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In a few sentences, summarize Darwin's theory of natural selection. - correct answer- - Natural selection posited that more offspring were produced than an environment could actually support. Survival in a crowded environment would lead to struggle within a population, so the offspring that inherited the most desirable traits for a certain environment would ultimately survive. Over time, variations would evolve in offspring that would make them more adaptive, and ultimately over time, new species could evolve. Name 2 types of animal models that are used for genetics research. Describe one trait that each model possesses that makes it a useful genetic tool. - correct answer- - Mouse- similar genome to human, easy to breed Fruit fly- extremely cheap, short life, easy to breed, small genome Worms- inexpensive, simple nervous system, easy to use, short life span Zebrafish- transparent larvae and embryo How does preformation differ from epigenesis? - correct answer- - Preformation postulated that a fertilized egg contained a miniaturized version of a tiny human, called a homunculus. Epigenesis directly contradicted that theory by stating that a fertilized egg undergoes a series of developmental events that eventually form a human. What type of plants did Gregor Mendel use in his famous experiments? - correct answer- - pea plants The chromosomal theory of inheritance states that: - correct answer- - Genes, contributed from each parent, are carried on chromosomes.

True or False: Nucleotides are the basic building blocks that make up DNA. Correct! - correct answer- - true Explain how the use of biotechnology has contributed to modern agriculture. - correct answer- - Transgenic plants have been engineered to resist insects and harsh environments, grow bigger and more prolifically, or to enhance nutrition. True or False: The theory of spontaneous generation posits that living things can spontaneously generate from nonliving things. Correct! - correct answer- - true Natural selection posits that organisms that have the most advantageous characteristics will survive their environment. Do humans have the same selective pressures for natural selection that their animal counterparts do? Are humans still evolving? - correct answer- - Modern humans have overcome the survival barriers that most animals face. They (typically) do not face harsh environments or predators because of their ability to shelter; they do not need to hunt or gather for food because there are markets; they have equipment and clothing to help them to be strong, to climb, etc. So, humans do not face the same selective pressures that other animals do for survival. That being said, they do continue to evolve. Genetic mutations occur within populations that may be slightly advantageous to a certain lifestyle (eg evolving the ability to digest milk even into adulthood), and these mutations may be selected for within a population. So, evolution occurs even though it is no longer a true "natural selection" for survival. Cell theory was introduced by: - correct answer- - Matthias Schleiden and Theodor Schwann Charles Darwin's publication on evolution is called: - correct answer- - the origin of species Propose examples of certain traits that could benefit a mammal that lives in a mountainous environment. - correct answer- - The ability to climb easily, have good balance, blend in

with the colors of mountains (snow or rocks), to deal with low oxygen levels, and to find food on rough terrain are traits that would benefit a mountain animal. Answers may vary. The _________hypothesized that heredity and development depend on the passing of genetic information via _______that are contained within chromosomes. - correct answer- - Chromosomal theory of inheritance; genes The number of total chromosomes in a normal human chromosome set is____. Chromosomes exist in matched numbers of____. - correct answer- - 46; ______ genes are the "normal" genes, such as the red eye color in the fruit fly. A mutation of a gene is referred to as an ______. - correct answer- - wild type;allele How many nucleotides make up DNA? In which combinations do they pair? - correct answer- - 4 ; A-T and G-C Corn and soybeans are 90% transgenic crops. What does this mean? - correct answer- - A transgenic crop has had advantageous traits introduced via recombinant DNA technology. The FDA-approved ATryn used to treat blood clots, was derived from genetically engineered

• correct answer- - goats A ________is carrier DNA in which a gene can be inserted using specific ________. - correct answer- - vector;restriction enzymes Which two scientists won the Nobel Prize for their model of the double-stranded DNA helix? - correct answer- - james watson and francis crick

