A collection of blog posts connected to my teaching on biomedical sciences and biochemistry degrees. All views and opinions expressed are my own, and not connected to my past, present or future employers.
Maths and Chemistry Refresher for Life and Biomedical Scientists
The book is a refresher for life, biomedical sciences and chemistry students who may be a little unsure of some of the key maths and chemistry skill they need and covers:
Elements, atoms, ions, molecules, and compounds
Atomic weight, isotopes and molecular weight
Amounts, volumes, and concentrations
The SI units and the SI unit prefixes (m, µ, n, p etc.)
Scientific Notation
Dealing with unit prefixes (m, µ, n, p etc.) in calculations
In the video, I discuss why meiosis is important, meiosis I and II, the key steps in Prophase I (Leptotene, Zygotene, Pachytene, Diplotene and Diakinesis), and the consequence when it goes wrong.
In this video, I examine cell growth (hypertrophy) and proliferation (hyperplasia), with the content mainly focused on hyperplasia and the cell cycle.
The cell cycle is a sophisticated series of events that cells undergo to duplicate themselves. It's divided into four main phases:
G1 Phase: The cell grows and synthesises proteins (cells may sit in G0 phase before entering G1).
S Phase: Chromosomes are duplicated.
G2 Phase: The cell prepares for mitosis.
M Phase: Mitosis occurs, and chromosomes are separated into daughter cells.
Most of a cell's life is spent in the interphase, which includes the G1 (G0), S, and G2 phases. This period is crucial for the cell as it performs its regular functions, replicates proteins, synthesises RNAs, and maintains organelles.
The cycle is regulated by the Mitosis-Promoting Factor (MPF), consisting of cyclin and cyclin-dependent kinase (Cdk). These proteins are essential for the progression of the cell cycle, particularly in phosphorylating specific amino acids on proteins that need to be activated or deactivated for the cycle to proceed.
Drawing graphs is essential in educational and professional settings, as it helps communicate information clearly and efficiently. Whether you're a student, a scientist, or just looking to present data compellingly, knowing how to create an effective graph is invaluable. Here’s a guide to help you draw graphs that are not only informative but also visually appealing.
1. Utilise Your Graph Paper Fully
The first step in drawing a graph is to make the best use of the available space on your graph paper. Avoid cramming all data into one corner; instead, spread out your data across the graph. This approach helps in better visualisation and interpretation later on.
2. Tools of the Trade
Always use a sharp pencil to mark points and draw lines. This ensures precision in your work, making your graph more readable and professional.
3. Plotting Your Points
Begin by placing your data points on the graph. Be precise and ensure each point is placed correctly according to the values it represents. This accuracy is crucial for the reliability of your graph.
4. Deciding on the Line of Best Fit
Once your points are plotted, decide whether to connect the dots directly or to use a line of best fit. If you opt for a line of best fit, ensure it appropriately represents the trend in your data, with the points evenly distributed around the line.
5. Drawing Lines
Whether connecting points directly or drawing a line of best fit, use a ruler to keep your lines straight and neat. For curves, maintain a smooth, consistent shape.
6. Labelling is Key
Clearly label your axes and include units of measurement. This step is crucial as it provides context to your data, making the graph informative and easy to understand. Remember to label both the x-axis and y-axis accurately. Don't forget the units.
7. Title Your Graph
Always give your graph a descriptive title that captures the essence of the data it represents. A well-chosen title can effectively communicate the purpose of the graph at a glance.
8. Setting Up Axes
Select sensible ranges for your axes to avoid data clustering that can occur if the ranges are too narrow. Proper scaling enhances the graph's clarity and makes it easier to interpret the data.
9. Interpreting Data
For instance, plotting a standard curve for protein concentration against absorbance, start with known concentrations on the x-axis and absorbance on the y-axis. Adjust the axis range to ensure all points are visible and not squished at the bottom.
10. Calculating and Using the Gradient
Once your graph is complete if you need to calculate the gradient of a straight line, draw the largest possible triangle under the line and use the formula (rise/run). This gradient could represent a specific value of interest, such as an extinction coefficient in spectrophotometry.
11. Dealing with Multiple Data Sets
If your graph contains multiple data sets, differentiate each set using various styles of points and lines. This distinction makes it easier to compare and contrast the data sets visually.
12. Avoid Extrapolation
Never extrapolate your data beyond the measured range. Doing so can lead to inaccurate conclusions. For data points that exceed the range of your graph, note that these values are beyond measured limits.
Final Thoughts
Graphing doesn't have to be daunting. With the right tools and a careful approach, anyone can create clear, informative, and visually appealing graphs. Remember, a good graph tells a story that speaks with clarity and impact.
In this video, I discuss embryonic development, a fascinating journey that can be studied in detail using the African clawed frog (Xenopus laevis) as a model organism.
The frog oocyte (egg) is asymmetrical, with a pigmented upper half (animal pole) and a white lower half (vegetal pole), which contains most of the yolk. Development occurs outside the body of the frog and this makes it ideal for studying development.
The video covers fertilisation and the 30-degree rotation of the oocyte's cortex to form the "grey crescent" that determines the future dorsal side (back) of the embryo. This rotation begins the transformation into a three-dimensional body plan with three lines of asymmetry: left-right, anterior-posterior (top-bottom), and dorsal-ventral (back-front).
The video also looks at the formation of the blastula, a hollow ball of about 4,000 cells. The subsequent gastrulation process establishes three germ layers:
Mesoderm: Forms muscles, bones, and cartilage.
Ectoderm: Develops into nerve tissue and the epidermis.
Endoderm: Creates the gut lining and related structures.
The localisation of key messenger RNAs like VegT and Wnt11 and the mapping studies which determined the fate of cells in the mature frog.
In this video, I look at how, after the haploid sperm fuses with the haploid oocyte to form a zygote, we go from one diploid cell to over 200 different cell types and 3 times 10 to the power of 13 (3 with 13 zeros after it) cells. That is a lot of cells and the process is called cellular differentiation.
