Biochemisistry Question

[dentheartthrob]

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Solution A has a PH of 7.0 and solution B has a pH of 6.0. Both solutions are equal volume, which of the following statements about solution A and B are true?

A. A has 1/10 as many hdrogen ions as B
B. A has 10 times more hydrogen ions than B
C. A has 7/6 of hydrogen ions concentration of B
D. A has 6/7 of the hydrogen concentration of B

I'd like to answer D since power of hydrogen are in powers of 10. my explanation is because pH went down by just one would it be safe to say that at a pH of 6 that there is 10 to the power n-1 number H+ ions dissociated? Maybe some one has a better explanation?

 

[dentheartthrob]

thanks 🙂

 

[dentheartthrob]

which of the following statements BEST applies to saliva?
a. Phospahte is the main buffer
b. Supplies sialate for additional mucins
c. main source of enzymes for protein digestion
d. supplies calcium and phosphate for remineralization
e. undersaturated with respect to hydroxyapatatie at neutral pH

 

[quest_life]

Ans:

which of the following statements BEST applies to saliva?
a. Phospahte is the main buffer
b. Supplies sialate for additional mucins
c. main source of enzymes for protein digestion
d. supplies calcium and phosphate for remineralization (ANSWER)
e. undersaturated with respect to hydroxyapatatie at neutral pH

 

[sharabi23]

can someone explain this question. thanks guys.


In a right lateral excursion, the mesiofacial cusp of the maxillary right first molar passes through which of the following grooves of the mandibular right first molar?

1. Lingual groove
2. Central groove
3. Facial groove
4. Distofacial groove

 

[sharabi23]

The answer is the facial groove. Why? First, let's consider the overall layout of teeth in proper occlusion. Because the Maxillary central incisors are larger than the mandibular centrals, that creates the necessary offset in the arches to allow for proper occlusion. Therefore, the mandibular cusp is more mesial than the respective maxillary cusp. In your question, this relates to the mandibular mesiofacial cusp resting on the distal marginal ridge of the max 2nd pre and the mesial marginal ridge of the max 1st molar. The mandibular disofacial cusp lies in the central pit of the max 1st molar. The max mesiofacial cusp doesn't occlude, but lies facial to the facial groove. The max distofacial cusp doesn't occlude, but lies facial to the distofacial groove.

OK, we have our basic occlusion lesson down, so we can look at the paths cusps follow when the mandible goes into a right lateral excursion.

1. Lingual groove - the mesiolingual cusp travels through it.
2. Central groove - this groove only has a cusp traveling through it in protrusive / retrusive movements
3. Facial groove - the mesiofacial cusp travels through it since this cusp is what is lying facial to the facial groove when the man. travels laterally across the mesiofacial cusp
4. Distofacial groove - the distofacial cusp travels through it

This is so much easier when you can explain this with a model to someone. Hope this doesn't confuse you too much.

thanks for your detail explaination doc. I picked the same answer, but the answer key on the exam states that its Lingual not FACIAL. there is actual two questions like these and both indicates the answer as Lingual not facial. I think the answer key could be not correct. lates and hppy 4th everyone.