Biology Chapter: Homologous2 Chromosomes3

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Questions and Answers

The term "homologous chromosomes" refers to:

A single set of chromosomes - such as a haploid set

A pair of chromosomes that contain similar or corresponding genes (correct)

Chromosomes that are similar in a number of different species

None of the above

an exchange between non-homologous chromosomes, resulting in chromosomes with new genes adjacent to each other.

loss of genes in part of a chromosome

an extra copy of the genes on part of a chromosome (correct)

a reversal of order of genes on a chromosome

an extra set of chromosomes in an organism

The chromosome on the photo below is: (bild med centrosome näst högst upp)

metacentric

acrocentric

submetacentric (correct)

fragile X-chromosome

Which of the following conditions are required for a population to be in Hardy-Weinberg equilibrium?

All of these are conditions of Hardy-Weinberg equilibrium Signup and view all the answers

Down syndrome is the result of:

Additional chromosome 21 Signup and view all the answers

What components should be added to a polymerase chain reaction (PCR)?

DNA polymerase, dNTPs, Mg ions, DNA. Signup and view all the answers

Which genetic condition is revealed in the photos above? bilder visar blåa ögon, fel på en hand och fel på foten

Down syndrome Signup and view all the answers

Identical twins are:

Monozygous Signup and view all the answers

The chromosome on the photo above is : bilden visar centromer i mitten

Metacentric Signup and view all the answers

The photo represents agarose gel electrophoresis patterns of ACE gene polymorphism. Which of the lanes

den som är dubbla sträck var 5,6,9

5,6,9 Signup and view all the answers

Examine the pedigree in the figure above, where individuals that have the genetic condition being tested arcircles. Which of the following inheritance patterns is most likely correct for this condition?

autosomal dominant Signup and view all the answers

Deletion is a type of mutation when:

If fragment of a chromosome is lost Signup and view all the answers

Fraternal (dizygotic) twins are produced when:

Two eggs are fertilized simultaneously Signup and view all the answers

The polymerase chain reaction or PCR is a technique that

uses short DNA primers and a thermostable DNA polymerase to replicate specific DNA sequences in vitro. Signup and view all the answers

Which of the following is an example of monosomy?

45,X Signup and view all the answers

Hemochromatosis is an autosomal recessive disease that is relatively common in the population (1 in 500).successfully by periodic removal of blood (serial phlebotomy) but failure to recognize it can lead to a numbePopulation screening for carriers is being considered. What is the expected carrier frequency in the popula

8,5 % Signup and view all the answers

A woman brings her 16-year old daughter to a physician because she has not yet begun menstruating. Althmeters, the patient is 1.5 meters and has always been below the 50th percentile in height. Physical examinadevelopment. She has no problems in school and is of normal inteligence.What is the most likely underly

A 45,X karyotype Signup and view all the answers

On physical examination, a newborn is found to have micrognathia, a prominent occiput, low-set ears, andlittle mental development during the first month of life, and the infant dies of cardiac complications after 8of this child would show which of the following?

Trisomy 18 Signup and view all the answers

A nondisjunction of chromosome 21 in meiosis II in a male would yield which combination of the following

one sperm with two chromosome 21s, one with no chromosome 21s and two sperm with one chromo Signup and view all the answers

Which of the following diagnostic techniques is of great value for the diagnosis of neural tube defects?

Ultrasonography Signup and view all the answers

The pregnant mother of a 6-year-old son with glucose-6-phosphate dehydrogenase deficiency is very worriethe disease. The father and mother are clinically normal. Which of the following is true about her baby?

The baby has 50% chance of being a carrier Signup and view all the answers

Which of the following statements is accurate in regards to prenatal diagnosis?

Low AFP, high HCG, and low unconjugated estriol on a second trimester triple screen indicates an incresyndrome. Signup and view all the answers

Certain combinations of chromosomes in Robertsonian translocation carry a risk for the carriers of these cochildren because the possible trisomies that can result are viable (can be born alive). Other combinations cachildren, but can result in what is perceived as infertility because abnormal conceptions may not be recognabort. Which one of the folowing Robertsonian translocations in a carrier confers the greatest risk for havin Select one:

t(14;21) Signup and view all the answers

The patient has flat occiput, Brushfield spots, atrioventricular canal cardiac defect, single palmar creases. MSelect one:

Trisomy 21 Signup and view all the answers

Characteristics of women with Turner's syndrome include which of the following?

They almost always display short stature. Signup and view all the answers

A tall male with gynecomastia and small testes should have a cytogenetic study to diagnose which of the foSelect one:

Klinefelter syndrome Signup and view all the answers

The proband and both his parents suffer from hereditary multiple exostoses, while two of his brothers are hProband’s maternal grandfather and paternal grandmother also suffered from the disease. Their spouses wean affected child in proband’s family, if he marries a woman without the disease. Select one:

0,25 Signup and view all the answers

Which pedigree represents X – linked dominant inheritance?

