Genetics exam 1
In the genetic code, how many nucleotides are necessary to specify one amino acid?
3
Assume a tautomeric shift occurred, which was followed by two rounds of DNA replication. If the mutation is not repaired, the result would be an
AT to GC mutation in one of the four daughter molecules.
In trinucleotide repeat expansion disorders, when the expansion occurs in the coding sequence of the gene, the repeat sequence is usually
CAG
Adenine, thymine, guanine and cytosine are nitrogen-containing bases found in
DNA
the largest macromolecule found in living cells
DNA
what is the genetic material of all living organisms composed of?
DNA
Which is the best description of the particulate theory of inheritance?
Genes are inherited as discrete units that remain unchanged from generation to generation.
What is translation?
The synthesis of a polypeptide based on the sequence of mRNA
What is gene expression?
The use of a gene sequence to affect the characteristics of a cell or organism.
How do alleles differ from one another?
They have slightly different DNA sequences.
A trinucleotide repeat expansion commonly occurs via the formation of
a hairpin that interferes with DNA replication.
characteristic of an organism
a trait
The genetic code directs the order of ______ within a polypeptide based on the sequence of nucleotides within a DNA molecule.
amino acids
The covalent bond between deoxyribose and a purine base is rather unstable and can undergo a spontaneous reaction with water. The breaking of the bond releases the base, and leaves a(n) _____ site in the DNA.
apurinic
Mutations that affect the phenotype only under certain circumstances are called
conditional mutations
Which of these bases is most readily deaminated?
cytosine
breaking of chemical bonds during the degradation of small molecules (i.e. amino acids and glucose) provides _____ to drive cellular processes
energy
A position effect can alter gene expression in cases when the gene is moved from a less condensed, or ______ chromosome, where it is active, to a very highly condensed, or ______ chromosome, where its expression may be turned off.
euchromatic; heterochromatic
The process of using a gene sequence to affect the characteristics of cells and organisms is called gene ______.
expression
unit of heredity (intricate molecular units that manifest themselves as critical contributors to cell structure and function)
gene
Most genes contain the information to direct the synthesis of a polypeptide. The order of amino acids in the polypeptide is specified according to the ______ code.
genetic
describes the combination of alleles an individual has.
genotype
The two main mechanisms used to repair DNA double-strand breaks are ____ recombination repair and ______ end joining.
homologous; non homologous
For a tautomeric shift to cause a mutation, it must occur
immediately prior to DNA replication
The mutation rate is commonly expressed as the number of new mutations
in a given gene per cell generation.
What is the main function of a cell's genetic material?
it encodes proteins
Examples of trinucleotide repeat expansion (TRNE) disorders include _____ muscular dystrophy and ____ X syndrome.
myotonic; fragile
A DNA molecule is a linear sequence of subunits called
nucleotides
Changes to DNA structure caused by reactive oxygen species are termed ______ DNA damage
oxidative
An imbalance between the production of reactive oxygen species and an organism's ability to break them down is known as
oxidative stress
DNA stores information in the _____ of it bases
sequence
Bacteria possess
several different DNA repair systems.
The fact that genetic determinants are inherited as discrete units that are unchanged when passed from generation to generation is best explained by
the particulate theory of inheritance.
Mutations in the 5'-UTR or 3'-UTR of an mRNA molecule are most likely to affect what?
the stability of mRNA, the mRNA's ability to be translated
In trinucleotide repeat expansion diseases, the phenomenon of anticipation varies based on the gender of the transmitting parent, suggesting that
there are differences in expansion in oogenesis vs. spermatogenesis.
In the genetic code, there are 64 codons consisting of ______ nucleotide(s) each that specify the 20 different amino acids. (Your answer will be a number).
three
Which of the following bases is produced by the deamination of 5-methylcytosine?
thymine
What are the four nitrogen-containing bases found in the nucleotides that make up DNA?
thymine, cytosine, guanine, adenine
When a gene is expressed, its DNA sequence is ______ into RNA, which is then ______ to produce a polypeptide.
transcripted; translated
The synthesis of a polypeptide based on the nucleotide sequence of a messenger RNA molecule is called
translation
The inheritance of genes and the way that genes influence traits is the focus of ______ genetics.
transmission
what is a species?
A group of organisms that maintains a distinctive set of attributes
For Mendel's pea plants, the tall phenotype is determined by a dominant allele and the dwarf phenotype is determined by a recessive allele. In the first or F1 generation, what is the outcome of a cross between true-breeding tall and true-breeding dwarf plants?
All of the offspring will be tall.
Genetic anticipation refers to what phenomenon?
An increase in severity of the symptoms as a disease is passed through future generations
What is a model organism?
