GENETICS exam 3 Flashcards _ Quizlet

12/13/23, 1:38 AM GENETICS exam 3 Flashcards | Quizlet https://quizlet.com/791402187/genetics-exam-3-flash-cards/ 1/10 Try the fastest way to create flashcards GENETICS exam 3 Leave the first rating Students also viewed Terms in this set (216) Try Magic Notes and save time Upload notes Unit 6 43 terms tpett82 Preview Genetics 16 terms quizlette36042950 Preview Micro lab ch 24/25 59 terms erin2006ms Preview Biology Cha 32 terms delacruc True or False: Chromosomes are in a condensed form through most of the cell cycle. false Match the following each of the following terms with the correct description Plasma Membrane.. protects nuclear membrane.. dissolves nucleus... contain er... studded cytosol.. jelly like Which of the following is correct Centrioles are responsible for the formation of spindle fibers. At which cell cycle phase does the nuclear membrane break down? Prophase The genetic flow of material between organisms is NOT dependent on which of these criteria? Independent assortment of the genes Learn

12/13/23, 1:38 AM GENETICS exam 3 Flashcards | Quizlet https://quizlet.com/791402187/genetics-exam-3-flash-cards/ 2/10 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. 1. histone 2. positively 3. negatively Interphase marks the period of the cell cycle just before active cell division. Label the rest of the cell cycle in order, from 1-5. 1 2 3 4 5 s-phase prophase metaphase anaphase telophase Which of the following is true about anaphase? Chromatids undergo disjunction to travel to opposite poles A chiasma is a point during meiosis at which the non-homologous sister chromatids Intertwine Which of the following statements is correct? Incorrect segregation of X and Y chromosomes (for instance, a female with XXX or X genotype) can produce viable offspring, albeit usually with some problems. True or false: Linked genes are part of the same chromosome. true Consider genes A, B, and C, which are located on a chromosome in that order. If genes A and B cross over 30% 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? (0.3) * (0.3) = 0.09, 9% chance of this crossover Determination of sex in humans is located on the _(1)_ chromosome, specifically on the __(2)__ gene. 1. Y 2. SRY The sex disorder that exhibits an XXY phenotype is known as ___(1)___. This disorder is found on the __(2)__ sex chromosome 1. Klinefelter syndrome 2. male Indicate whether each of the following statements is True or False. 1. G0 is an actively dividing cell cycle phase. False 2. Cells enter G0 when the environmental conditions are not ideal for survival. True 3. Cells in G0 do not undergo active replication. True 4. When conditions become normal, cells may go back into the cell cycle. True false true true true Learn

12/13/23, 1:38 AM GENETICS exam 3 Flashcards | Quizlet https://quizlet.com/791402187/genetics-exam-3-flash-cards/ 4/10 Pointy ears and knobby knees are dominant genes over round ears and smooth knees. What would be the result of an F1 cross between one homozygous parent for pointy ears and knobby knees and one homozygous for round ears and smooth knees? What would the F2 cross look like if the F1 was bred to F1? If the parents are PPKK x ppkk, then the F1 generation is entirely PpKk and will have pointy ears and knobby knees. The F2 generation will be as follows: 9:3:3:1- 1 round ear, smooth knee; 3 round, knobby; 3 pointy, smooth; 9 pointy, knobby Consider the following 4 independent dominant traits: short, red, glossy, and tall. Use the product law to predict the likelihood of inheriting three of these dominant traits and one recessive trait 3 dominant + 1 recessive = (3/4) (3/4) (3/4) * (1/4) = 27/256 Explain why an individual who is heterozygous for a genetic disorder may go for a very long time as a carrier of that disorder without realizing that they have it? If an individual is heterozygous for a gene that causes a disorder, the gene that expresses the normal allele may compensate and produce proteins in enough quantity that it can function normally. This effect is known as the threshold effect and essentially can go undetected unless that individual produces offspring that inherit the recessive gene for the disorder from both individuals. When the recessive gene from two unaffected individuals are expressed in the offspring, there is no gene activity produced and the phenotype of the disorder is seen. The presence of the ABO antigens on the surface of blood cells is an example of codominance. If a mother is Type AB (AB) and the father is Type A (AO), what are the possible combinations for the child's blood type? Type A (AA or AO), Type B (BO), Type AB (AB) are all possible. In the case of determining the likelihood of inheriting 5 independent alleles, would you use a Punnett square to make these calculations? If not, what would you use instead and why? In determining the likelihood of inheriting 5 independent alleles, you would use the product law because it will make the calculations much simpler than writing out all the many possibilities of 5 different traits in an individual. True or False: A person can only be homozygous or heterozygous for a given gene. True What is the purpose of a testcross, and how is it done? A test cross is used to determine whether a plant that is exhibiting a dominant phenotype is homozygous or heterozygous for that trait. To do a testcross, the organism with the unknown genotype and dominant phenotype is crossed with a known homozygous organism. A homozygous individual will yield all dominant phenotypes whereas a heterozygous individual will yield a 1:1 mixture of phenotypes. Let us put the testcross to work. The gene for yellow flowers is dominant on our favorite plant. The gene for white flowers is recessive. Our plant has yellow flowers, but we are unsure of its genotype. When we crossbreed our unknown with a plant with white flowers, we get 3 plants with yellow flowers and 3 plants with white flowers. What does that tell us about the genotype of the yellow plant? Draw it out. If the unknown was YY (homozygous), then YY x yy would yield offspring of Yy, Yy, Yy, and Yy - all yellow. If the unknown was Yy (heterozygous), the Yy x yy would yield offspring of Yy, Yy, yy, and yy - half yellow and half white. Therefore, our unknown yellow plant must be heterozygous for the yellow gene (Yy) Learn

