TTU Biology 1402 Exam 2- Dr. Held Latest Update Already Passed

TTU Biology 1402 Exam 2- Dr. Held Latest Update Already Passed Karyotyping (#chromosome) -To determine if the patient has an abnormal # of chromosomes - "A photographic inventory of an individual's chromosomes." - ordered display of chromosomes, doubled. Criss- Cross Inheritance Sons inherit their X chromosome from their mother Codominance -The heterozygote expresses both traits (alleles). -"A" and "B" genes make structures (not enzymes)= sugar types. -Ex) Blood types (A,B, AB, O) Multiple Alleles (complication) - 2 alleles/genes in the population (=more suits/decks of cards). -Ex. 1: Blood types (3 alleles): A,B,O. -EX. 2: *Major Histocompatibility complex (MHC) has dozens of alleles*-- *tissue/transplant rejections* Epistasis -One gene masks or "dominates" the effects of another. -(ex. colour of fur in dogs. BB=black, Bb=black, bb= brown, ee=no pigment-- yellow) Polygenic Traits -One trait is caused by *many genes* (whose effects are additive). -Quantitive traits (height, weight, etc.)= often polygenic. -Ex). Human skin colour: 4 genes. Shades of brown Pleiotropy -One gene causes *many traits*. Ex). Albino mutation-- white hair, pink iris, crossed eyes X chromosome inactivation -Occurs in mammals and leads to Mosaicism (purpose= dosage comp) mRNA -Messenger RNA -Encodes amino acid sequences and carries information into the cytoplasm rRNA -Ribosome RNA -This and proteins make ribosomes (most abundant kind of RNA) tRNA -Transfer RNA -Interprets codons into proteins Double Helix -Shape of DNA found by Watson & Crick in 1953 - a twisted ladder: rungs=base+ base bond, sides =sugar+ phosphate bond. A2+T or G2+C Complimentary -Property of DNA