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Human Genetics

Description: This test is based on certain topics from biology which are highly beneficial for medical aspirants.
Number of Questions: 25
Created by:
Tags: Genes heredity Mendel haemophlilia linkage variations etc Mendalian Inheritance Mendel-s Law of Inheritance Inheritance Pattern of Haemophilia and Blood Groups in Human Beings Genetics and Evolution
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Why each generation of offspring bears impregnation of maternal and paternal traits ?

  1. Because each cell carries same number of chromosomes.

  2. Because of the frequent grabbing of chromosomes by the microtubules during metaphase I

  3. Because of the biological composition of the chromosomes

  4. Because of the high frequency of viral invasion


Correct Option: B
Explanation:

Each generation of offspring bears so many possible impregnation of maternal and paternal traits as a consequence of the frequent grabbing of chromosomes by the microtubules during metaphase I.

The same base sequencing in DNA will be similar in

  1. a male parent and his male offspring

  2. identical twins

  3. siblings

  4. a female parent and her offspring


Correct Option: B
Explanation:

The identical twins will have the same base sequencing in their DNA because they originates from the same egg and sperm of the parents.

A recessive allele p is responsible for a condition called hypertonia. In a couple, male has this condition. One of their four children also has this condition. Suggest the possible genotypes of the man and woman.

  1. Father is Pp and mother is PP.

  2. Father is pp and mother is PP.

  3. Both parents are pp.

  4. Father is pp and mother is Pp


Correct Option: D
Explanation:

This is the only option that fits the criteria in the question. Since father is hypertonic so he must beĀ pp & mother is carrier so she must be Pp.

The shrinking and disorganizing of cytoskeleton are seen in the cell, which is generally

  1. cancerous

  2. ready to start mitosis

  3. getting engulfed by a phagocyte

  4. shutting down one of its X chromosomes as dosage compensation


Correct Option: C
Explanation:

Phagocytes literally means eating of the cells. To do this, and be able to get the nutrients from inside the cell, it has to break down the outer defenses (cell walls, cell membranes, plasma membranes). The cytoskeleton provides the structural integrity for the cell, so it should be disassembled.

Pick out the true statement regarding Gregor Mendel.

  1. His discoveries regarding genetic inheritance were eventually accepted by the scientific community in the mid 19th century.

  2. He concluded that genetic traits of parents will generally inherit in their offsprings.

  3. His postulates of gene & inheritance apply equally to plants and animals.

  4. His experimental plant was cross-pollinating.


Correct Option: C
Explanation:

He gave us the basis for understanding genetic inheritance in all living things, including humans. His realization that we inherit units or genes was the key to it.

Why DNA does not duplicate between meiosis I and meiosis II?

  1. To reduce the chromosome number to haploid in the resulting daughter cells

  2. To produce genetically identical daughter cells

  3. To increase genetic variability

  4. The chromosomes already duplicated twice during meiosis I.


Correct Option: A
Explanation:

In the process of meiosis, four haploid daughter cells are formed. In humans, cells that go through meiosis are the sperms and egg cells. The reason why DNA does not duplicate between meiosis I and meiosis II is because only half the number of chromosomes is necessary in a sperm or egg cell. That's why, when a sperm fertilizes an egg, each cell has half the number of chromosomes necessary to create an organism, so together, they have the correct amount of chromosomes.

According to Mendel, the characteristics of Pisum sativum were determined by

  1. inheritance of genes from both parents

  2. inheritance of genes from one parent only

  3. comparitive health of each parent plants at the time of pollination

  4. comparitive health of each parent plants at the time of fertilisation


Correct Option: A
Explanation:

Mendel called genes as factors. In all the individuals, each inherited trait is determined by at least one gene from each parent.

An allele can be described as

  1. a homozygous genotype

  2. a heterozygous genotype

  3. a substitute for a gene

  4. one of several possible forms of a gene


Correct Option: D
Explanation:

An allele is an alternate form of a gene. If an individual is homozygous (YY or GG) for a trait, it has inherited the same allele from both parents. If it is heterozygous (YG), it has inherited different alleles for the trait.

The concept that different pairs of alleles are passed to progenies autonomously describes Mendel's principle of

  1. independent assortment

  2. segregation

  3. unit inheritance

  4. dominance


Correct Option: A
Explanation:

This is a definition of principle of independent assortment. Stated in other words, the genes that determine a trait assort independently of the genes for other traits. As a result, new combinations of genes, present in neither parent, are possible.

In an individual, phenotype expresses

  1. genetic makeup

  2. physical appearance

  3. a recessive allele

  4. genome


Correct Option: B
Explanation:

Phenotype is the observable characteristic, including physical appearance. It results from the genotype and environmental influences. A phenotype includes not only easily measured traits like hair colour but also less apparent ones such as blood type.

A persons's ABO blood type is generally determined by

  1. genetic factors as well as environmental factors

  2. environmental influences alone

  3. the presence of one of A, B, or O alleles inherited from the parents

  4. antibodies present in the blood


Correct Option: C
Explanation:

In most cases, these alleles are totally responsible for determining blood type phenotypes. The inheritance usually follows simple Mendelian patterns.

Which of the following is considered as the least reliable proof of paternity?

  1. ABO blood type evidence

  2. HLA type evidence

  3. DNA sequence evidence

  4. All are equally likely to be accepted


Correct Option: A
Explanation:

Because of the Bombay Phenotype and other possible exceptions, the ABO blood type system is not conclusive in determining whether or not someone could be a parent of a particular child.

Pick the true statement regarding the ABO blood system.

