GENETICS

Question 1

• GENETICS

Answer 1

a branch of biology study the heredity and variation of organism

Question 2

• genome

Answer 2

• the genetic material of an organism

Question 3

• how much genes in the human genome ?

Answer 3

• the human genome consists of approximately 20,000 GENES .

Question 4

• what do genes make ?

Answer 4

• each of these genes is an instruction to build a single protein

Question 5

• trait ?

Answer 5

• it is any characteristic that can be passed from parent to offspring .

Question 6

• gene ?

Answer 6

• its a unit of heredity that controls the development of one trait ,
• Each chromosome carries many genes ,
• Most genes are composed of two alleles .

Question 7

• alleles ?

Answer 7

• two forms of a gene ,
• Each one comes from each parent ,
• One allele is dominant and the other is recessive,
• each one is represented by a single letter .

Question 8

• locus ?

Answer 8

• its the position in a chromosome of a particular gene or allele .

Question 9

• who is the father of GENETIC ?

Answer 9

• Gregor Johann Mendel , Father of modern genetics born in July 20, 1822 - January 6, 1884 .

Question 10

• do the recessive alleles are expressed when dominant alleles are present ?

Answer 10

• NO , Recessive alleles are only expressed when no dominant allele is present .

Question 11

• when can the recessive alleles be expressed ?

Answer 11

• it can be expressed when all the recessive alleles are located in the homologous chromosomes .

Question 12

• ¨ TT ¨ or ¨ tt ¨ ?

Answer 12

• are homologues alleles .

Question 13

• ¨ Tt ¨ ¨ tT ¨ ?

Answer 13

• are heterologous alleles .

Question 14

• F1 generation ?

Answer 14

• first-generation offspring are bred among themselves

( self-fertilized ) , to produce the second generation .

Question 15

• F2 generation ?

Answer 15

• mendelian ratios are based on this generation results .

Question 16

• Punnett square ?

Answer 16

• its a method of visualizing inheritance crosses

- used to solve genetic problems .

Question 17

• there is two types of genetic crosses ?

Answer 17

• yes, :
• the first is “monohybrid cross” .
• the second is “dihybrid cross “ .

Question 18

• monohybrid cross ?

Answer 18

• in this cross the parent organisms differ is a single characteristic .

Question 19

• dihybrid cross ?

Answer 19

• in this one the parent differ in two characteristic .

Question 20

• there is two types of Genotype ?

Answer 20

• yes, :
• ” heterozygous genotype “ .
• ” homozygous genotype “ .

Question 21

• heterozygous genotype ?

Answer 21

• gene combination of one dominant and one recessive “ Tt “ . ( are hybrid genotype ) .

Question 22

• homozygous genotype ?

Answer 22

• gene combination involving two dominant “ TT “ or two recessive “ tt “ . ( are pure genotype ) .

Question 23

• what is the phenotype ?

Answer 23

• its the physical traits resulting from a genotype . as color and length .

Question 24

• what does determines the phenotype ?

Answer 24

• phenotype is determined by its genotype .