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Heredity and Genetics
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Living Environment Regents June 2003 Question 04 |
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Correct Answer: (2) scientific inquiry involves the collection of information from a large number of sources.
In this case, physical appearance, skills, knowledge and personality were not enough information about the performance of a potential employee or as a health insurance holder. Genetic information can be added in order to be accurate in making decisions.
Incorrect Answers:
Scientific theories were proven through the use of several studies and information like experimentation and calculation. A single evidence is not enough to further conclude scientific dogmas.
Genetic study is not purely disadvantageous to the society. One advantage of genetics is the prenatal genetic tests like chorionic villus sampling, amniocentesis, and percutaneous umbilical blood sampling. These are done to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic disorders prior to birth.
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Living Environment Regents June 2003 Question 09 |
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Correct Answer: (3) Environments in which they were raised were different enough to affect the expression of their genes.
The twins have the same genotype or full hereditary information. However, they have different phenotypes. Phenotype refers to any observable traits of an organism like morphology and behavior. Phenotypes result from the expression of an organism's genes as well as the influence of environmental factors and possible interactions between the two.
Other options are false statements about heredity.
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Living Environment Regents June 2003 Question 10 |
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Correct Answer: (1) Replication
The DNA separates or unwinds at the origin to synthesize new strands. This forms a replication fork. This "semiconservative process" of separation of the DNA strands happens so that the original double-stranded DNA serves as template for the reproduction of the complementary strand. Hence, following DNA replication, two identical DNA molecules have been produced from a single double-stranded DNA molecule.
Incorrect Options:
Fertilization is the union of two different gametes during sexual reproduction.
Differentiation is the process of changing in structure to perform a specialized task.
Evolution is the alteration of genetic composition of a population from one generation to the next.
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Living Environment Regents June 2003 Question 11 |
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Correct Answer: (2) bases in DNA in the nucleus
The arrangement of the bases in the DNA codes for proteins which will be formed for the body of the organism through replication, transcription and translation of the DNA into protein.
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Living Environment Regents June 2003 Question 12 |
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Correct Answer: (1) It is always known as mutation.
Mutation refers to any change in the DNA sequence.
Incorrect Answers:
Change if the DNA is not always advantageous to an individual. Deletion in the DNA sequence caused by high energy radiation, chemicals, and high temperatures often causes harmful effects to humans.
The changes may or may not be passed to the offspring.
Chromatography is a laboratory technique used for separation of mixtures.
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Living Environment Regents June 2003 Question 15 |
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Correct Answer: (1) a combination of inheritable traits that can appear in the offspring
The illustration shows the process called crossing over during prophase 1 of meiosis. Crossing over or chromosomal crossover is the exchange of genetic material between homologous chromosomes. The outcome of this process is an exchange of genes, thus a new combination of characteristics for the offspring.
Incorrect options:
The chromosomes can still be passed on to the next generation.
The part of chromosomes did break but still reconnects to be functional chromosomes.
There was only an exchange of chromosome parts, therefore, the number of chromosomes was not changed.
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Living Environment Regents June 2003 Question 16 |
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Correct Answer: (1) A
Ovary or Organ A contains the female gametes. Radiation can affect the reproductive cells of an organism by changing the sequence of nucleotides within a gene in a sperm or an egg cell and further result to formation of structural and functional problems in cells of the offspring.
Incorrect Options:
Organs B (fallopian tube), C (uterus), and D (urinary bladder) does not contain the female gametes. If their cells' DNA is mutated, the mutated gene will not be passed on the offspring, but may cause problems to the individual parent.
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Living Environment Regents June 2003 Question 18 |
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Correct Answer: (1) the presence of genes and chemicals in each cell in stages 1-7
The genes dictate the following actions of the cells together with chemicals.
Incorrect options:
The number of cells increased, instead of the number of genes.
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Living Environment Regents June 2003 Question 19 |
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Correct Answer: (2) This insulin may have fewer side effects than the insulin previously extracted from the pancreas of other animals.
Although the insulin derived from other animals are similar with the human insulin, some human individuals encounter problems. Their immune systems produce antibodies against the insulin from the animals. This led scientists to produce Humulin. It is produced by E. coli after human insulin has been injected on it.
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Living Environment Regents June 2003 Question 24 |
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Correct Answer: (3) Recombinant DNA technology
This is a technique in which gene segments from different sources are recombined in vitro and transferred into cells, where the DNA may be expressed.
Incorrect Answers:
Cloning is the process of creating exact copies of the genetic makeup (or DNA fragments only-molecular cloning) an organism.
Meiotic division is a two-stage of ell division in sexually reproducing organisms that results in gametes with half the chromosome number of the original cell.
Selective breeding is the process of breeding plants and animals for particular genetic traits. There is no mechanical alteration of the DNA, but this is done my choosing the organisms with the preferred traits and bred to produce a crossbreed (animals) or a hybrid(plant).
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Living Environment Regents June 2003 Question 39 |
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Correct Answer: (4) DNA from a dead organism can become active in another organism
As observed in the experiment, healthy mice died of the same disease caused by the dead pathogenic bacteria.
Incorrect Answers:
DNA is present even if dead organisms. For example, to identify the relationships of Egyptian mummies found in Egypt, they used DNA sampling and compared the DNA bands of the mummies.
Though DNA is transferred, it was still pathogenic.
The DNA did not transform the mice into bacteria, thus, statement 3 is incorrect.
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Living Environment Regents June 2003 Question 69 |
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- The potato plant will be resistant from any insect, and thus, produce a healthy plant.
- The gardener does not need to buy insecticide and apply it to the plant. He will save not just money, but also time.
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