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.
Answer:
1. A. Pseudomonas and E. coli
2. B. Red without black center
3. B. Salmon/orange
Explanation:
Pseudomonas is referred to as an oxidase positive bacteria while E. Coli is an oxidase negative bacteria. The use of the oxidase test will be helpful in the differentiation of the two Bacteria according to their oxidase activity/properties.
Colonies of Red without black center color is what is expected on HE agar if shigellosis is suspected.
Colonies of Salmon/Orange color is what is expected on HE agar if Enterococcus sp. is suspected.
The autonomic nervous system is divided into the sympathetic and parasympathetic subdivisions.
In humans sperms can survive 3 -5 days within the female reproductive tract.
The ideal time of fertilization is around ovulation when the egg is in the fallopian tube. After travelling through the vaginal canal, the strongest sperm make it to the cervix. From here, the sperm must travel through the uterus and into one of the fallopian tubes.
carbohydrates is the answer
