Answer:
50%
Explanation:
According to this question involving a gene coding for seed shape in pea plant, the allele for round seeds (R) is dominant to the allele for wrinkled seeds (r). This means that a heterozygous pea plant (Rr) will have a round seed shape.
If a plant that is heterozygous for seed type (Rr) is crossed with one that has only homzygous wrinkled seeds (rr), the following gametes will be produced by each parent plant:
Rr - R and r
rr - r and r
Using these gametes in a punnet square (see attached image), the following proportions of offsprings will be produced:
Rr, Rr, rr and rr
Rr = round seed offsprings
rr = wrinkled seed offsprings
Since 1 out of 2 offsprings has wrinkled seeds, 1/2 × 100 = 50% is the percentage of offsprings expected to have wrinkled seeds.
If you are asking if it is a true or false statement, it is a false statement. A mutation cannot possibly occur during polypeptide production or any protein synthesis or process. However, mutation may occur if the protein or enzyme is involved in any DNA replication or transcription process.
Answer:
D. Calcium ions.
Explanation:
Here we are talking about the mechanism of muscle contraction. The most accepted theory of muscle contraction is sliding filament theory. It was given by Huxley and Huxley. During the process actin filaments slides over myosin filament by forming cross bridges. The sequence of events are as follows:
a. An action potential propagates through the motor nerve and reach the nerve endings on the muscle fiber at neuro-muscular junction.
b. Neurotransmitter called acetylcholine is released by the nerve endings.
c. Acetylcholine binds to the receptors on muscle fiber and opens the gated channels which causes flow of Na+ ions into the muscle fiber.
d. This influx of sodium ions initiates an action potential in the muscle fiber which reaches the T- tubules or transverse tubules. Here it causes the sarcoplasmic reticulum to release large amounts of calcium ion.
e. Calcium ions are responsible for initiating the attractive forces between actin and myosin filaments. Cross bridges are formed, actin slides over myosin causing the contraction of muscle.
The last part is the anus.
