Leading Strand & Lagging Strand Double-stranded DNA consists of two antiparallel strands (oriented in opposite directions) During DNA replication, the two strands are ‘unzipped’ and DNA polymer...
Nucleosomes Unlike most prokaryotic DNA which is referred to as ‘naked’, eukaryotic nuclear DNA is associated with proteins called histones (to form chromatin) Histones package the DNA into structu...
Male & Female Diagrams You should be able to annotate diagrams of the female and male reproductive systems to show the names of the different structures You should also be able to recall the fu...
Oestrogen & Progesterone During early development an embryo develops embryonic gonads that will either become ovaries in females or testes in males The factor that determines whether the embryo...
按往年惯例，通常9月份开始，不同考区就开始陆续报名。科目选择会让不少学生纠结，好在CollegeBoard给出了“官方标准”，列举了不同年级热门报考科目。目前AP开设了22个门类，37个学科的AP课程。AP课程共有38门学科...
SRY Gene In sexual reproduction in humans, a sperm from a male fuses with, or fertilises, an egg from a female to form a zygote, which then develops into an embryo To begin with the embryo develops...
William Harvey & Sexual Reproduction in Deer William Harvey (1578 - 1657) was an English physician who contributed greatly to our understanding of anatomy and physiology He is mainly remembered...
Leptin Leptin is a hormone that is secreted by fat storage cells known as adipose cells The concentration of leptin in the blood is controlled by the amount of adipose tissue in the body As we eat ...
Insulin & Glucagon The pancreas is an organ found in the abdomen of mammals It functions as both an endocrine gland and an exocrine gland Endocrine glands secrete hormones directly into the blo...
Analysis of Oscilloscope Traces It is possible to measure membrane potentials in neurones by placing electrodes on each side of the membrane A membrane potential is the difference in charge between...
Synapses Where two neurones meet, they do not actually come into physical contact with each other Instead, a very small gap, known as the synaptic cleft, separates them The ends of the two neurones...
Resting Potential Neurones transmit information in the form of impulses, which travel extremely quickly along the neurone from one end to the other Note that an impulse is not an electrical current...
