Cells are the basis of every living organism. But they are made differently depending on the living being they belong to. They even change according to the part of the organism they compose. In this biology course , you will find every necessary information on cells for GCSE level students.
To read completely the document, register on digiSchool Documents. Then you will be able to download the lesson for free and access a large number of other documents.
Course written by stephlebo
Is this document useful?
Content of this document of Sciences > Biology
All living things are made up of cells . Prokaryotes are (usually) unicellular without a nucleus or other membrane bound organelles. For example: bacteria. Eukaryotes are (usually) multi cellular and contain a nucleus and membrane bound structures. Examples include; animals, plants, fungi and protists.
Animal cells contain ; Cell Membrane: A thin skin layer around the cell to give it its shape and control what enters and exits the cell. Cytoplasm: A jelly-like substance in which most of the chemical reactions needed for life take place. [...]
Plant Cells contain all of the above and the following: Cell Wall: The cell wall is made of cellulose and is there to strengthen and support the cell. Chloroplasts: Are found in the green parts of plants. They are green because they contain chlorophyll. Chlorophyll absorbs light energy to make food by photosynthesis. [...]
Bacteria are single cellular microorganisms consisting of a cytoplasm; a cell membrane and they are surrounded by a cell wall. The genetic material floats freely within the cell, as they don’t contain a nucleus. Some will be surrounded by a slime [...]
Yeast is a single cellular microorganism that contains a nucleus with the genetic information, cytoplasm, cell membrane and is surrounded by a cell wall. Yeast cells are able to survive for a long time even when there is little oxygen available. [...]
Cells may be specialized for a particular function. Their structure will be specific to the function they are carrying out. For example:
Fat cells contain a small amount of cytoplasm and large amounts of fat and are able to expand 1000x their size in order to store excess fat that the body produces when more food is consumed than necessary. [...]
Cone cells from human eye
Cone cells are the light sensitive layer of your eye and are what allows us to see in colour. The outer segment contains visual pigment, which changes chemically in colored light. It requires energy to change it back to its original form. [...]
Root hair cells
Root hair cells are found close to the tips of growing roots. Plants need to take in a lot of water and dissolved mineral ions. The root hair increases the surface area for absorption and allows them to do this more efficiently. [...]
Sperm cells are generally released a long way from the egg they are going to fertilise. They carry the genetic information from the male parent and have to be able to travel the distance and then penetrate the egg to fertilise it. [...]
The typical size of a cell is very small: 20um (0.02mm) in width. As a cell grows, its surface area to volume ratio decreases and its requirement for more oxygen and food increases. [...]
Tissues and organs
Cells are the building blocks of life. A group of similar cells which all carry out the same job, are called a tissue. Your muscle tissue is all made up of identical muscle cells. [...]