Nokea
Which of the following is necessary for cell diffusion?
- A. water
- B. membrane
- C. ATP
- D. gradient
Correct Answer: A
Rationale: Water is necessary for cell diffusion because it serves as the medium through which particles move across cell membranes. Diffusion is the passive movement of particles from an area of higher concentration to an area of lower concentration, and water plays a crucial role in facilitating this process by dissolving molecules and allowing them to move freely. Membranes provide the barrier for diffusion to occur, ATP is not directly involved in the process of diffusion, and a gradient is the difference in concentration that drives diffusion but is not a necessary component for diffusion itself.
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What are the three types of muscle tissue?
- A. Cardiac, smooth, skeletal
- B. Smooth, skeletal, cardiac
- C. Neuron, epithelial, collagen
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: Smooth, skeletal, cardiac. Muscle tissue is classified into three main types: smooth muscle, skeletal muscle, and cardiac muscle. Smooth muscles are found in the walls of internal organs, blood vessels, and the digestive tract. Skeletal muscles are attached to bones and help in body movements. Cardiac muscles are found in the heart and are responsible for its rhythmic contractions.
How does a bacterium reproduce?
- A. Mitosis
- B. Meiosis
- C. Binary fission
- D. Cytokinesis
Correct Answer: C
Rationale: Bacteria reproduce through binary fission, a process in which a single bacterium divides into two identical daughter cells. Mitosis and meiosis are processes specific to eukaryotic cells, not bacteria. Cytokinesis is the final step of the cell cycle where the cytoplasm divides, but it is not the primary reproductive method for bacteria.
In a Punnett square, a capital letter represents what type of allele?
- A. Dominant.
- B. Ryeesive.
- C. Homozygous.
- D. Heterozygous.
Correct Answer: A
Rationale: Correct Answer: A: Dominant.
Rationale:
1. In a Punnett square, capital letters denote dominant alleles.
2. Dominant alleles are expressed in the phenotype over recessive alleles.
3. This representation helps predict the possible offspring genotypes.
4. Choice B is incorrect as it's a misspelling of 'Recessive.'
5. Choices C and D refer to genotype combinations, not allele types.
Summary:
The capital letter in a Punnett square signifies a dominant allele that will be expressed in the offspring's phenotype. This helps in predicting genetic outcomes accurately.
Why is DNA crucial for the metabolic activities of the cell?
- A. It initiates cellular mitosis.
- B. It provides cell wall stability.
- C. It increases glucose absorption.
- D. It controls the synthesis of enzymes.
Correct Answer: D
Rationale: DNA is crucial for the metabolic activities of the cell because it contains the genetic information necessary to regulate the synthesis of enzymes. Enzymes are essential for catalyzing biochemical reactions involved in metabolic processes within the cell. DNA controls the production of enzymes, which are vital for driving various metabolic pathways. Therefore, the correct answer is D, as DNA's role in controlling enzyme synthesis is fundamental for the cell's metabolic activities.
Why is homeostasis necessary?
- A. It maintains temperature.
- B. It maintains pH.
- C. It maintains glucose levels.
- D. All of the above.
Correct Answer: D
Rationale: Homeostasis is essential for maintaining the internal balance and stability of the body. It regulates various factors, such as temperature, pH levels, and glucose levels, to ensure optimal physiological function. Therefore, all the choices (temperature, pH, and glucose levels) are correct as they are all essential components of homeostasis, working together to keep the body's internal environment stable and functioning properly.