Globular Proteins – Flashcards
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| What is the difference between globular proteins and fibrous proteins? |
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| globular- spherical shape; fibrous- long, thin fibers |
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| What are some examples of globular proteins? |
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| insulin, hemoglobin, enzymes, antibodies |
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| What are examples of fibrous proteins? |
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| skin, hair, nails, wool |
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| What are the oxygen binding proteins? |
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| Myoglobin, Hemoglobin, Cytochromes |
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| What transports oxygen from the lungs to various tissues? |
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| hemoglobin |
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| Oxygen gets dumped to ___________ because of its __________ affinity for oxygen. |
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| myoglobin; higher |
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| Myoglobin has a lesser/higher affinity for oxygen than hemoglobin? |
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| higher |
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| The oxygen binding curve for hemoglobin is: |
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| sigmoidal |
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| The oxygen binding curve for myoglobin is: |
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| hyperbolic |
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| oxygen carriers are ___________ proteins. |
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| globular |
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| How many polypeptide chains make up hemoglobin (tetramer)? |
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| four |
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| One heme molecule of hemoglobin binds ____ oxygen molecules. |
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| 4 |
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| Taut is low/high affinity? |
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| low |
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| Relaxed is low/high affinity? |
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| high |
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| Hemoglobin changes from ______ to ______ when it binds with O2. |
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| taut; relaxed |
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| What are the different forms of hemoglobin? |
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| oxyhemoglobin, deoxyhemoglobin, methemoglobin |
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| hemoglobin plus O2; relaxed (R ) state, more stable (higher affinity for oxygen; more stable than T when oxygen is bound) |
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| oxyhemoglobin |
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| has a vacant O2 binding site; tense (T) state (low affinity state; more stable than R when no oxygen bound) |
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| deoxyhemoglobin |
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| iron in the oxidized state (Fe+3) plus hemoglobin (Fe+3 can’t bind oxygen) |
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| methemoglobin |
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| ___ and ___ : have higher affinity for heme (Fe+2) than oxygen; can displace oxygen from Hb |
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| CO; NO |
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| What percent of hemoglobin is HbA? |
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| 95% |
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| What percent of hemoglobin is HbA2? |
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| 4% |
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| What form of hemoglobin is HbF? |
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| 1% |
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| Where is HbF usually found? |
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| fetus during 2nd and 3rd trimester |
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| HbF-Interaction with 2,3-BPG is _______ resulting in an _______ affinity for O2 and a greater stabilization of the R state. This allows for a more efficient transfer of O2 from maternal to fetal hemoglobin |
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| weaker; increased |
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| There are ___ O2 binding sites on one hemoglobin. |
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| 4 |
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| Each O2 binding site is __________. |
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| cooperative |
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| Oxygen is a ________ _________ effector. |
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| homotropic positive |
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| Positive effectors shift the binding curve to the ______. |
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| left |
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| If the binding curve is shifted left, this means that you achieve oxygen saturation slower/quicker? |
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| quicker |
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| oxygen saturation is a combination of _________ and __________ hemoglobin. |
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| oxygenated; deoxygenated |
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| percentage of hemoglobin molecules that are oxygenated is called: |
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| oxygen saturation |
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| Saturation is maximum at _____ O2 pressure, such as in the ______. |
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| high; lungs |
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| As hemoglobin moves to peripheral organs and the O2 pressure ____, _______ drops allowing O2 to be supplied to the ________. |
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| drops; saturation; tissues |
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| At _______ pO2, small differences in O2 pressure result in big changes in O2 saturation of hemoglobin. This facilitates _________ of O2 in _________ __________. |
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| lower; dissociation; peripheral tissues |
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| Describes the rightwards shift in the O2 saturation curve with increasing H+ concentration because oxygen is released more readily (higher CO2 & BPG cause same effect) |
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| The Bohr Effect |
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| O2 is released in tissues where [H+] is____ due to CO2 production by metabolism |
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| high |
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| What is the byproduct of anaerobic glycolysis if the RBC? |
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| 2,3-Bisphosphoglycerate |
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| 2,3-Bisphosphoglycerate reacts with what? |
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| only deoxygenated RBC |
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| when pO2 is decreased, as in chronic tissue deprivation of O2, the level of 2,3-BPG _________. This results in a further_________ shift of the curve facilitating O2 release to the deprived tissues |
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| increases; rightward |
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| What causes carbon monoxide poisoning? |
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| Affinity of globin bound heme for CO is 104 times more then that for O2; thus, it will bind preferentially |
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| Bound CO allosterically _______ hemoglobin (shifts O2 saturation curve to the _____) |
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| activates; left |
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| During carbon monoxide poisoning, Any __ already bound can/can not be released (trapped in R state) so its transport to tissues becomes seriously compromised |
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| O2; cannnot |
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| How do you treat CO2 poisoning? |
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| Hyperbaric O2 therapy (administration of 100% O2) is used to treat CO poisoning |
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| Fibrous proteins exhibit special _________ properties, based on structure obtained from combination of specific amino acids in regular, ___________ structural elements |
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| mechanical; secondary |
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| Fibrous protein molecules have _______, _________ shape |
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| long, narrow |
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| Fibrous proteins usually exist as __________ aggregates (fibers) of many protein chains. |
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| insoluble |
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| _________ is a structural connective tissue accounting 30% of total body protein. |
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| collagen |
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| Collagen has how many aa residues per chain? |
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| 1000 |
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| How much of our protein is collagen? |
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| 30% |
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| Many types of collagen super-family exist. Types I-III are _____ forming while IV is ________ type. |
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| fiber; membrane |
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| What are some properties of collagen and where do you find it in the body? |
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| insoluble, high tensile strength, tendons, ligaments, cartilage, cornea |
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| What is the primary amino acid sequence for collagen? |
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| (Gly-X-Y) is the primary amino acid sequence, X is often proline. |
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| Collagen contains what? |
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| Contain hydroxyproline & hydroxylysine |
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| Collagen may also be _________-addition of glucose or galactose before triple helix formation |
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| glycosylated |
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| Collagen is synthesized by: |
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| fibroblasts, osteoblasts and condrocytes |
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| Where is elastin found? |
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| vascular wall, skin, and lungs |
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| What is the difference between elastin and collagen? |
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| Contain proline and glycine like collagen but the protein is not glycosylated and has minimal hydroxylation |
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| What gives tissues (bladder, skin, lung blood vessels) their elasticity & resilience (recoil after a stretch) |
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| elastin |
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| Large ________ ______ fibrils are interwoven to ______ the stretching and prevent the tissue from _________. |
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| inelastic collagen; limit; tearing |
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| Aka brittle bone disease Mutation in type I collagen genes 1. Prevent triple helix formation 2. Bendy bones, fracture, rotated & twisted spine 3. humpback 4. Type II OI-fatal in utero |
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| Osteogenesis imperfecta |
