Cells

• Cells are the building blocks of living organisms.
• Cells can be categorised as Eukaryotes, Prokaryotes, and Viruses.
• Eukaryotic cells have membrane-bound organelles, a nucleus, and are found in organisms such as animals, plants, fungi, and protists.
• The Golgi body modifies and packages proteins, and thyroglobulins are transported to the cell membrane via vesicles produced by the Golgi body.
• Ribosomes carry out protein synthesis, and thyroglobulins are proteins.
• Prokaryotic cells, which do not have membrane-bound organelles or a nucleus, are found in organisms such as Archaea and Bacteria.
• Cell theory states that all living organisms are composed of one or more cells, the cell is the fundamental unit of structure, function and organisation in all living organisms, and cells can only arise from pre-existing cells.
• Some organisms are made from one cell only, these are known as unicellular organisms, which make up the majority of all organisms.
• All organisms with more than one cell are called multicellular.
• An organism is defined as all the systems of the body (or cell) working together, making it a discrete individual.
• Cells are the smallest level of organisation in living organisms.
• Tissues are a group of similar cells with a common origin.
• An organ is a group of different tissues which carry out a specific function.
• Cells can be categorised as single-celled (unicellular) organisms which carry out all life functions in one cell, and multicellular organisms which need specialised cells to carry out particular functions.
• Eukaryotic cells contain membrane-bound organelles.
• Eukaryotic cells are more complex cells which contain many membrane-bound organelles.
• An organ system is composed of two or more different organs that work together to provide a common function.
• Plant cells contain a cell wall, chloroplasts, a large vacuole, and starch grains.
• A capillary is a type of blood vessel.
• Tissue is a collection of cells with a common function.
• A cell is the basic unit of life.
• A bacterium is a unicellular organism.
• As cells develop, they become specialised in their structure to suit the role they will carry out.
• Bacteria are at least 3.5 billion years old, are small (1 – 10 µm), divide by binary fission, and do not contain membrane-bound organelles.
• An organelle is an organized and specialized structure within a living cell.
• Animal cells do not contain a cell wall, chloroplasts, a large vacuole, or starch grains.
• A sperm cell is a type of male gamete.
• Prokaryotic cells, such as bacteria, are simple cells which do not contain any membrane-bound organelles.
• An organ is an aggregation of several tissues that carry out a specific function for the whole organism.
• Leaves are composed of different tissues.
• Tissues are a collection of specialised cells carrying out a specific function, and there are four primary tissue types in the human body: Epithelial tissue, Muscle tissue, Connective tissue, and Nerve tissue.
• Slime capsule is involved in protecting the cell from antibiotics/ disinfectant, can be used to adhere to smooth surfaces, and is found in the cytoplasm.
• Prokaryotic DNA is circular, found in the cytoplasm, not attached to histone proteins, and is very few eukaryotes have plasmids (e.g. Yeast) and many have plasmids that contain genes.
• Viruses contain genetic material (DNA or RNA) that codes for viral protein, a capsid that protects the genetic material, and some viruses have a lipid envelope that protects the genetic material and helps facilitate entry into host cell.
• Flagellum is a tail for movement, is located in the cytoplasm, and is not attached to histone proteins.
• Eukaryotic cell has a nucleus, mitochondria, Golgi body, endoplasmic reticulum, and a cell wall, and is not acellular.
• Eukaryotic DNA is found in membrane-bound organelles (nuclear envelope, mitochondria, chloroplast), is linear, attached to histone proteins, and is not circular.
• Mesosome is a prokaryotic cell structure, located in the cytoplasm, and is not attached to histone proteins.
• Ribosomes are 70S, found in the cytoplasm, and are not attached to histone proteins.
• Viruses have an attachment protein on their surface that binds to receptors on cells.