ATI TEAS 7
ATI TEAS 7 science review
1. What is the difference between a homozygous recessive genotype and a homozygous dominant genotype?
- A. Both have the same phenotype, but different genotypes.
- B. Both have the same genotype, but different phenotypes.
- C. Homozygous recessive has two dominant alleles, while homozygous dominant has two recessive alleles.
- D. Homozygous recessive has two identical recessive alleles, while homozygous dominant has two identical dominant alleles.
Correct answer: D
Rationale: - Homozygous recessive genotype refers to an individual having two identical recessive alleles for a particular gene (e.g., rr for a trait where r represents the recessive allele). - Homozygous dominant genotype refers to an individual having two identical dominant alleles for a particular gene (e.g., RR for a trait where R represents the dominant allele). - The difference between the two genotypes lies in the specific alleles present in each case, with homozygous recessive having two recessive alleles and homozygous dominant having two dominant alleles. - This genetic difference results in different phenotypes being expressed, as the dominant allele typically masks the expression of the recessive allele in heterozygous individuals.
2. What is the building block of DNA?
- A. Amino acid
- B. Nucleotide
- C. Phosphate group
- D. Fatty acid
Correct answer: B
Rationale: - Amino acids are the building blocks of proteins, not DNA. - Nucleotide is the correct building block of DNA. A nucleotide consists of a sugar (deoxyribose in DNA), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). - The option 'C) Phosphate group' is incorrect as it is only part of a nucleotide, not the complete building block of DNA. - Fatty acids are not the building blocks of DNA; they are a type of lipid molecule.
3. Which of the following inventions likely had the greatest impact on combating nutrition deficiencies in developing countries?
- A. Food products fortified with dietary vitamins and minerals
- B. Integrated statistical models of fish populations
- C. Advances enabling microscopes to use thicker tissue samples
- D. Refrigerated train cars for transportation of food
Correct answer: A
Rationale: Food products fortified with dietary vitamins and minerals have had the greatest impact on combating nutrition deficiencies in developing countries. By fortifying food products with essential nutrients such as vitamins and minerals, it becomes easier to address specific deficiencies in populations that may not have access to a diverse range of foods. This innovation has been particularly impactful in addressing common deficiencies like vitamin A, iron, zinc, and folic acid, improving overall health outcomes in populations with limited access to nutrient-rich foods. Choices B, C, and D are incorrect. Integrated statistical models of fish populations, advances in microscopy, and refrigerated train cars, while important in their own right, do not directly address combating nutrition deficiencies in developing countries as effectively as food fortification with essential nutrients.
4. What is the process by which a population gradually loses genetic variation?
- A. Founder effect
- B. Bottleneck effect
- C. Gene flow
- D. Speciation
Correct answer: B
Rationale: A) Founder effect: This occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation compared to the original population. It does not necessarily result in a gradual loss of genetic variation in an existing population. B) Bottleneck effect: This process occurs when a population is drastically reduced in size, leading to a significant loss of genetic variation due to the limited number of individuals contributing to the gene pool. The reduced genetic diversity can have long-term effects on the population's ability to adapt to environmental changes. C) Gene flow: This refers to the movement of genes between populations, which can introduce new genetic variation and prevent populations from diverging. Gene flow does not lead to a gradual loss of genetic variation within a population. D) Speciation: This is the process by which new species evolve from existing species, often involving the accumulation of genetic differences that l
5. What is the body's primary defense against pathogens?
- A. Phagocytes
- B. Antibodies
- C. Memory B cells
- D. T lymphocytes
Correct answer: A
Rationale: The correct answer is A: Phagocytes. Phagocytes are the body's first line of defense against pathogens. They are innate immune cells that engulf and digest foreign particles like bacteria and viruses, preventing infections. Phagocytes act as the initial barrier to invading pathogens and are part of the innate immune response. Choice B, Antibodies, are produced by B cells in the adaptive immune response. Choice C, Memory B cells, are also part of the adaptive immune response and provide a faster and stronger response upon re-exposure to pathogens. Choice D, T lymphocytes, are part of the adaptive immune response, particularly involved in cell-mediated immunity.
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