chapter 11 study guide- Human Gen.

Genetic imprinting is caused by ____.

​epigenetic changes to DNA

base analogs

Chemical mutagens that incorporate into DNA or RNA molecules

Why is it difficult to identify the source of an autosomal recessive mutation in a family pedigree?

Heterozygous carriers can remain undetected for generations.

Beckwith-Wiedemann syndrome is a cell growth disorder that causes enlarged organs, high birth weight, and predisposition to cancer.

True

​PBDEs have not been linked directly to cancer in test animals.

True

New ____ mutations can often be detected by examining the inheritance of the trait in males.

X-linked

frameshift mutation

​Insertion or deletion of a nucleotide in a gene causes a type of mutation

Huntington Disease results from extra copies of trinucleotide repeats in the Huntingtin gene. This is an example of a(n) ________ mutation.

allelic expansion

Tautomeric shifts

allow(s) for noncomplementary base pairing, which results in permanent mutations after DNA replication.

allelic expansion

are mutations involving the increase of the number of repeat sequences in genes. trinucleotide repeats

Mutations that occur in somatic cells ________.

are not passed onto the offspring

If a genetic disorder appears in a family with no prior history, and is fully expressed by everyone carrying that allele, it is most likely a(n) ____ trait.

autosomal dominant

​In sickle cell anemia, affected individuals carry ____.

​the same single nucleotide substitution

Several lines of research provide strong evidence that ____ to environmental signals influence behavior.

epigenetic responses

genetic imprinting

epigenetics passed down from Dad or Mom, affects a few genes, gets erased and re-imprinted for the next generation (ex: Prader-Willi, Angelman, Beckwith-Wiedemann syndromes)

mutations in germ cells

passed on to future generations

What is the largest single source of radiation exposure for the average person in the U.S.?

radon

Mutagenic chemicals that ____ and are incorporated into DNA or RNA during synthesis are called base analogs.

resemble nucleotides

Epigenetics and imprinting

reversible changes to the genome that alter gene expression

​When the number of trinucleotide repeats in a gene is significantly above normal, it can produce a mutant phenotype.

true

DNA methylation in promoter regions of genes ________.

turns off gene expression

​When ____ is incorporated into DNA or RNA during synthesis, it will create a(n) ____.

​5-bromouracil; nucleotide substitution mutation

What occurs in a missense mutation?

​A single amino acid is substituted for another in a protein.

​As radiation strikes molecules in cells, it creates ____.

​charged atoms called ions

Sense mutations produce ____.

​elongated proteins

Several genetic disorders, including Fanconi anemia and ataxia telangiectasia, are caused by mutations in ____.

DNA repair genes

mutations in somatic (body) cells

- passed on by cell division to daughter cells -not transmitted to future generation -underlie many cancers

________ genes tend to have high DNA mutation rates.

. Trinucleotide repeat-containing

DNA repair systems

1) Proofreading during DNA replicaiton- mismatch repair 2) Recognation of distortions- mismatch repair 3) Repair damage- caused by UV light 4) Repair breakage

In some parts of the United States where PBDEs are not banned, samples of human milk contain ________ PBDEs than in European countries, where this chemical is banned.

10 to 100 times more

base analong

A purine or pyrimidine that differs in chemical structure from those normally found in DNA or RNA

frameshift mutation

A two-nucleotide insertion mutation that results in conversion of an amino acid codon to a stop codon

Halogen-containing organic compounds persist in the environment for approximately five years.

False

Nonsense mutations change termination codons into amino acid codons.

False

proofreading

The ability of DNA polymerase to repair its own nucleotide mismatches

epigenome

The epigenetic state of a cell

​Radiation in the environment that contributes to radiation exposure is called ________ radiation.

background

PBDEs are ____.

banned in many European countries but permitted in most states in the United States

Mutations in_____ cells will be passed on by cell division, but cannot be transmitted to future generations.

body

DNA polymerase

build(s) new DNA molecules and proofreads the new strand to detect and correct any errors.

Mutations are changes in the nucleotide sequence of DNA that ____.

can be passed on to daughter cells

The flaking of skin after a sunburn is an example of ________.

cell suicide as a result of too much DNA damage

mutations

changes in the DNA that are passed onto future generations (heritable)

As DNA polymerase synthesizes a new DNA strand, it can ____.

detect an incorrect nucleotide

Because many imprinted genes control the timing and patterns of prenatal growth, abnormal imprinting can cause ________, which is seen in disorders such as Beckwith-Wiedemann syndrome.

growth disorders

Measuring how DNA methylation patterns on the glucocorticoid receptor gene promoter change in response to environmental signals can reveal ________

how epigenetics controls the stress response

​Beckwith-Wiedemann syndrome results from abnormalities of

imprinting

Mutations that result in the production of a defective CFTR protein inserted into the cell membrane cause ________ disease phenotypes.

milder

A mutation in the Factor VIII gene − required for blood clotting − changes a CGT codon to CAT, and changes the amino acid from arginine to histidine. This is an example of a ________ mutation.

missense

nucleotide substitution

missense- mistake in one nucleotide (HbS, CF)

​Mutation rates of human genes are expressed as the number of ____.

mutated alleles per gene in each generation

sporadic/spontaneous mutations

mutation that arises naturally and not as a result of exposure to mutagens.

induced mutations

mutation that is produced by treatment with a physical or chemical agent that affects the deoxyribonucleic acid molecules of a living organism

Epigenetics

the study of phenotypic changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself -DNA methylation -histone acetylation -microRNAs- RNA interference