Outline the stages of interphase.
Cells spend majority of the time in the interphase which has three parts, G1 stage, S stage, and G2 stage. In the first stage the cell is growing and preparing, for example making sure the DNA is not damaged before replication. In the S phase the DNA copies and doubles but does not split. In the G2 stage the cell if checked for replication and devices when necessary.
Why are long waves from the sun worse than short waves to our skin?
Long waves penetrate the skin more deeply than short waves do and damage skin cells called keratinocytes in the basal layer of the epidermis, where most skin cancers occur.
Visible light and ultraviolet radiation are commonly called shortwave radiation, while infrared radiation is referred to as longwave radiation. Solar radiation is usually considered shortwave radiation. The Earth produces virtually no visible light, or ultraviolet radiation which is why shortwave radiation is not as damaging to our skin as longwave radiation which is almost all of the natural radiation created by the Earth is infrared, or heat.
Please note that long and short wave are relative terms and if we are talking about long waves like radio waves you should know that these are NOT worse for you. I think what you are discussing is long and short wave UV light. Shorter wavelength = more energy = more potential for damage.
How is nitrogen diffused into the blood from the air.
When we breath in, oxygen in air diffuses into the blood across the respiratory membrane. This is due to the idea that blood in the lungs are low in oxygen resulting in a one way flow from high oxygen concentration in alveoli, to low concentration in blood.
Actually nitrogen from the air cannot be used by humans! We have to obtain the nitrogen we use by eating plants which in turn get it from nitrogen-fixing bacteria.
What are the functions of insulin, glucagon, and glucose?
Insulin and glucagon work together to keep blood glucose concentrations normal.
Glucose is used as an energy source for the body.
Both Insulin and Glucagon are hormones secreted within the pancreas to help control blood glucose levels. Insulin is secreted by beta cells in response to high blood glucose levels in order to lower it while glucagon is secreted in response to low blood glucose levels to increase it.
Since pump proteins use ATP for energy can any substance be pumped through them? Are there any requirements?
There are different kinds of protein pumps for each substance. They are mostly used for polar substances because they cannot pass through the hydrophobic portion of the phospholipid bilayer, or moving against the concentration gradient.
At what point do cells differentiate? And can cells dedifferentaite and get a new role?
It's different for different types of cells. Many cells differentiate during embryogenesis, due to gene expression that will specialize the cell to create a functioning organism. But stem cells are able to differentiate much later. Dedifferentiation can occur, but normally in animals such as worms or amphibians and it can also happen in plants.
Outline the process of muscle contractions.
When an impulse reaches the muscle fibers of a motor unit, it stimulates a reaction in each sarcomere between the actin and myosin filaments.
How do antibiotics work? Are they always effective? Are there any side effects?
Antibiotics can work in many ways. Some can block the specific membrane proteins, and others might prevent new membrane from forming. Side effects are always a concern, but are dependent on the drug.
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