Producing a serial dilution is a really useful skill for all sort of biology experiments. In this article we will look at how to prepare a serial dilution, and how it could be used to produce a calibration curve for a colorimeter experiment. How to prepare a serial dilution In A-Level biology, you will probably... Continue Reading →
In A-Level biology, there are four biochemical tests to learn for four different biological molecules. This article gives full details of the tests, and a helpful colour summary at the bottom. Test for reducing and non-reducing sugars A sugar is a monosaccharide or disaccharide. The vast majority of sugars learnt about in A-Level biology (glucose,... Continue Reading →
The kidneys are important organs for maintaining blood water potential and excreting waste products from the blood. In this article, we will look at the structure of the kidneys and how substances are filtered out and reabsorbed into the blood using ultrafiltration and selective reabsorption. Kidney structure The kidneys have an outer layer called the... Continue Reading →
In the last article we looked at how the body uses negative feedback mechanisms to control the concentration of glucose in the blood. Diabetes mellitus is a condition where these feedback systems fail and blood glucose is not controlled, with potentially fatal consequences if left untreated. In this article we will look at the two... Continue Reading →
Control of blood glucose is very important. Sufficient glucose must be delivered to cells for respiration, but too much glucose can eventually result in coma or even death. The concentration of glucose is affected by factors such as eating and exercise, and must be brought back to the normal level of about 4mmol/L to 5.5mmol/L.... Continue Reading →
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 →
In this series we are going to be looking at respiration. This is the process that releases energy from glucose to produce ATP. In the first few articles we'll be focusing on aerobic respiration (which uses oxygen) and then we will cover anaerobic respiration (which doesn't use oxygen) in the last article. Aerobic Respiration Equation... Continue Reading →
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 →
So far we have looked at the passive movement of substances across cell membranes by diffusion and osmosis. Sometimes substances need to move against a concentration gradient, which is when active transport comes into action. Active transport Active transport uses energy from ATP to transport substances from an area of low concentration to an area... Continue Reading →
Glucose is a really important carbohydrate for living organisms because it is a reactant in respiration. It is a monosaccharide - a single sugar monomer that can be used to build other types of carbohydrates called polysaccharides. We will cover polymers of glucose in a separate article - today we will look at the structure... Continue Reading →
