Which of the following microorganisms lack their own metabolic pathways and can only reproduce inside of a host cell?
A. Bacteria
B. Protozoa
C. Helminths
D. Viruses
Viruses.
Viruses lack essential machinery needed to reproduce by themselves.
In fact, viruses can only reproduce after infecting a living cell - a process called viral replication.
Once inside a living cell, viruses re-program the cell’s machinery to produce viral proteins and genetic material to make new copies of themselves.
Choice A, Bacteria, is not the correct answer because bacteria have their own metabolic pathways and can reproduce outside of a host cell.
Choice B, Protozoa, is also not the correct answer because protozoa are singlecelled eukaryotes that have their own metabolic pathways and can reproduce outside of a host cell.
Choice C, Helminths, is not the correct answer because helminths are multicellular parasitic worms that have their own metabolic pathways and can reproduce outside of a host cell.
Therefore, the Correct Answer is D.
More Questions on TEAS 7 Science
-
Q #1: Which of the following is the main function of centrosomes in animal cells?
A. . Organelle trafficking.
B. Pathogen digestion.
C. Cytoplasm formation
D. Microtubule organization
Answer Explanation
Microtubule organization.
Centrosomes are organelles that serve as the main microtubule-organizing centers for animal cells.
They regulate the movement of microtubules and other cytoskeletal structures, thereby facilitating changes in the shapes of the membranes of animal cells.
Choice A, Organelle trafficking, is not the correct answer because while centrosomes do play a role in intracellular trafficking during interphase by organizing an astral ray of microtubules, their main function is microtubule organization.
Choice B, Pathogen digestion, is not the correct answer because centrosomes do not play a direct role in pathogen digestion.
Choice C, Cytoplasm formation, is not the correct answer because centrosomes do not play a direct role in cytoplasm formation.
-
Q #2: In a hypertonic solution, water flows through aquaporins embedded in the plasma membrane of the cell. This type of transport is best known as which of the following?
A. Facilitated diffusion
B. Active transport
C. Osmosis
D. Diffusion
Answer Explanation
Osmosis is the movement of water molecules across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.
In a hypertonic solution, the concentration of solutes outside the cell is higher than inside the cell, so water flows out of the cell through aquaporins embedded in the plasma membrane to balance the concentration gradient.
Choice A.
Facilitated diffusion is not correct because it is a type of passive transport that involves the movement of molecules across a membrane through specific transport proteins, but it does not specifically refer to the movement of water molecules.
Choice B.
Active transport is not correct because it is a type of transport that involves the movement of molecules against their concentration gradient and requires energy in the form of ATP, but osmosis is a passive process that does not require energy.
Choice D.
Diffusion is not correct because it refers to the movement of molecules from an area of higher concentration to an area of lower concentration, but it does not specifically refer to the movement of water molecules.
-
Q #3: Which of the following is the process in which an ovarian follicle matures and releases a reproductive egg?
A. Menstruation
B. Fertilization
C. Ovulation
D. Oogenesis
Answer Explanation
Ovulation is the process in which an ovarian follicle matures and releases a reproductive egg.
During ovulation, a mature egg is released from the female ovary, enabling it to be fertilized by male sperm cells 1.
Choice A is incorrect because menstruation is the process of shedding the uterine lining, which occurs when an egg is not fertilized.
Choice B is incorrect because fertilization is the process of a sperm cell joining with an egg cell to form a zygote.
Choice D is incorrect because oogenesis is the process of forming female gametes (eggs) in the ovaries.
