Biochemistry Video 13
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- What are the nine hydrophobic amino acids?.... why are these important
- glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, tyrosine, tryptophan.... These amino acids will most likey be used in the N-terminus of the secreted protein, such as insulin, or membrane or organelle protein
- What are the 6 nonpolar, amino acids with aliphatic side chains?
- glycine, alanine, valine, leucine, isoleucine, proline
- What re the 3 amino acids with aromatic side chains ?
- phenylalanine, tyrosine, tryptophan
- What is the smallest amino acid?
- glycine
- Which amino acids will disrupte the alpha helixes of membranes?
- glycine, because it is so small... proline , because it’s R group is attached to it’s amino group.
- What are the amino acids with branched chains?... Why are these important?
- Leucine... Isoleucine... Valine... These amino acids require BRANCHED CHAIN DEHYDROGENASE which is DEFICIENT IN MAPLE SYRUP URINE DISEASE
- What is the difference between penylalanine and tyrosine?
- OH group is on the aromatic ring of tyrosine, while it is absent on phenylalanine
- What is the only amino acid with a phenol group
- tyrosine
- What is tyrosine a precursure of?
- thyroid hormone, catacholamines, melanin
- What is needed for the conversion of tyrosine to catachole?
- addition of another OH group to the already present phenol on the tyrosine?
- What is tryptophan used for?
- major procurer of serotonin, and is used for NAD and NADP synthesis
- What are the hydrophilic amino acids?
- lysine, arginine, histidine, aspartate, glutamate, serine, threonine, cysteine, methionine, asparagine, glutamine
- Which amino acids have positively charged R groups?
- lysine, arginine, histidine
- Which amino acids have negatively charged R groups?
- aspartate glutamate
- Which amino acids have polar, uncharged R groups?
- serine, threonine, cysteine, methionine, asparagine, glutamine
- What gives the positively charged amino acids their charge?
- an extra amino group
- Which amino acids would be abundant in histones?
- lysine and arginine because it is a positively charged protein
- Where is the amino group on lysine?
- it is on the very end of the R group⬦this position is known as the epsilon position
- Why is the epsilon position on amino acid important?
- it is on the epsilon amin o group of lysine that glycosylation of hemoglobin occurs
- What gives the negatively charged R groups their negative charge?
- Their side chains contain an extra carboxylic acid group
- What is the significance of both negatively charged amino acids?
- Aspartate and glutamate are both excitatory neurotransmitters in the CNS⬦⬦⬦⬦⬦⬦⬦.glutamate is also a precursor of GABA.
- Which amino acid is notorious for being a great physiological buffer?
- histidine
- Which amino acids contain S in their side chains?
- cysteine and methionine
- Which amino acids has an SH at the end of its side chain and why is this important?
- cysteine⬦.it is pmportant because it is between these SH group that disulfide bonds between proteins are made⬦..this SH group on cysteine in the protein glutathione which mops up free redicals
- Which amino acids have an extra OH group in the side chain?
- serine, threonine
- What is the importance of the OH groups on the proteins?
- These are sites where posttranslation al modification can perform glycosylation and phosphorylation of protein.
- What medication is given to people experiencing free radical damage, such as Tylenol or acetomeniphen overdose?
- N-acetylcysteine
- What is the importance of methionine?
- it is a key methyl group donator and thus is a main component of the SAM enzyme.
- What is the name of the proteins that wraps up free radicals in cells and what is this due to?
- glutathione mops up free radicals and it is due to the SH bonds on cysteins amino acids in the protein
- What are some key reactions of the SAM protein?
- methylation of norepinephrine to epinephrine⬦⬦⬦⬦⬦..or adding a methyl to the guanine to form the methyl guanine cap.
- What is the importance of asparagine and glutamine?
- These proteins have H2N on the end of their R group and thus allow N glycosylation of the end of their side chains
- What is the importance of glutamine?
- it can detoxify ammonia due to the activity of glutamine synthetase
- What is the pK value for the amino group on amino acids?
- 9
- What is the pK value for the acid group on amino acids?
- 2
- What are the positively chargesd amino acids and what is the pK of their extra amino group?
- arginine = 13... Lysine = 10... Histadine = 6.5
- What are the negatively charged amino acids and what is the pK of their extra acid groups?
- Aspartate = 4... glutamate = 4
- What is an isoelectric point of a molecule?
- this is the oint at which the pH and PK is balanced and there is no overall charge on the molecule , and thus it will not migrate the positive or negative electrode
- What is a characteristic of asprin and how is this used?
- asprin is a weak acid and thus is order to make it more water soluble, the urine is alkalized and that asprin gains a charge and dissolves in water. When a weak acid is in acid, it is uncharged, and thus not soluble in water, but if the weak acid is in basic solution it will lose it H+, gain a neg. charge and thus become soluble.
- What is a quick way to find the approximate pK?
- average the two closest pKs.
- Why is histidine such a good buffer?
- it has the third pK at a value of 6.5
- What are the important intracellular buffers?
- Proteins (due to histidine R groups).... Phosphate.... Organic phosphates
- What is an important extracellular buffer?
- bicarbonate, the most important buffer
- What are the ten essential amino acids?
- PVT TIM HALL ⬦⬦⬦Phenylalanine⬦⬦⬦⬦Valine⬦⬦⬦⬦.. Tryptophan⬦... Threonine⬦⬦⬦⬦Isoleucine ⬦⬦Methionine ⬦⬦⬦.Histidine.... Arginine⬦⬦⬦..Leucine⬦⬦.Lysine
- What of the essential amino acids are only required during period of growth?
- Arginine
- What is a negative nitrogen balance?
- When the losses exceed the amount of nitrogen input.
- What is the main parameter of the energy of a reaction?
- delta G⬦.negative delta G means that there is an energy loss and thus it is spontaneous⬦.but tells nothing at all about the rate
- What are the parameters of the rate of a reaction?
- Km and Vmax