Question

1.All cells in a human body undergo the process of meiosis.

True

False

2. Most cells in the human body contain 46 chromosomes.

True

False

3. The chances that any two siblings will be genetically identical is astronomically small.

True

False

4. Each time protein synthesis occurs; all of the DNA of a cell is copied.

True

False

5. RNA creation occurs in the nucleus of a cell; protein synthesis occurs on the ribosomes.

True

False

6. Tay-Sachs syndrome is a fatal recessive condition found primarily in people of Ashkenazi (Eastern European Jewish) ancestry. It is estimated that 1 in every 28 Ashkenazi Jews is heterozygous for Tay-Sachs. A child with Tay-Sachs develops normally until about the second year. At that time the child’s central nervous system begins irreversibly to deteriorate. Using the alleles T and t, match the phenotypic descriptions to the correct genotypes.

a carrier for Tay-Sachs syndrome a person with Tay-Sachs syndrome    an individual that is heterozygous for Tay-Sachs syndrome an individual that is homozygous dominant for Tay-Sachs syndrome    an individual that is homozygous recessive for Tay-Sachs syndrome

A. Tt B. tt C. TT D. none of the above

QUESTION 7

Match the description to the correct nucleic acid.

- contains the nitrogenous base adenine                                                 - contains the nitrogenous base thymine                                                 - possesses codons                                                 - remains in the nucleus                                                 - contains the nitrogenous base uracil

A. RNA B. RNA C. ATP D. DNA E. all of these

8. A woman with type A blood just had her first child. The child had type A blood. What are all of the possible blood types of the father? Explain you answer.

9. Jaden and Jordan are twins. Jaden has sickle cell trait, a genetically inherited disorder of the hemoglobin. Jordan does not have sickle cell trait. Are Jaden and Jordan fraternal or identical twins? Explain how these type of twins form.

10. What is the relationship between DNA, chromosomes, genes, RNA, and proteins?

Answer 1

1. Meiosis or reduction division causes reduction in the orgininal genetic material or information into half. It occurs in the germ cells only in the human body. When fertilization occurs the fusion of male and female germ cells again brings the original ammount of genetic material or information. Whereas mitosis is the division of somatic cells which retains the original amount of genetic material. Hence, false.

2. As if I discussed above that meiosis occur in germ cells and causes reduction in the genetic material. The chromosome number for a human is 46 chromosomes that is 23 pairs(2n). But in the germ cells this number is 23 chromosomes(n). So, all cells in the human body does not have 46 chromosomes. Hence, true.

3. Any siblings share only 50% of the genetic material which make them similar to each other but not identical. This all makes because of recombination. Genetically identical twins is a rare phenomenon which happens when a single zygote formed due to fertilization divide making its two excat copies. Then, those individuals only will be genetically identical. Hence, true.

4. The protein synthesis depends on the requirement of the cell. When cell requires a prticular protein for its biological activity then, the process of DNA replication, transcription and translation begins in the same order. But only the required part of DNA that codes for that particular protein is copied not all of the DNA. Hence, false.

5. In case of eukaryotes the process of transcription of DNA into mRNA takes place in the nucleus but the process of translation of protein from mRNA takes place in the cytoplasm with the help of ribosomes. Hence, true.

6. For Tay-Sachs syndrome the individual with the homozygous pair of TT(dominant) will be diseased and the individual with the heterozygous pair of Tt will not be infected or diseased but will carry the allele of T which could cause the Tay-Sachs syndrome in their progeny. The individuals with homozygous pair of tt(recessive) will be neither diseased nor carrier of the disease to their progeny. Hence, for first it will be option A, for second it will be option C, for third it will be option A, for fourth it will be option C and for fifth it will be option B.

7.Now this comes to the molecular basis of inheritance and structure of nucleic acid. DNA is deoxyribonucleic acid which lack oxygen at the 2' position of carbon and contains adenine(purine), guanine(purine), thymine(pyrimidine) and cytosine(pyrimidine) as nitrogenous bases. RNA is ribonucleic acid which contains oxygen at the 2' position of carbon and contains adenine(purine), guanine(purine), uracil(pyrimidine) and cytosine(pyrimidine). ATP is the energy currency of the cell which contains adenosine made up of an adenine ring and ribose sugar. RNA contains the triplet codon which is read by the ribosomes during translation and produce protein. Hence, for first it will be option E, for second it will be option C, for third it will be both options A and B, for fourth it will be option C and for fifth it will be both options A and B.

8.9. If Jaden and Jorden would have been identical twins then, they would have been genetically identical as I have mentioned above. And both both have been same copy of each other but it is not the case. They both are faternal twins that are created by two separate fertilized eggs which are fertilized at the same time that's why they are twins but not excatly identical. Hence, that difference in sickle cell trait is seen.

10. DNA, RNA and proteins are linked by central dogma.DNA constitute the genes. And genes are present on the chromosomes which is present in the nucleus. These all are the root of molecular basis of inheritance.

Central Dogma of Molecular Biology It explains one way or unidirectional flow of information from master copy DNA to working copy RNA and from RNA to building molecule or trait expressing molecule polypeptide. Central dogma of molecular biology was proposed by Francis Crick. Replication DNA transcription, mRNA translation Protein Central dogma