Question

In one type of genetic therapy, healthy cells are introduced into diseased tissues. Which of the following is a serious problem with ​this kind of therapy?

​A) It is technically very difficult to transfer cells into tissues

​B) Rejection of the introduced cells by the recipient’s immune system

​C) Since each person’s DNA is unique, the donor DNA may not function in the recipient’s tissues

​D) Every person has different cell types

Which of the following is true about the process of crossing over of chromosomes?

​A) It ensures that replication of the chromosomes is as error-free as possible

​B) It acts to ensure that the gametes that result from meiosis are all genetically alike

​C) It increases the genetic diversity of gametes by creating chromosome types that are not identical to any ​​​​​​​​​maternal or paternal types

​D) It happens during mitosis as well as meiosis

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Which of the following gives a good idea of what the science of genetics is all about?

​A) Genetics tries to establish patterns and mechanisms of heredity of traits from generation to generation

​B) Genetics tries to work out the rules and processes governing overall cellular metabolism

​C) Genetics focuses on mitosis and DNA replication more than anything else

​D) Genetics, unlike other branches of science, does not proceed by the scientific method, since it is nearly impossible to do ​​​​meaningful genetics experiments

Answer 1

Question 1:-

The right option is option (b) Rejection of the introduced cells by the recipient’s immune system.

Explanation:-

One of the most common problem faced in any kind of transplantation, whether tossue, organ or cells,is that the recipient body may reject it. The common reason behind this is that HLA antigen which are present nearly on every cells are highly polymorphic and of many types. So if the donor and recipient are not same or monozygotic twins, then there is very rare chance that the HLA antigens will be same.

If donor have any extra type of HLA antigen then the transplanted biological tissue will be rejected by the host T-cells as they mount a very rigorous immune attack on the tissue.

Question 2:-

The right option is option (​C) It increases the genetic diversity of gametes by creating chromosome types that are not identical to the parents.

Explanation:-

The crossing over which happens only during the Meiosis 1 is the phenomenon which happens only in those organisms which divide sexually and have sexual mode of reproduction.

This event does not do anything in ensuring that the replication is error free as that role is dedicated to proteins and cell check points. The role of this event is to create variety as homologous chromosomes share their genetic material and this gives rise to chromosome which is unique as it have some of the paternal chromosome DNA and some of the maternal DNA. This creates variation among the species and population.

Question 3:-

The right option is option (​A) Genetics tries to establish patterns and mechanisms of heredity of traits from generation to generation

Explanation:-

Genetics is the branch of biology which is concerned with the study of inheritance patterns and genes. In this field of science, experts try to deduce how genes are inherited in a population among progenies and how genes are related and linked to each other.

Through the study of inheritance, geneticists have made chromosomal maps and also deduced expected probability of inheritance in terms of linked as well as unlinked genes.

Genetics plays a role in determining the probability of a child inheriting a disease which have a family history.