gene mutation and DNA repair

Change in the genetic code >>>> different ______ >>>>>> useless _______ >>>>> major problems!

amino acids, proteins

nitrous acid replaces amino groups with keto groups in a process called ______

deamination

a _______ mutation can occur directly in a sperm or egg cell, or it can occur in precursor cell that produces the gametes

germ-line

________ mutations are caused by environmental agents

induced

reverse in the direction of parts of the chromosomes is __________

inversion

agents known to alter the structure of DNA which lead to mutations are called _______

mutagens

cellular enzymes such as ______ have been shown to activate some mutagens

oxidase

aberrant ______ of chromosomes during meiosis can cause changes in chromosome number

segregation

_______ (5BU) is a thymine analog that can be incorporated into DNA instead of thymine and pair with adenine

5-bromouracil

_______ causes a mutation in which. TA base pair is changed to a 5BU-G base pair during a tautomeric shift

5BU

sickle cell anemia involves a mutation in the _______ gene, which alters the polypeptide sequence so the sixth amino acid is changed from a ________ to _____

B-globin, glutamic acid, valine

______ can recognize an abnormal base and cleave the bond between it and the sugar in the DNA backbone, creating an apurinc or apyrimidinic site

DNA N-glycosylase

base exision repair (BER) involves the function of a category of enzymes known as _________

DNA N-glycosylase

______ can make a mistake during DNA replication by putting the wrong base in a newly synthesized strand

DNA polymerase

_________ reverse DNA damage before it results in a mutation that could potentially have negative consequences

DNA repair systems

living cells produce several _______ that can fix different types of DNA alterations

DNA repair systems

_________ proposed that physiological events such as the use or disuse of muscles determines whether traits are passed along to offspring

Jean-Baptiste Lamarck

________ was used as a chemical weapon during WWI

Mustard gas

during ______, methyl or ethyl groups are covalently attached to bases

alkylation

a protein known as ________ can remove methyl or ethyl groups from guanine bases that have been mutagenized by alkylating agents such as nitrogen mustard and EMS

alkyltransferase

with regard to their phenotypical effects, mutations can be _______, ________ or ________

beneficial, neutral, detrimental

environmental agents (mutagenic agrnts) that cause mutation can be either _______ or ______

chemical, physical

normal metabolic processes may produce _______ within the cell that can react directly with the DNA and alter it's structure

chemicals

_______ involve changes in the structure or number of chromosomes

chromosomal mutations

deamination changes ______ to ______ and ______ to ______

cytosine, uracil, adenine, hypoxanthine

loss of all or part of a chromosome is ________

deletion

there are four main types of chromosomal mutations ________, _______, ________ and _________

deletion, duplication, inversion, translocation

a base is removed from the nucleotide sequence in ________

deletions

extra copies of chromosomes being produced is _________

duplication

in a few cases, the covalent modification of nucleotides by mutagens can be reversed by specific cellular _______

enzymes

________ mutation involves the addition or deletion of a number of nucleotides that is not divisible by three

frame shift

insertions and deletions are called ________ mutations because they shift the letters of the genetic message

frame shift

ionizing radiation can penetrate deeply into biological materials, where it produces chemically reactive molecules known as ______

free radicals

__________ are molecular changes in the DNA sequence of a gene

gene mutation

there are two main types of mutations: ________ and ________ mutations

gene, chromosomal

an individual that has somatic regions that are genotypically different from each other is called a _______

genetic mosaic

an additional base is inserted into the nucleotide sequence in _______

insertions

________ mutations are base substitutions in which an amino acid change does occur

missense

______ occurs when the structure of DNA has been changed permanently and this alteration can be passed from generation to generation

mutation

_________ provide the variation that enables species to change and adapt to their environment

mutation

the term ______ refers to heritable change in genetic material

mutation

_______ mutations involve a change from a normal codon to a stop codon

nonsense

an important general process for DNA repair is the ______ (NER) system

nucleotide excision repair

_________ can repair different types of DNA damage, including thymine dimers, chemically modified bases, missing bases, and certain types of crosslinks

nucleotide excision repair systems

alkyltransferase can only be used _______

once

Bacteria, fungi, most plants and some animals produce an enzyme called _______ that recognizes thymine dimers and splits them, which returns the DNA to it'd original condition

photolyase

_________ contains two light-sensitive cofactors

photolyase

a ______ is a change in a single base pair within a DNA

point mutation

_______ involves changes in one or few nucleotides

point mutations

_________ contains flat structures that intercalate, or insert themselves between adjacent base pairs, thereby distorting the helical structure

proflavin

DNA molecules are also sensitive to physical agents such as ________

radiation

an example of a missense mutation is _______

sickle cell anemia

a ______ mutation are those that do not alter the amino acid sequence of the polypeptide even though the nucleotide sequence has changed

silent

_________ mutations are changes in DNA structure that result from biological or chemical processes

spontaneous

one base is substituted for another base in ________

substitutions

there are three main types of point mutations _________, _________, _______

substitutions, insertions, deletions

UV light causes the formation of ________

thymine dimers

a change of a pyrimidine to another pyrimidine or a purine to another purine is called a _______

transition

part of one chromosome breaks off and attaches to another in_________

translocation

a change in which purines and pyrimidines are interchanged is called

transversion

radiation of short ______ and high ______, known as _______ can alter DNA structure

wavelength, energy, ionizing radiation