GENETICS Flashcards
genetics
a branch of biology study the heredity and variation of organisms
genome
- the genetic material of an organism
- the human genome consists of approximately 20,000 genes
- each of these genes is instruction for building a single protein
triat
-any characteristic that can be passed from parent to offspring
gene
- a unite of heredity that controls the development of one trait
- each chromosome carries many genes
- most genes are composed of two alleles
alleles
two form of a gene ‘ one allele is dominant and the other one recessive ‘ , one allele comes from each parent represented by a single letter
locus
the position in a chromosome of a particular gene or alleles
TT or tt
homologous alleles
Tt or tT
heterologous alleles
The recessive allele is not expressed in the presence of the dominant allele true or false
true
first generation occurs
self fertilization
first generation produce
the self fertilization that occurs in the first one produce the second generation ,
mendelian ratios are based on witch generation
mendelian ratios are based on second generation
Punnett square
its a method of visualizing inheritance crosses used to help solving genetic problems
types of genetic crosses
dihybrid
monohybrid
dihybrid
in this cross the parent differ in two characteristic
for example , flower colour and plant height
monohybrid
in this cross the parent organisms differ in a single characteristic for example , just flower colour
genotype
A genotype is an organism’s set of heritable genes that can be passed down from parents to offspring. The genes take part in determining the characteristics that are observable (phenotype) in an organism, such as hair color, height, etc.
genotypes
heterozygous
homozygous
heterozygous
gene combination of one dominant ‘T’ with one recessive ‘t’ and called ‘ hybrid genotype ‘
homozygous
gene combination of two recessives ‘tt’ or gene combination of two dominants ‘ TT’ and called pure genotype
phenotype
A phenotype is an individual’s observable traits, such as height, eye color, and blood type. The genetic contribution to the phenotype is called the genotype. Some traits are largely determined by the genotype, while other traits are largely determined by environmental factors.