  1. It was discovered in the 1950's.

  2. It was discovered by Karl Landsteiner.

  3. Determining ABO blood types is a difficult procedure.

  4. Type AB-negative is the universal donor.


Correct Option: B
Explanation:

Karl Landsteiner discovered the ABO system in 1900 and 1901, while trying to understand why blood transfusions sometimes saved lives and at other times caused death.

Pick out the true statement regarding the antigen & antibody present in the blood, which helps in determining the blood group of the person.

  1. Individuals having A antigen will not produce the anti-A antibodies.

  2. AB types blood group individuals produce both anti-A and anti-B antibodies.

  3. AB type blood normally does not have either A or B antigens.

  4. O type blood contains both the antigens.


Correct Option: A
Explanation:

If they produced anti-A antibodies, it would destroy their own blood. However, they do normally produce anti-B antibodies since B type blood would be alien to them.

The severe medical problem associated with the Rh blood group is

  1. transfusion incompatibility

  2. chronic anemia for Rh negative persons

  3. Chronic anemia for Rh positive persons

  4. None of these


Correct Option: D
Explanation:

The most life threatening problem is the result of Rh blood type incompatibility between a mother and her developing fetus.

Select the true statements regarding the Rh blood system.

  1. It is the first blood system to be discovered by Landsteiner.

  2. It is genetically more complicated than the ABO system.

  3. There are 25 Rh blood types.

  4. It was first discovered in chimpanzee.


Correct Option: B
Explanation:

The Rh system apparently is genetically much more complex since it involves 45 different antigens on the surface of red cells that are controlled by 2 closely linked genes on chromosome 1. In most cases, the ABO system is controlled by only 2 antigens.

What conclusion is made while analysing the phenotypes of the ABO blood system?

  1. O is dominant over A.

  2. B is dominant over A.

  3. O is recessive to all other alleles.

  4. A is dominant over B.


Correct Option: C
Explanation:

The rules of dominance for the ABO system are that A and B are both dominant over O (i.e. O is recessive) and A and B are co-dominant.

The condition of erythroblastosis arises when the respective Rh of mother and foetus, are

  1. Rh positive & Rh positive

  2. Rh positive & Rh negative

  3. Rh negative & Rh positive

  4. Rh negative & Rh negative


Correct Option: C
Explanation:

In order for the fetus to be Rh positive, the father must also be Rh positive. As a result, when the mother is Rh negative and the father is Rh positive (or his Rh type is unknown), doctors usually assume that there will be a serious medical problem.

Who discovered the Rh factor in humans?

  1. Alexander Wiener

  2. Karl Landsteiner

  3. Erwin Popper

  4. Constantin Levaditi


Correct Option: A
Explanation:

Alexander Wiener was an outstanding leader in the fields of forensic medicine, serology, and immunogenetics. His pioneer work led to discovery of the Rh factor in 1937. Since the progeny could inherit A or O alleles from one parent and B or O alleles from the other, you could be any of the 4 ABO types. Look at the other answers to see how this could be true.

Select the true statement regarding the Rh positive people.

  1. They may be homozygous dominant (DD) or heterozygous (Dd) for this trait.

  2. They all are strictly homozygous dominant (DD) for the trait.

  3. They all are strictly homozygous recessive (dd).

  4. They may be homozygous recessive (dd) or heterozygous (Dd) for the trait.


Correct Option: A
Explanation:

The Rh blood factor is a dominant trait. Therefore, both DD and Dd people have the Rh antigen on the surface of their red cells which makes them Rh positive.

Which of the following races is more suspected to Rh mother-foetus incompatibility problems?

  1. Asians

  2. Africans

  3. Native Americans

  4. Europeans


Correct Option: D
Explanation:

Europeans have the highest frequency of Rh negative people (40%), which puts them at the highest risk for this problem. About 13% of newborn Europeans are at risk, but we can now prevent the life threatening complications in most cases.

In a couple, male is Rh positive and the female is Rh negative, what are the chances that there will be a mother-foetus incompatibility problem? Assume that the couple has already had a child and that there has been no medical treatment to prevent this problem.

  1. 100%

  2. at least 50%

  3. lesser than 50%

  4. 0%


Correct Option: B
Explanation:

If the father is homozygous dominant (DD) the chances of the fetus being Rh positive and an incompatibility problem occurring will be 100%. If the father is heterozygous (Dd), the chances are 50%. There will be no problem if the fetus is Rh negative.

The medical condition where the foetus' blood is agglutinated by his own mother's Rh antibodies, is termed as

  1. immunization

  2. erythroblastosis foetalis

  3. ectopic pregnancy

  4. erythropoiesis


Correct Option: B
Explanation:

In addition to suffering life threatening anemia, they also also suffers from jaundice, fever, quite swollen, and have an enlarge liver and spleen.

Mother-foetus incompatibility problems originate from

  1. the mother's antibodies agglutinating the embryo's Rh positive RBCs

  2. the embryo's antibodies agglutinating his own RBCs.

  3. the embryo's antibodies agglutinating his mother's RBCs.

  4. the mother & embryo's antibodies agglutinating each other's RBCs.


Correct Option: A
Explanation:

As a result of fetal blood entering the mother's system during her first pregnancy with an Rh positive baby, she will regularly produce antibodies to Rh antigens. They will pass through the placental barrier into her fetus and agglutinate its blood.

In the ABO type blood system, the universal blood donor(s) is/ are

  1. A

  2. B

  3. AB

  4. O


Correct Option: D
Explanation:

Since, type O blood normally lacks both A and B antigens, it will not be recognized as an alien type by the blood of anyone. As a result, anyone usually can be transfused with O blood without concern about rejection for this blood group.

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