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66 Cards in this Set
- Front
- Back
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What is a karyotype?
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A picture of chromosomes
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What are the sex chromosomes?
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The X and Y chromosomes (2)
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What are autosomes?
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Non-sex chromosomes (44), 22 different kinds
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What is a pedigree?
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A chart which shows relationships within a family
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All human egg cells carry a single ________ chromosome.
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X
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Half of all sperm cells carry an ___________ chromosome and half carry a ________ chromosome.
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X, Y
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What does this ensure?
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That just about half of the zygotes will be 46,XX and half will be 46,XY
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What is the human genome?
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Our complete set of genetic information
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Why is it critical that a person knows their blood group?
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Because using the wrong type of blood for a transfusion during a medical procedure can be fatal.
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What are the two best known blood groups responsible for human blood groups?
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The ABO group and the Rh group
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What does "Rh" stand for and why was it named this?
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It was named after the "rhesus monkey", this is where the factor was discovered
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What is Tay-Sachs disease?
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Lipid accumulation in brain cells; mental deficiency; blindness; death in early childhood
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What is Phenylketonuria?
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Ppl with PKU lack the enzyme that is needed to break down phenylalanine. Accumulation of phenylalanine in tissues; lack of normal skin pigment; mental retardation
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What do these two diseases have in common?
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They are both caused by recessive alleles.
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What is achondroplasia?
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It causes a form of dwarfism
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What is Huntington Disease?
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A nervous disease, loss of muscle control and mental function until death.
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What do these two diseases have in common?
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They are both caused by dominant alleles
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What do cystic fibrosis and sickle cell disease have in common?
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They both have a small change in the DNA of a single gene that affects the structure of a protein, causing a serious genetic disorder
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What is cystic fibrosis?
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It caused by a recessive allele on chromosome 7, in children it causes serious digestive problems and a heavy mucus that clogs lungs and breathing passage ways.
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What is the genetic defect that causes cystic fibrosis?
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The deletion of three bases in the DNA of a single gene
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What type of allele causes sickle cell?
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Codominant alleles
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Who is it common for sickle cell to appear in?
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African Americans
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What happens in sickle cell?
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There is a bent and twisted shape of the red blood cells. The red blood cells are more rigid than normal cells, and get stuck in the capillaries, and as a result, blood stops moving through vessels damaging tissues and organs.
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What causes the cells to be in a shape of a sickle?
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One DNA base is changed, then the amino acid valine is substituted for glutamic acid. As a result, the abnormal hemoglobin is less soluble. This decrease in O2 levels causes the hemoglobin molecules to stick together, forming the sickle shape.
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What two chromosomes are the smallest human chromosomes?
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Chromosome 21 and 22
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What are sex-linked genes?
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Genes associated with either the X or Y chromosome
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Males only have one X chromosome so...
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All X-linked alleles are expressed in males even if they are recessive
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Why is it more likely for males to be colorblind?
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B/c the genes associated with color vision are on the X-chromosome, and they are recessive, so for a female to have colorblindness, both the X-chromosomes would have to have the defect.
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What is Hemophilia?
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A sex-linked disorder, a protein needed for blood clotting is missing on one of two genes carried on the X-chromosome
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What is Duchenne Muscular Dystrophy?
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Sex-linked disorder that results in weakening and loss of muscle. Caused by defect in gene that codes for muscle protein.
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What is nondisjuntion?
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An error in meiosis, homologous chromosomes fail to separate
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What is Down Syndrome?
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If two copies of an autosomal chromosome fail to separate during meiosis, an individual may be born with three copies of a chromosome. When it's chromosome 21, it's Down Syndrome.
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What is Turner's syndrome?
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Nondisjuntion can lead to it, women only inherit one X-chromosome, so they cannot reproduce.
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What is Klinefelter's syndrome?
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In males, nondisjunction can lead to it, there is an extra X-chromosome which interferes with meiosis, they cannot reproduce
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What can you do if you wanted to know if you could have a genetic disorder?
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You can run genetic testing that can spot the differences
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What is DNA fingerprinting?
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DNA fingerprinting analyzes sections of DNA that have little or no known function but vary widely from one individual to another
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What is the Human Genome Project?
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AN ongoing effort to analyze the human DNA sequence
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What is "shotgun sequencing"?
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Method involving butting DNA into random fragments and then determining the sequence of bases in each fragment.
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About how many genes do humans have in their DNA?
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25,000
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What is gene therapy?
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The process of changing the gene that causes a genetic disorder.
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What exactly happens in gene therapy?
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A faulty gene is replaced by a normal one
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What are Mendel's four principles?
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-Principle of Dominance=some alleles are dominant and some are recessive
-Principle of Segregation=each unit character separates into a different sex cell -Principle of Unit Characters=Individuals pass info as individual traits -Principle of Independent Assortment=genes segregate according to chance |
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Are all alleles dominant or recessive?
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No, some are neither
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What is incomplete dominance?
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The phenotype is a mix between both alleles b/c neither is dominant
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What is codominance?
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When both alleles are dominant and the phenotype shows both traits.
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What is multiple alleles?
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When genes have more than two alleles.
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What are polygenic traits?
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Traits having many genes
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What is homologous?
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The four chromosomes from meiosis have the same chromosome from each parent
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What is a diploid?
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Two sets of chromosomes and genes
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What does 2N=D mean?
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That there are two sets aka a diploid
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What is a haploid?
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One set of genes and chromosomes
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What are the stages of meiosis I (in order)?
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Prophase I, Metaphase I, Anaphase I, Telophase I and Cytokinesis
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What stage comes before meiosis I?
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Interphase I
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What happens in Prophase I?
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Each chromosome pairs w/ it's homologous chromosome
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What happens in Metaphase I?
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Spindle attaches to chromosomes
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What happens in Anaphase I?
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The fibers pull the chromosomes toward opposite sides of the cell
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What happens in Telophase I and Cytokinesis?
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Nuclear membranes form, the cells separates into two cells
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What happens in Prophase II?
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Meiosis I results in two daughter cells (w/ half the # of chromosomes).
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What happens in Metaphase II?
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Chromosomes line up
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What happens in Anaphase II?
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Sister chromatids separate and move towards opposite ends of the cell
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What happens in Telophase II and Cytokinesis?
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Four haploid daughter cells
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What is a tetrad?
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When the chromosome pairs w/ it's corresponding homologous chromosome to form this structure
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What is crossing-over?
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When tetrads exchange portions of their chromatids
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What is the difference between meiosis and mitosis?
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Mitosis produces 2 identical diploids, and meiosis produces 4 different haploids
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Do individual genes assort independently?
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No, chromosomes do
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What is a gene map?
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It shows the relative locations of each known gene
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