Chapter 6 Flashcards
What race of peas did mendel use in his experiments?
Seven contrasting trait pairs of Pisum sativum
bcuz the pea plant is easy to cultivate
short and fast lifecycle
many contrasting traits like sharp differences
Pisum sativum is self fertilizin, anf cross pollination is possible, with the offspring being fertile
state and explain mendel’s law of segregation
traits are det of two organisms by alleles which separate in gametes and join in fertilization.
conditions are; true breeding varieties possess two factors for any given trait.
F1 generation possessed one allele from each parent, carried by gametes.
alleles retain their individuality in the F1 generation
Dom alleles shows effect in the f1 generation and recessive factor appears in f2 generation in homozygous condition
What is hybridization?
crossing of two different varieties to produce a new better variety. (cabbage, cauliflower, kale, and broccoli.)
What is mendel’s law of independent assortment
when two pairs of contrasting alleles are followed in the same cross pollinated batch, their alleles assort in independent gametes.
What is Heterozygnous reactions?
Mendel’s studies show complete domination by one allele over another, however, this is not always the case, as some traits show co- or incomplete dominance.
What is co-dominance
Both alleles express independently so both phenotypes appear at the same time in a heterozygous individual at the same time. For example, AB blood type in humans is controlled by the alleles of the I gene. Three alleles are IA, IB, and i. IA and IB are co-dominant while i is recessive to both IA and IB.
What is incomplete dominance
in which both alleles express in a way that the phenotype of the heterozygote is a blend of both.
What is biological variation?
Differences in characteristics shown by individuals of the same species i,.e cats and dog breeds.
Studies show that two forms of variations occur, Discontinuous Variation and Continues Variation.
what are the sources of variation?
crossing over produces genetic recombination during gamete formation
independent assortments of chromosomes forming different combos of chromosomes in gametes
fertilization
mutation in germ cells which form gametes
Gene flow (gene’s movement between different populations of the same species)
what is Discontinuous Variation and Continuous Variation
Studies of large populations show that two forms of variations occur, Discontinuous Variation and Continues Variation.
Traits that show clear phenotypes with no immediate forms like the ability to roll your tongue and ABO blood type is discontinuous variation.
Characteristics that show gradation between two extremes are continuous variations. They are a result of many different genes and are affected by the environment (height, color, intelligence etc.)
charlie darwin man
Proposed the theory of natural selection in 1838 after a five year voyage around the world. Published a book on the origins of species in 1859.
difference between antigens and antibody
Antigens are foreign substances (like viruses, bacteria, or toxins) that trigger an immune response.
Antibodies are proteins produced by the immune system to recognize and neutralize specific antigens.
two white sheep produce a black sheep. What must the parents’s genotype for color be what is the probability that the next offspring will be black
For two white sheep to produce a black sheep, both parents must carry the recessive allele for black color, meaning their genotype must be heterozygous (Bb). This is because white is recessive (bb), and the presence of one dominant black allele (B) results in black wool. When both parents are Bb, the possible genotypes of their offspring, based on a Punnett square, are 25% BB (black), 50% Bb (black), and 25% bb (white). Therefore, the probability that the next offspring will be black is 75%.
