CBSE Class 12 Biology Molecular Basis of Inheritance Cross Word

CBSE Class 12 Biology Molecular Basis of Inheritance Cross Word. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

[Figure: A crossword puzzle grid numbered 1 to 14 containing across and down blank rows and columns for answers related to Molecular Basis of Inheritance]

ACROSS: [1 Mark each]

5. Causative organism of pneumonia [1 Mark]

Answer:
1. Pneumococcus (Streptococcus pneumoniae)

Teacher's Note:
a) Streptococcus pneumoniae is the primary bacterial pathogen causing pneumonia.
b) Ensure correct spelling of the genus and species names.

6. An acidic substance present in nucleus [1 Mark]

Answer:
1. Nucleic acid (DNA or RNA)

Teacher's Note:
a) Friedrich Miescher initially identified this substance as nuclein.
b) The acidic nature is due to the presence of phosphate groups.

8. Chromatin densely packed and inactive [1 Mark]

Answer:
1. Heterochromatin

Teacher's Note:
a) Heterochromatin stains darkly with basic dyes.
b) It is transcriptionally inactive.

9. Helps in joining the fragments [1 Mark]

Answer:
1. DNA ligase

Teacher's Note:
a) Seals nicks in the sugar-phosphate backbone.
b) Crucial during lagging strand DNA replication.

12. A set of positively charged base proteins [1 Mark]

Answer:
1. Histones

Teacher's Note:
a) Rich in basic amino acids lysine and arginine.
b) Core octamer packages DNA into nucleosomes.

13. Chromatin loosely packed and active [1 Mark]

Answer:
1. Euchromatin

Teacher's Note:
a) Stains light with basic dyes.
b) Transcriptionally active region of chromatin.

14. Process of removing introns from processed RNA [1 Mark]

Answer:
1. Splicing

Teacher's Note:
a) Removes non-coding introns and joins exons.
b) Performed by the spliceosome machinery in eukaryotes.

DOWN: [1 Mark each]

1. Formed by N-glyccosidic linkage [1 Mark]

Answer:
1. Nucleoside

Teacher's Note:
a) Formed by attachment of a nitrogenous base to a pentose sugar.
b) Contrast with nucleotide which also includes a phosphate group.

2. largest known human gene at 2.4 billon bases [1 Mark]

Answer:
1. Dystrophin

Teacher's Note:
a) Mutations in this gene cause Duchenne muscular dystrophy.
b) Note that the transcript contains 2.4 million bases (typo in source paper stating billion).

3. Substrate of lac-operon [1 Mark]

Answer:
1. Lactose

Teacher's Note:
a) Acts as an inducer in the lac operon system.
b) Binds to the repressor protein to allow transcription.

4. Process of protein synthesis from RNA [1 Mark]

Answer:
1. Translation

Teacher's Note:
a) Occurs on ribosomes in the cytoplasm.
b) Translates mRNA codon sequence into amino acid sequence.

5. Variation at genetic level [1 Mark]

Answer:
1. Mutation

Teacher's Note:
a) Source of all new alleles and genetic diversity.
b) Can be point mutations or chromosomal aberrations.

7. Bacteria infected with viruses [1 Mark]

Answer:
1. Bacteriophage

Teacher's Note:
a) Viruses that specifically parasitize bacteria.
b) Used in the Hershey and Chase radioactive labeling experiments.

10. A segment of DNA coding for polypeptide [1 Mark]

Answer:
1. Cistron

Teacher's Note:
a) Functional unit of inheritance analogous to a gene.
b) Can be monocistronic in eukaryotes or polycistronic in prokaryotes.

11. Present in RNA ay the place of Thymine [1 Mark]

Answer:
1. Uracil

Teacher's Note:
a) A pyrimidine base found exclusively in RNA.
b) Pairs with adenine during transcription.