True or False: Proteins are responsible for carrying the genetic information within organisms. - correct answer- - false Which of the following statements is correct? - correct answer- - Dominance and recessiveness are not linked to the sex chromosomes. True or False: A dominant gene will always cause the expression of a dominant phenotype in any genetic cross. - correct answer- - false People with sickle-cell disease can become very sick under what conditions? - correct answer- - high altitudes A homozygous long-haired cat is bred to a homozygous short-haired cat. Assuming that the gene for long hair is completely dominant, what are the chances of the F1 offspring being long-haired? - correct answer- - 100% A dog breeder is looking to cross a long-haired female dog with a short-haired male dog. The gene for hair length has incomplete dominance. By crossing the F1 offspring, what percentage of the F2 generation are predicted to be short-haired? - correct answer- - A 1:2:1 ratio predicts 25% of the offspring to be homozygous short-haired. Consider 3 genes that assort independently in squirrels. A gene for brown color is dominant (D), a gene for a bushy tail is dominant (B), and a gene for reflux after eating acorns is recessive (a). Use the product law to predict the likelihood of producing a squirrel (from parents that are heterozygous for each trait individually) that is brown, bushy-tailed, and has reflux from all those acorns. - correct answer- - (3/4) x (3/4) x (1/4) = 9/64 probability of this squirrel being brown, bushy-tailed, and having reflux. Two individuals with widow's peaks have a child with a straight hairline. A. Is the gene for a widow's peak likely dominant or recessive?

B. Could you predict the genotype of the parents, assuming there is no codominance? C. If the child with the straight hairline someday marries a person with a widow's peak, can you predict for certain whether their offspring will have a widow's peak? - correct answer- - Dominant (WW or Ww) would produce a widow's peak. Because both parents have widow's peaks, only a homozygous recessive (ww) would result in the opposing phenotype of a straight hairline. B. The parents are likely heterozygous for a widow's peak (Ww) to pass along a ww genotype. C. You cannot predict for certain, because the other parent could be heterozygous (Ww) or homozygous (WW) for a widow's peak, and either phenotype (Ww or ww) could be produced. Alternate forms of a gene are termed: - correct answer- - alleles A karyotype is a snapshot of the ______ within the cell. _______ cells are isolated and stained so that a trained geneticist can organize them into __________ chromosomes to detect genetic abnormalities. - correct answer- - chromosomes; white blood; homologous or paired True or False: A normal chromosome set always has paired X and Y chromosomes. - correct answer- - false The phenotype for sickle-cell anemia is distortion of the ______ in afflicted people. This results in depletion of ______ in the blood and poses a significant risk to the patients at high_____. Sickle-cell anemia is caused by ______ mutation(s) in the protein sequence. - correct answer- - red blood cells; oxygen; altitude;one Why did Mendel choose the pea plant as his genetics model? Correct! - correct answer- - it was self fertilizer

In a cross, the original generation is known as the ______ generation and the first generation of their offspring is known as the ______ generation. - correct answer- - p1 or parental; f Which of Mendel's hypotheses needs a correction? Make the correction. Genetic characters are controlled by unit factors existing in pairs in individual organisms. When two unlike unit factors responsible for a single characteristic are present in a single individual, one unit factor is said to be dominant to the other, which is said to be recessive. During the formation of gametes, the paired unit factors separate, or segregate, randomly so that each gamete receives one or the other with equal likelihood. During gamete formation, segregating pairs of unit factors assort in pairs. - correct answer-

• 4. During gamete formation, segregating pairs of unit factors assort independently to each other. True or False: A change in genotype does not always affect a change in phenotype. - correct answer- - true A mutation in which gene is responsible for a large number of breast cancers? - correct answer- - BRCA The minimum amount of gene product needed to meet a normal phenotypic expression in an individual is known as: - correct answer- - the threshold effect True or False: In codominance, two alleles are fully expressed regardless of the sex of the organism. - correct answer- - true The O phenotype in ABO genotyping possesses how many antigens on the surface of red blood cells? - correct answer- - 0

