The movement of alleles into and out of a gene pool - Micro evolutionary Biology Notes Essay introduction.
These are briefly discussed below. Nucleotides are also known as nitrogenous bases or DNA bases. Nitrogenous base are of two types, viz.
Main features of pyrimidines are given below: Main features or purines are given below: Thus, in DNA there are four different types of nitrogenous bases, viz. In RNA, the pyrimidine base thymine is replace by uracil. The purine and pyrimidine bases always pair in a definite fashion.
Adenine will always pair with thymine and guanine with cytosine. Adenine and thymine are joined by double hydrogen bonds while guanine and cytosine are joined by triple hydrogen bonds. However, these bonds are weak which help in separation of DNA strands during replication.
This is a pentose sugar having five carbon atoms. The four carbon atoms are inside the ring and the fifth one is with CH2 group. This has three OH groups on 1, 3 and 5 carbon positions. Hydrogen atoms are attached to carbon atoms one to four.
The phosphate molecule is arranged in an alternate manner to deoxyribose molecule. Thus there is deoxyribose on both sides of phosphate. The phosphate is joined with carbon atom 3 of deoxyribose at one side and with carbon atom 5 of deoxyribose on the other side.
A combination of deoxyribose sugar and nitrogenous base is known as nucleoside and a combination of nucleoside and phosphate is called nucleotide. Nucleosides differ from nucleotides in that they lack phosphate groups.
The DNA backbone is a polymer with an alternating sugar-phosphate sequence. Depending upon the nucleotide base per turn of the helix, pitch of the helix, tilt of the base pair and humidity of the sample, the DNA can be observed in four different forms namely, A, B, C and D.
Main features of B form of DNA are given below: This is the most common form of DNA. The coiling is in the right direction. The number of base is 10 per turn of helix. The pitch is 3.
The sugar phosphate linkage is normal. The helix is narrower and more elongated than A form. The major groove is wide which is easily accessible to proteins.
The minor groove is narrow. The conformation is favored at high water concentrations. The base pairing is nearly perpendicular to helix axis.
The number of bases is The pitch is 2. The major groove is deep and narrow which is not easily accessible to proteins. The minor groove is wide and shallow which is accessible to proteins, but information content is lower than major groove.
The helix is shorter and wider than B form. The conformation is favored at low water concentrations.Final Exam notes (Spring ) Final Paper: Tips & Examples. Midterm Exam Q&A (Spring ) Biology Final Exam Essay Questions (May ) Contents. DNA helicase- is an enzyme that opens or unzips the double helix so there are two strands ready to be replicated.
SSBP are proteins that keep the strands apart from each other, and DNA. Genetics: Notes on Cell Biology Essay. A male tiger contributes sperm to a female tiger’s egg to produce a zygote - Genetics: Notes on Cell Biology Essay introduction.
The process that produces haploid gamete (sex cells) is called meiosis. ADVERTISEMENTS: In this article we will discuss about: 1. Meaning of DNA 2. Features of DNA 3. Molecular Structure 4. Components 5. Forms. Contents: Essay on the Meaning of DNA Essay on the Features of DNA Essay on the Molecular Structure of DNA Essay on the Components of DNA Essay on the Forms of DNA [ ].
Essay on Biology Notes BIOLOGY EVIDENCE OF EVOLUTION 1. Outline the impact on the evolution of plants and animals of: changes in physical conditions in the environment - changes in chemical conditions in the environment - competition for resources Changes in the environment of living organisms can lead to the evolution of plant and animal species.
- MOLECULAR BIOLOGY INTRODUCTION AND BACKGROUND INFORMATION Molecular biology is to characterize the structure, function and relationships between two types of . Each Dna nucleotide consist of: a. the sugar deoxyribose. b. a N base. The lone difference between the four types of Dna is at that place nitrogen bases.
The four N bases of Deoxyribonucleic acid are the organic ring constructions. a. A. b. T. c. G. d. C.
One manner to find the construction of .