Presentation on theme: "Bell Ringer: Copy the following words to define for homework. 1)Carrier 2)Pedigree 3)Autosome 4)Codominance 5)Incomplete Dominance 6)Multiple Alleles 7)Sex."— Presentation transcript:
Bell Ringer: Copy the following words to define for homework. 1)Carrier 2)Pedigree 3)Autosome 4)Codominance 5)Incomplete Dominance 6)Multiple Alleles 7)Sex Chromosome 8)Sex-Linked Trait 9)Karyotype 10)Nondisjunction 11)Telomere 12)Deletion 13)Inversion 14)Translocation 15)Down Syndrome 16)Turners Syndrome 17)Klinefelters Syndrome
Benchmark Test Info Point Breakdown 52 pts Participation 48 pts (2pts each) for the 24 questions weve already covered. TALKING/LOOKING AROUND will result in the loss of your 52 participation points.
Bell-Ringer Grab a packet of guided notes from the back table.
The Big Idea Human inheritance does not always follow Mendels laws.
Main Idea #1 The inheritance of a trait over several generations can be shown in a pedigree.
Recessive 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.
Common Recessive Disorders Cystic Fibrosis Affects the mucus-producing glands, digestive enzymes, and sweat glands Chloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in the sweat Without sufficient chloride ions in the cells, a thick mucus is secreted The mucus clogs ducts in the pancreas, causes problems with digestion, and blocks some of the tiny passages in the respiratory system.
Common Recessive Disorders Albinism Caused by altered genes, resulting in the absence of melanin (color pigment) in the hair and eyes Common characteristics include: white hair, very pale skin, and pink pupils Tay-Sachs Disease Caused by the absence of an enzyme responsible for breaking down fatty acids The fats begin accumulating in the brain, destroying brain cells and mental deterioration.
Dominant 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. Huntingtons Disease Disease that gradually destroys the nervous system. Symptoms usually begin between the ages of 30 and 50. Achondroplasia Genetic condition that causes small body size and limbs that are comparatively short. This is the most common form of dwarfism.
Pedigrees A 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.
Lets Practice!!! Make this correction: Second question for #3 should read, What are the sexes of the children?
Main Idea #3 Chromosomes can be studied using karyotypes.
Karyotypes A karyotype is a picture of a persons 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.
Telomeres Telomere caps consist of DNA associated with proteins.
Nondisjunction Homologous 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).
Down Syndrome One 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.
Disorders Due to Nondisjunction of Sex Chromosomes Klinefelter Syndrome (XXY) Jacobs Syndrome (XYY) Turners Syndrome (XO) Trisomy X Syndrome (XXX)
Types of Mutations Mutations can involve an entire chromosome or a single DNA nucleotide, and they may take place in any cell. Germ-cell mutations occur in an organisms 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 organisms 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.
Chromosome Mutations Deletion (1)- results in the loss of a piece of chromosome due to the breakage of that chromosome; genetic information will be lost Duplication (2)- results in the copying of a segment of the chromosome Inversion (3)- a segment of a chromosome breaks off and reattaches itself to the chromosome in a reversed order
Chromosome Mutations Insertion (1) - a segment of a chromosome breaks off and reattaches itself to another homologous chromosome Translocation (2) - segments of chromosomes break off and exchange places on different chromosomes
Chromosome Mutations Nondisjunction is also a type of chromosome mutation. It affects the total number of chromosomes instead of pieces of individual chromosomes.
Bell-Ringer Copy your homework for the week! 1/13 – 1/17 Homework: Monday: Chapter 11 Assessment pg. 319-321 1-30 Omit #s 11, 16, 18, 19, 20, 27, 28 Tuesday: STUDY FOR TEST Wednesday: Ch. 12 Vocab BRING YOUR BOOK THURSDAY Thursday: Finish Ch. 12 Guided Reading Friday: NONE
Genetic Disorder Foldable 1.Achondroplasia 2.Albinism 3.Cystic Fibrosis 4.Down Syndrome 5.Huntingtons Disease 6.Klinefelter Syndrome 7.Sex-Linked 8.Tay-Sachs 9.Turners Syndrome Tell 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.