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47 Cards in this Set
- Front
- Back
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Explain how kinase and photophase enzymes interact in protein.
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Kinases can be activated by phosphoryoyzing them, and deactivated by removal by phosphotase.
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List 3 facts about calmodulin.
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Calmodulin mediates many calcium-regulated processes in cells.
When calcium ions bind to it, calmodulin changes conformation and then binds to other proteins, activating or inactivating them. The proteins most often regulated by calmodulin are protein kinases and phosphatases |
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Describe a phophorylation cascade model.
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A series of reactions in which the products act as enzymes to catalyse the next reaction.
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How would an animal cell reduce its intracellular Ca2+ levels?
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-cell membrane
-ER -Mitochondria All involve calcium ion pumps 1 pump pumps calcium out of cell through cell membrane Calcium pumps pump it into ER and mitochondria. |
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What molecule combines with CdK that activates numerous proteins that facilitate mitosis?
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Cyclin. Both make MPF
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What happens during the S phase?
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'S-phase' is short for synthesis phase. Cells go through different phases each time they multiply. S-phase is the time when the cells copy their DNA so that the new cells each have a full set of genes. They 'synthesise' DNA just before the begin to divide. So the proportion of cells in s-phase in your pathology sample gives your doctor an idea of how active the cancer is. The more cells that are in s-phase, the more that are dividing, so the faster the cancer will grow.
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In which phase are when the two centrosomes reach opposite poles?
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Metaphase
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How does a centromere differ from a centrosome?
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Centromere holds chromatids together.
Centrosomes are where spindle fibers come out and move apart in prophase |
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A human cell has how many chromosomes? How many chromatids would each human cell have at the start of mitosis?
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46 chromosomes. 2 chromatids.
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What is the haploid number for humans?
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23 is the haploid number.
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Which molecules concentration seems to show fluctuations during the cell cycle?
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Cyclin
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What are the spindles made of?
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Microtubules
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Most cells that have stopped dividing and differentiating are in the phase.
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In the G1 phase of the cell cycle
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In yeast cells, what does mating type a secrete?
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A factor More info on P 198
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What causes myxobacteria to aggregate and form spores?
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Release single molecule, causes them to go into set rep cycle
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What do growth factors attach to, on target cells?
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tyrosine-kinase receptors. The receptor for a growth factor is often a tyrosine-kinase receptor, one of a major class of plasma membrane receptors characterized by having enzymatic activity. Part of the receptor protein on the cytoplasmic side of the membrane functions as an enzyme, called tyrosine kinase, that catalyzes the transfer of phosphate groups from ATP to the amino acid tyrosine on a substrate protein. Thus tyrosine-kinase receptors are membrane receptors that attach phosphates to protein tyrosines.
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What is paracrine signaling?
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Glytohystomines being released, cells swell up
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What gas causes fruits to ripen faster? How does it work?
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Ethylene
Tissues of ripening fruits, nodes of stems, aging leves and flowers Promotes fruit ripening, opposes some auxin effects; promotes or inhibits growth and development of roots, leaves, and flowers, depending on species |
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What are the three stages of cell signaling?
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The three stages of cell signaling are reception, transduction, and response.
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How does epinepherine affect glycogen?
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Trigger liver cells to break down glycogen into glucose
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How would the graph differ if you substituted a CAM plant?
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CAM store CO2 at night, release during day.
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If you measured the pH of the Elodea over a 24hr period, draw a graph of the expected change in pH.
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Day pH = higher
Night pH = lower ßcell respiration releases CO2 |
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List 3 advantages of cell signaling
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amplification
regulation can be modified Amplification- As a result of the signals amplification, a small number of epinephrine molecules binding to receptors on the surface of a liver cell or muscle cell can lead to the release of hundreds of millions of glucose molecules from glycogen. Regulation- Evidence for cytoplasmic chemical signals in cell cycle regulation. Cultured mammalian cells can be induced to fuse, forming a single cell with two nuclei. The results of fusing cells at two different phases of the cell cycle suggested that chemicals control the progression of phases. For example, when a cell in M phase was fused with a cell in any other phase, the second nucleus immediately began mitosis. If the second cell was in G1, as here, the condensed chromosomes that appeared had single chromatids. |
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Describe a LIGAND.
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Signal molecule which binds to a receptor protein
This triggers G receptor protein |
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If a cell underwent mitosis without cytokinesis, what will happen?
