Biology 1 Marks Question

Phosphoester bond.

Transfer RNA (t-RNA)

(i) Pentose sugar
(ii) Nitrogen base either purine or pyrimidine.

Gene Gun : It is a method in which the plant cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA.

(i) It codes for methionine amino acid
(ii) It acts as a initiation codon.

Rho factor is a protein involved in the termination of transcription. It binds to a site on the newly formed transcript, using its ATP as source of energy to dissociate this transcript and release in cytoplasm. in prokaryote, termination sites have been divided into two groups : (i) rho dependent terminator (ii) rho independent terminator

5'-AAGUUACUAGAC-3

(i) It is Universally triplet in nature.
(ii) It is read continuously without any punctuation mark.
(iii) It shows degeneracy i.e. one genetic code on can codify only one amino acid.
(iv) Genetic code do not show ambiguity..

(i) This molecule should be capable to make its own copy.
(ii) It should be situated on the basis of composition and chemical organization.
(iii) There is a possibility of slow changes (mutation) which are necessary for development.
(iv) It should express itself according to Mendel's

Repeatitive DNA and Satellite DNA.

Frederick Sanger

BAC = Bacterial Artificial Chromosome
YAC = Yeast Artificial Chromosome

DNA replication.

About 60 types of tRNA.

mRNA, RNA, RNA, hnRNA, snRNA, scRNA, miRNA etc.

The length of a DNA helix is 34A and there are 20/10 pairs nitrogen bases in one helix.

A chain of enzymes taking part in DNA replication is known as replisome.

When mRNA has the message for coding only one polypeptide chain it is called monocystronic mRNA.

There are two types of mRNA on the basis of number of cistrons called monocistronic e.g. eukaryotes and polycystronic m-RNA c.g. prokaryotes.

t-RNA is the smallest RNA which consist of 75 to 80 nucleotides.

Small nuclear ribonucleoprotein

There exist no punctuation mark between two successive codon.

When the product of regulator gene inhibit the expression of a gene it is called negative regulation of gene. e.g. Lac Operon.

Introns

Jacob and Monod.

Peptidyl transferase

Introns

Phospho di-ester bonding.

Alfred Harshey and M. Chase.