Studied by 1 personFetal testing
________ is recommended for older mothers to check for Down syndrome in the embryo.
IO
________ is recessive to both IA and IB, while IA and IB are codominant when paired together.
IAIB genotype
For ________, both antigen A and antigen B are expressed since each of the alleles produces its own antigen.
Phenotype
an observable characteristic of an organism.
sexual reproduction
Each organism inherits one allele from the mother and one allele from the father during ________.
DNA
The part of chromosome, which contains genetic information used in the development and functioning of all organisms.
Down syndrome
a condition caused by a chromosome mutation during meiosis (gamete production)
Co dominance
The state when both alleles contribute equally to the phenotype.
Mutation
a change in gene or chromosomal structure.
Hereditary factors
________ are responsible for transmission of characteristics from one generation to the next.
human blood groups
The gene for ________ is said to have multiple alleles since it exists in more than two alleles.
single amino
It causes a(n) ________ acid in the normal haemoglobin chain to be replaced by another amino acid.
HbS molecules
________ clump together under low oxygen concentration, causing red blood cells to become sickle- shaped.
body cells
The zygote inherits 3 copies of chromosome 21 instead of 2, and this mutation is present in all ________ due to mitosis during zygote development.
surface of red blood cells
The gene for blood group codes for a protein present on the ________, called an antigen.
Mutagens
________ are physical or chemical agents that increase the rate of mutation.
allele IA
The ________ codes for antigen A, IB codes for antigen B, and no antigen is expressed for allele IO.
Mutations
________ can also be caused by exposure to mutagens.
Human blood groups
Characteristics determined by 3 alleles for 1 gene: IA, IB and IO.
Gene
a DNA segment located in a chromosome, which codes for a single unit of inheritance.
Allele
different versions of the same gene.
Genotype
The genetic make-up of an organism.
dominant allele
the allele that is fully expressed in the phenotype under both homozygous and heterozygous conditions.
Recessive allele
the allele that is only expressed in the phenotype under the homozygous condition.
Complete dominance
when the heterozygote has the same phenotype as the dominant homozygote.
Mutation
a change in gene or chromosomal structure.
Sickle cell anaemia
a blood disorder where red blood cells possess a rigid, sickle shape when oxygen concentration in the blood is low.
Natural Selection
Selection occurs when natural environmental conditions change
Artificial selection
Selection where humans select the varieties of organism that suit their need
Note
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