Molecular means of inheritance Flashcards
What type of trait is tongue rolling
a simple Mendelian trait
What did Gregor Mendel’s pea experiments lead to the discovery of
many of the rules of heredity, including dominance and recessiveness, and the idea that traits are inherited independently.
How did Mendel study the peas
Mendel grew pea plants in his monastery garden for eight years.
He chose pea plants because they are easy to grow, have visible traits, and can be cross-pollinated by hand.
He studied pea traits like seed color, pod color, and plant height.
He cross-pollinated pea plants with different traits.
He counted the number of plants with each trait in each generation.
He observed that some traits were dominant and others recessive.
What is Mendel’s work considered to be
the foundation of modern genetics.
How do you set out an answer, representing monohybrid inheritance
Note the parents phenotype, parents genotype, Gametes, Offspring 1 (F1) genotypes
How can you find out if an organism with a dominant characteristic is heterozygous or homozygous
Cross organism with double recessive type e.g. tt. If TT (homozygous) = all offspring will be of dominant phenotype. If Tt (heterozygous) = at least 1 offspring will have recessive phenotype
Do cells ignore recessive genes when a dominant gene is present
No, rather, the effect of the recessive allele is masked by the dominant allele’s expression, not its presence being entirely erased.
what types of interactions are dominance and recessiveness
Phenotypic Interactions
What do the terms dominant and recessive refer to
the interaction between different versions (alleles) of a gene as they influence the observable traits (phenotype) of an organism, not a physical “ignore” function of the cell.
What colour eyes will someone who has a blue eye allele and brown eye allele have
brown eyes because the brown-eye allele is dominant.
What did Gregor Mendel discover
Traits are inherited as dominant and recessive pairs, which contradicted the view that offspring exhibited a blend of their parents’ traits.
What makes alleles co dominant
If they are both expressed in the phenotype of a heterozygote.
How can codominant alleles be represented
By two capital letters superscript to the letter representing the gene.
For example, flower colour in snapdragons Antirrhinum majus.
C^R = red flowers C^W = white flowers
C^RC^W = Pink Flowers
What is sickle cell caused by
A gene that directs the synthesis for haemoglobin
What happens to the red blood cells in someone with sickle cell
Haemoglobin causes a change in the red blood cell, causing a ‘C’ shaped cell and inhibits its oxygen carrying capacity.
How do represent a normal red blood cell and a blood cell with sickle cell
Hemoglobin (Hb) and the allele for a normal cell is (A), and the sickle cell anemia is (S). The genotype for a normal cell would be Hb^AHb^A and for sickle cell anemia Hb^SHb^S.
What does happens to someone who is heterozygous with sickle cell
A heterozygous mix Hb^AHb^S, creates individuals with the sickle cell trait. An individual expresses both normal cells and sickle cells. This can be advantageous to individuals because it gives an individual a resistance to malaria.
