Nokea
In meiosis, how many divisions occur, and how many daughter cells are produced?
- A. One division, two daughter cells
- B. Two divisions, four daughter cells
- C. Four divisions, eight daughter cells
- D. Eight divisions, sixteen daughter cells
Correct Answer: B
Rationale: In meiosis, there are two divisions: meiosis I and meiosis II. During meiosis I, homologous chromosomes separate, resulting in two daughter cells with half the number of chromosomes as the parent cell. In meiosis II, sister chromatids separate, resulting in a total of four daughter cells, each with a haploid set of chromosomes. Therefore, meiosis involves two divisions and produces four daughter cells. Choice A is incorrect because meiosis involves two divisions, not one. Choice C and D are incorrect as meiosis does not go through four or eight divisions, resulting in eight or sixteen daughter cells.
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Which organelle is responsible for packaging and secreting proteins into the extracellular space?
- A. Golgi apparatus
- B. Mitochondria
- C. Ribosomes
- D. Endoplasmic reticulum
Correct Answer: A
Rationale: A) Golgi apparatus: The Golgi apparatus is responsible for modifying, sorting, and packaging proteins into vesicles for secretion outside the cell or for use within the cell. It acts as a distribution and shipping department for the cell, ensuring proteins are properly processed and sent to their correct destinations like the extracellular space. Golgi apparatus is the correct answer because it directly handles the packaging and secretion of proteins.
B) Mitochondria: Mitochondria are known as the powerhouse of the cell and are responsible for generating energy in the form of ATP through cellular respiration. They are not involved in packaging and secreting proteins into the extracellular space.
C) Ribosomes: Ribosomes are responsible for protein synthesis, where they translate mRNA into proteins. They are not involved in packaging and secreting proteins into the extracellular space.
D) Endoplasmic reticulum: The endoplasmic reticulum (ER) plays a role in protein synthesis and folding, but it is the rough ER specifically that is involved in synthesizing proteins that are then transported to the Golgi apparatus for further processing and packaging. The Golgi apparatus is primarily responsible for packaging and secreting proteins, making it the correct answer for this question.
Where is the major site for nutrient absorption in the digestive system?
- A. Mouth
- B. Stomach
- C. Small intestine
- D. Large intestine
Correct Answer: C
Rationale: The small intestine is recognized as the major site for nutrient absorption in the digestive system. It plays a crucial role in the digestion and absorption of nutrients from food. The small intestine's villi and microvilli provide a large surface area specialized for absorbing nutrients like carbohydrates, proteins, fats, vitamins, and minerals. This efficient absorption process is essential for supplying the body with the necessary nutrients for energy production, growth, and overall functioning. The mouth is primarily involved in the initial stages of digestion through mechanical and chemical breakdown of food. The stomach aids in further mechanical and chemical digestion but is not the primary site for nutrient absorption. The large intestine's main function is to absorb water and electrolytes, not nutrients.
As a water wave approaches a shallow beach, what happens to its speed, wavelength, and frequency?
- A. Speed increases, wavelength decreases, frequency increases.
- B. Speed decreases, wavelength decreases, frequency remains the same.
- C. Speed increases, wavelength increases, frequency decreases.
- D. Speed, wavelength, and frequency remain the same.
Correct Answer: B
Rationale: As a water wave approaches a shallow beach, the speed of the wave decreases due to the change in medium from deep to shallow water. According to the wave equation (speed = frequency x wavelength), if the speed decreases and the frequency remains the same, the wavelength must also decrease to maintain the equation balanced. This phenomenon occurs due to the wavefronts being slowed down by the shallower water, causing the wavelength to decrease while the frequency remains constant. Choice A is incorrect as the speed of the wave decreases in shallow water. Choice C is incorrect because the speed increases in deep water, not in shallow water. Choice D is incorrect as all the wave characteristics change when moving from deep to shallow water.
Which of the following is NOT true about fossils?
- A. They can provide evidence for the order of appearance of different species
- B. They can be used to estimate the age of rocks and layers
- C. They can tell us about the behavior of extinct organisms
- D. They are always perfectly preserved
Correct Answer: D
Rationale: A) This statement is true. Fossils can provide evidence for the order of appearance of different species through the study of the fossil record.
B) This statement is true. Fossils can be used to estimate the age of rocks and layers through relative dating methods such as stratigraphy and absolute dating methods like radiometric dating.
C) This statement is true. Fossils can provide information about the behavior of extinct organisms through the study of their preserved remains and traces.
D) This statement is NOT true. Fossils are not always perfectly preserved. In many cases, fossils are incomplete, fragmented, or altered over time due to geological processes. The level of preservation can vary depending on factors such as the type of organism, the environment in which it lived, and the processes involved in fossilization.
Antigen-antibody binding is the principle behind:
- A. Vaccination
- B. Disinfection
- C. Sterilization
- D. Antibiotic resistance
Correct Answer: A
Rationale: Antigen-antibody binding is the principle behind vaccination. When a vaccine containing antigens (weakened or killed pathogens) is introduced into the body, the immune system produces antibodies that bind to these antigens. This binding triggers an immune response, leading to the production of memory cells that provide immunity against future infections by the same pathogen. Vaccination helps the body develop immunity without causing the disease itself, thereby protecting individuals from infectious diseases. Disinfection and sterilization involve different processes to eliminate or reduce pathogens on surfaces or objects. Antibiotic resistance is a phenomenon where bacteria evolve to resist the effects of antibiotics and is not directly related to antigen-antibody binding.