Dna and Base Substitution Mutation Essay

Submitted By ellennnkh
Words: 549
Pages: 3
Open Document
Chromosomes, genes, alleles and mutations
4.1.1 State that eukaryote chromosomes are made of DNA and proteins.
Eukaryotic chromosomes consist of DNA wrapped around histone proteins
This forms the basic structure of the nucleosome, which is packed together to form chromatin (in a 'beads on a string' arrangement)
Chromatin will supercoil and condense during prophase to form chromosomes that can be visualised under a light microscope
Prokaryotic DNA is not wrapped around proteins and is thus considered to be 'naked'
4.1.2 Define gene, allele and genome.
Gene: a heritable factor that controls a specific characteristic.
Allele: one specific form of a gene, differing from other alleles by one or a few bases only and occupying the same gene locus as other alleles of the gene.
Genome: the whole of the genetic information of an organism.
4.1.3 Define gene mutation.
Gene mutation: a change to the base sequence of a gene.
4.1.4 Explain the consequence of a base substitution mutation in relation to the processes of transcription and translation, using the example of sickle-cell anemia.
Sickle cell anaemia is a genetic disease that affects red blood cells in the body. It is due to a mutation on the Hb gene which codes for a polypeptide of 146 amino acids which is part of haemoglobin (haemoglobin is an important protein component in red blood cells). In sickle cell anaemia the codon GAG found in the normal Hb gene is mutated to GTG. This is called a base substitution mutation as adenine (A) is replaced by thymine (T). This means that when the mutated gene is transcribed, a codon in the messenger RNA will be different. Instead of the normal codon GAG, the messenger RNA will contain the codon GUG. This in turn will result in a mistake during translation. In a healthy individual the codon GAG on the messenger RNA matches with the anticodon CUC on the transfer RNA carrying the amino acid glutamic acid. However, if the mutated gene is present then GUG on the messenger RNA matches with the anticodon CAC on the transfer RNA which carries the amino acid valine. So the base substitution mutation has caused glutamic acid to be replaced by
Show More

Related Documents: Dna and Base Substitution Mutation Essay

Nucleotide Mutations Research Paper

Genetic mutations are changes in the genetic code. These changes can cause different illnesses in humans and animals. These changes can have extremely noticeable effects, or effects that do not change anything. Most everyone has a genetic mutation of some kind, even if it is unnoticeable. There are two types of genetic mutations. Nucleotide and chromosomal are the two types. There are three types of nucleotide mutations, and five types of chromosomal mutations. The changes that are caused by the…

Words 650 - Pages 3

Disorders Of Replication Essay

developing embryo Not serious, but phenotype of cell changes Mutation by Base Substitution (animation) A mutation occurs by base substitution when an incorrect base is incorporated into DNA. Some base substitutions occur because purines and pyrimidines exist in 2 structural forms The most common form results in base-pairing between adenine and thymine and between guanine and cytosine However, the hydrogen atoms can move to form a base with altered hydrogen bonding properties, creating a tautomeric…

Words 629 - Pages 3

Pt1420 Unit 3 Assignment

Q1 The DNA-base mutation of a protein means the base substitutions which is a transition between pyrimidine and purine. The mutation type is determined by the adduct's position on a specific DNA base. When point mutation happens, the entire DNA sequence is altered during replication which changes the amino acid sequence and finally causes the changes to a protein. 1. Nonsense mutation: The codon which codes amino acid’s changed to the stop codon when one nucleotide is substituted. The amino acid…

Words 471 - Pages 2

Essay on Genetics: Dna and Dna Molecule

REGULATION, AND MUTATION 1. A typical prokaryotic cell contains __________chromosome(s). 2. The basic building block of a DNA molecule is the__________________________ 3. The observable physical traits of an organism are collectively referred to as its ______________________ 4. An organism's genetic makeup is its_____________________________ 5. The nitrogenous bases found in DNA are ____________, ______________,_____________and ______________. 6. In a DNA molecule thymine…

Words 647 - Pages 3

Griffith's Experiment And Avery, Macleod, And Mccarty

determined that DNA in bacteria transmits a trait that kills mice. Griffith and Avery, Macleod, and McCarty’s experiments both concluded that the S type when mixed with the R type bacteria, changes the R type bacteria allowing it to develop a smooth coating that allows it to cause infection. They all found that there was something in the heated S strand that turned the R strand into a killer. (biology book) 2. Describe the three-dimensional structure of DNA. The structure of DNA looks like a spiraling…

Words 2225 - Pages 9

Bio Terms Essays

8.2 Nucleotide – monomer that forms DNA and has a phosphate group, a sugar, and a nitrogen base Double helix – model that compares the structure of a DNA molecule, in which two strands wind around one another, to that of a twisted ladder Base pairing rules – rule that describes how nucleotides form bonds in DNA; adenine (A) always bonds with thymine (T), and guanine (G) always bonds with cytosine (C) Chapter 8.3 Replication – process by which DNA is copied DNA polymerase – enzyme that makes bonds…

Words 747 - Pages 3

Essay Dna and Dna Strand

Unit 8 Study Guide Lesson 1 1. What is DNA short for and what is its definition? Deoxyribonucleic acid the genetic material of a cell 2. What DNA discovery happened in 1950 and who discovered it? Erwin Chargaff-that the amount of guanine always equals the amount of cytosine, and the amount of adenine equals the amount of thymine, these are known as Chargaff’s rules 3. What DNA discovery happened in 1951 and who discovered it? Rosalind Franklin and Maurice Wilkins when an x-ray passes through…

Words 968 - Pages 4

Human Population Bio Study Guide

Nucleic Acids (DNA & RNA)* DNA=Thymine; RNA=Uracil AT CG – DNA AU CG – RNA * Most important Proteins They direct chemical reactions through their role as enzymes Also act as hormones and transmitters Made up of sub-units called Amino Acids A proteins Structure depends on its amino acid sequence A proteins Function depends on its structure Nucleic Acids DNA is combined with protein material to form chromosomes DNA Replication Parent Cell Divides into 2 daughter cells DNA Subunits –> Nucleotides…

Words 1364 - Pages 6

Essay about Cells Test Review: Part 2

and acts as the instructions for making a protein b. mRNA- carries the codes copied from DNA in 3 base codes (called codon) that specifies on the amino acid from the nucleus to the cytoplasm c. tRNA- it carries a specific amino acid to the ribosome to be added onto the polypeptide chain d. rRNA- The sites in which proteins are made e. Codon- a sequence of three nucleotides that make up a genetic code in a DNA and RNA molecule. f. Anticodon- a sequence of three nucleotides forming a unit of genetic…

Words 748 - Pages 3

Essay on Biology DNA Study Guide

GUIDE (DNA) DNA STRUCTURE/DNA REPLICATION 6-Watson and Crick: Used Franklin’s and Chargaff’s info to make the first ever accurate DNA model 1-DNA is double helix and is built from nucleotides which consist of a phosphate, a base, and a sugar. The bases include G,C,A,T which are connected by hydrogen bonds. DNA polymerase is also located behind the DNA where bases connect to each other. 4/8-A=T and G=C only these combinations can form hydrogen bonds. 4-A nucleotide consists of a base, a phosphate…

Words 324 - Pages 2