function and structure of four cells

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 Jody Wells

With aid of annotated diagrams, discuss the relationship between the structure and function of four specialised human cells.

The human body is made up of trillions of different cells; all play a huge role in the running and function of the body. They are the foundation of all living things. Each different cell has its own exclusive job. Without cells the human body would simply fail. All cells contain organelles which are the structures of the cells itself, organelles have individual functions. This essay will investigate the structure and function of four cells and how they contribute to the performance of the human body.

Sperm cells, also known as spermatozoon are reproductive cells. The main function is to fertilize the ovum. At the head of the sperm is a large nucleus surrounded by acrosome, the acrosome covers the head of the sperm, when the ovum is reached the acrosome releases hydrolytic enzymes to break through the egg wall. The nucleus is where all genetic information and enzymes are and half of the 23 chromosomes. One pair coming from the sperm cell and the other from the mother, these are called homologous pairs. The acrosome releases an enzyme which helps penetrate the egg cell membrane. ‘The sperm cell consists of a head, a midpiece and a tail. The head contains the nucleus with densely coiled chromatin fibres, surrounded anteriorly by an acrosome, which contains enzymes used for penetrating the female egg’. (News-medical, 2012). The neck of the sperm contains centrioles which form the structure of the flagella also known as the tail of the sperm. The flagellum creates movement in order to swim to the ovum. The flagellum is composed of microtubules, with proteins known as axoneme. Axoneme is the core of the flagella, it has two centrial filaments and is enclosed by nine other pairs which motor movement. The middle section of the sperm is full of mitochondrion which produces a molecule, ATP which fuels energy needed for the sperm to swim successfully to the ovum. The ovum is one of the largest cells in the body. Unlike other cells it is not capable of independent movement and relies on the body’s function to create movement e.g., the fallopian tubes. It contains a nucleus which is the heart of cells where all the genes are situated, like the sperm cell the ovum contains only half the number of chromosomes as a normal cell containing the full 46. The cytoplasm is gel like and holds all the organelles together. All of the cells activities take place here to keep it alive and functioning. The zona pellucida is the wall of the egg; the structure is what allows the sperm to enter the egg. As time goes on this structure of the wall hardens, the reason the egg may not be fertilized. Attached to the zona pellucida is the corona radiata consisting of two to three layers of cells from the follicle, they supply much needed proteins to the cell ‘In humans, the ovum is the largest cell visible to the naked eye. It is about 0.1 mm in size in humans. It is produced in the ovary and eventually released into the fallopian tube during ovulation. It consists of protoplasm (with some yolk) surrounded by a think cell wall (vitelline membrane). It may also have a noncellular covering (zona pellucida). Within the cell is a large nucleus (germinal vesicle), with a nucleolus (germinal spot). The cell is haploid so that when a sperm cell fertilizes it, it forms a diploid zygote.’. (Biology-online, 2009).

Red blood cells known as erythrocytes are a fundamental part of the survival for the human body; they make up 45% of a normal blood count. Bloods main purpose is to transport materials around the body and also protect against disease. Red blood cells carry oxygen around the body and remove carbon dioxide. They are small in size and are a flat disc like shape, so they can pass through minute...
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