Alteration in the gene brings a change in the structure of the protein part of haemoglobin molecule. Due to the change in the protein molecule, the red blood cell (RBC) that carries the haemoglobin is sickle shaped. Points to Remember Variations are quite apparent among closely related groups of organisms. Mendel had choosen seven pairs of distinguishing traits: flower colour, position, seed colour, shape, pod colour, pod shape, stem length.
Every pea plant has two ‘factors’ which are responsible for producing a particular character or trait is called allele. The process of acquiring characters or traits from parents is called ‘Heredity’. Each human cell contains pairs of chromosomes. Out of these pairs are called autosomes and one pair is called allosomes.
A chromosome consists of the regions: primary constriction, centromere, secondary constriction, telomere and satellite. Based on the position of the centromere, the chromosomes are classified as telocentric, acrocentric, sub metacentric and metacentric chromosomes. Each nucleotide of DNA consists of a deoxyribose sugar, a nitrogenous base and a phosphate group. Pairing is always between a purine and a pyrimidine.
The sperm, produced by the father, determines the sex of the child. The mother is not responsible in determining the sex of the child. Mutation is an inheritable change in the genetic material of an organism. Genetics I.
Choose the correct answer . According to Mendel alleles have the following character a) Pair of genes b) Responsible for character c) Production of gametes d) Recessive factors . : : : ratio is due to a) Segregation b) Crossing over c) Independent assortment d) Recessiveness . The region of the chromosome where the spindle fibres get attached during cell division a) Chromomere b) Centrosome c) Centromere d) Chromonema .
The centromere is found at the centre of the chromosome. a) Telocentric b) Metacentric c) Sub-metacentric d) Acrocentric . The units form the backbone of the DNA. a) carbon sugar b) Phosphate c) Nitrogenous bases d) Sugar