Bio exam 2 – Flashcards
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The offspring produced via sexual reproduction are genetically ________ to the parents.
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unique
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Upon fertilization, the egg and sperm fuse to form a single cell called a(n) ________
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zygote
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Dead or damaged cells are replaced by ________.
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mitosis
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Except during __________, cell division in humans results in daughter cells that have the same number of chromosomes and are genetically identical to each other and to the parent cell.
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sexual reproduction
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Human white blood cells are often multinucleated. How many chromosomes would be present in a white blood cell with two nuclei?
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92
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How much of your DNA is identical to that of another person of the same sex?
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99.5%
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Name the part of the chromosome indicated by the arrow. (Middle of X)
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centromere
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If it were to be stretched out, the DNA in one of your cells would be taller than you. How does such a large quantity of DNA fit within the nucleus of one of your cells?
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DNA is associated with proteins that compact the DNA to form a package called chromatin
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What are attached at the centromere?
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sister chromatids
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What type of cells undergo mitosis?
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neither gametes nor bacterial cells
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Duplication of the chromosomes by a cell occurs __________
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before a cell divides
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During which phase of the cell cycle are the chromosomes duplicated?
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interphase
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Which process specifically refers to a cell physically dividing into two cells?
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cytokinesis
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By what means does a zygote divide?
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mitosis
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How many chromosomes did you inherit from your father?
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23
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Somatic cells are ________.
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diploid (2n)
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After fertilization, the resulting zygote undergoes _____.
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mitosis
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If a cell had 12 chromosomes at the beginning of meiosis II, how many would each daughter cell have after the completion of meiosis II?
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12
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If mitosis makes somatic cells, what does meiosis make?
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sex cells
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What is the name of the syndrome that produces the XXY combination of sex chromosomes?
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Klinefelter syndrome
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Is an individual with the XXY combination of chromosomes anatomically male or female?
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male
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What is different between two alleles of the same gene?
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their base sequence
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The tall allele is dominant and the dwarf allele is recessive. What is the abbreviation for the dwarf allele?
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t
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When I say a flower is "purple," what have I described?
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its phenotype
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Imagine that, in cats, eye color is controlled by a single gene and that black eyes are dominant to orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele for black eyes is __________ the allele for orange eyes.
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dominant to
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A true-breeding milk chocolate Easter bunny is crossed with a true-breeding dark chocolate Easter bunny. Assuming dark chocolate is dominant over milk chocolate and the traits segregate according to Mendelian genetics, which traits will the offspring express?
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all dark
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If your grandparents were in the F1 generation, what generation are you?
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F3
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Assuming complete dominance, what is the expected phenotypic ratio of the offspring following the cross of two heterozygotes?
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3:1
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What do we call a genetic cross that follows two separate characters, such as pea seed color and pea seed shape?
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a dihybrid cross
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Huntington's disease is a rare genetic disorder. Which of the following statements regarding the genes for Huntington's must be true?
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Huntington's is a mutant trait, but we cannot say whether it is dominant or recessive.
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What is a carrier?
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an individual who is heterozygous for a particular recessive trait
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Assuming incomplete dominance, if a homozygous red-flowered plant is crossed with a homozygous white-flowered plant, what will be the color of the offspring?
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pink
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Genes located near one another on the same chromosome are often inherited together. These are called ________
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linked genes
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The inheritance pattern for red-green color blindness is different for males compared to females. Similar to the inheritance pattern for hemophilia in the royal families of Europe, red-green color blindness is rare in females although they can be carriers for this trait. Why is the inheritance pattern different for males and females?
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the gene for this trait is located on the X chromosome
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Would a human clone have a bellybutton?
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yes
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How could an embryonic stem cell be used to repair a severed spine?
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Embryonic stem cells can grow into any other cell type, including a nerve cell.
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What do the letters D-N-A stand for?
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deoxyribonucleic acid
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What is different from one DNA nucleotide to the next?
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the base
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Which part of a nucleotide molecule encodes genetic information?
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the base
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According to the base pairing rules of DNA, if the sequence of bases on one strand was AGGCTTA, what would be the sequence of bases on the complementary strand?
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TCCGAAT
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During DNA replication, __________.
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each of the two daughter DNA molecules contains one strand from the original DNA molecule and one newly synthesized strand
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What is not a structural difference between DNA and RNA?
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Where DNA has a phosphate group, RNA has a methyl group
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If DNA directs the production of RNA, what does RNA make?
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RNA makes proteins
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DNA and RNA have three important structural differences. These include all of the following EXCEPT that _________
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DNA contains phosphate while RNA does not
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Why does transcription occur in the nucleus and not in the cytoplasm?
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DNA cannot leave the nucleus
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What is a gene?
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All of these and more are part of the expanding definition of a gene.