True or False: Chromosomes are uncondensed and diffuse for only a short time during the cell cycle. You Answered - correct answer- - false Which of the following is correct? - correct answer- - sister chromatids are held together by cohesin The longest of the stages during mitosis is: Correct! - correct answer- - prophase The genetic flow of material between organisms is NOT dependent on which of these criteria? - correct answer- - independent assortment of the genes DNA is condensed within the nucleus (cellular compartment) by coiling around ____(1)____ proteins. Modification of these ____(2)____charged proteins alters them to become either neutral or negatively charged. Thus, the interaction with ____(3)____charged DNA is interrupted, and the interactions loosen. - correct answer- - histone;positively;negatively Which of the following is true about anaphase? - correct answer- - chromatids undergo disjunction to travel to opposite poles A chiasma is a point during meiosis at which the non-homologous sister chromatids: - correct answer- - intertwine Which of the following statements is correct? - correct answer- - The Y chromosome is the driving determinant for sex of an offspring. Genes that are part of the same chromosome are said to be ________. - correct answer- - linked

Consider genes A, B, and C, which are located on a chromosome in that order. If genes A and B cross over 40% of the time, and genes B and C cross over 30% of the time, what is the probability of a double crossover between A B and C? - correct answer- - (0.4) * (0.3) = 0.12, 12% chance of this crossover The (1) chromosome and specifically the (2) gene on that chromosome, appear to determine the sex of a human. - correct answer- - y;SRY Klinefelter syndrome is a disorder of the (1) sex chromosome and displays a genotype of (2). - correct answer- - male;XXY Indicate whether each of the following statements is True or False. G0 is an actively dividing cell cycle phase. False Cells enter G0 when the environmental conditions are not ideal for survival. True Cells in G0 do not undergo active replication. True When conditions become normal, cells may go back into the cell cycle. True - correct answer- - false;true;true;true A fertilized egg that is the result of fusion of two gametes is called a ________. - correct answer- - zygote The primary male gamete is the (1) and the primary (2) gamete is the oocyte. - correct answer- - sperm;female Which of the following criteria must be met in order to successfully map genes? - correct answer- - There must be a distinct phenotype for all genes since genotypes cannot be observed.

True or False: At fertilization, the phenotype of a male or female is immediately evident. - correct answer- - false When cells become quiescent during G0, they are: Correct! - correct answer- - resting The X and Y sex chromosomes are known as _______ chromosomes. - correct answer- - heteromorphic Why is modification of histone proteins critically important to DNA transcription? - correct answer- - Modifications of the histone proteins allow for them to either wrap tightly around DNA or to loosen their grip on DNA. This is very important for transcription because when histones loosen their grip on DNA, it allows access to the transcriptional machinery so that DNA can be transcribed. Conversely, when the histones are tightly wrapped with the DNA, transcription is shut off because the machinery cannot access the DNA within the space. True or false: The eggs of a female undergo both meiosis I and meiosis II before she is even born. - correct answer- - false Explain how have multidrug-resistant pathogens in agriculture been propagated. - correct answer- - Livestock and animals are provided food treated with continuous low-dose antibiotics, which are used to enhance the growth of the animals. Over time, bacteria accrue mutations that lead to resistance to these antibiotics and eventually pathogenic bacteria are borne with the same resistance, and standard antibiotic treatment no longer works. Two auxotrophic bacterial strains are propagated in the laboratory, one deficient for leucine and the other deficient for biotin. When cultured alone, they cannot grow on minimal medium, and when combined in the same culture media, they still cannot grow in the minimal media. Can you tell if genetic transmission occurred in this experiment in the case of genes that control synthesis of biotin or leucine? - correct answer- - It does not appear

that genetic transmission has occurred in this experiment involving these genes because even with direct contact, there is no growth rescue for either of these auxotrophs. Does spontaneous mutation positively or negatively affect evolution? Briefly explain your answer. - correct answer- - Spontaneous mutations positively affect evolution because the mutations that make the organism better able to function or tolerate its environment help it to survive longer than its wild-type counterparts. The longer-lived organisms are likely to produce more offspring than those with short survival times. Thus, an advantageous mutation will be passed on to future generations, and if it truly enhances survival, it will eventually become the normal (wild-type) gene. Fill in the blank: A bacterium that can grow well on minimal medium is an example of a __________. - correct answer- - prototroph A gene that is expressed all of the time regardless of conditions is called: - correct answer-

