Amino Acids and Proteins Flashcards

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1
Q

What is the central dogma?

A

DNA to RNA to Protein

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2
Q

What are the three groups that make up an amino acid structure?

A

Amino group, carboxyl group and an R-group (side chain)

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3
Q

How are peptide bonds formed?

A

Carboxyl group reacting with the amino acid group from another amino acid.

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4
Q

Standard amino acids are encoded by ______

A

DNA

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5
Q

Nonstandard amino acids are synthesized by chemical modifications of ___________

A

Standard amino acids

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6
Q

21st proteinogenic amino acid - coded by a stop codon

A

Selenocysteine

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7
Q

What polar amino acids are positively charged? (Basic amino acids)

A

Histidine
Arginine
Lysine

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8
Q

What polar amino acids are negatively charged?

A

Aspartic Acid
Glutamic Acid

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9
Q

What non-polar amino acid contains a thio (-SH) group, important for disulfide bond formation?

A

Cysteine

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10
Q

What Secondary non-polar amino acid forms a rigid 5 ring aromatic structure- important in collagen formation in the body?

A

Proline

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11
Q

What non-polar amino acid has no side chain (only has an H)?

A

Glycine

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12
Q

What type of side chain has a net zero charge at physiological pH?

A

Polar

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13
Q

What type of side chain does not gain or lose protons or participate in H/Ionic bonding?

A

Non Polar

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14
Q

What two non-polar AA’s can lose a proton at alkaline pH?

A

Cysteine and Tyrosine

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15
Q

What polar amino acid has a side chain that can be either + or neutral charged and acts as a buffer?

A

Histidine

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16
Q

What 3 polar amino acids have a polar hydroxyl group?

A

Serine
Threonine
Tyrosine

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17
Q

What polar amino acids have a carbonyl group and an amine group? They also participate in H bonding.

A

Asparagine and Glutamine

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18
Q

At physiological pH, aspartic acid and glutamic acid have what charge?

A

Negative- fully ionized

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19
Q

At physiological pH, Histidine has what charge?

A

Positive- fully ionized

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20
Q

How do non-polar amino acids cluster in a soluble protein?

A

They cluster in the interior of the soluble protein

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21
Q

How do polar amino acids cluster in a soluble protein?

A

They cluster on the surface of soluble proteins

22
Q

How do non-polar amino acids cluster in membrane proteins?

A

They cluster on the surface of membrane proteins

23
Q

What are the 6 amino acid derivatives?

A

Tyrosine
Taurine
Tryptophan
Glutamate
Histidine
Lysine

24
Q

What amino acid derivative is responsible for thyroid hormones and dopamine?

A

Tyrosine

25
Q

What amino acid derivative is responsible for bile acids?

A

Taurine

26
Q

What amino acid derivative is responsible for GABA (inhibitory neurotransmitter)?

A

Glutamate

27
Q

What amino acid derivative is responsible for digestion, mood, sleeping, healing, etc.

A

Tryptophan

28
Q

What amino acid derivative is responsible for lipid oxidation?

A

Lysine

29
Q

What is the physiological relevance of the peptide hormone oxytocin? Where is it produced?

A

Uterine contractions and milk secretion, produced in hypothalamus

30
Q

What is the physiological relevance of the peptide ADH? Where is it produced?

A

Essential for maintenance of water balance, produced in hypothalamus

31
Q

What is the physiological relevance of the peptide Creatine?

A

Energy production in muscle and cardiac cells

32
Q

What is the physiological relevance of the peptide Bradykinin?

A

Vascoactivity (vasocontriction and vasodilation)

33
Q

What is the physiological relevance of the peptide angiotensin II?

A

It is a potent vasocontrictor

34
Q

What is the physiological relevance of the peptide melanin?

A

Pigment occurring in several tissues, synthesized from tyrosine via DOPA

35
Q

What is the physiological relevance of the polypeptide Gastrin?

A

Stomach hormone that stimulates secretion of the gastric glands

36
Q

What is the physiological relevance of the polypeptide Glucagon?

A

Stimulates glycogenolysis

37
Q

What is produced by alpha-cells in the pancreas?

A

Glucagon

38
Q

What is the physiological relevance of CCK?

A

It stimulates pancreas and liver secretions. (ie. bile)

39
Q

What is the physiological relevance of ANP?

A

It is essential for regulation of blood volume and blood pressure.

40
Q

Where is ANP produced?

A

Atrium of the heart

41
Q

What facilitates enzymatic hydrolysis?

A

HCl

42
Q

What is stimulated by gastrin?

A

HCl and pepsinogen secretion

43
Q

Where is pepsinogen secreted?

A

In the stomach

44
Q

True/False
Many amino acids are removed by the liver on “First Pass” (Hepatic Portal Circulation), and then are transported to system circulation.

A

False
They do NOT reach systemic circulation

45
Q

What happens to excess amino acids?

A

They are rapidly degraded

46
Q

What happens to most free ammonia?

A

It is used in the Urea cycle

47
Q

What is the most important route for disposing nitrogen from the body?

A

Urea Cycle

48
Q

What are the three steps to post-transcriptional modifications?

A
  1. Addition of a 5’ cap
  2. Splicing
  3. Additon of 3’ poly-adenylation tail
49
Q

What are the five steps in protein biosynthesis?

A
  1. Activation
  2. Initiation
  3. Elongation
  4. Termination
  5. Folding and PTM
50
Q

What are the three steps of elongation?

A
  1. Arrival - Binding to A-site
  2. Generation of peptide bond in P-site
  3. Movement to E-site (exit)