Answer:
Explanation:
Translation ends in a process that called ( termination) .
Termination happens when a stop codon in the mRNA (UAA , UAG , UGA ) enters the A site.
Stop codons are recognized by proteins called release factors,
which fit neatly into the P site (Though they aren't tRNAs ) .
Answer:
The word biology is about An organism is a living entity consisting of one cell e.g. bacteria, or several cells e.g. animals, plants and fungi.
Explanation:
Neuron is the correct answer. They form a network that is connected to the brain through the spinal cord. This results in an impulse which allows you to do whatever it is you have to do.
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.