• constitutive Fill in the Blank: IPTG is a gratuitous inducer of the _____ operon. - correct answer- - lac True or False: A temperate bacteriophage is capable of either lysis or acting as a prophage within a bacterial cell. - correct answer- - true Match the structural gene of the lac operon with its protein product and its function. a. lacZ 1. Permease i. May help to remove built- up toxins b. lacY 2. Transacetylase ii. Converts lactose into glucose and galactose c. lacA 3. b-galactosidase iii. Facilitates lactose entry into the bacterial cell - correct answer- - a, 3, ii b, 1, iii c, 2, i

A _______ phage will always lyse its bacterial host, a phage that is integrated into the bacterial ______ is called a prophage, and a phage that is capable of either lysis or integration is known as a ________ phage. - correct answer- - virulent; chromosome; temperate Name 2 reasons that bacteria are an excellent tool for genetics research. - correct answer-

• Large amounts of bacteria can be grown in a short time frame. It is very easy to isolate one species or strain of bacteria through selection. They can be grown in almost any environment with relatively low risk. They are extremely inexpensive to grow. True or False: Genetic information can be transferred between bacteria on a double- stranded RNA molecule called a plasmid. - correct answer- - false True or False: Bacterial cells contain DNA and plasmids within the cytoplasm. - correct answer- - true True or false: Bacteria can be grown only in liquid culture on minimal medium. You Answered - correct answer- - false In order to undergo transformation, bacteria must be physiologically ________, which sometimes is done through the use of chemicals and heat or electroporation. The DNA is then taken up through ______ in the membrane, and subsequently one strand is digested by_________. The single remaining strand forms a heteroduplex with the host chromosome, and eventually is integrated to become part of the chromosome. - correct answer- - competent;pores;nucleases

The ______ in a phage is packaged in the head, which is shaped like a capsule. The sheath of the phage pushes the DNA through the host cell ________ much like a syringe. - correct answer- - DNA;membrane True or False: Phages must either be virulent or prophages. - correct answer- - false When genes are very closely mapped, they can be transduced together via phage in a process called __________. - correct answer- - cotransduction True or false: Enzymes can never be turned off. - correct answer- - false Fill in the blank: A virulent phage must ______ its host to release progeny. - correct answer-

• lyse In E. coli, RyhB is a negative regulator of gene activity. RyhB is an example of a(n)__________. - correct answer- - sRNA Consider the following DNA sequence: 3'-AAC TAC TGT GTA - 5' a. Write out the complementary RNA sequence, including the 5' and 3'. b. Translation starts on which end of the RNA (5' or 3')? c. Identify the start codon in the complementary sequence you wrote in part a. of this question. - correct answer- - a. 5'-UUG AUG ACA CAU - 3' b. 5' c. AUG True or False: Transcription of DNA into mRNA requires an RNA primer. - correct answer- - false Why must the DNA within eukaryotes be complexed with histone proteins, but not in bacteria? What happens to these complexes during DNA replication? - correct answer- -

There is a huge amount of DNA within a eukaryotic cell, and it needs to be stored within a tiny space within the nucleus. Therefore, it is complexed with proteins into chromatin that help to condense it into an extremely compact form. When it is time for DNA replication to occur, the complexes relax due to the proteins dissociating from it. Then as soon as replication is complete at a certain point, the DNA winds around the histone proteins and recondenses. Define the wobble hypothesis and explain why it is important for the degeneracy in coding.

• correct answer- - The wobble hypothesis allows for flexible base-pairing rules in the third position of a codon. In several cases, the first two bases are the same for a specific amino acid, and the third position can be any of the four bases. Because there are only 40 tRNAs to encode amino acids for 60+ codons, the wobble hypothesis allows for some degeneracy in the coding, whereby one tRNA can recognize several codons to encode one amino acid. Fill in the Blank: The Pribnow element is a (1)-acting element that is located ____(2)_____ from the site of transcription initiation. - correct answer- - cis;upstream True or False: A silencer element is always located close to the gene that it affects, but an enhancer element can be far away. - correct answer- - false What is the enzyme that contributes to the growth of a nucleotide chain and also helps in the proofreading process? - correct answer- - polymerase Fill in the Blank: In the process of RNA ______, introns are removed from the pre-mRNA and ______ are rejoined to make a mature mRNA. - correct answer- - splicing;exons How does alternative splicing enhance the diversity of the genetic code? - correct answer-
• Alternative splicing means that different combinations of introns can be spliced out of a single mRNA, producing multiple different mature mRNAs. Therefore, several proteins can be encoded from the same nucleotide chain.

