Biology

Heredity

1-Heredity is the genetic information passing for traits from parents to their offspring, either through asexual reproduction or sexual reproduction.

2-The study of heredity in biology is called genetics, which includes the field of epigenetics.

3-Inherited traits are controlled by genes and the complete set of genes within an organism’s genome is called its genotype.

4-The complete set of observable traits of the structure and behavior of an organism is called its phenotype.

5-Heritable traits are known to be passed from one generation to the next via DNA, a molecule that encodes genetic information.

6- Within cells, the long strands of DNA form condensed structures called chromosomes.

7- The specific location of a DNA sequence within a chromosome is known as a locus.

8-If the DNA sequence at a particular locus varies between individuals, the different forms of this sequence are called alleles.

9- Charles Darwin proposed his theory of evolution in 1859

10-The idea of particulate inheritance of genes can be attributed to the Moravian monk Gregor Mendel who published his work on pea plants in 1865.

11-A human chromosome can have up to 500 million base pairs of DNA with thousands of genes.

12-The existence of discrete inheritable units was first suggested by Gregor Mendel (1822–1884)

13-Darwin used the term gemmule to describe hypothetical particles that would mix during reproduction.

14- In 1905, the word genetics was first used by William Bateson.

15-In 1909 the Danish botanist Wilhelm Johannsen shortened the name to “gene”.

16-The structure of DNA was studied by Rosalind Franklin and Maurice Wilkins using X-ray crystallography, which led James D. Watson and Francis Crick to publish a model of the double-stranded DNA molecule.

17-The modern study of genetics at the level of DNA is known as molecular genetics.

18-In 1972, Walter Fiers and his team at the University of Ghent were the first to determine the sequence of a gene: the gene for Bacteriophage MS2 coat protein.

19-RNA also contains the base uracil in place of thymine.

20-RNA molecules are less stable than DNA and are typically single-stranded.

21-The process of producing a biologically functional molecule of either RNA or protein is called gene expression, and the resulting molecule is called a gene product.

Biology

HEREDITY

1- Mendel (Father of genetics) experiments stands for Heredity.

2-Differences in characters with in closely related groups of organisms are called variations.

Externally visible characters are called phenotype.

3-TT or YY, Tt or Yy are responsible for a dominant character.

4-There are nearly 180 vestigial (not useful) organs in man (moving museum of vestigial organs).
Ex. Pinna, hair on skin, appendix

5-The process of acquiring change is called evolution.

6-The allosomes (sex chromosomes) present in female are XX and in males are XY.

7-The phenotypic ratio in monohybrid cross is 3:1, and genotypic ratio is 1:2:1.

8-Evolution of man: 1. Homo habilus 2. Homo erectus 3. Homo sapiens neanderthalensis 3.Homo sapiens(present man).

9-The study of fossils (evidence of ancient life forms) is called palaeontology.

10-Mendel had chosen 7 pairs of characteristics for his study in pea plants.

11-Phenotypic ratio in di hybrid cross is 9:3:3:1.

12-Alleles are same for character in homologous and different in heterologous.

13-Paleontologists determine the age of fossils by carbon dating.

14-Change in frequency of genes in small population is known as genetic drift.

15-Transmission of characters from parent to offspring is called heredity and the process is called inheritance.

16-Each human cell contains 22 (autosomes) + 1 (allosomes) pairs of chromosomes.

17-Variations are formed during sexual reproduction or because of errors in DNA copying.

18-Augustus Weismann proved in rats that the body changes won’t be passed to its offspring.

19-Mendel factors are now known as genes (segment of DNA).

20-The law of inheritance of acquired characters was proposed by Lamarck.

21-Evolution of new species is called speciation (macro evolution).

22-Charles Lyell wrote the book “The principals of geology”.

23-Theory of natural selection was proposed by Darwin.

24-Evolution of homologous traits is called divergent and heterologous is convergent evolution.