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