What is the translated amino acid sequence of the two following codon sequences? 5'- AUG CCA GGA CGA GGG UAA - 3' 3'- AAU UCA GGA CCG CCC GUA-5' (Hint: make sure you read the right way) - correct answer- - A. Met-Pro-Gly-Arg-Gly-Stop B. The sequence needs to be read 5' to 3'. Met-Pro-Ala-Arg-Thr-Stop The Shine-Delgarno or Kozak sequence is the initiation sequence for translation - correct answer- - false Why is the mRNA of eukaryotes protected much more so than that of bacteria? - correct answer- - The mRNA of eukaryotes is preserved for up to 10 hours, which is much longer than its counterpart in bacteria. An abundance of proteins needs to be produced in eukaryotic cells (because they are huge and complex), so the long-lived mRNA allows proteins to be translated many times before it is degraded. The nucleotide sequences on the ends of chromosomes that protect the genome from nucleolytic degradation, unnecessary recombination, repair, and interchromosomal fusion are called telomeres. - correct answer- - true Why do scientists believe that telomere shortening has a strong correlation with aging? - correct answer- - It is believed that over time, the telomeres are shortened, and eventually, the ends of the chromosomes start to shorten. When a large amount of chromosomal damage occurs, the cell goes into a state of senescence whereby the metabolic function of the cell becomes very inefficient. Some scientists believe that this shortening is associated with the phenotypes that are associated with typical aging.

The small subunit of the ribosome is responsible for recognition of the codon sequences as the mRNA comes through the ribosome. It contains both the aminoacyl and the peptidyl sites. - correct answer- - true ranscription occurs on the template strand. - correct answer- - true The charging of a tRNA so that it can properly interact with an amino acid to bring it to the growing peptidyl chain is called aminoacylation. - correct answer- - true The fact that several codons can encode for a single amino acid in the genetic code means that we call the code ________. - correct answer- - degenerate DNA and RNA differ in their structure in two ways. What are they? - correct answer- - The nucleoside base uracil in RNA is thymine in DNA. The sugar is 2-deoxyribose in DNA but is ribose in RNA. When the polymerase enzyme encounters a wrong base pair, it pauses, reverses direction, and excises the base. - correct answer- - true Amino acids are added in the _________ process until an mRNA sequence encodes for a stop codon. - correct answer- - elongation A chromosomal aberration is an alteration to the chromosome that results in a change to the total number of chromosomes, deletions or additions to the chromosome, or even complete rearrangement of chromosomal segments. - correct answer- - true Sex chromosomes are the only exception to the rule that chromosomes occur in pairs. - correct answer- - true

Trisomy and monosomy in autosomal chromosomes are generally not tolerated in animals or plants. - correct answer- - false Is Down syndrome considered a monosomy or trisomy disorder? Does its incidence increase or decrease with maternal age? - correct answer- - Down syndrome is trisomy disorder, the incidence of which seems to increase with maternal age. True or False: Individuals that are afflicted with Down syndrome typically exhibit only a subset of the stereotypical characteristics of the disorder. - correct answer- - true The region of the chromosome 21 that is thought to be typically responsible for the phenotype of Down syndrome is the _________ - correct answer- - DSCR Why do researchers think that individuals with Down syndrome are protected from cancers that cause solid tumors? - correct answer- - The DSCR region that is responsible for the phenotype of Down syndrome holds a gene called DSCR1, which encodes for a protein that blocks VEGF (vascular epithelial growth factor). VEGF stimulates the growth of blood vessels, which is extremely important for the vasculature of tumor cells. By blocking VEGF, tumor cells cannot develop the vasculature necessary for the support of tumor growth. The most recent and non-invasive genetic test to determine whether a mother is carrying a baby at risk for Down syndrome (or any genetic disorder) is called ________. This process allows the mother to donate a sample from the blood to establish a _____ for the risk of genetic disorders. - correct answer- - noninvasive prenatal genetic screening (NPGS); karyotype In a few sentences, what are the current thoughts on why the incidence of Down syndrome increases drastically after age 40 in a mother? - correct answer- - While speculative, the current thought is that the eggs undergo meiosis I in a female fetus, and then are arrested until the female goes through puberty. At that point, with each passing month, the eggs continue to age until they are released monthly during the female cycle to undergo meiosis II. A female that is 40 years old has eggs that are approximately 25 years older than the eggs