12/13/23, 1:38 AM GENETICS exam 3 Flashcards | Quizlet https://quizlet.com/791402187/genetics-exam-3-flash-cards/ 5/10 When a mutation does not affect the function or phenotype of a given gene, it is called a _______ mutation. Neutral or silent In a few sentences, summarize Darwin's theory of natural selection. 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. 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? 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? pea plants The chromosomal theory of inheritance states that: Genes, contributed from each parent, are carried on chromosomes. True or False: Nucleotides are the basic building blocks that make up DNA. Correct! true Explain how the use of biotechnology has contributed to modern agriculture. 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! 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? 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: Matthias Schleiden and Theodor Schwann Learn

12/13/23, 1:38 AM GENETICS exam 3 Flashcards | Quizlet https://quizlet.com/791402187/genetics-exam-3-flash-cards/ 7/10 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? 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? 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. (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? 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: 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. chromosomes; white blood; homologous or paired True or False: A normal chromosome set always has paired X and Y chromosomes. 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. red blood cells; oxygen; altitude;one Why did Mendel choose the pea plant as his genetics model? Correct! it was self fertilizer Learn

12/13/23, 1:38 AM GENETICS exam 3 Flashcards | Quizlet https://quizlet.com/791402187/genetics-exam-3-flash-cards/ 8/10 See an expert-written answer! In a cross, the original generation is known as the ______ generation and the first generation of their offspring is known as the ______ generation. p1 or parental; f1 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. 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. true A mutation in which gene is responsible for a large number of breast cancers? BRCA1 The minimum amount of gene product needed to meet a normal phenotypic expression in an individual is known as: the threshold effect True or False: In codominance, two alleles are fully expressed regardless of the sex of the organism. true The O phenotype in ABO genotyping possesses how many antigens on the surface of red blood cells? 0 True or False: Chromosomes are uncondensed and diffuse for only a short time during the cell cycle. You Answered false Which of the following is correct? sister chromatids are held together by cohesin The longest of the stages during mitosis is: Correct! prophase The genetic flow of material between organisms is NOT dependent on which of these criteria? independent assortment of the genes Learn

12/13/23, 1:38 AM GENETICS exam 3 Flashcards | Quizlet https://quizlet.com/791402187/genetics-exam-3-flash-cards/ 10/10 When cells become quiescent during G0, they are: Correct! resting The X and Y sex chromosomes are known as _______ chromosomes. heteromorphic Why is modification of histone proteins critically important to DNA transcription? 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. false Explain how have multidrug-resistant pathogens in agriculture been propagated. 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? 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. 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 __________. prototroph A gene that is expressed all of the time regardless of conditions is called: constitutive Learn