gene

Question 1

what is the Incomplete Dominance ?

Answer 1

a cross between parents with contrasting traits that generate offspring with an intermediate phenotype.

Question 2

what is the tay sachs disease ?

Answer 2

lysosomal storage disorder caused by a mutation in a gene on chromosome 15 which codes for a iysosomal enzyme called beta hexosaminidase that normally breaks dowm a lipid called GM2 which is found in neurons

Question 3

what is the codominnce ?

Answer 3

the joint expression of both alleles in a heterozygote ,

Question 4

The simplest case of multiple alleles occurs when three alternative alleles of one gene exist. This situation is illustrated in the inheritance of the ABO blood groups in humans

Answer 4

فهم

Question 5

. If an antigen is present on the surface of the person’s red blood cells, it will react with the corresponding antibody and cause clumping,

Answer 5

فهم

Question 6

the IA and IB alleles are dominant tothe i allele, but codominant to each other.

Answer 6

فهم

Question 7

The A and B antigens are actually carbohydrate groups (sugars) that are bound to lipid molecules (fatty acids) protruding from the membrane of the red blood cell

Answer 7

فهم

Question 8

H substance itself contains three sugar molecules ?

Answer 8

Galactose (Gal), N-acetylglucosamine(AcGluNH)Fucose—chemically linked together

Question 9

what is gene interaction ?

Answer 9

the cellular function of numerous gene products contributes to the development of a common phenotype.

Question 10

what is pleiotropy ?

Answer 10

where expression of a single gene has multiple phenotypic effects,

Question 11

what is the expressivity ?

Answer 11

patients with same genotype have varying phenotypes

Question 12

what is the Penetrance ?

Answer 12

The percentage of individuals that show at least some degree of expression of a mutant genotype

Question 13

prader willi syndrome ?

Answer 13

maternally drived genes are silenced when THE PATERNAL ALLE IS DELETED

besity intellectual disability

chromosome 15 of paternal

Question 14

angelman syndrome ?

Answer 14

parenally derived UBE3A IS SILENCED WHEN the maternal allele is deleted or mutated

seizures ataxia intellectual disability
cromosome 15

Question 15

what is the Crossing over ?

Answer 15

is the swapping of genetic material that occurs in the germ line. During the formation of egg and sperm cells,

Question 16

Categories of medical Genetic disease:

Answer 16

Chromosome disorders
Single-gene defects
Multifactorial disease with complex inheritance

Question 17

what is Chromosome disorders ?

Answer 17

an excess
or a deficiency of the genes located on entire chromosomes or chromosome segments.

Question 18

what is Down syndrome ?

Answer 18

of an extra copy of one chromosome, chromosome 21

Question 19

what is Single-gene defects ?

Answer 19

pathogenic mutations in individual genes. The mutation may be present on both chromosomes or on only one chromosome of a pair

Question 20

ex Single-gene defects ?

Answer 20

Cystic fibrosis
Sickle cell anemia
Marfan syndrome

Question 21

what is the multifactorial disease ?

Answer 21

the majority of diseases in which there is a genetic contribution

Question 22

ex Multifactorial disease

Answer 22

Hirschsprung disease
Cleft lip and palate
Congenital heart defects

Question 23

what is gene mean ?

Answer 23

the basic physical and functional unit of heredity are made up of DNA.

Question 24

what is chromosome mean ?

Answer 24

a long DNA molecule with part or all of the genetic material of an organism

Question 25

what is chromatin mean ?

Answer 25

a substance within a chromosome consisting of DNA and protein

Question 26

what is Chromatid mean ?

Answer 26

one of two halves of replicated chromosome