that underwent meiosis II during puberty. With each passing year of age, the eggs are thought to have an increased issue with both cell division as well as significant time to develop abnormalities. True or False: Karyotyping of spontaneously aborted fetuses showed definitively that many monosomies do not survive to full term. B.) Fill in the Blank: Other than Down syndrome, one example of a trisomy disorder that survives to full term is ________. C.) Do any known human autosomal monosomy disorders survive to full-term? - correct answer- - .) False B.) Patau syndrome or Edwards syndrome C.) No An intercalary deletion occurs ______ the chromosome, whereas a terminal deletion occurs at the _______ of the chromosome. - correct answer- - within;end The hallmark phenotype of cri cu chat syndrome, which is a _______ in chromosome 5, is a(n) _______. - correct answer- - deletion;cat like cry Duplications of DNA sequences are widely variable in numbers among individuals of the same organism. This is referred to as: - correct answer- - copy number variation (CNV) Which two statements are true? - correct answer- - Mitochondria house their own DNA. Infectious heredity results from the transmission of genetic information due to an infectious species in the host cell.

The endosymbiotic theory states that free living bacteria were engulfed by eukaryotes to form a symbiotic relationship. - correct answer- - true Name two ways that human mtDNA is different than nuclear DNA. - correct answer- - Any two of these are correct: Mitochondria have their own set of ribosomes that are different sizes; mtDNA is a double-stranded closed circle; there are generally no introns in organisms with smaller mtDNA; a more complex animal does NOT mean more complex or larger mtDNA; the cellular machinery is derived from both mtDNA and nuclear DNA. Why are mutations in mitochondria generally considered so significant (i.e., why do they contribute to such a huge number of disorders)? - correct answer- - Mitochondria are the powerhouse for making energy in the cell- 90% of the energy created for the cell comes from the mitochondria. A mutation in this DNA impacts the energy source to every physiological system, so can have broad effects. Additionally, mutations in mitochondria tend to happen more often because the DNA is not protected by proteins as it is in the nucleus. It also does not have the intricate DNA repair systems that the nuclear DNA is privy to. Finally, the process of cellular respiration leads to production of reactive oxygen species, which are highly toxic to the organelle. Homoplasmy is the presence of a mix of mutated and normal mitochondria. - correct answer- - false List TWO of the three criteria required for a disorder to be attributed to mitochondrial mutations? - correct answer- - The inheritance pattern must be maternal, not Mendelian. The disorder is directly caused by a deficiency in the bioenergetic function of mitochondria. There must be at least one, if not more, mutations detected in mitochondria. In mitochondrial replacement therapy, the offspring receives the DNA from ______ different parents. An egg with normal mitochondria receives the ______ from an egg with mutated mitochondria prior to fertilization. - correct answer- - three;nucleus

Which of the following is commonly used as a simple, scalable, and repeatable way to measure the mutagenicity of a compound? - correct answer- - ames test No chromosomal aberrations are lethal. - correct answer- - false The loss or gain of one chromosome, but not the entire set, is referred to as ________. The most common forms of aneuploidy are monosomy (2n-1) and ______ (2n+1). - correct answer- - aneuploidy;trisomy Few cancer gene mutations are inherited. - correct answer- - true A tumor that can invade other issues is called a _______ tumor. If it does not yet have the capacity to invade tissues, that tumor is called a ________ tumor. - correct answer- - malignant;benign In order to be classified as cancer, a cell must demonstrate what two properties? - correct answer- - Abnormal growth/proliferation The ability to relocate to other areas of the body (Metastasis) The two major therapies currently available to cancer patients are ________ and __________.

