BIO Midterm #2-Chapter 9

25 July 2022
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Mendel formulated his principles of inheritance based on _____.
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observations on the outcomes of breeding experiments. The underlying processes were unknown at the time.
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Mendel observed that pairs of alleles were separated or segregated in gametes and that they were rejoined in fertilization. We know that pairs of _____ are segregated in _____ and then are rejoined through fertilization.
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homologous chromosomes ... meiosis
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As we now understand it, the Law of Independent Assortment applies _____.
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to pairs of genes that are on different chromosomes, but NOT to pairs of genes that are close together on the same chromosome
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If you are a male, the Law of Independent Assortment indicates that your gametes contain _____.
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a random mix of the chromosomes you inherited from each parent
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How have Mendel's laws fared as we have learned more about cell biology and processes such as meiosis?
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Our new knowledge has helped to explain some of the exceptions to Mendel's laws of inheritance.
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The scientific study of heredity is called _____.
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genetics
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An allele is __________.
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an alternative version of a gene
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a ___________ is an inherited feature that varies from individual to individual
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character
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a _________ is one particular variation of a character
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trait
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a genetic cross involving parents that differ in a single character is called a
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monohybrid cross
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most human genes come in alternative versions called
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alleles
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the physical traits of an organism are called its
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phenotype
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the __________ is the genetic makeup of the organism
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genotype
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The disease hemophilia is caused by a _______ gene that is located on the _____ chromosome
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single, X
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hemophilia is a _______ disease
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recessive
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GgTt pea plants can produce _____ type(s) of gamete(s), but a ggtt plant can produce _____ type(s) of gamete(s).
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four........one
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Mendel worked in a _______
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monastery
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A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would produce a(n) ______.
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hybrid
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According to Mendel's law of segregation, ______.
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gametes have one copy of each allele
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Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). What is the expected phenotypic ratio of a cross between an RrYy and an rryy individual?
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1:1:1:1
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A couple has two female children. What is the probability that their next child will be male?
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50%
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Close relatives who mate are more likely to have children with genetic diseases because __________.
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close relatives are likely to carry the same genetic disorders
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all individuals with _______ conditions have an affected parent. An affected individual _______ have affected offspring,.
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dominant, might not
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In humans, the __________ determines the sex of the offspring because __________.
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male ... the male can contribute either an X or a Y chromosome
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Color blindness is a recessive, sex-linked trait in humans that is located on the X chromosome. The color-blindness trait shows up only in males because __________.
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males have only a single X chromosome and thus no wild-type allele to offset the recessive allele
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The development of many different breeds of dogs from a single ancestor has been the result of _____.
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artificial selection
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Why are human males much more likely than human females to inherit the recessive condition hemophilia?
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hemophilia is sex linked
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what is hemophilia?
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a failure of the blood to clot properly
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To determine the genotype of an individual who expresses a dominant trait, you would cross that individual with an individual who ______.
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is homozygous recessive for that trait
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n general, the frequency with which crossing over occurs between two linked genes depends on __________.
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how far apart they are on the chromosome
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Which of the following is behind the concept of creating exon-skipping drugs?
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Improperly working genes can be corrected.
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Just one error in the genetic code can lead to problems in protein creation because which of the following are being incorrectly coded for?
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amino acids
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character
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a heritable feature that varies among individuals, such as flower color
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trait
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a variant of a character, such as white flowers
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gene
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segment of a chromosome that is responsible for a genetic trait.
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locus
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specific position of a particular gene on a chromosome
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alleles
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- alternate forms (flavors) of the same gene on a pair of homologs
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dominant allele
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- Allele that codes for dominant trait. -It is always expressed in individual
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recessive allele
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Allele that codes for recessive trait. -expressed only if the dominant allele is not present.
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genotype
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all of an individual's genes
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phenotype
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any observable trait. - Those genes that are expressed.
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mono-hybrid cross
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A genetic cross between homozygous individuals but with different alleles for a single gene locus of interest. the parents differ in only one character (flower color)
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dihybrid cross
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the mating of paternal varieties differing in two characters
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mendel's law of segregation
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a sperm of egg carries only one allele for each inherited character because the two allels for a character segregate (separate) from each other during the production of gametes in meiosis
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mendel's law of independent assortment
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each pair of alleles segregates independently of the other pairs of alleles during gamete formation. i.e, the inheritance of one character has no effect on the inheritance of another
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testcross
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a mating between an individual of dominant phenotype but unknown genotype
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independent assortment uses a _______ cross
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dihybrid
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law of segregation uses a _________ cross
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monohybrid
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incomplete dominance
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One allele is not fully dominant over its partner. white+red=pink flowers
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complete dominance
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the effect of one allele in a heterozygous genotype completely masks the effect of the other
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co-dominance
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both alleles are expressed in heterozygous individuals (IAIB who have type AB blood)
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type a blood
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red blood cells coated with carbohydrate a
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type b blood
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red blood cells coated with carbohydrate b
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type ab blood
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red blood cells coated with carb a and carb b
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type o blood
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red blood cells coated with NEITHER carb a or carb b
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three alleles for blood type
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I^A, I^B, i
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universal donor
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type o
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universal recipient
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type ab
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pleiotropy
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one gene influences several characters
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example of pleiotripy
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sickle cell disease
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polygenic inheritance
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a particular trait is produced by the interaction of many genes
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example of polygenic inheritance
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height
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linked genes
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genes that are located close together on a chromosome
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sex linked recessive disease
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hemophilia
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wild-type traits
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those seen most often in nature