Category: O level biology
Why Earthworms Are a Gardener’s Best Friend
Earthworms are considered a gardener’s best friend for several reasons: Soil aeration: Earthworms burrow through the soil, creating tunnels and air pockets that allow air, water, and nutrients to penetrate the soil more easily. This improves soil aeration, which is important for plant root health. Soil structure: Earthworms also help to improve soil structure by…
Plasma membrane
Delimiting membrane or boundary of all cells providing the characteristic shape to the cell. Structure ● Composed of approx. 7 nm thick phospholipid bilayer with hydrophilic heads facing outward from both sides into aqueous environment and hydrophobic tails facing inside the bilayer. ● A symmetrical the presence of proteins, floating in the bilayer imparts a…
Mutation
Mutation is a change in the DNA sequence of an organism’s genetic material. DNA, or deoxyribonucleic acid, is the molecule that carries the genetic instructions for the development and function of all living things. DNA is made up of four chemical bases, adenine (A), cytosine (C), guanine (G), and thymine (T), which are arranged in…
Chromosome
A chromosome is a structure found in cells that is made up of a long strand of DNA, which is the genetic material that contains the instructions for the development and function of all living organisms. Chromosomes are found in the nucleus of eukaryotic cells and play a crucial role in the cell cycle, replication,…
Sir Alexander Fleming
(August 6 , 1881 – March 11, 1955) Early life and Education Sir Alexander Fleming was a Scottish physician, microbiologist, and pharmacologist, who was born on August 6, 1881 at Lochfield farm near Darvel, in Ayrshire, Scotland. Alexander was the third of four children of farmer Hugh Fleming (1816–1888) from his second marriage to Grace…
True Or False On Carbohydrates
Movement of Substances Quiz
Diffusion – Movement of Substances
Table of Contents Diffusion Defination Diffusion is the net movement of molecules and ions from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movement. What is Diffusion The molecules of a gas such as oxygen are moving about all the…
Blood vessels and their functions
Arteries are blood vessels which carry blood away from the heart. They have thick, muscular and elastic walls that can withstand the surge of the high-pressure blood pumped out of the heart.
