C11: Inheritance Flashcards
What is monohybrid inheritance
involves inheritance of one characteristic and contrasting traits controlled by a gene
who is father of modern genetics
Gregor Mendel
how purebreed pea plants are produced
by self-cross plant which have similar traits in terms of genetic contents
why did mendel chose to use the pea plant
- can be easily grown and bears many seedlings
- has both male and female reproductive structure
- has short generation intervals
- has obvious characteristic
define gene
basic unit of inheritance which consist DNA segment located in specific locus of a chromosome
define allele
alternative form of gene for a specific trait that is located in a same locus of a pair of homologous chromosome
what is diff between characteristic and trait
- characteristic: heritable features
- trait: variation of specific characteristic
define genotype and phenotype
- Phenotype: observable characteristic
- height
- Genotype: genetic composition which cannot be seen
- TT and Tt (genotype for tall)
contrast homozygote and heterozygote
- homozygote: both alleles at loci are the same
- heterozygote: alleles at loci are different
what is parental and filial generation
- parental: first generation of two individuals which are mated to predict or analyse genotype of their offspring
- filial: a successive generation in a result of mating purebreed parental generation
Bb x Bb
- phenotype: 3:1
- genotype: 1:2:1
BB x bb
all same
RrTt x RrTt
- phenotype: 9:3:3:1
RrTt x rrtt
- phenotype: 1:1:1:1
Define Mendel’s First Law (Law of Segregation)
a characteristic of an organism is controlled by a pair of alleles, only one pair of allele of allelic pair is inherited in a gamate
state homozygous dominant, homozygous recessive, and heterozygous genotype
- HD: TT
- HR: tt
- HG: Tt
Define dihybrid inheritance
inheritance of two characteristics which controlled by different gene located at different locus.
Define Mendel’s Second Law (Law of Independent Assortment)
During gamete formation, each allele from a pair of alleles can combine with another allele from another pair of alleles
autosome
- chromosome pairs from number 1 to 22
- to control characteristic of somatic cells
- height, blood type, skin colour
sex chromosome
- chromosome pairs number 23
- consist of genes which determine gender
- XX (female) , XY (male)
what is karyotype
the number and structure the chromosomes present in a cell nucleus
how do chromosomes to be arranged
based on
- sizes
- centromere locations
- banding pattern
How nondisjunction occur
- changes in number of total chromosome
- due to failure of homologous chromosome to separate during anaphase 1
- or sister chromatids to separate during anaphase 2
3 diseases caused by nondisjunction of chromosome
- Down Syndrome
- Turner Syndrome
- Klinefelter Syndrome
Explain down syndrome
- 47 chromosomes
- 45+XY
- extra chromosomes for pair 21
- trisomy 21
explain turner syndrome
- 45 chromosome
- 45+XO
- missing Y chromosome
- female
explain klinefelter syndrome
- 47 chromosomes
- 44+XXY
- extra X
- male
- secondary sex characteristics are not well-developed
state the dominant and recessive allele in blood group
dominant: IA , IB
recessive: IO
codominant: IAIB (AB blood group genotype)
what allele in blood group gene determine
the type of antigens present on surface membrane of red blood cells
a child has rhesus factors. who cause that
- father
what cause thalassemia
- gene mutation on chromosome 11 or 16
- due to abnormality and low number of haemoglobin
- smaller and paler red blood cells
symptoms of thalassemia
- tiredness
- paleness
- breathing difficulty
- changes in facial bone formation (3-18months)
what is sex-linked genes
the genes located in sex chromosomes which control specific characteristic but not sex determination.
why do traits in males are observed in X chromosome
- Y chromosome is shorter than X
- does not contain as many alleles as X
what cause colour blindness
recessive allele found in the X chromosome
- most are males
what cause haemophilia
- recessive allele in X chromosome
what can be shown in family pedigree
- ancestral relationship
- inheritance of characteristic
function of Punnett square
- to predict the ratios and probabilities of genotype and phenotype of offsprings
