Bio 16

males are hemizygous for x-linked genes

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punnett square steps

1) write down genotype for both parents 2) write down the possible gamete that each parent can make 3)create an empty Punnett square. 4) fill in the empty Punnett square. 5) determine the relative proportions of the genotype.

3 important ideas about the properties and transmission of traits from parents to offspring

1)Dominant and recessive traits. 2)people carry 2 genes for a given charater; genes have variant forms called allleles 3) the 2 alleles of a gene separate during gamete formation so that each sperm and egg receives only one allele.

chromosome theory of inheritance

1. chromosomes contain DNA 2.chromosomes are passed from parent to offspring. 3.the Nucleus of a diploid cel contains two sets of chromosomes. 4. at meiosis, one member of chromosome pair segregates into one daughter nucleus and its homolog segregates into other daughter nucleus. 5. Gametes are haploid cels that combine to form a diploid cell during fertilization. each gamete transmits one set of chromosomes to offspring.

Chromosome orientation with 4 chromosomes Cells from the fruit fly Drosophila melanogaster contain four pairs of chromosomes. What is the number of possible chromosome orientations in that cell? 4 8 16 24 32

16

law of segeration

3:1 ratio between the dominant and recessive traits. Two copies of a gene segregate from each other during transmission from parent to offspring.

monohybrid cross

A CROSS IN WHICH THE INHERITANCE OF ONLY ONE TRAIT IS FOLLOWED.

Understanding recessive aleles In Mendelian inheritance patterns, which of the following statements is accurate about recessive alleles? Check all that apply. A recessive allele will have no noticeable effects on an organism's phenotype if a dominant allele is present A recessive allele will never have a noticeable effect on an organism's phenotype A recessive allele is a weaker form of a dominant allele A recessive allele will have an effect on an organism's phenotype if the individual is homozygous for the recessive allele A recessive allele will have an effect on an organism's phenotype only if the individual is heterozygous Recessive alleles can be either on the maternal chromosome or the paternal chromosome

A recessive allele will have no noticeable effects on an organism's phenotype if a dominant allele is present A recessive allele will have an effect on an organism's phenotype if the individual is homozygous for the recessive allele Recessive alleles can be either on the maternal chromosome or the paternal chromosome

true-breeding line

A strain that continues to exhibit the same trait after several generations of self-fertilization or inbreeding.

Maternal and paternal alignment not following independent assortment What would be a likely outcome if the alignment of maternal and paternal chromosomes during metaphase of meiosis did not adhere to Mendel's Law of Independent Assortment? Alleles for genes would tend to be inherited together because chromosome pairs would align non-randomly. Alleles for genes would tend to be inherited separately because chromosome pairs would align non-randomly. Alleles for genes would tend to be inherited together because chromosome pairs would align randomly. Alleles for genes would tend to be inherited separately because chromosome pairs would align randomly.

Alleles for genes would tend to be inherited together because chromosome pairs would align non-randomly.

Understanding genotype In humans, the allele for freckles is dominant (F) and the allele for no freckles is recessive (f). An individual who is heterozygous for freckles would have which of the following genotypes? FF Freckled Ff ff no freckles

Ff

Understanding phenotype In humans, the allele for freckles is dominant (F) and the allele for no freckles is recessive (f). An individual who is heterozygous for freckles would have which of the following phenotypes? Ff Freckles FF No freckles ff

Freckles

Inheritance without independent assortment A diploid parent cell with genes H, T, and Q has a maternal genotype HTQ and paternal genotype htq. What would be the most likely daughter cell genotype if independent assortment does NOT occur? HtQ hTQ HTQ hTq

HTQ

Maternal and paternal chromosome pairing The fact that maternal and paternal chromosome pairs align and orient randomly during metaphase of meiosis supports Mendel's rev: 11_08_2013_QC_ 39535 Law of Probability Law of Segregation Law of Independent Assortment Law of Addition

Law of Independent Assortment

Monohybrid cross: Looking at offspring, determine genotypes of parents In pea plants, a single gene controls pea texture. Smooth (S) peas are dominant over wrinkled (s) peas. A plant with smooth peas is crossed with a plant with wrinkled peas. Of the progeny, 252 are smooth and 247 are wrinkled. What are the genotypes of the parent plants? SS and ss ss and ss Ss and ss Ss and Ss SS and Ss

Ss and ss

monohybrids

The f1 offspring ,also called single-trair hybrids, of true breeding parents that differ with regard to a single trait.

