Mutations and DNA repair

What is deletion?

A base being deleted from the DNA code

Define gene mutation.

A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people.

What is the main difference between a gene mutation and a genome mutation?

A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. A genome mutation is an alteration to the general number of chromosomes e.g. excess or deficiency of chromosomes, Down syndrome

What is a frameshift mutation?

A mutation caused by the addition or deletion of a base pair or base pairs in the DNA of a gene resulting in the translation of the genetic code in an unnatural reading frame from the position of the mutation to the end of the gene.

What is an another name for Trisomy 21?

Down Syndrome

What happens during prophase 1 in meiosis that enables the exchange of genetic material?

During prophase 1, exchange of parts of chromatids (visible as X-shaped structures called chiasmata) follows chromosome pairing (crossing over).

What is an another name for Trisomy 18?

Edwards Syndrome

What happens to chromosome number 18 in monosomy 18P?

Genetic condition caused by a deletion of all or part of the short arm (the p arm) of chromosome 18.

What is the name given to negative effects of mutations?

Genetic disorders

What kind of mutation, and in which gene, is sickle cell anaemia caused by?

Point mutation in the haemoglobin gene

What do neutral inherited mutations lead to?

Polygenic phenotypic characters

How often can mutations have positive consequences?

Rarely

What does a gene mutation result from?

Results when the specific sequence of a gene changes.

Name a genetic mutation/condition that affects the red blood cells in your body?

Sickle cell anaemia

What is the chiasmata?

The X shaped structures in crossing over of chromatids

1.) In gene therapy, what kind of gene is inserted into the person's genome to replace a mutated gene? 2.) What kind of molecule must be used to deliver this therapeutic gene to the patient's target cells?

1.) A "wild type" gene 2.) A carrier molecule called a vector

1.) What is Homology Directed Repair? 2.) What is HDR important for suppressing? 3.) How does HDR maintain genomic stability? 4.) Why is it assumed to be error free?

1.) A mechanism in cells to repair double strand DNA lesions 2.) HDR is important for suppressing the formation of cancer. 3.) HDR maintains genomic stability by repairing broken DNA strands 4.) It is assumed to be error free because of the use of a (undamaged) template.

1.) What is Non-Homologous end joining? 2.) How does it repair the DNA? 3.) What will this create? 4.) What is this process prone to? 5.) As a result, what will this disrupt?

1.) A mechanism that repairs double strand breaks in DNA 2.) Repairs it by inserting or deleting base pairs 3.) Creates a frameshift 4.) Exon skipping 5.) Gene translation

What is insertion and how does it affect the gene? SAM MET BAT MAN SAM MEL TBA TMA N

1.) Addition of an extra base into the DNA code. All bases following the insertion are affected 2.) Alter the reading frame of the genetic message, the triplet grouping of nucleotides on the mRNA that is read during translation

1.) What are neutral mutations? 2.) Give some examples

1.) Mutations can be neutral (neither positive nor negative consequences). Neither beneficial nor detrimental to the ability of an organism to survive and reproduce. 2.) Eye colour, ear lobe form, hair colour

1.) What can't cure genetic orders? 2.) What kind of therapies are mostly used?

1.) Pharmaceutical intervention 2.) Symptomatic treatments - is any medical therapy of a disease that only affects its symptoms, not its cause

1.) What kind of mutation is Cystic Fibrosis caused by? 2.) Which gene becomes mutated? 3.) What does the CTFR gene create and what does this molecule regulate? 4.) What happens to the human body in this condition?

1.) Point mutations. 2.) CTFR gene 3.) CFTR gene normally creates a protein that regulates levels of sodium and chloride in cells. If the CFTR gene is defective, it results in a build-up of thick, sticky mucus. 4.) Cystic fibrosis is a genetic condition in which the lungs and digestive system become clogged with thick sticky mucus.

1.) Define deletions 2.) Define duplications ( or amplifications ) 3.) Define insertions 4.) Define inversions 5.) Define translocations

1.) Removal of a large chromosomal region, leading to loss of genes. 2.) Lead to multiple copies of a chromosomal region, increasing the number of the genes. 3.) The addition of material from one chromosome to a non-homologous chromosome. 4.) Reversing the orientation of a chromosomal segment. 5.) Interchange of genetic material.

What are the disadvantages of the abnormal red blood cells in sickle cell anaemia?

1.) Unable to move around as easily as normal red blood cells 2.) Can block blood vessels, resulting in tissue and organ damage and episodes of severe pain

What substances or factors can cause a gene to mutate?

1.) Viruses 2.) Cigarette smoke 3.) Alcohol 4.) Radiation 5.) Chemicals

1.) Are all mutations heritable? 2.) Are all mutations capable in being passed onto future generations? 3.) Give an example where a mutation will not inherited by the future generation, and give an example. 4.) What sort of mutations will be passed onto the offspring?

1.) Yes, as in the mutated gene will be copied during DNA replication 2.) No, not all of them 3.) Somatic mutations : Mutations to the cells of the body, nongermline tissues. Mutations that don't occur in the germ line cells. e.g. Mutation in tumour only ( breast) 4.) Only changes that affect the genetic information contained in the reproductive cells of an organism, called germ cell mutations, will be passed on to offspring.

Which chromosome becomes affected in Trisomy 21 and how?

21. 3 copies of the genes on chromosome 21.

What is the most common vector that is used in gene therapy, and how is it modified to carry out its job safely?

A virus that has been genetically altered to carry normal human DNA

Which receptor does the HIV virus bind to on white blood cells in order to enter them?

CCR5 delta 32 receptor

What is point mutation?

Changes in a single nucleotide pair of a gene. New gene may still make sense

What can the mutation of the CCR5 delta 32 receptor lead to?

Hampers the ability of the virus to bind to immune cells. Some people are born with a mutation that prevents CCR5 from appearing on their cells, making them resistant to HIV. Some experimental gene therapy approaches aim to mimic this mutation in AIDS patients

Which gene is affected in Neurofibromatosis type 1 and how?

Mutation in or deletion of the Neurofibromin 1 gene

What are the differences between the red blood cells in normal blood and sickle cell anaemia?

Normal red blood cells are flexible and disc-shaped Sickle cell anaemia, they become rigid and shaped like a sickle

How is the second X chromosome affected in Turner Syndrome (Monosomy X)?

Partly or completely missing

What is an another name for Trisomy 13?

Patau Syndrome

How many bases makes up a codon, eventually coding for an amino acid?

Three bases

Gene mutation can occur any time during the life of a cell, true or false?

True