Cell Structure
The DNA in a prokaryotic cell is in the ________ region of the cytoplasm.
What is the nucleoid
What are the main functions of the plasma membrane.
What is: isolates the cell's internal environment from the external environment, regulates the flow of materials into and out of the cell, and allows for interaction with other cells.
Difference between kinetic energy and potential energy, & give example of each.
What is: Kinetic energy is the energy of motion (examples include heat, light, electricity, a car moving), and potential energy is stored energy (examples include energy in chemical bonds, batteries, child sitting at the top of a slide).
Explain how the leaf is adapted for capturing energy from sunlight and for acquiring carbon dioxide and water.
What is: CO2 comes through adjustable pores, or stomata, and water comes from the vascular bundles (or veins) to the mesophyll cells. Leaves are broad and flat to provide a large surface area to the sun. Chlorophyll molecules embedded in the thylakoid membrane of the chloroplast absorb sunlight.
What happens to the photosynthetic reactions when no sunlight is present?
What is: ATP and NADPH levels from the light reactions become limiting, and that in turn can lead to a decrease in sugar production following the Calvin cycle.
How is the vacuole involved in support of non-woody parts of the plant?
What is: The vacuole allows for the buildup of turgor pressure in plant cells, which prevents wilting.
How does the cell membrane act as a "gatekeeper" for the cell?
What is: It separates the internal and external cell environments, it regulates the exchange of substances between the external environment and the cytoplasm, and it allows for communication between cells.
Briefly explain the two laws of thermodynamics.
What is: The law of the conservation of energy states that although the form of energy changes, the total amount remains the same. The second law states that as energy changes from one form to another, the amount of useful energy decreases.
What is the role of the green pigment chlorophyll in photosynthesis?
Chlorophyll is critical in light reactions to harness light energy and begin the flow of electrons, which in turn creates the proton gradient allowing for ATP formation, which is required for the Calvin cycle.
Describe the molecular difference between ATP and ADP.
What is: : Both ATP and ADP contain an adenosine and a sugar. In ATP, three phosphate groups are attached, whereas in ADP, only two phosphate groups are attached.
Why are cells generally small?
What is: Cells need sufficient surface area for the exchange of nutrients and wastes with the external environment.
Compare and contrast facilitated diffusion and active transport.
What is: : Both require membrane transport proteins. However, facilitated diffusion does not require energy and moves substances down a concentration gradient. Active transport requires energy and moves substances against a concentration gradient.
What is a simple definition of energy, from a biological perspective? Give some examples of how energy is used in a cell.
What is: Energy is the ability of a cell to do work. The cell uses energy to synthesize molecules, move objects, and generate heat (other examples could be used).
Describe the two major components of a photosystem. What is the function of each?
What is: The light-harvesting complex absorbs light and passes the energy to a specific chlorophyll molecule called the reaction center. The electron transport system is a series of electron-carrier molecules that are responsible for directly donating electrons to the electron carrier molecule NADP+ and indirectly driving the synthesis of ATP.
Why does the cell perform endocytosis in addition to active and passive transport?
What is: : Endocytosis is required for the transport of proteins, microbes, extracellular fluid, and specific molecules that are all larger than the molecule size transported by active and passive transport.
What components do all cells possess?
What is: DNA (at some point in their life cycle), a cell membrane, ribosomes, and cytoplasm
Compare and contrast osmosis and simple diffusion.
What is: Both are passive processes. However, osmosis refers to the movement of water down its concentration gradient across a selectively permeable membrane. No membrane or membrane protein is required for simple diffusion.
Compare endergonic and exergonic chemical reactions using an analogy from everyday life.
What is: Rolling a boulder up a hill requires an input of energy (an endergonic process), whereas the same boulder, once given a push, rolls down the hill spontaneously (an exergonic process).
Is glucose a direct product of the Calvin cycle? Explain.
What is: No; G3P is the carbohydrate produced, and two of these molecules must combine to form one molecule of glucose.
Why is the cytoskeleton such an important structural component of cells?
What is: The cytoskeleton maintains cell shape, facilitates cell and organelle movement, and is involved in cell division.
What are the three main components of modern cell theory?
What is: All living organisms are composed of one or more cells, the cell is the smallest functional unit of life, and all cells come from preexisting cells.
Why is the biological membrane said to be selectively permeable?
What is:
It allows only some molecules to pass through while barring others.
Describe how ATP acts as an energy carrier in cells.
What is: ATP stores energy in its chemical bonds and releases the energy when needed with the breaking of the third phosphate bond (forming ADP and phosphate).
How are the light reactions and the Calvin cycle related to each other?
What is: The light reactions produce the ATP and NADPH required to drive the Calvin cycle, which results in the synthesis of sugar (glucose).
What is: I know you can do it!