- Assertion : Grasshopper is an example of XY type of
sex determination, similar to Drosophila.
Reason : Males have X and Y chromosomes, while
females have a pair of X chromosomes.
- Assertion : Despite difference in morphology, X and
Y chromosomes synapse during zygotene.
Reason : The homologous part possesses similar
genes, called XY linked genes.
- Assertion : A male can pass sex linked traits to his
grandson through his daughter.
Reason : This type of cris-cross inheritance is called
dia-andric inheritance.
- Assertion : Translocation does not add any genes or
gene groups.
Reason : It results in new linkages and in position
effect, resulting in chromosomal aberrations, in some
cases.
Figure Based Questions- Refer to the given figure showing the pedigree A
with shaded symbols.
Identify whether the shaded symbol refers to:
(i) a dominant or a recessive allele.
(ii) an autosomal or a sex linked allele.- Observe the pedigree A again, and give its genotype
in pedigree B.ChApTEr-6 : MOLECULAr
BASIS OF InhErITAnCE
Multiple Choice Questions- If the sequence of bases in the coding strand of
a double stranded DNA is 5’-GTTCGAGTC-3’, the
sequence of bases in its transcript will be
(a) 5’-GACUCGAAC-3’ (b) 5’-CAAGCUCAG-3’
(c) 5’-GUUCGAGUC-3’ (d) 5’-CUGAGCUUG-3’. - The result of which of the following reaction
experiments carried out by Avery et al on Streptococcus
pneumoniae has proved conclusively that DNA is the
genetic material?
(a) Live ‘R’ strain + DNA from ‘S’ strain + RNAase
(b) Live ‘R’ strain + DNA from ‘S’ strain + DNAase
(c) Live ‘R’ strain + Denatured DNA of ‘S’ strain +
Protease
(d) Heat killed ‘R’ strain + DNA from ‘S’ strain +
DNAase - Which of the following events would occur in ‘lac
operon’ of E. coli when the growth medium has high
concentration of lactose?
(a) The repressor protein attaches to the promoter
sequence and derepresses the operator.
(b) The structural genes fail to produce polycistronic
mRNA.
(c) The inducer molecule binds to repressor
protein and RNA polymerase binds to promoter
sequence.
(d) The repressor protein binds to RNA polymerase
and prevents translation. - The figure gives an important concept in the genetic
implication of DNA.
Fill the blanks A, B and C.
(a) A-Maurice Wilkins, B-Transcription, C-Translation
(b) A-James Watson, B-Replication, C-Extension
(c) A-Erwin Chargaff, B-Translation, C-Replication
(d) A-Francis Crick, B-Translation, C-Transcription- Select the correct statement regarding protein
synthesis.
(a) When the small subunit of the ribosome
encounters an mRNA the process of translation
begins.
(b) Peptidase catalyses the formation of peptide
bond.