What spontaneously aggregates, and crosslinks form between lysine and hydroxylysine ?

 # ________ spontaneously aggregates, and crosslinks form between lysine and hydroxylysine.

A. Carbohydrate

B. Fiber

C. Tropocollagen

D. Collagen

The correct answer is C. Tropocollagen.

Tropocollagen spontaneously aggregates, and crosslinks form between lysine and hydroxylysine. 

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Which classification of lipid consist of hydrophobic and hydrophilic ?

 # Which classification of lipid consist of hydrophobic and hydrophilic?

A. Sphingophospholipids

B. Glycolipids

C. Phospholipids

D. Phosphoglycerides

The correct answer is C. Phospholipids.

Phospholipids are composed of glycerol or sphingosine, two fatty acids, and phosphoric acid. They are an important component of membranes since they have hydrophobic (fatty acid) and hydrophilic (phosphoric acid) domains. Phosphoglycerides are composed of glycerol, fatty acids and phosphate.

Glycolipids (glycosphingolipids) are composed of carbohydrate, sphingosine, and fatty acid.

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Henderson-Hasselbalch equation

 # Which of the following is true?

A. The Henderson-Hasselbalch equation fails to describe the relationship between pK and pH

B. The Henderson-Hasselbalch equation describes the relationship between pK and pH

C. The Henderson-Hasselbalch equation cannot be used to determine the dissociation of ionizable groups at a given pH

D. The Henderson-Hasselbalch equation is not valid or viable

The correct answer is B. The Henderson-Hasselbalch equation describes the relationship between pK and pH.

The Henderson-Hasselbalch equation describes the relationship between pK and pH. The Henderson-Hasselbalch equation can be used to determine the dissociation of ionizable groups at a given pH.

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What contain an aldehyde as their most oxidized functional group?

 # _______ contain an aldehyde as their most oxidized functional group.

A. Glycosidic bonds

B. Fructose

C. Ketose

D. Aldoses

The correct answer is D. Aldoses.

Aldoses contain an aldehyde as their most oxidized functional group. They may contain any number of carbons. Ketose contain  a keto group as their most oxidized functional group. Fructose is a ketohexose. Glycosidic bonds are bonds formed between two sugars or a sugar and another non carbohydrate molecule. 

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Which of the following is true in lipid terminology?

 # Which of the following is true in lipid terminology?

A. Fatty acids do not possess a terminal carboxyl group that provides polarity to the molecule

B. Fatty acids are straight chained compounds containing an even number of hydrocarbons

C. Fatty acids are not amphipathic

D. Fatty acids are found only in adult body

The correct answer is B.  Fatty acids are straight chained compounds containing an even number of hydrocarbons.

 Fatty acids are straight chained compounds containing an even number of hydrocarbons. They possess a terminal carboxy group that provides polarity to the molecule. Because of this characteristic, fatty acids are amphipathic.

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Meat of Polar Bear may cause:

 # A man during his visit to the Arctic ocean happened to eat meat of polar bear. He suffered from intense headache, drowsiness and vomiting. This is most likely due to:

A. Cold diarrhea

B. Vitamin A toxicity

C. Food allergy

D. Vitamin K toxicity

The correct answer is B. Vitamin A toxicity.

Acute poisoning has been described after consumption of polar bear liver which contains 30,000 IU/g vit A. Single massive ingestion (> 1 million IU) produces intense headache, drowsiness, irritability, rise in intracranial tension, vomiting, liver enlargement and shedding of skin. Due to saturation of RBP, excess retinol esters circulate in the free state or loosely associated with lipoprotein. These have surfactant property which damages tissues.

Treatment consists of stopping further ingestion, supportive measures, and vit E which promotes storage of retinol in tissues and speeds recovery. Most signs regress in a week, some persist for months. Excess intake of carotenoids does not produce hypervitaminosis A, because conversion to retinol has a ceiling.

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Number of point angles in class 3 cavity preparation is:

 # Number of point angles in class 3 cavity preparation is:

A. 4

B. 5

C. 3

D. 11

The correct answer is C. 3.

The three point angles are: 

i) Incisal Point Angle

ii) Axiofaciogingival point angle, and 

iii) Axiogingivolingual point angle.

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