The Human Genome Flashcard

Sex-linked recessive disorders are more common
in males than in females because any male receiving a recessive allele from his mother will express that trait because males only have one copy of the X-chromosome.
If a diploid cell for a dog has 78 chromosomes, then a haploid cell would have
39 chromosomes.
A monosomy is most likely to be found
in the X-chromosome in humans.
Chargaff
determined the approximate amounts of bases (A, G, C, T) relative to each other in DNA.
The leading strand is (x3)
-replicated continuously
-only needs one RNA primer
-is synthesized in the 5′ to 3′ direction
(it is NOT the only strand that is replicated as the lagging strand is also replicated)
Hydrogen bonds connect
the base pairs in the DNA double helix.
An individual who has two copies of the same allele is said to be
homozygous.
DNA replication is called
semiconservative because half of the original double helix appears in the newly formed helix upon a single round of replication.
Levene
discovered the nucleotide composition and deoxyribose as the sugar molecule that helped lay the foundation for Watson and Crick’s DNA model
Topoisomerases
are enzymes/proteins essential for DNA replication because they assist in the unwinding of the DNA double helix.
In terms of organizing DNA, the largest is
chromosomes.
Black fur (B) is dominant and white (b) is recessive. Short haired fur (S) is dominant and long haired fur (s) is recessive. Genotypes of the parents = BbSs and bbSS. The phenotype of the offspring will
all have short haired fur.
Flaws of eugenics research (x3)
-assumed that complex disorders had simple inheritance patterns
-relied on data collection by untrained individuals or biased researchers
-ignored the environmental factors
If the sequence of one strand of a DNA molecule is 5′-ATGGCAT-3′, the sequence of the complementary strand is
3′-TACCGTA-5′
If human DNA contains 30% adenine, then the percentage of thymine would be
30%.
The experiments done by Oswald Avery, Maclin McCarty, and Colin MacCleod (1944)
utilized enzymes to breakdown the different possible candidates: DNA, RNA, and proteins.
The term phenotype refers to
the appearance of a trait in an individual.
Independent assortment can NOT be demonstrated in a monohybrid cross because
you must examine the transmission of two or more genes.
In the transformation observed by Griffith
a mixture of heat-killed S strain bacteria and R strain bacteria killed the mice.
Preimplantation genetic diagnosis is
a prenatal test done for detecting chromosomal abnormalities before an embryo is implanted.
Mutations at the DNA level (x3)
-mutations to DNA may be caused by environmental factors (exposure to UV radiation – epigenetics)
-though mutations do occur, the complex machinery of DNA has built in mechanisms to correct many of the errors
-substitutions that occur may or may not result in an observable error when the DNA is translated to proteins
The direct product of translation is
a protein.
Three substances involved in transcription are
DNA, mRNA, and RNA polymerase.
The process of translation ends when
a stop codon is added to the protein chain.
RNA splicing occurs
after transcription and results in the removal of introns from the RNA sequence.
RNA differs from DNA (x3)
-in DNA adenine pairs with thymine but in RNA adenine pairs with uracil
-the DNA sugar is deoxyribose but the RNA sugar is ribose
-DNA is double stranded but RNA is single stranded
A codon (x3)
-consists of three nucleotides
-may code for the same amino acid as another codon
-never codes for more than one amino acid
Regarding genetically engineered plants, currently
there are serious biological and environmental issues regarding their use.
In recombinant DNA technology,
DNA ligase may be used to join sections of DNA together.
Polymerase Chain Reaction (PCR) is
a technique similar to a molecular copy machine for DNA.
In the Sanger method of DNA sequencing,
DNA synthesis stops when a dideoxynucleotide (ddNTP) is incorporated.
Polymerase chain reaction (PCR) can be conveniently performed because
Taq polymerase is not damaged by heating.
Plasmids are
circular pieces of DNA that can be used to carry foreign DNA cells such as bacteria.
Insulin was targeted as the first genetically engineered drug because
people sometimes had an adverse reaction to the porcine or bovine insulin that was available.
mRNA is modified after it is transcribed by (x3)
-adding the poly-A tail
-adding a 5′ cap
-removing the introns
Restriction enzymes are used (x3)
-to cut a plasmid so a gene of interest can be inserted
-to cut a gene of interest from a strand of DNA
-to attack invading foreign DNA when it enters a host
Francis Collins
served as the second director of the public Human Genome Project and is the current head of the NIH.
Sickle cell anemia is caused by
a single base substitution resulting in the incorporation of the wrong amino acid into the protein.
rRNA is
the structural and functional component of the ribosome
Beadle and Tatum’s experiment
identified that one gene specifies the production of a particular enzyme using bread mold.
DNA technology is used for many medical applications such as (x3)
-prenatal identification of genetic disease genes
-genetic testing for carriers of harmful alleles
-production of viral vectors for use in gene therapy
(NOT used for introduction of genetically engineered genes into human sperm and egg cells)
Gene therapy is
the process used to insert genes into human cells to correct disorders.
Huntington’s disease (x3)
-the first disease-causing gene mapped to a specific chromosome using linkage analysis
-genetic testing is available for individuals with a family history of the disease
-autosomal dominant disorder
(immediately after it was mapped the cause of the disease was NOT determined)
Gene therapy targeting the germ-line
is heritable.
The most controversial type of cells are
embryonic stem cells.
The disadvantage of adult stem cells over embryonic stem cells is because
they are difficult to locate.
The death of Jesse Gelsinger
was considered a major setback for the advancement of gene therapy.
Genome Wide Association Studies (GWAS) (x3)
-seek to identify naturally occurring single nucleotide polymorphisms (SNPs) and determine how these are distributed across populations
-rely on studying the genomes of both healthy and diseased individuals to correlate SNPs with instances of disease
-allow for linking a disease to multiple genes
(NO indication that two disorders with different symptoms are linked to a single gene)
Reasons why DNA extracted from fossils to understand human origins are not always suitable for sequencing because (x2)
-the DNA that is extracted will have been degraded by microorganisms and water, making it fragmented and damaged
-the DNA may be contaminated by the researchers making it difficult to know what is ancient versus modern DNA
Blood stem cells are
multipotent.
Proteomics is
the study of the collection of proteins produced in a particular cell.
The two properties of mitochondrial DNA that molecular anthropologists find valuable are that
-it is passed from mother to child
-it is more abundant than nuclear DNA
Mitochondrial DNA is
the genetic information that can be used to trace maternal lineage.
Shinya Yamanaka is credited with
the discovery of iPS cells.
Huntington’s disease is caused by
an expanding triplet repeat.
Epigenetic changes
affect the availability of genes for expression.
During enzyme replacement therapy
a functional form of the enzyme is supplied to the patient.
Induced pluripotent stem cells (iPS cells) are
adult somatic cells reprogrammed to assume a stem cell-like state.
Molecular cloning is
the introduction of a gene into a foreign cell through the use of a vector that will serve in the production of large quantities of the product encoded by the gene.
From the Human Genome Project the most recent discovery which has altered our understanding of the non-coding regions of DNA (formerly known as junk DNA) is
that the non-coding regions are in fact very active, containing the switched that control/regulate gene activity.

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