Pedigree C Signup and view all the answers

Father has a trait, which is inherited in X linked recessive mode of inheritance. Calculate the probability to hmarriage with a female who is a carrier of recessive allele. Select one:

1/4 Signup and view all the answers

In South Africa, variegate porphyria is found in white South Africans at a higher frequency than would be exHardy-Weinberg eqiulibrium. This population originated from a small group of Dutch settlers. The most likefrequency of variegate in this population is: Select one:

The founder effect Signup and view all the answers

A sample of 100 000 of human disclosed 30 persons ill with retinoblastoma (autosomal dominant trait). Caldominat allele in this population Select one:

0,00016. Signup and view all the answers

Inherited methemoglobinemia (a certain anemia type)is caused by an autosomal recessive allele. In the Eskmethemoglobinemia. Calculate the frequency of the recessive allele in the Eskimo population? Select one:

0,3. Signup and view all the answers

H (heritability) values indicate primary environmental determination, if they are in the range: Select one:

0 - 0,3. Signup and view all the answers

Huntington disease is an autosomal dominant disease in which those who are homozygous for the diseaseis no different from that of heterozygotes. In a population where the frequency of the Huntington gene is 0those who are homozygous for the gene? Select one:

0,0064 Signup and view all the answers

A woman and her spouse both show the normal phenotype for pigmentation, but both had one parent whoautosomal recessive trait. What is the probability that their first child will be an albino? Select one:

1/4 Signup and view all the answers

How many second polar bodies will be produced from secondary oocyte in the end of meiosis? Select one:

1 Signup and view all the answers

Which of the following cells are diploid?

Primary oocyte Signup and view all the answers

Hemophilia is a sex-linked recessive trait in humans. If a father and a son are both hemophiliacs, but the mmust be:

XH Xh Signup and view all the answers

The pedigree chart below is for a family, some of whose members exhibit the autosomal dominant trait, broindividuals are indicated by a dark square or circle. Use the chart to answer the following question: what is Select one:

Ww Signup and view all the answers

The following scheme shows a stage of cell division for an eukaryotic diploid cell. Indicate the correct statement.

The scheme may represent a stage of meiosis II. Signup and view all the answers

Study Notes

Homologous Chromosomes

Homologous chromosomes are a pair of chromosomes with the same genes in the same order.
They are not identical; each chromosome may have different alleles for the same gene.

Down Syndrome

Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21.

Polymerase Chain Reaction (PCR)

PCR is a technique used to amplify DNA sequences.
It requires the following components:
- DNA template
- Primers
- DNA polymerase
- Nucleotides

Identical Twins

Identical twins are produced from a single fertilized egg that splits into two embryos.
They have identical DNA.

Pedigree Analysis

Pedigree analysis is a tool used to track the inheritance of traits within families.
It helps determine the mode of inheritance for a trait.

Autosomal Recessive Inheritance

Autosomal recessive inheritance is a pattern of inheritance where two copies of a recessive allele are required for an individual to exhibit the trait.
Example: Hemochromatosis is an autosomal recessive disorder.

Population Screening

Carrier screening is a test offered to individuals to determine their chances of having a child with a genetic disorder.
The expected carrier frequency for an autosomal recessive disease can be calculated using the Hardy-Weinberg equation.

Turner Syndrome

Turner syndrome is a genetic disorder that affects females.
It is caused by the absence or partial deletion of one of the X chromosomes.
Characteristics include short stature, webbed neck, and infertility.

Hemophilia

Hemophilia is a sex-linked recessive disorder that affects clotting factors.
It is primarily associated with males because they only have one X chromosome.

X-linked Dominant Inheritance

X-linked dominant inheritance is a pattern of inheritance where a dominant allele on the X chromosome is expressed in both males and females.

Variate Porphyria

Variate porphyria is a genetic disorder that affects the production of heme.
It is more common in populations that have experienced a founder effect, where a small group of individuals establishes a new population.

Heritability

Heritability (H) is a measure of the proportion of the variance in a trait that is due to genetic factors.
H values between 0 and 1 indicate the extent to which a trait is influenced by genetics.

Huntington Disease

Huntington disease (HD) is an autosomal dominant disorder that affects the nervous system.
Individuals who are homozygous for the HD gene have the same severity of symptoms as heterozygotes.

Meiosis

Meiosis is cell division that produces haploid gametes.
During meiosis, two rounds of cell division occur, resulting in four daughter cells.

Genetic Disorders and Prenatal Diagnosis

Prenatal diagnosis is a method of testing fetuses for genetic disorders during pregnancy.
Examples:
- Amniocentesis
- Chorionic villus sampling
- Ultrasound

Robertsonian Translocations

Robertsonian translocations are a type of chromosomal rearrangement that involves the fusion of two acrocentric chromosomes.
Certain combinations of Robertsonian translocations can lead to an increased risk of trisomy in offspring.

Trisomy 21

Trisomy 21 is the presence of an extra copy of chromosome 21.
It is the most common cause of Down syndrome.

Neural Tube Defects (NTDs)

Neural tube defects are birth defects that occur during fetal development when the neural tube does not close completely.
Alpha-fetoprotein (AFP) levels in maternal blood are elevated in cases of NTDs.

Glucose-6-phosphate Dehydrogenase (G6PD) Deficiency

G6PD deficiency is a sex-linked recessive disorder that affects the function of the enzyme glucose-6-phosphate dehydrogenase.
Individuals with G6PD deficiency are more susceptible to certain types of anemia.

Mendel's Laws of Inheritance

Law of Segregation: allele pairs separate during gamete formation.
Law of Independent Assortment: allele pairs for different traits sort independently of one another during gamete formation.

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Description

Test your understanding of homologous chromosomes and their significance in genetics. This quiz explores the definition, characteristics, and roles of these important biological structures. Enhance your knowledge of chromosome behavior during meiosis and genetic variation.