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During transcription of a specific gene, only one DNA strand serves as a template for the formation of RNA.
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true
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What does "transfer RNA" actually transfer?
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Amino Acids
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If the codon is AAA, what is the complementary anticodon?
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UUU
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Ribosomes are made out of which macromolecule?
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Nucleic Acids and Proteins
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How is translation initiated?
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Two ribosomal subunits bind to the mRNA transcript
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How many nucleotides in sequence are required to code for 10 amino acids?
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30
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Every cell in your body can express every one of your genes
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false
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The type of mutation that alters the nucleotide sequence of a gene but does not alter the amino acid sequence of the protein produced from that gene is called ________ mutation.
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silent
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The Ames test uses bacteria to test whether particular substances can cause mutations. Substances that test positive on the Ames test should also be considered to be possible carcinogens.
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true
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How does a cell typically know when to divide?
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Proto-oncogenes code for growth factor proteins that initiate cell division.
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The spread of cancer cells from their site of origin to sites distant in the body is called ________
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metastasis
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What is a "benign" tumor?
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A mass of cells that grows out of control but remains at the site of origin
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What does "burn" refer to in the typical cancer treatment regime?
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radiation therapy
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What is the minimum amount of regular physical activity that has been shown to reduce the risk of cancer?
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30 minutes at a time, 3 times per week
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A benign tumor CANNOT spread from its original location.
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true
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According to the American Cancer Society, what is the single best lifestyle choice that you can make to reduce your risk of cancer?
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dont smoke
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Why can a person who is unable to produce insulin, be successfully treated with insulin derived from genetically modified bacteria?
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The gene that produces insulin in humans was inserted into the bacteria where it continues to produce human insulin.
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A cloned mammal is made by a similar technique as the one used to produce transgenic animals, except the entire genome is replaced instead of a single gene. This is accomplished by removing the DNA from the unfertilized egg of an egg donor, replacing it with DNA from a normal body cell of a mature animal, and then implanting that cell into the uterus of a surrogate mother. The cell then divides and behaves as if it were a normal embryo. Answer the following question regarding a clone. Of whom is the baby a clone?
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DNA donor
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Three of the following statements are correct. Identify the statement that is not correct regarding genetically modified organisms.
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There are no risks associated with GM crops
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Both genetically modified plants and animals make up a significant part of our food supply.
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false
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What specific field of science is interested in examining the complete set of proteins encoded by a genome?
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proteotics
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Through mapping the entire human genome, researchers have learned that only 1.5% of the human genome encodes for proteins.
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true
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What is the success rate of gene therapy?
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Poor, as there have been few successes but many disappointments
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How would you describe the current status of gene therapy research?
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Gene therapy has had limited success in a few cases. However, there is still a long way to go before gene therapy is deemed safe and effective enough for widespread use in curing genetic diseases
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Prior to the publication of Charles Darwin's book, On the Origin of Species, what was the prevailing public consensus regarding species evolution?
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That species were permanent and unchanging
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What prompted Darwin to publish his book decades after he began writing it?
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A colleague was about to publish a similar manuscript.
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Which two observations led Darwin to conclude that there is competition for survival?
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Overproduction and limited resources
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Individuals with variations that make them best suited to their environment will, on average, be more likely to ________
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survive and reproduce
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Others had suggested mechanisms for evolution before Darwin published his work. By what means did Darwin propose species evolved over time?
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natural selection
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Can you inherit physical traits that your parents acquired during their lifetime?
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no
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How does antibiotic resistance evolve in bacterial populations?
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In any population of bacteria, some individuals are more resistant to particular antibiotics and some individuals are less resistant. In the presence of an antibiotic, susceptible individuals die off. Over time, the frequency of resistant bacteria within the population increases.
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Comparing DNA and protein sequences to find evidence of a shared evolutionary history is called ________
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bioinformatics
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What is the smallest unit that can evolve?
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the population
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What is the original source of variation?
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mutation
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What defines a population?
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Interbreeding members of the same species
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What does "fitness" mean when speaking in terms of evolution?
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How many offspring an individual produces
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Darwinian fitness is measured only in terms of the number of healthy offspring produced.
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true
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What is the leading hypothesis for what might have brought about the extinction of the dinosaurs?
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an asteroid impact
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Sixty-five million years ago, approximately 50% of all species became extinct, including dinosaurs. This is the largest mass extinction in the fossil record
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false
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During which geological era did life first appear on the planet?
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precambrian
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The slow drifting of sections of the earth's crust, sometimes separating, other times colliding, is known as ________.
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plate tectonics
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Horses and donkeys can reproduce to produce mules. Thus, horses and donkeys are considered to be a single species.
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false
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Which of the following might be a cause of sympatric speciation?
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genetic compatibility
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The varieties of species found on the different Galapagos Islands is most likely an example of which form of speciation?
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allopatric
