Presentation on theme: "Bell Ringer: Copy the following words to define for homework."— Presentation transcript:
1Bell Ringer: Copy the following words to define for homework. CarrierNondisjunctionPedigreeTelomereAutosomeDeletionCodominanceInversionIncomplete DominanceTranslocationMultiple AllelesDown SyndromeSex ChromosomeTurner’s SyndromeSex-Linked TraitKlinefelter’s SyndromeKaryotype
2Benchmark Test Info Point Breakdown 52 pts Participation 48 pts (2pts each) for the 24 questions we’ve already covered.TALKING/LOOKING AROUND will result in the loss of your 52 participation points.
3Grab a packet of guided notes from the back table. Bell-RingerGrab a packet of guided notes from the back table.
5Human inheritance does not always follow Mendel’s laws. The Big IdeaHuman inheritance does not always follow Mendel’s laws.
6Main Idea #1The inheritance of a trait over several generations can be shown in a pedigree.
7Recessive Genetic Disorders Remember - recessive traits can be masked by a dominant trait.Therefore, a person who is heterozygous for a characteristic may be considered a carrier for that trait since it will not be expressed.Even though a carrier is not affected by the trait, they can pass the trait on to future generations.In order for the recessive trait to show in the individual, the person must be homozygous recessive.
8Common Recessive Disorders Cystic FibrosisAffects the mucus-producing glands, digestive enzymes, and sweat glandsChloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in the sweatWithout sufficient chloride ions in the cells, a thick mucus is secretedThe mucus clogs ducts in the pancreas, causes problems with digestion, and blocks some of the tiny passages in the respiratory system.
9Common Recessive Disorders AlbinismCaused by altered genes, resulting in the absence of melanin (color pigment) in the hair and eyesCommon characteristics include: white hair, very pale skin, and pink pupilsTay-Sachs DiseaseCaused by the absence of an enzyme responsible for breaking down fatty acidsThe fats begin accumulating in the brain, destroying brain cells and mental deterioration.
10Dominant Genetic Disorders Some genetic disorders are controlled by a dominant allele.People who have only one copy of this allele will display the trait. Only those who are homozygous recessive will not have the disorder.Huntington’s DiseaseDisease that gradually destroys the nervous system. Symptoms usually begin between the ages of 30 and 50.AchondroplasiaGenetic condition that causes small body size and limbs that are comparatively short. This is the most common form of dwarfism.
11PedigreesA pedigree is a diagram that traces the inheritance of a particular trait through several generations.Males are represented by squares, and females by circles.One who is affected by the trait will have a symbol that is colored in, while those that are unaffected by the trait will have an unfilled symbol.
13Let’s Practice!!! Make this correction: Second question for #3 should read, What are the sexes of the children?
14Chromosomes can be studied using karyotypes. Main Idea #3Chromosomes can be studied using karyotypes.
15Karyotypes A karyotype is a picture of a person’s chromosomes. Chromosomes are taken from the stage of metaphase and stained.They are then placed in order of decreasing size. The last pair is the sex chromosome pair.Disorders caused by an incorrect number of chromosomes or malformed chromosomes are the easiest to identify using a karyotype.
17TelomeresTelomere caps consist of DNA associated with proteins.
18NondisjunctionHomologous chromosomes separate during the final steps of meiosis to ensure that each developing sperm or egg receives one copy of each chromosome.Nondisjunction is the failure of a pair of homologous chromosomes to separate properly.Resulting sex cells will either have an extra chromosome (trisomy) or a missing chromosome (monosomy).
19Down SyndromeOne of the most common disorders due to nondisjunction is Down syndrome, also known as trisomy 21.Down syndrome occurs when the person has a third copy of the 21st chromosome.Common features include: short stature, heart defects, distinctive facial features, and mental disability.
20Disorders Due to Nondisjunction of Sex Chromosomes Klinefelter Syndrome (XXY)Jacob’sSyndrome(XYY)Turner’s(XO)Trisomy X Syndrome (XXX)
21Types of MutationsMutations can involve an entire chromosome or a single DNA nucleotide, and they may take place in any cell.Germ-cell mutations occur in an organism’s gametes (germ cells).These do not affect that organism, but may be passed on to their offspring the germ cell becomes fertilized.Somatic mutations occur in an organism’s body cells and can affect the organism.These mutations cannot be passed on to offspring.Some examples include skin cancer and leukemia.Lethal mutations cause death, usually before birth.
22Chromosome MutationsDeletion (1)- results in the loss of a piece of chromosome due to the breakage of that chromosome; genetic information will be lostDuplication (2)- results in the copying of a segment of the chromosomeInversion (3)- a segment of a chromosome breaks off and reattaches itself to the chromosome in a reversed order
23Chromosome MutationsInsertion (1) - a segment of a chromosome breaks off and reattaches itself to another homologous chromosomeTranslocation (2) - segments of chromosomes break off and exchange places on different chromosomes
24Chromosome MutationsNondisjunction is also a type of chromosome mutation. It affects the total number of chromosomes instead of pieces of individual chromosomes.
25Copy your homework for the week! Bell-RingerCopy your homework for the week!1/13 – 1/17 Homework:Monday: Chapter 11 Assessment pg1-30 Omit #s 11, 16, 18, 19, 20, 27, 28Tuesday: STUDY FOR TESTWednesday: Ch. 12 VocabBRING YOUR BOOK THURSDAYThursday: Finish Ch. 12 Guided ReadingFriday: NONE
26Genetic Disorder Foldable AchondroplasiaSex-LinkedAlbinismTay-SachsCystic FibrosisTurner’s SyndromeDown SyndromeHuntington’s DiseaseKlinefelter SyndromeTell if the listed disorders are dominant or recessive and give a brief description of each.For Sex-Linked describe the two that we discussed in class.