Why is muscular dystrophy more common in boys? Muscular dystrophy (MD) is a group of disorders that involve muscle weakness and loss of muscle tissue. Duchenne muscular dystrophy (DMD) is a rapidly-worsening form of MD. DMD is caused by a defect in the dystrophin gene. The dystrophin protein is a vital part of a protein complex involved in muscle support and structure. DMD is much more common in boys than in girls ( about 1/3500 boys have DMD, girls rarely have DMD). Which statements about DMD are ACCURATE? Check all that apply. The gene for dystrophin must be on the X chromosome The gene for dystrophin must be on the Y chromosome The gene for dystrophin is likely on an autosome If a female has a defective dystrophin allele, she will likely have a normal allele to act as a "back up" Males are hemizygous, so they will have DMD even if they have only one defective allele. DMD is inherited as an X-linked recessive trait DMD is an autosomal dominant trait A woman who is a carrier for DMD will pass the defective allele to half her sons, and those sons will have DMD A man who has DMD will pass the defective allele to all of his sons, and those sons will have DMD

The gene for dystrophin must be on the X chromosome If a female has a defective dystrophin allele, she will likely have a normal allele to act as a "back up" Males are hemizygous, so they will have DMD even if they have only one defective allele. DMD is inherited as an X-linked recessive trait A woman who is a carrier for DMD will pass the defective allele to half her sons, and those sons will have DMD

Dihybrid Cross: the F1 generation In pea plants, yellow seeds (Y) are dominant to green seeds (y) and round seeds (R) are dominant to wrinkled seeds (r). The genes for seed color and seed shape are on different chromosomes. Two true-breeding parents, one with yellow round peas and the other with green wrinkled peas, are crossed. Which of the following is/are accurate regarding the resulting F1 plants? Check all that apply. The genotype of the F1 plants is YyRr Half the F1 plants have the genotype YYRR and half have the genotype yyrr Half the F1 plants have the genotype YR and half have the genotype yr The F1 plants have the following phenotypes - yellow round, yellow wrinkled, green round, green wrinkled - in equal proportions All of the F1 plants have yellow round seeds Half of the F1 plants have yellow round seeds and half have green wrinkled seeds All of the F1 plants have green wrinkled seeds The F1 plants make only YR and yr gametes The F1 plants make YR, Yr, yR, and yr gametes in equal proportions

The genotype of the F1 plants is YyRr All of the F1 plants have yellow round seeds The F1 plants make YR, Yr, yR, and yr gametes in equal proportions

Dihybrid Cross: the F1 generation In pea plants, yellow seeds (Y) are dominant to green seeds (y) and round seeds (R) are dominant to wrinkled seeds (r). The genes for seed color and seed shape are on different chromosomes. Two true-breeding parents, one with yellow round peas and the other with green wrinkled peas, are crossed. What are the genotypes of the parents, and what kind of gametes will they produce? rev: 11_14_2013_QC_40279 The genotype of the plant with yellow round seeds will be yyrr and produce yr gametes, while the genotype of the plant with green wrinkled seeds will be YYRR and produce YR gametes. The genotype of the plant with yellow round seeds will be YYRR and produce YR gametes, while the genotype of the plant with green wrinkled seeds will be yyrr and produce yr gametes. The genotype of the plant with yellow round seeds can be YYRR or YyRr and will produce YR, Yr, yR and yr gametes, while the genotype of the plant with green wrinkled seeds will be yyrr and produce yr gametes. The genotype of the plant with yellow round seeds will be YR and produce Y and R gametes, while the genotype of the plant with green wrinkled seeds will be yr and produce y and r gametes. The genotype of the plant with yellow round seeds will be YYRR and produce Y gametes and R gametes, while the genotype of the plant with green wrinkled seeds will be yyrr and produce y gametes and r gametes.

