miller and levine biology online textbook pdf
The life of a sperm––it’s like the rest of us!
- Sperm are complex cells. They are produced in the testes and can swim because of a long tail.
- The whole structure of sperm cells is a head, body and tail. The head has enzymes that can digest the outer layer of an egg cell to allow for fertilization.
- Sperm are very small measuring about 0.05 mm in length. As it is so small as compared to other cells, it cannot be seen by naked eyes easily and needs a microscope to see them clearly.
Sperm is made up of the head, body, neck, tail and flagella.
The sperm is made up of the head, body, neck and flagellum. The head is the largest part of the sperm, but it is still smaller than a red blood cell. The head contains the nucleus that stores DNA, which will fertilize the egg when it penetrates. The body is responsible for storing energy, which it gets from glucose.
The neck is where the flagellum attaches and contains enzymes to penetrate the egg when it reaches its destination.
The tail, or flagellum is what allows the sperm to move (swim) through female reproductive system until it reaches its destination – an egg in the fallopian tube!
The head travels down the vas deferens to meet with the egg.
In some species, the head travels down the vas deferens to meet with the egg. In other species, a sperm may burrow into another sperm to form a zygote. The zygote then develops into an egg and is released from the ovary. The process of fertilization is controlled by hormones from the nerve cells that control development of eggs and sperm.
The body carries an important load of enzymes in order to take out the DNA from the egg.
The body carries an important load of enzymes in order to take out the DNA from the egg. The enzymes break down the egg membrane and release the sperm into the cytoplasm of the egg. As soon as this happens, a second enzyme system is activated which hardens and thickens the membrane so that no other sperm can enter. The body also contains mitochondria, which are used to power the tail (flagella) of sperm during its journey through the cervix, uterus and fallopian tubes until it reaches its destination: the ovum.
The body contains enzymes that help break down carbohydrates and proteins; however, these enzymes don’t break down fats because there are no lipases present within them. Lipases are found in both saliva and pancreatic secretions, but they’re only released when food enters these organs; otherwise they remain inactive till then.
The neck releases chemicals to help penetrate the egg membrane.
Hormones are released by cells in the neck of the sperm as it nears contact with the egg. These hormones trigger other organs that release enzymes that help penetrate the egg membrane. The neck also releases chemicals to help penetrate the egg membrane. After penetrating the egg membrane, a chemical change occurs in the tail to cause it to fall off and allow it to enter into a flagellum-like whip mode that is necessary for pushing through cytoplasm.
While swimming, tail flagellum helps sperm swim forward and right itself when tilted too far.
- Use of the tail flagellum. While swimming, the tail flagellum helps sperm swim forward and right itself when tilted too far. This movement is accomplished by sending waves through the flagellum in a whip-like manner, which pulls the head forward. Even though this structure is called a “tail” it is not a muscle; instead, it consists of many proteins that are arranged in a nine-plus-two pattern that allows for movement. The proteins are arranged on the outside of two microtubules made up of tubulin molecules. The flexibility of this structure allows it to bend any direction and coil around other cells during its journey to fertilize an egg cell.
What happens when you produce many sperm?
You’ve probably heard the phrase, “A penny saved is a penny earned.” It’s true. If you’re saving for your future, you’re making an investment in yourself. But how much should you save?
If you’re saving for a down payment on a car, or saving money to go to college, or saving money to buy your own house or apartment one day, those are great things. However, those big things aren’t necessarily going to make you happy if you don’t first save some money to pay off your bills and get out of debt.
For example, if all you do every month is work and pay bills (and maybe have some fun), all of your extra cash will stay tied up in paying off credit card debt and other loans. That means that if something unexpected happens — like an illness — it will be very difficult for you to get ahead financially. And that could mean that instead of spending money on the things that matter most to you (like travel), all of your money will go toward trying to keep the lights on and food on the table each month!
Don’t worry about getting it right because nature will take care of the rest.
You don’t need to manually design or create the parts of a sperm. The system is automated, so nature will take care of the rest.
The head carries the DNA and moves at a slow pace, while the flagella rapidly propel the sperm forward. The body contains enzymes that dissolve the egg’s membrane surrounding it, while the neck delivers these chemicals to the egg.