An organism that is studied so that researchers can determine broadly applicable scientific principles
What is a genetic cross?
The breeding of two individuals and the analysis of their offspring
What can cause a frameshift mutation?
addition or deletion of nucleotides
Escherichia coli
bacterium
Which of these are used by cells to limit the harmful effects of reactive oxygen species?
catalase, vitamin c, superoxide dismutase
Which of the following are genomic alterations that may induce genetic variation?
changes in chromosome number; gene mutations; changes in chromosome structure
Which of the following methods would best be applied to determine if the observed phenotypic ratios of a two-factor cross fit the expected ratios by Mendelian inheritance?
chi square test
In living cells, DNA is found in large structures called ______, which are contained in the nucleus of a eukaryotic cell.
chromosomes
What structures in a cell contain DNA?
chromosomes
The rare enol form of thymine pairs with the
common keto form of guanine.
Silent mutations are possible because the genetic code is
degenerate
The removal of a purine (adenine or guanine) from DNA is called
depurination
Cells can prevent the buildup of reactive oxygen species by using enzymes such catalase and superoxide ____
dismutase
Proteins associated with trinucleotide repeat expansion disorders typically contain long tracts of the amino acid
glutamine
When a protein-encoding gene is transcribed, the RNA molecule that is produced is referred to as ______ RNA (mRNA).
messenger
base substitutions for which an amino acid change does result
missense mutations
A DNA sequence is transcribed in to RNA, which is translated into protein.
molecular level
In a DNA molecule, information is contained in the sequence of
nitrogenous bases
A silent mutation is a mutation that results in
no change to the amino acid sequence of the polypeptide.
Which term refers to the imbalance between an organism's production of ROS and the ability to break them down?
oxidative stress
Guanine is commonly
oxidized to 8-oxoguanine.
A(n) ______ mutation refers to a mutation in which just one base is changed within the DNA sequence.
point
Reactive oxygen species (ROS) are
products of oxygen metabolism in all aerobic organisms.
Products of oxygen metabolism, such as hydrogen peroxide, superoxide, and hydroxyl radical, are collectively called ______ species.
reactive oxygen
A mutation that does not change the amino acid sequence of a polypeptide is known as a(n) _____ mutation.
silent
Mutations in eukaryotic genes that change the ______ recognition sequences may affect the order and/or number of exons contained in the mature mRNA.
splice
Errors in DNA replication are examples of ______ mutations, while mutations caused by ultraviolet light are ______ mutations.
spontaneous; induced
Which field of genetics focuses on how genes are passed on from parents to offspring?
transmission genetics
purines and pyrimidines are interchanges in this type of mutation
transverison
The oxidized form of guanine, 8-oxoguanine, can produce a
transversion mutations
Differences in inherited traits among individuals within a population are referred to as genetic
variation
Trinucleotide repeat expansions are repeated sequences of three bases
which increase generation after generation.
In trinucleotide repeat expansion diseases, the phenomenon of anticipation can vary depending on
which parent the allele was inherited from.
The field of genetics that focuses on the relationship of genetic variation to an organism's environment is called
population genetics
The expression of an intact gene may be altered when it is moved to a new location. This is due to a(n)
position effect
at the molecular level, ____ is a segment of DNA that has information to produce a functional product (i.e. polypeptide) and influences one or more traits of an organism
a gene
small organic molecules such as ________ are produced by the linkage of atoms via chemical bonds
glucose and amino acids
The common stable form of guanine and thymine is the ______ form.
keto
A gamete has only one copy of each gene. Which of Mendel's laws defines this fact?
law of segregation
Which law states that two copies of a gene separate from each other during transmission from parent to offspring?
law of segregation
The rare imino form of cytosine pairs with the common amino form of
adenine
The amino form is the common stable form of which bases?
adenine & cytosine
The function of a protein in a cell affects the structure and function of the cell.
cellular level
a linear sequence of amino acids that folds into units that constitute proteins
polypeptide
functional product of most genes
polypeptide
Chromosomes that differ between males and females are called
sex chromosomes
Trinucleotide repeats can form hairpins due to
slipped mispairing during DNA replication.
A change of one base for another is described as a base ______ mutation.
substitution
A temporary change in base structure due to movement of hydrogen atoms is called a(n)
tautomeric shift
Bases which exist in keto and enol or amino and imino forms are best described as
tautomers
Saccharomyces cerevisiae
yeast
subunits of DNA
nucelotides
The base cytosine is deaminated to produce the base
uracil
Arabidopsis thaliana
flowering plant
What type of RNA contains the information required to synthesize a protein?
mRNA
nucleic acids, proteins, and carbohydrates form _____ that are composed of many repeating units of smaller building blocks
macromolecules