Answer:
Multiple alleles can modify the classical Mendelian ratio by increasing the number of phenotypes.
For example, in a monohybrid cross, Mendel gets only 2 phenotypes however, in ABO blood groups (a classical example of multiple alleles) there are four phenotypes present in a population.
Lethal alleles are the alleles which when expressed result in the death of an organism. These alleles can be dominant, recessive or conditional (depends on interaction with another gene).
Thus, lethal allele reduces the ratio of the phenotype associated with it by affecting the survival of the organism.
For example, lethal yellow allele in mice results changes the phenotype ratio from 3:1 to 2:1
I would say B). Hope this helps!
Answer:
Tibia, Fibula, Interosseous Membrane.
Explanation:
Tibialis posterior muscles originates from the proximal tibia and fibula. The medial origin is on the posterior surface of the interosseous membrane.
I’m assuming you mean if the sun dies out. If so, then most things on earth would die within a few days due to lack of photosynthesis and to freezing temperatures (which is what would cause humans to die).
Answer: The calcium ion binds to troponin, and this slides the tropomyosin rods away from the binding sites.
Explanation:
Contraction and relaxation of muscle cells brings about movements of the body. The contractile myofilament called sarcomeres are bounded at each end by a dense stripe called the Z - line, to which the myosin fibres are attached, and lying in the middle of the sarcomere are the actin filaments, overlapping with the myosin.
When action potential spreads from the nerve along the sarcolemma (muscle cell membrane), it penetrates deep into the muscle cell through the sarcoplasm (cytoplasm of muscle cell), and releases CALCIUM from the intracellular stores.CALCIUM triggers the binding of myosin to the actin filament next to it forming CROSS BRIDGES.
For this to occur, ACTIN BINDING SITE has to be made available. TROPOMYOSIN is a protein that winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The first step in the process of contraction is for calcium ions to bind to troponin so that tropomyosin can slide away from the binding sites on the actin strands.
