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pentose sugar - deoxyribose
phosphate group four types of nitrogenous bases |
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human nuclear genome contains how many base pairs
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3 billion base pairs in haploid cells (egg and sperm)
6 billion base pairs in diploid cells such as skin and liver cells |
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idea that one of two strands of new DNA helix are newly replicated
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semi-conservative replication
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chromatin is composed of this
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DNA and Histones and Acidic protein complex
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each chromosome composed of this many helices
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each chromosome has a single double helix DNA
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basic unit of dna and its structure
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nucleosome, has about 146 nucleotides surrounding cluster of 8 histone proteins
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connects nucleosomes
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linker DNA
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change in phenotype without a change in DNA sequence
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epigenetics (methylation etc)
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in nucleosomes, acetylation of histones is associated with this
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active transcription
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in nucleosomes, methylation of histones is associated with this
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repression of transcription
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transcription of nucleosomes possible under these conditions
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active (open) chromatin
unmethylated cytosines acetylated histones |
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transcription of nucleosomes impeded under these conditions
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silent (condensed) chromatin
methylated cytosines deacetylated histones |
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long strings of nucleosomes
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30 nm solenoid fibers
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fundamental unit of chromatin organization
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solenoid fiber
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solenoid fibers are packed into..
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loops or domains attached to protein scaffold/matrix
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two DNA classifications
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unique or single copy DNA - 75%
repetitive DNA: satellite DNA - 10% dispersed repetitive DNA - 15% |
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chromosome with arms of same size
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metacentric
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chromosome with medium sized short arm (p) and regular long arm (q)
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submetacentric
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chromsome with short short arm (p) and regular long arm (q)
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acrocentric
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in chromosome nomenclature, lower number is where
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near centromere
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number of genes in humans
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about 20-25,000, less than mouse, rice and maize
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the whole set of molecular interactions in cells
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interactome
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what percentage of dna conserved across ethnicities and races
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99.0
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0.9% variability in races due to this
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copy number variation
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0.1% variability in races due to this
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SNPs
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90 percent of human genome variation comes from this
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SNPs
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mutations in this gene cause alkaptonuria
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HGO
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two cells that go through meiosis
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egg and sperm
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dna synthesis occurs in this phase of the cell cycle
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S phase
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mitosis occurs in this phase of the cell cycle
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M phase
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order of phases in cell cycle
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M g1 S g2 M
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when can duplicated DNA be seen in the chromosomes
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when they condense in prophase
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this joins the two double helices to form a chromosome
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centromere
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half of the replicated chromosome is called this
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chromatid
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what its called when 4 chromosomes line up together
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tetrad
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stage of prophase: chromsomes become visible as thin threads
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leptotene
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stage of prophase: homologous chromosomes pair (synapsis)
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zygotene
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stage of prophase: chromsomes appear as bivalent or tetrads, crossing over occurs
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pachytene
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stage of prophase: bivalents repel one another and are held together by chiasmata
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diplotene
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stage of prophase: chromsomes reach maximum condensation
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diakinesis
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a protein structure that forms between two homologous chromosomes during meiosis and that is thought to mediate chromosome pairing, synapsis, and recombination (crossing-over)
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synaptonemal complex
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structure of synaptonemal complex
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two lateral elements and one central element
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in random assortment, how many different chromsome combinations are there
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2^23
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crossing over occurs between:
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nonsister chromatids
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cnv occurs when:
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nonsister chromatids line up out of phase
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chances of inheriting two chromosomes from a parent when they are neither far apart nor close
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(100-x) / 2 for parental
x/2 for recombinant |
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in calculating linkage with 100-x/2, x is between 0 and 50. which means they are far apart?
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50
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homologs pair up in this
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meiosis not mitosis
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how long is male spermogenesis
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64 days
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number of cell divisions in spermatogenesis
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30 + 23n + 5 where n=age in years minus 15
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number of cells in spermatogensis at birth
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1.2 e 9
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total number of sperm cells made over life time
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10^12
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order of spermatogenesis
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testis -> spermatogonium -> primary spermatocyte -> secondary spermatocyte -> spermatids
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name of cells in spermatogenesis
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primordial germ cell in embryo
spermaogonial stem cell spermatogonium primary spermatocyte secondary spermatocyte early spermatid sperm |
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name of cells in oogenesis
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primordial germ cell
oogonium primary oocyte secondary oocyte fertilized egg |
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when is oogenesis stopped
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arrested in pirmary oocyte prophase I until puberty
secondary oocyte, arrested at metaphase of meiosis II until fertilization |
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in oogenesis, 3 polar bodies are made. when?
