AQA A Level Biology复习笔记8.2.1 Totipotent Cells
Totipotent Cells A stem cell is a cell that can divide (by mitosis) an unlimited number of times Each new cell that is produced when a stem cell divides has the potential to remain a stem cell or t...
AQA A Level Biology复习笔记8.1.1 Genetic Mutations
Gene Mutations A gene mutation is a change in the sequence of base pairs in a DNA molecule that may result in an altered polypeptide Mutations occur continuously and spontaneously Errors in the DNA...
AQA A Level Biology复习笔记7.4.1 Communities
The Definition of a Community Species do not exist by themselves in their own isolated environment, they interact with other species forming communities A community can be defined as: Multiple popu...
Edexcel IGCSE Maths复习笔记 1.9.1 Compound Interest
Edexcel IGCSE Maths复习笔记 1.9.1 Compound Interest What is compound interest? Compound interest is where interest is paid on the interest from the year (or whatever time frame is being used) befor...
Edexcel IGCSE Maths复习笔记 1.8.1 Reverse Percentages
What is a reverse percentage? A reverse percentage question is one where we are given the value after a percentage increase or decrease and asked to find the value before the change How to do rever...
AQA A Level Biology复习笔记7.3.1 Genetic Variation
Genetic Variation Phenotype variation The observable characteristics of an organism are its phenotype Phenotypic variation is the difference in phenotypes between organisms of the same speci...
Edexcel IGCSE Maths复习笔记 1.7.2 Percentage Increases & Decreases
Edexcel IGCSE Maths复习笔记 1.7.2 Percentage Increases & Decreases How do I increase or decrease by a percentage? Identify “before” & “after” quantities Find percentage of “before” that we ...
AQA A Level Biology复习笔记7.2.1 Populations
Species Exist in Populations A species can be defined as a group of similar organisms that can reproduce to give fertile offspring Organisms of the same species have the same number of chromosomes ...
AQA A Level Biology复习笔记7.1.1 Key Terms in Genetics
Key Terms in Genetics Genes & alleles The DNA contained within chromosomes is essential for cell survival Every chromosome consists of a long DNA molecule which codes for several differe...