• correct answer- - chemotherapy;radiation therapy The fused chromosome that forms a mutated BCR-ABL gene in chronic myelogenous leukemia is known as the ____________ chromosome. - correct answer- - philadelphia Using the development of colon cancer as an example, explain how the process of tumorigenesis can occur in distinct stages through the accumulation of mutations. - correct answer- - The first stage of colon cancer involves the growth of a polyp, or adenoma,

which is a small cluster of cells that is defective in a gene called APC (adenomatous polyposis coli). APC encodes for the differentiation of normal intestinal cells, so the polyp accumulates undifferentiated cells. A polyp is still benign and localized to its spot in the colon. Over time, genetic mutations occur in the polyp, and typically the mutation of the Kras gene, which regulates cell growth, causes it to become constitutively active. The polyp becomes quite large at this point, up to 1 cm. In the third stage of colon cancer, more mutations occur in the polyp that control cell growth, death, and cell cycle regulation. The adenoma becomes a carcinoma and can invade other regions of the colon as well as travel to other regions of the body to form metastases. Most scientists believe that the biggest driver of a cancer phenotype is ________. - correct answer- - The inability of a cancer cell to repair DNA damage Differentiated cells have matured to provide a specific function in the body. - correct answer- - true Give three examples of differentiated cells that still divide. - correct answer- - Any two of the following are good examples of differentiated, dividing cells: Cells lining the gastrointestinal tract, epithelial cells in the skin, hair follicle cells, cells in the immune system. The two classes of proteins that monitor the progression of the cell cycle are cyclins and cyclin-dependent kinases (CDKs). Correct! - correct answer- - true Why is cyclin D expressed early and for much of the cell cycle? Why does cyclin B arise late in G2 and before M phase? Why do the levels of these cyclins differ so much during the cell cycle? - correct answer- - Cyclin D complexes are responsible for the transcription of gene products that are needed for DNA replication, which occurs through most of the cell cycle before mitosis.

2.) Cyclin B complexes, which peak in mitosis, phosphorylate proteins that induce mitosis, such as nuclear breakdown and chromosome condensation. They are not needed until this point. 3.) The levels of these cyclins (and their CDKs) come up when they are needed in the cell cycle and then are rapidly degraded when not needed. This is important so that one phase of the cell cycle signaling is reversed so that the next phase of the cell cycle can commence. The two major families of proteins that control apoptosis are the ________ BAX protein family and the ________ Bcl2 protein family. - correct answer- - proapoptotic; antiapoptotic Which gene product is referred to as the "guardian of the genome"? True or False: The gene product in answer A is continuously produced in low levels. The expression of ______ by p53 drives a negative feedback loop. - correct answer- - p53

2. True
3. MDM2 Explain how cancer cells control the extracellular matrix to drive the process of metastasis. Give an example of a protein we discussed that controls this in breast cancer cells. - correct answer- - Metastatic cancer cells secrete large amounts of proteases that are responsible for digesting the extracellular matrix, which normally inhibits the migration of cells throughout the body. In addition to digesting the matrix, metastatic cells must also possess the ability to form secondary tumors in other areas of the body. These involve mutations in proteins that control structural integrity, cell adhesion, or proteolytic enzymes. Examples are metalloproteinase genes MMP1 and MMP2, which are present at very high levels in breast cancer tumors. One of the most carcinogenic compounds known, which occurs as a natural mold on peanut and corn crops is called ________. - correct answer- - aflatoxin

List two ways in which our bodies create their own carcinogens. - correct answer- - The human gut creating carcinogenic alkylating agents Oxidative end products, free oxygen radicals, created by mitochondria Hormones Growth factors Stimulation of constant tissue repair by autoimmune disorders or chronic inflammation Epigenetic therapy does not depend on changes in the DNA sequence. - correct answer- - true