Review for Genetics Exam 3

modules 7 and 8

What type of chromosomal aberration is Triple X/Klinefelter syndrome?

Trisomy

If the haploid number for a cell is 10 chromosomes, how many chromosomes would be found in an individual with triploidy?

30

Which of the following ratios of sperm-fertillized offspring would result from nondisjunction during Meiosis II?

1/4 monosomy, 1/2 disomy, 1/4 trisomy

What are the types of major chromosomal aberration?

duplication: additional copy of gene

deletion: gene is deleted

inversion: both sides of a section of gene are severed, flipped, and reattached

translocation: section of gene is moved. if reciprocal, it is replaced, if nonreciprocal it is not.

What aberration is most difficult to detect by karyotype?

inversion because nothing moves outwardly, it just reorients

What are the two types of deletion?

terminal: end of chromosome snaps off.

intercalary: loop structure forms and snaps off in the middle of a gene

Nondisjunction risk is increased by what environmental factor?

High maternal age

What is genetic anticipation?

there are increased numbers of chromosomal repeats over generations

Ploidy vs somy?

Somy = # of chromosome

Ploidy = # of chromosome sets

Which of the following ratios of sperm-fertillized offspring would result from nondisjunction during Meiosis I?

½ trisomic, ½ monosomic

what are some diagnostic testing that can be used to determine karyotype of fetus?

amniocentesis or chorionic vilus sampling (take amniotic fluid from near baby); noninvasive prenatal genetic diagnosis (fetal cells and DNA from maternal circulation)

Polyploidy can be caused by?

Autopolyploidy: from same species (diploid gamete accidentally produced or two sperm fertilize one egg)

allopolyploidy: different but closely related species mate and chromosomes are not homologous, so they can’t synapse in meiosis. (sets are doubled)

what is endopolyploidy?

some cells are diploid. some haploid

What type of chromosomal aberration is turner syndrome?

monosomy

If the diploid number for a cell is 20 chromosomes, how many chromosomes would be found in an individual with trisomy?

21

Which tools is most useful in quickly and cheaply determining that an individual has Down syndrome?

karyotyping

Which phenomena is thought to be the evolutionary origin of new genes?

duplication: leads to divergence of otherwise identical genes in separate environments

Which phenomena involves two nonhomologous chromosomes swapping sections?

reciprocal translocation

Cri du chat syndrome is a result of what aberration?

Terminal deletion on a chromosome

Which type of chromosomal aberrations may include the formation of loops?

Deletion and inversion

Which chromosomal feature is often associated with "fragile" sites?

loose chromatin

what are the 3 types of extranuclear inheritance?

infectious: foreign body enters cell and genes duplicate

organelle: organelles like mitochondria and chloroplasts have their own DNA which can be passed down and is outside of nucleus. can have their own mutations.

maternal: environment of mother’s womb affects genetics of offspring.

The storage of nuclear gene products in an egg and transmission to embryo to influence the phenotype is related to which type of extranuclear inheritance?

maternal effect

The endosymbiotic theory is related to which type of extranuclear inheritance?

organelle

A mitochondrial mutation would be most likely to affect which process?

aerobic metabolism

What are the abbreviated terms for mitochondrial DNA and chloroplast DNA?

mtDNA and cpDNA

What is the inheritance pattern for mitochondrial mutations?

Mother gives to all children. mothers are the only suppliers of mtDNA.

PKU involves an error in converting one amino acid to another. Which ones? what is PKU?

phenylalanine and tyrosine —> phenylalanine can be consumed in diet. if it can’t be converted to tyrosine, it can’t be metabolized. could lead to metabolic block and could be fatal.

What is the one-gene one-enzyme hypothesis?

developed by George Beadle. argued that genes are directly responsible for the synthesis of enzymes. later renamed to one gene one polypeptide hypothesis, since some proteins are not enzymes and have multiple subunits (polypeptides).

What kind of mutation is responsible for sickle-cell anemia?

A single-base substitution.

Which genetic technique relies on identifying "marker" sequences? (hint: these were previously used as paternity tests)

RFLP

how do RFLP, PCR w/ ASOs, microarrays work?

see worksheet/post mod 8 open response

Mitochondrial DNA is particularly vulnerable to ROS. What does ROS stand for?

Reactive oxygen species. These oxygens bond with other molecules and break them apart or fuse with them, preventing them from working properly.

Type II diabetes, anemia, parkinsons, and alzheimer’s are all connected to dysfunction/mutation in what region?

mitochondria

What is the most effective treatment for phenylketonuria (PKU)?

diet change (don’t eat phenylanaline to avoid blockage)

The One-Gene: One-Enzyme Hypothesis developed based on experiments with which organism?

Neurospora (bread mold)

How many different TYPES of polypeptides are needed to form hemoglobin?

2 (alpha and beta). 4 subunits are needed.

Which type of genetic testing can be used to examine expression patterns for thousands of genes at once?

DNA microarray

What is the purpose of a "probe" in genetic testing?

identify a specific sequence

What similarities do mitochondria and chloroplasts share, evolutionarily?

both share a lot of characteristics with bacteria (endosymbiotic theory)