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118 Cards in this Set
- Front
- Back
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What is the study of chromosome abnormalities?
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cytogenetics
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Cell with normal chromosome number
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euploid
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Cell with missing or extra chromosomes
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aneuploid
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Is missing or adding genetic material more deleterious?
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missing
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centromere in middle of chromosome
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metacentric
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centromere near tip of chromosome
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acrocentric
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centromere between end and middle of chromosome
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submetacentric
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short arm of acrocentric chromosome
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"p" arm
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long arm of acrocentric chromosome
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"q" arm
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one homologue is missing
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monosomy
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one extra chromosome
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trisomy
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When does nondisjunction usually occur?
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oogenesis in mothers over 35
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Trisomy 21
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Down Syndrome
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Mode of inheritance of Down Syndrome
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autosomal
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Features of Down Syndrome
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-palpebral fissures slant upwards
-flat maxillary region -short neck -hypotonia -increased risk of leukemia -congenital heart defects -GI obstructions -degree of mental retardation -life expectancy in 50's |
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Describe possibility of translocation in Down Syndrome
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piece of chromosome 21 breaks off and attaches to another chromosome (usually 14)
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Trisomy 18
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Edwards Syndrome
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Features of Edwards Syndrome
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-elfin features
-SGA (small for gestational age) -clenched fist with outer fingers overlapping middle fingers -heart malformations VSD (ventricular septal defect) -1 in 6,000 births -fatal within first year |
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Trisomy 13
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Patau Syndrome
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Features of Patau Syndrome
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-cleft palate
-atrial septal defects -inguinal hernia -degree of mental retardation -1 in 1,000 births |
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What is the test for women of advanced maternal age to rule out chromosomal abnormalities?
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13, 18, 21
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oocyte with no chromosomes, fertilized by X
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Turner Syndrome 45X
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Features of Turner Syndrome
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-1 in 2500
-short -webbed neck -no secondary female sex characterisitcs -may be mild retardation -diagnosed at puberty -no Barr body in affected cell -usually due to mosaicism |
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How can Turner Syndrome be treated if diagnosed early?
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estrogen
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What is 47XXY?
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Klinefelter Syndrome
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Features of Klinefelter Syndrome
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-tall
-diagnosed when infertility is discovered -1 in 1000 -body out of proportion -gynecomastia -small testes -degree of learning disabilities -risk of osteoporosis/breast cancer |
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Treatment of Klinefelter Syndrome
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testosterone if caught early
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Characteristics of XXX
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mild or none
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Characterisitics of XYY
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-males with few physical problems
-tall -minor behavioral problems |
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Features of Fragile X Syndrome
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-X chromosome almost has piece falling off
-large head, elongated face -prominent ears -affects boys -more frequently mother to son |
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What role does FMR1 have in Fragile X Syndrome?
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affects protein product shuttles between nucleus and cytoplasm
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What is the term describing a disorder that becomes more severe and more frequent over generations?
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anticipation
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What nucleotide sequence is repeated in disorders of increasing severity?
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CGG
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How many nucleotide repeats is considered normal?
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5-50
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How many nucleotide repeats is considered a pre-mutation?
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50-200
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How many nucleotide repeats is considered an affected individual?
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200-4000
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During which cycle would the liklihood of nucleotide repeats occur?
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oogenesis
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What disorder requires a diet low in protein?
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phenylketonuria
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What is the treatment of classic galactosemia?
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avoid dairy products
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Features of classic galactosemia
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-failure to thrive
-developmentally delayed -hepatic insufficiencies -cataracts |
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What disorder is characterized by an accumulation of metabolic by-products?
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lysosomal disorders
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What systems deteriorate in lysosomal disorders?
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-cardiovascular
-joints -hearing/vision |
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What is an example of a lysosomal disorder?
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Hurler syndrome
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What is treatment for Hurler's syndrome?
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enzymes
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What are features of Hurler's syndrome?
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-coarse facial features
-crouched stance |
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What disorder is characterized by a build-up of fatty acids?
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MCAD deficiency
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What must be remembered when giving someone with MCAD deficiency an IV?
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supplement saline with sugar
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What are features of MCAD deficiency?
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-vomiting
-lethargy -cerebral edema -liver/kidney problems -fatal if not diagnosed |
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When does MCAD deficiency present?
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after period of fasting
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What happens one week after fertilization?
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migration through fallopian tubes to uterus
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What is the term for a zygote at the 2-cell stage?
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embryo
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What is the term for cells that have the potential to give an entire animal?
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totipotent
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Up to what cell stage are cells totipotent?