The genotype of the plant with yellow round seeds will be YYRR and produce YR gametes, while the genotype of the plant with green wrinkled seeds will be yyrr and produce yr gametes.

what is the ration of the Tallele to the tallele in the F2 generaton? Dose this ration differ from the 3:1 phenotype ratio? if so , explain why.

The ratio of allele(T to t) is 1:1. The reason why the phenotypic ratio is 3:1 is because T is dominate to t.

Diploid cell that contains genes Y, R, and Z on separate chromosomes Consider a diploid cell that contains genes Y, R, and Z on separate chromosomes. What is the likely genotype of a daughter cell if the parent cell with genotype YyRRZz undergoes meiosis? rev: 12_09_2013_QC_42130 YrZ YyRRZz YYRRZZ YRZ

YRZ

characters

a character of an organism such as appearance of seeds, pods, flowers or stems.

test cross

a cross to determine of an individual with a dominat phenotype is homozygote or a heterozygote.Also a cross to determine if two different genes are linked.

norm of reaction

a decription of how a trait may change depending on environmental conditions.

trait

a identifiable characteristic; usually refers to a variant.

hybridization

a situation in which two individuals with different characteristics are mated individuals or crossed to each other: the offspring are referred to as hybrids.

law of Independent assortment

alleles of different genes assort independently of each other during gamete formation.

when we say that alleles segregate, what does the word segregate mean? how is this related to meiosis?

alleles segregate from each other during the process of meiosis

mutant alleles

an allele that has been altered by a mutation

homozygous

an individual with two identical alleles of a gene. Example: TT , tt

dihybrid

an offspring that is a hybrid with respect to two traits.

during which phase of cellular division does Mendel's law of segregation physically occur? a. mitosis b. meiosis 1 c. meiosis 2 d. all of the above e. b and c only

b. meiosis 1

a man and a women are both heterozygous for the recessive allele that causes cyctic fibrosis. What is the probability that their first 2 offspring will have the disorder? a. 1 b. 1/4 c. 1/16 d. 1/32 e. 0

c. 1/16

Based on Mendels experimental crosses, what is the expected F2 phenotypic ration of a monohybrid cross? a. 1:2:1 b. 2:1 c. 3:1 d. 9:3:3:1 e. 4:1

c. 3:1

which of mendels laws cannot be observed in a monohybrid cross? a. segregation b. dominance/recessiveness c. independent assortment d. codominance e. all of the above can be observed in a monohybrid cross

c. independent assortment

a women is heterozygous for an x-linked trait, hemophilia A if she has a child with a man without hemophilia A, what is the probability that the child wll be a male with hemophilia A? a.100% b. 75% c. 50% d. 25% e. 0%

d. 25%

an individual has two different alleles of a particular gene is said to be a. dihybrird b. recessive c. homozygous d. heterozygous e. hemizygous

d. heterozygous

a hypothetical floweringg plant species produces blue,light blue and white flowers. to determine the inheritance pattern, the following crosses were conducted with the results indicated: blue x blue = all blue white x white = all white blue x white = all light blue what type of inheritance pattern does this reperesent? a simple mendelian b. x-linked c. codominance d. incomplete dominance e. pleiotropy

d. incomplete dominance

the gene that affects more than one phenotypic trait is said to be a. dominant b. wild type c. dihybrid d. pleiotropic e. heterozygous.

d. pleiotropic

genes located in a sex chromosome are said to be a. sex-linked b. dominant c. hemizygous d. sex-linked e. autosomal

d. sex-linked

during a ____ cross, an individual with the dominant phenotype and unknown genotype is crossed with a ___ individual to determine the unknown genotype. a. monohybrid, homozygous recessive b. dihybrid,heterozygous c. test, homozygous dominant e. test, homozygous recessive

e. test, homozygous recessive

cross-fertilization

fertilization that involves the union of a female and a male gamete from different individuals.

