Class 12 Biology Chapter 20 Notes
Important Complete Notes Class 12 Biology Chapter 20 Notes written by Professor Mr. Feroz Qadir Suib. These notes are very helpful in the preparation of Class 12 Biology Chapter 20 Notes of Biology for the students of the 12 class and these are according to the paper patterns of all Punjab boards.
Summary and Contents:
Topics which are discussed in the notes are given below:
- Important biology class 12 chapter 20 notes for Intermediate part-II students.
- What is transformation? OR Define transformation. In which bacterium it was discovered?
- What is translation?
- What are mutagens? Give one example.
- What are the contributions of P.A. Levene for determining the structure of DNA?
- What is phenylketonuria? OR What is alkaptonuria? OR Differentiate between alkaptonuria and phenylketonuria.
- What is central dogma?
- Important chapter 20 biology class 12 mcqs for Intermediate part-II students.
- What is genetic code? OR What are non-sense codons? OR Enlist non-sense codons and their function. OR Differentiate between genetic code and stop codon.
- Where are codon and anticodon situated?
- What is heterochromatin? OR What is euchromatin? OR Differentiate between heterochromatin and euchromatin.
- What is mutation? OR What do you mean by mutations? OR Define mutation and differentiate between chromosomal aberration and point mutation.
- Important biology chapter 20 class 12 short questions for Intermediate part-II students.
- What is phosphodiester linkage? Draw structural formula. OR What is phosphodiester bond or linkage? OR Sketch phosphodiester linkage between two nucleotides.
- Compare replication, transcription, and translation.
- Define chromosomal theory of inheritance.
- Define karyotype. OR What is karyotype? OR What do you mean by karyotype? Give its significance. OR What is karyotype? Give its application in species recognition.
- Important class 12 biology chapter 20 short questions for Intermediate part-II students.
- Define nucleosome.
- Define nucleotide and nucleoside. OR What is nucleotide? OR Differentiate between nucleotide and nucleoside.
- Define one gene/one polypeptide hypothesis?
- Define point mutation. OR State point mutation with examples. OR Define point mutations. Give one example. OR What is point mutation? Give an example.
- Define transcription and how it is initiated? OR What is the function of RNA polymerase in transcription?
- Important class 12 biology chapter 6 questions and answers for Intermediate part-II students.
- Differentiate between leading and lagging strand.
- Differentiate between sense and antisense strands of DNA. OR What is the difference between template and sense strand?
- Enlist different shapes of chromosome.
- Give the length of Okazaki fragment. OR What are Okazaki fragments?
- Give the role and kinds of tRNA.
- Write two characteristics of DNA polymerase III.
- Important class 12 biology chapter 6 important questions for Intermediate part-II students.
- Why does every genetic code consist of three nucleotides?
- What do you know about the minimal medium used by Beadle and Tatum?
- What is X-ray diffraction? In this analysis a molecule is bombarded with a beam of X-rays. When individual rays encounter atoms their path is bent or diffracted and the diffraction pattern is recorded on the photographic film. When carefully analyzed this pattern gives three dimensional structure of a molecule.
- What is Alkaptonuria? It is disorder in which the patients produced urine that contained homogentisic acid. This substance oxidized rapidly when exposed to air, turning the urine black. In normal individuals, homogentisic acid is broken down into simpler substances.
- Why Beadle and Tatum are famous for? Beadle and Tatum performed experiment on Neurospora, fungus, and concluded that each gene encodes the structure of one enzyme. This is also called one gene one enzyme hypothesis.
- Why Sanger was famous for? In 1953, Frederick Sanger, described the complete sequence of amino acids of insulin. Sanger's achievement was significant, as it was demonstrated for the first time that proteins consisted of definable sequences of amino acids.
- Why Vernon Ingram is famous for? Vernon Ingram in 1956 discovered the molecular basis of sickle cell anaemia. He showed that sickle cell anaemia is caused by a change from glautamic acid to valine at position 6 in one chain of haemoglobin.
- What are Point mutations? Point mutations are mutational changes which affect the message itself, producing alterations in the sequence of DNA molecule. If alterations involve only one or a few base pairs in the coding sequence they are called point mutation.