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4-8 cells
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When does compaction occur?
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during 16-cell stage
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What allows cells to communicate with each other?
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gap junctions
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What gives rise to the entire embryo?
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inner cell mass
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What are the cells surrounding the embryo that don't give rise to any part of the embryo?
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trophoblast
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T or F - The inner cell mass is pluripotent
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T
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What needs male influence to form?
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trophoblast
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Which part of the embryo implants into endometrial lining?
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trophoblast
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What secretes enzymes to break down tissue of endometrium?
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synctiotrophoblast
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What two parts is the trophoblast separated into?
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1. daughter cells
2. cytotrophoblast |
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Describe the daughter cells of the trophoblast
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syncytium
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What does the cytotrophoblast give rise to?
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cellular portion of fetal placenta, chorion
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What is the inner cell mass called when it flattens into a layer of tissue?
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epiblast
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How does the epiblast form the amnion?
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edges roll up to form a dome
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What is the process of the epiblast becoming three layers?
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gastrulation
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What are the three germ layers?
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1. ectoderm
2. mesoderm 3. endoderm |
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What does the ectoderm form?
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skin, hair, nails
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What does the mesoderm form?
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muscle, bone, cardio
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What does the endoderm form?
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lining of gut from mouth to anus
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At what age is the embryo considered a fetus and displays facial features?
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8 weeks
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What is the rod of mesodermal cells that forms the brain and spinal cord?
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notochord
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What controls which genes do/don't get transcribed and is in the receiving cell?
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transcription factors
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What happens when the notochord is removed?
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no further development
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What happens when an extra notochord is inserted?
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two embryos
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Describe the limb bud
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ectodermal jacket around mesoderm
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What is the pile of ectoderm at the tip of the limb bud?
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apical ectodermal ridge
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What happens when the AER is removed?
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development stops
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What is in the posterior region of the mesoderm and determines the polarity of digits?
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zone of polarizing activity
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What happens when the ZPA is removed?
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AER goes away and development stops
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What instructs the tissue as to what it will be?
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diffusable morphogen
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Where is the diffusable morphogen more concentrated?
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closer to the source
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What forms a pattern under control of diffusable signal?
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positional information
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What is a teratogen that pregnant women should avoid?
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retinoic acid
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What does retinoic acid mimic?
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diffusable morphogen
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In salamanders, when a limb is severed what grows over the stump?
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ectocap
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What happens to tissue under the ectocap?
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de-differentiates to regeneration blastema
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What happens when the severed limb of a salamander is treated with retinoic acid?
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new limb grows
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What eminates from the AER?
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FGF (fibroblast growth factor)
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What are freely diffusable signaling molecules?
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secreted ligands
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What is at the root of telling cells what to become?
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sonic hedgehog (shh)
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Where is Shh?
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ZPA, notochord
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What is the homeotic gene that is 180 base pairs long and is the code for DNA binding proteins?
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Hox
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What tweaks the protein into specific shape to bind to DNA and chooses which genes are read?
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homeodomain
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What is caused by a mutation in Shh?
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holoprosencephaly
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What gene is found in everything and determines basic differentiation?
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Hox
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What maintains stem cells?
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Hox
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What is an increased number of cells without obvious change to tissue?
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hyperplasia
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What is increased cell growth with obvious change to cell?
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dysplasia
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What is spreading and invasiveness of changing cells?
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cancer
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one cell is transformed and all tissue of tumor is descendant of that one cell
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monoclonal
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What is epithelial cancer?
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carcinoma
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What is connective tissue/muscle cancer?
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sarcoma
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What is lymph cancer?
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lymphoma
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What are three features of transformed cells?
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1. lack contact inhibition
2. angiogenesis 3. don't drop out of cell cycle |
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What is a mitosis promotion factor?
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cdk (cyclin-dependant kinase)
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How does cyclin work when mutated growth factors?
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Cdk on all the time and cells divide
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What are normal genes for normal growth factor?
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proto-oncogenes
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What are mutated genes that signal unlimited cell division?
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oncogenes
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What are factors that stop growth in the case of chromosome abnormalities?
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tumor suppressors
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What occurs if DNA repair is not possible?
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apoptosis
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What initiates inhibition of cdk-cyclin?
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p53
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T or F - Most cancer cells are aneuploid
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T
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What is the term for aging of the cell?
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senesence
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What is the end of the chromosome that repeats to protect DNA?
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telomere
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How does senesence occur?
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as DNA is copied, telomeres shorten, which doesn't allow ends to tuck over to protect DNA
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What is secreted by tumors, placental cells that allows telomere lengthening?
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telomerase
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