Self-fertilization

fertilization that involves the union of the female gamete and male gamete from the same individual.

Starting with a 2n=32 cell Starting with a 2n=32 cell, at the end of meiosis II there will be four cells, each n=32 two cells, each n=32 two cells, each 2n=16 four cells each 2n=16 four cells, each n=16

four cells, each n=16

Is having blue eye a character, a variant or both?

having blue eyes is a variant (also called a trait). a charater is a more general term, which in this case would refer to eye color.

Blending hypothesis

idea that genetic material from both paretns blend together.

why are the stamens removed from the purple flower?

in this procedure, stamens are removed from the purple flower to prevent self-fertilization,

hetrozygous

individual that carries two different alleles of a gene. Exampe: Tt

mendlian inheritance

inheritance patterns of genes that segregate and assort independently.

pedigree analysis

inherited traits are analyzed over the course of a few generations in one family.

let's suppose you had a plant with purple flowers and unknown genotype and conducted a testcross to determine its genotype. you obtained 41 plants: 20 white flowers and 21 with purple flowers. what was the original purple flowered plant?

it was Pp. to produce whit offspring, which are pp. the orginal plant had to have atleast one copy of the p allele. because it had purple flowers, it also had to have one copy of the P allele. So, its genotype must be Pp

could you study the norm of reaction in a wild population of squirrels?

no you need a genetically homogenous population to study the norm of reaction. a wild population of squirrels is not genetically homogenous, so it could not be used.

wild-type allele

one or more prevalent alleles in a population

particulate hpothesis

parents pass on discrete heritable genes.

sex chromosomes

refers to a distinctive pair of chromosomes that are different in males and female and determine sex.

multiple alleles

refers to the occurrence o agene that exists as three or more alleles in a population.

explain the relationship between sexual reproduction and homologous chromosomes.

sexual reproduction is the process in which two haploid gametes combine with eachother to begin the life of a new individual. each gamete contributes one set of chromosomes. the resulting zygote has chromosomes that occur in pairs. The members of each pair are called homologs of each other; they carry the same types of genes

phenotype

the charateristics of an organism that are the result of the expression of its genes.

Genotype

the genetic composition of an individual.

if a person was born with only one x chromosome and no y chromosome, would you expect that person to be male or female?

the person would be a female because the presence of the y chromosome cause maleness.

incomplete dominance

the phenomenon in which a heterozygote that carries two different alleles exhibits a phenotype that is intermediate between the corresponding homozygous individuals.

pleiotropy

the phenomenon in which a mutation in a single ggene can have multiple effects on an individuals phenotype.

codominance

the phenomenon in which a single individual expresses two alleles.

why do offspring of the F1 generation exhibit only one variant of each character?

the reason why offspring of the F1 generation exhibit only one variant of each character is because one trait is dominant over the other.

let's suppose that a cell is heterozygous for three different genes (Aa Bb Cc) and that each gene is on a different chromosome. How many different ways can these three pairs of homologous chromosomes align themselves during metaphase 1 and how may different types of gametes can be produced?

there would be four possible ways of aliging the chromosomes and eight different types of gamete( ABC,abc,ABc, abC, Abc. aBC.AbC, aBc) could be produced.

Which of the following best reflects Mendel's principle of segregation Mendel's Principle of Segregation states that two chromosomes separate during gamete formation such that every gamete receives both parental forms of the chromosome. two alleles of a gene separate during gamete formation such that every gamete receives only one allele. two alleles of a gene duplicate during gamete formation such that every gamete receives both alleles. all alleles of a gene separate during gamete formation such that each gamete receives two variants of a gene. two chromosomes separate during gamete formation such that each gamete receives two copies of each parental gene.

two alleles of a gene separate during gamete formation such that every gamete receives only one allele.