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one after meiosis 1, and two after meiosis 2
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in oogenesis, when are primary oocytes formed
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third month of fetal development
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how many oocytes formed before birth
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2.8 x 10^6
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how many oocytes actually mature and are ovulated?
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about 400
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most common mutational mechanism and is responsible for a large percentage of chromosomally abnormal fetuses
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nondisjunction
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when does nondisjunction occur
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during meiosis 1 or 2
remember that only two per cell, and the sperm adds the third |
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this can lead to chromosomal mosaicism
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mitotic nondisjunction
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transcription carried out by:
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RNA polymerase
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translation performed on the:
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ribosomes
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are exons or introns conserved more in organisms
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exons - no evolutionary pressure on the introns
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conserved region rich in ATs about 25-30 upstream of start site
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TATA box
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sequence of CCAAT upstream of TATA box
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CAT box
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sequences of DNA responsible for proper initiation of transcription
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promoters
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these are absent in housekeeping genes and are replaced by CpG Rich promoters
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CAT and TATA boxes
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three regulatory elements
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enhancers - act far away from gene and stimulate transcription
silences locus control regions |
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these control which and when genes are turned on
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locus control region
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type of RNA that carries information specifying amino acid sequences of proteins from DNA to ribosomes
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mRNA messenger
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type of RNA that serves as an adapter molecule in protein synthesis; translates mRNA codons into amino acids
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tRNA transfer
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type of RNA that plays catalytic (ribozyme) roles and structural roles in ribosomes
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ribosomal RNA rRNA
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type of RNA that serves as a precursor to mRNA, rRNA, or tRNA before being processed by splicing or cleavage. Some intro RNA acts as a ribozyme, catalyzing its own splicing
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primary transcript
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explain how introns are removed
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forms a lariat in the RNA, spliceosome attaches and cuts it out
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three parts of translation
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initiation, elongation, termination
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type of RNA that plays a structural and catalytic role in spliceosome, the complexes of protein and RNA that splice pre-mRNA
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snRNA small nuclear
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type of RNA that is a compotnent of the signal recognition particle SRP, the protein-RNA complex that recognizes the signal peptides of polypeptides targeted to the ER
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SRP RNA
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type of RNA that aids in processing of pre-rRNA transcripts for ribosome subunit formation in the nucleolus
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small nucleolar DNA snoRNA
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type of RNA that is involved in regulation of gene expression
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small interfering RNA siRNA and microRNA miRNA
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has an important role in defending cells against parasitic genes – viruses and transposons – but also in directing development as well as gene expression in general.
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RNA interference RNAi
can clear up genetic disorders |
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name some phenotypic variations
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dietary intolerances
adverse response to drugs susceptibility to infections susceptibility to common diseases predisposition to cancer |
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chromosome missegregation like trisomy 21 categorized as:
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genomic mutation
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rearrangement of chromosomes such as translocation called:
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chromosome mutation
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three codon changes that are gene mutations
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silent, missense, nonsense
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which type of mutation causes the most diseases
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missense mutations
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mutation that disrupts existing splice sites
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splice mutation
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how many mutations cause sickle cell
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1
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how many mutations cause tay sachs
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3
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how many mutations cause gaucher
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4
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how many mutations cause alpha 1 antitrypsin deficiency
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1
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this disease has over 300 mutations that cause it but they are all family specific
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fabry
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mutations in this gene cause cystic fibrosis
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CFTR
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this mutation causes fabry
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alpha galactosidase A mutation
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if alleles present in greater than 1 percent of heterozygote individuals in population, variation is called:
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polymorphism
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if alleles are present in less than 1 percent of heterozygote individuals in population, the variations are called
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sequence variants or mutations if they cause disease
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vntr aka
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minisatellites
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str aka
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microsatellites
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A antigen has this side group on the H
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N-acetyl galactosamine
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B antigen has this side group on the H
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Galactose
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H + A-transferase makes this
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H and A antigen
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