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Cell with more than one nucleus inside
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What does MPF to do cyclin?
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The peaks of MPF activity correspond to the peaks of cyclin concentration. The cyclin level rises sharply throughout interphase (G, S, and G2), then falls abruptly during mitosis (m)
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How does cytokinesis differ from mitosis?
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Mitosis-Division of the nucleus
Cytokinesis-Division of the cytoplasm |
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What causes cytokinesis in higher plants?
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Cell wall, specifically cell plate
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Why do platelets release PFGF in the vicinity of an injury?
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Causes surrounding cells to divide and heal injury
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List 3 characteristics of signal molecules.
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A signal molecule binds to a receptor protein, causing the protein to change shape.
A cell targeted by a particular chemical signal has molecules of a receptor protein that recognize the signal molecule. The signal molecule is complementary in shape to a specific site on the receptor and attaches there, like a key in a lock or a substrate in the catalytic site of an enzyme. The signal molecule behaves as a ligand, the term for a small molecule that specifically binds to a larger one. Ligand binding generally causes a receptor protein to undergo a change in conformation--that is, to change shape. For many receptors, this shape change directly activates the receptor so that it can interact with another cellular molecule. For other kinds of receptors, as well see shortly, the immediate effect of ligand binding is more limited, mainly causing the aggregation of two or more receptor molecules. |
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What does GTP do to the G protein?
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G protein is activated, turns to GDP.
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What is the function of protein kinase?
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The phosphorylation cascade shown here begins after a relay molecule activates an enzyme we call protein kinase 1.
1. Active protein kinase 1 transfers a phosphate from ATP to an inactive molecule of protein kinase 2, thus activating this second kinase. 2. Active protein kinase 2 then catalyzes the phosphorylation (and activation) of protein kinase 3. 3. Finally, active protein kinase 3 phosphorylates a protein (pink) that brings about the cells response to the signal. The dashed arrows represent inactivation of the phosphorylated proteins; enzymes called phosphatases catalyze the removal of the phosphate groups from the proteins, making them available for reuse. The active and inactive proteins are represented by different shapes to remind you that activation is usually associated with a change in molecular conformation. |
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What is the name of plants that fix carbon dioxide at night into organic acids?
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CAN plants
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What kind of plants has a more efficient enxyme to first fix carbon dioxide?
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C4
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What is the proton gradient used for in chloroplasts?
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ATP
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What do red plants do to red light?
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Reflect the light
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Why is RuBP carboxylase the most abundant enzyme in the world?
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Because it is the first enzyme in the calvin cycle
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List four facts about photosystem II.
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-Moves plants
-Uses reaction P680 -Splits water -Has bi-product (waste product) oxygen O2 |
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What is the primary difference between autotrophs and heterotrophs?
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Autotrophs-Autotrophs are not totally self-sufficient, however; they are self-feeders only in the sense that they sustain themselves without eating other organisms or substances derived from other organisms. Autotrophs produce their organic molecules from CO2 and other inorganic raw materials obtained from the environment and are the ultimate sources of organic compounds for all non-autotrophic organisms. Plants are autotrophs; the only nutrients they require are carbon dioxide from the air, and water and minerals from the soil.
Heterotrophs-Heterotrophs obtain their organic material by the second major mode of nutrition. Unable to make their own food, they live on compounds produced by other organisms; heterotrophs are the biospheres consumers. The most obvious form of this "other-feeding" (hetero means "other, different") occurs when an animal eats plants or other animals. |
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Describe photorespiration.
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Photorespiration is the process by which plants produce energy at night.
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Name 3 products of noncyclic photophosphorylation.
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-O2
-NADPH -ATP cyclic and non-cyclic make ATP, but only non-cyclic makes NADPH |
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What colors are absorbed the most by photosynthesis?
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Blue and red. Green is reflected.
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Name what goes into and out of the Calvin cycle.
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Carbon enters in form of CO2, and leaves as sugar
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Why is the Calvin cycle also known as the dark reaction?
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It does not need light to occur
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What kind of plant decreases in photosynthetic rate as oxygen increases?
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C3 in the process of photorespiration
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If you blow carbon dioxide into water, what will happen to the pH? Why?
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Co2 Absorbed, less carbonic acid.
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If you put Elodea (an aquarium C3 plant) in water and shine a light on it, what will happen to the pH? Why?
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If you put Elodea (an aquarium C3 plant) in water and shine a light on it, what will happen to the pH? Why?
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