Question

17) A man is described as being Aa for the hemoglobin alleles. ‘Aa’ is referred to as his
       A. Phenotype        B. Genotype        C. Blood group        D. Genome

18) Down syndrome results from a mutation best described as________, caused by a mistake during _______.

A. Point; mitosis            B. Frameshift; crossing over

        C. Aneuploidy; meiosis        D. Deletion; mitosis

19) The ends (caps) of chromosomes are called _________ and tend to get shorter as cells age except in the case of ___________.
      A. telomeres; RBC    B. telomeres; cancer    C. centromeres; cancer        D. primers, nerves

20) An organism has guanine (G) as 30% of its bases. What percentage of its bases would be cytosine (C)?  
        A. 10%                 B. 20%         C. 30%             D. 40%

Answer 1

Answer

17) A man is described as being Aa for the hemoglobin alleles. ‘Aa’ is referred to as his

B. Genotype.  A and a are the two alleles of the gene hemoglobin. This genotype influences the phenotype of the gene

18) Down syndrome results from a mutation best described as aneuploidy caused by a mistake during meosis

C. Aneuploidy; meiosis. Aneuploidy means having an abnormal number of chromosomes. In Down syndrome, there is an extra full or partial copy of chromosome 21. During meosis, prior to conception, either in the sperm or the egg cell, pair of 21st chromosome fails to separate

19) The ends (caps) of chromosomes are called telomeres and tend to get shorter as cells age except in the case of cancer

B.Telomeres; cancer. Telomeres are ends of chromosomes which are truncated at the end of each cell division. Hence, in a normal cell the chromosomes tend to become shorter and loose the ability to divide. But in case of a cancer, the telomere does not get truncated, thus giving it the ability to divide progressively.

20) An organism has guanine (G) as 30% of its bases. What percentage of its bases would be cytosine (C)

C. 30%. Since, guanine pairs with cytosine (C), the percentage of cytosine will be equal to that of guanine (G) i.e. 30%