Meiosis is a little more complicated than mitosis, and has a different outcome. Meiosis is a method of nuclear division which only happens in the reproductive organs of organisms which reproduce by sexual reproduction. It produces genetically different gametes with half the number of chromosomes as the parent cell. These gametes (the egg cells and... Continue Reading →
Binary Fission – Cell Division Ep 3
In the last article we looked at mitosis as a method of cell division. However, mitosis can only take place in eukaryotic cells. Prokaryotic cells, which don't have a nucleus, divide by binary fission. This process produces two genetically identical daughter cells from the parent cell, and is a method of asexual reproduction. Binary fission... Continue Reading →
Mitosis – Cell Division Ep 2
Mitosis is a method of nuclear division used by multicellular organisms for growth and repair of tissues. Some plants and fungi (and rarely some animals) also use it for asexual reproduction - producing genetically identical offspring from one parent. Mitosis results in two daughter cells which are genetically identical to the parent cell. In this... Continue Reading →
Cell Membrane Structure – Exchange and Transport Ep 1
Today we are starting a new series looking at how substances are exchanged across cell membranes and transported around organisms. These processes are really important for getting essential resources such as oxygen and glucose to all the cells in an organism. We will start by taking a closer look at the structure of the cell... Continue Reading →
The SER, Vacuole, and Centriole – Cell Organelles Ep 6
We have come to the end of our cell organelle series! Today we are going to be looking at the remaining organelles in the A-Level specification which don't need covering in as much depth. Some exam boards also need a little information about cilia, eukaryotic flagella and amyloplasts, so make sure to revise those too... Continue Reading →
The Golgi Apparatus and Lysosomes – Cell Organelles Ep 5
Today we are going to take a look at the Golgi apparatus (sometimes called the Golgi body or Golgi complex) and its role in the cell, followed by the lysosomes. The Golgi apparatus We first came across the Golgi apparatus in the article about the ribosomes and rough endoplasmic reticulum (RER). Protein synthesis begins at... Continue Reading →
Chloroplasts – Cell Organelles Ep 4
So far, all the organelles we have looked at (the nucleus, mitochondria, ribosomes and RER) are found in both animal and plant cells. Today's organelle, the chloroplasts, are only found in plant cells and some eukaryotic algae. The main function of chloroplasts is to carry out photosynthesis - the reaction that uses light energy to... Continue Reading →
Ribosomes and the RER – Cell Organelles Ep 3
Ribosomes Ribosomes are very small organelles often drawn as dots in diagrams. They are free in the cytoplasm or attached to the rough endoplasmic reticulum (RER). One cell can contain millions of ribosomes if it needs to produce a lot of proteins. If we zoom right in, we find that ribosomes are actually made up... Continue Reading →
The Mitochondria – Cell Organelles Ep 2
I believe it is said in meme culture that the mitochondria are the powerhouses of the cell. I'm not going to pretend to know why that is a meme, but there is some truth in it. The main function of the mitochondria is to carry out aerobic respiration (except the first stage) which produces adenosine... Continue Reading →
The Nucleus – Cell Organelles Ep 1
Cell organelles, or subcellular structures, are specialised to carry out certain functions. The main function of the nucleus is to contain the genetic material (DNA) of the cell. And where better to begin A-Level biology revision than at the information center of the cell. The Nucleus The nucleus (plural nuclei) is often drawn as a... Continue Reading →
