Biology Test 2
Terms
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What is the structure of ATP?
- Sugar with an adenine group attached and three phosphate groups. ie : a nucleotide
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What are 2 functions of intermediary filaments?
What is an example of an intermediary filament protein?
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Helps position organelles & maintain cell shape
Lamins (in nucleus - gives it shape)
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What does enthalpy mean?
free energy?
Entropy?
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Enthalpy - total energy
Free energy - usable energy
Entropy - unusable energy - the measure of disorder
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What is the function of the lysosome?
Where does this organelle originate?
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Digest material ingested by the cell -- contain many enzymes to digest macromolecules
originates in the golgi
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What is the name of the protein that makes up microfilaments?
What are the 2 functions of microfilaments?
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Actin
helps cell contract (ameba)
stabilizes cell shape
- Describe an experiment that shows proteins can move in membranes.
- A mouse and human cell are mixed and fused together. At first it is clear that the membrane bound proteins are still separated. 40 minutes later the proteins are all intermixed.
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How can membranes affect diffusion? (permeable versus impermeable)
- In a permeable membrane sustances can cross readily, but impermeable membranes do not allow things to cross freely.
- How can the example of the steam locomotive explain the first and second laws of thermodynamics?
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It shows energy can be transformed from coal to steam and finally work, but some of the energy is loast as heat or friction.
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How does facilitated diffusion via channel proteins compare to facilitated diffusion via carrier proteins?
- With channel proteins the molecule being transported doesn't bind to the channel, but molecules do bind to carrier proteins as they pass through the membrane.
- Please describe the endosymbiont theory. What evidence support the theory?
- Origin of mitochondria & chloroplast -- large cell engulfs small cell & doesn't digest it -- small cell inside now has a new membrane from the large cell (they have 2 membranes) -- about the size of bacteria -- have their own DNA (circular lik
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Please describe the fluid dynamic mosaic model of cell membrane.
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sea of phospholipids with proteins floating in it
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State the first law of thermodynamics.
- Energy can be converted, but it can't be created or destroyed.
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State the second law of thermodynamics.
- When energy is converted from one form to another some of the energy becomes unavailable to do work.
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What are four functions of cellular membranes?
- *delineate cell & compartments inside *control over what enters/exits compartments (barrier) *process info *involved in energy transformation (make ATP)
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What are integral versus peripheral membrane proteins?
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integral - inserted into lipid bilayers, some actually go all the way across
peripheral - associated with membrane but not inserted into the bilaryer
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What are the overall characteristics of eukaryotic cells?
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Larger & more complex
plasma membrane, cytoplasm & ribosomes; but also membrane bound compartments and a cytoskeleton; more organelles
- What are the three functions of the plant cell vacuole?
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water for turgor pressure -- store toxic materials (deter animals from eating plant) -- store anthocyanins (blue pigments); gives color to flowers (attracts pollinators) & fruit (attracts seed dispensers)
- What are the types of of passive membrane transport?
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simple diffusion
facilitated diffusion
Osmosis
- What are three functions of microtubules?
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attach to chromosomes during cell division & move them-- position organelles-- microtubules can bind motor proteins that "walk" along microtubules & move material inside the cell
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What are three functions of the cytoskeleton?
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gives cell shape
position cellular compartments
cell movement
- What do the following terms mean: isotonic, hypotonic, hypertonic?
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Isotonic refers to a solution that has an equal number of solutes on each side. Hypotonic is a solution with less solutes on its side. Hypertonic is the opposite. These terms are relative and must be compared to something else. <
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What happens to a plant cell when in an isotonic, hypotonic, and hypertonic solution?
- Nothing happens to the cell in an isotonic solution, but in a hypotonic solution cell takes up water, but doesn't lyse it just becomes more turgid (prevented by cell wall). In a hypertonic solution the plasma membrane shrinks away from the cell
- What happens to a red blood cell in an isotonic, hypertonic, and hypotonic solution?
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Isotonic - nothing *Hypertonic solution - cell shrinks b/c all the water rushes out *hypotonic solution - cell lyses because all the water comes into the cell and causes it to burst
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What is active transport?
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It costs energy (ATP) to move things across a membrane.
The solutes are being moved up a concentration gradient.
- What is diffusion?
- occurs from a region of high conectration to low concentration due to random movement of particles.
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what is facilitated diffusion?
- Particles are moved with membrane proteins (these proteins go all the way through the membrane)
- What is osmosis?
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simple diffusion of water from high to low concentration
*** Remember: water is moving, not the particles
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What is simple diffusion?
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small, non-polar molecules can cross the membrane
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What is the function of the nucleolus?
- Ribosome assembly
- What is the function of the nucleus?
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Stores genetic information
DNA + proteins = chromatin (not condensed, long strings)
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What is the function of the rough ER?
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has ribosomes
synthesizes proteins to be secreted form the cell, inserted in membranes, or sent to another compartment
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What is the function of the smooth ER?
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no ribosomes
site of lipid synthesis to make more phospholipids, steroids, & cholesterol -- also detoxifies toxic chemicals
- What is the structure & function of the golgi?
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sacs of membranes connected by vesicles
site where cargo is sorted & modified before being sent ot their destination
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What is the structure and function of chloroplasts?
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Photosynthesis -- contain chlorophyll
thylakoid membranes - site of light energy capture
stroma - site where carbon dioxide is captured & converted to sugars
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What is the structure and function of ER?
- set of sacs & tubules made of membranes connected to the nucleus -- protein and lipid synthesis
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What is the structure and function of ribosomes?
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function - protein synthesis
structure - made of ribosomal RNA and ribosomal protein -- a small subunit & a large subunit
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What is the structure and function of the mitochondria?
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Site where energy is converted to the form of ATP -- cellular respiration
2-8 micrometers -- about the size of bacteria
- What macromolecule makes up the cytoskeleton?
- Proteins
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What organisms contain vacuoles?
- Plants and some protista
- What proteins make up microtubules?
- Tubulin
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What three types of plastids were presented in class?
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Chloroplast
Chromoplast
Leucoplast
- Where in a cell can ribosomes be found?
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cytoplasm (free-floating)
Attached to the ER