All the cells in multicellular organisms which are capable of division go through a cell cycle - a sequence of phases which incorporates cell growth, DNA replication, and division. However, remember that not all cells are capable of division e.g. red blood cells. The Cell Cycle The cell cycle begins just after mitosis with growth... Continue Reading →
Limiting Factors – Photosynthesis Ep 3
The environmental conditions must be just right for photosynthesis to take place at the fastest possible rate. Today we're going to take a look at how light intensity, temperature and carbon dioxide (CO2) concentration can affect and limit the rate of photosynthesis. They will also affect plant growth, because photosynthesis produces glucose. Plants require glucose... Continue Reading →
Light-Independent Reaction – Photosynthesis Ep 2
In the last article we left photosynthesis at a point where ATP, reduced NADP, and oxygen had been produced in the light-dependent reaction. Oxygen is a waste product of photosynthesis, however the ATP and reduced NADP are used for the light-independent reaction. So although light energy isn't specifically needed for any reaction in this next... Continue Reading →
Coenzymes and Cofactors – Enzymes Ep 4
So far in this series we have looked at how enzymes work, what can affect the rate at which they work, and how their action can be inhibited. Today we are looking at coenzymes and cofactors: non-proteins that are needed in order for some enzymes to be able to catalyse their reaction. Coenzymes Coenzymes are... Continue Reading →
Enzyme Inhibition – Enzymes Ep 3
An enzyme inhibitor is a molecule that binds to an enzyme and prevents it from catalysing a reaction. In this article we will look at two types of enzyme inhibition - competitive and non-competitive inhibition. Although enzyme inhibitors can sometimes have devastating consequences, some of them are actually quite important. We will look at some... Continue Reading →
Factors Affecting Enzyme Activity – Enzymes Ep 2
In the last article we looked at how enzymes work as biological catalysts. However, there are various factors affecting enzyme activity, and consequently the rate of the reactions they catalyse. Today we will look at the four main factors that influence the rate of enzyme activity. Substrate concentration This one makes quite good sense. If... Continue Reading →
Enzyme Basics – Enzymes Ep 1
You know when you look at a word too much and it starts to look weird? That will definitely happen with the word 'enzyme' as we move through this topic. Today we're going to take a look at the basics of what enzymes are and how they act. What are enzymes? Perhaps the first phrase... Continue Reading →
Digestion – Exchange and Transport Ep 13
So far in the exchange and transport series we have mainly been looking at exchange and transport of gases. However, organisms also need to absorb nutrients such as glucose and amino acids so they can carry out processes like respiration and protein synthesis. In this article we will cover how large food molecules are broken... Continue Reading →
Proteins – Biological Molecules Ep 9
We've already looked at the monomers that make up a protein: amino acids. But fully functioning proteins are often much more complex in structure than a simple polypeptide chain. Today we will look at the different levels of structure in proteins and some specific examples. Levels of protein structure So let's start with a quick... Continue Reading →
