BIOCHEM_MODULE 3.1_PROTEINS
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Considered as the MOST ABUNDANT molecules in the cells after water

PROTEINS

Are naturally occurring, unbranched polymer in which the monomer units are Amino Acids

PROTEINS

Monomer unit of proteins

AMINO ACIDS

Elemental Composition of Protein

<p>CARBON, HYDROGEN, OXYGEN, NITROGEN, SULFUR</p> Signup and view all the answers

Protein is Needed for the synthesis of _______, certain ________ & some blood components

<p>ENZYMES, HORMONES</p> Signup and view all the answers

Aids in the maintenance and repair of existing tissues

<p>PROTEINS</p> Signup and view all the answers

An organic compound that contains both an Amino & a Carboxyl group

<p>AMINO ACIDS</p> Signup and view all the answers

An amino acid in which the amino group and the carboxyl group are attached to the Alpha Carbon Atom

<p>ALPHA AMINO ACIDS</p> Signup and view all the answers

Alpha Amino Acid in which the amino group and the carboxyl group are attached to the _________

<p>ALPHA CARBON ATOM</p> Signup and view all the answers

The nature of the side-chain distinguishes alpha amino acids from each other, both physically and chemically

<p>ALPHA AMINO ACID</p> Signup and view all the answers

Contain one amino group , one carboxyl group, and a non-polar side chain

<p>NON-POLAR AMINO ACIDS</p> Signup and view all the answers

Non-Polar Amino Acids are generally found in the __________

<p>INTERIOR OF PROTEINS</p> Signup and view all the answers

An amino acid that contains one amino group, one carboxyl group, and a side chain that is polar but neutral

<p>POLAR NEUTRAL AMINO ACIDS</p> Signup and view all the answers

The side chain of a polar neutral amino acid is neither ______________

<p>NEITHER ACIDIC NOR BASIC (STATE OF EQUILIBRIUM)</p> Signup and view all the answers

An amino acid that contains one amino group and two carboxyl group, the second carboxyl group being part of the side chain.

<p>POLAR ACIDIC AMINO ACIDS</p> Signup and view all the answers

The side chain of a polar acidic amino acid bears a ______________

<p>NEGATIVE CHARGE</p> Signup and view all the answers

An amino acid that contains two amino and one carboxyl group, the second amino group being part of the side chain.

<p>POLAR BASIC AMINO ACIDS</p> Signup and view all the answers

The side chain of a polar basic amino acid bears a _____________

<p>POSITIVE (+) CHARGE</p> Signup and view all the answers

A standard amino acid needed for protein synthesis that must be obtained from dietary sources because the human body cannot synthesize it in adequate amounts from other substances

<p>ESSENTIAL AMINO ACIDS</p> Signup and view all the answers

Essential Amino Acids (Enumerate)

<p>Phenylalanine, Valine, Tryptophan Threonine, Isoleucine, Methionine Histidine, Arginine, Lysine, Leucine</p> Signup and view all the answers

Basic Amino Acids

<p>Histidine, Arginine, Lysine</p> Signup and view all the answers

Ketogenic Amino Acids

<p>Lysine, Leucine</p> Signup and view all the answers

Branched-Chain Amino Acids

<p>Leucine, Isoleucine, Valine</p> Signup and view all the answers

_________ is required for growth in children but is not an essential amino acid for adults.

<p>ARGININE</p> Signup and view all the answers

Four different groups are attached to the a- carbon atom in all of the standard amino acids except glycine, where the R group is a hydrogen atom.

<p>CHIRALITY OF AMINO ACIDS</p> Signup and view all the answers

For the Chirality of Amino Acids. ____________ are attached to the a- carbon atom in all of the standard amino acids except _____, where the R group is a ________ atom.

<p>4 DIFFERENT GROUPS, GLYCINE, HYDROGEN</p> Signup and view all the answers

________, the simplest of the standard amino acids, is achiral. All of the other standard amino acids are chiral.

<p>GLYCINE</p> Signup and view all the answers

Acid-base properties of amino acids. Both an ________ and a ________ are present on the same carbon in an a-amino acid.

<p>ACIDIC GROUP (-COOH) BASIC GROUP (-NH2)</p> Signup and view all the answers

Amino Acid. In neutral solution, carboxyl groups have a tendency to ________, producing a _______ charged species

<p>LOSE PROTONS, NEGATIVELY (-)</p> Signup and view all the answers

Amino Acids. In neutral solution, amino groups have a tendency to ________, producing a _______ charged species

<p>ACCEPT PROTONS, POSITIVELY (+)</p> Signup and view all the answers

Ionized form of amino acids

<p>ZWITTERION (ZWITTERIONIC FORM)</p> Signup and view all the answers

A molecule that has a positive charge on one atom and a negative charge on another atom, but which has _________

<p>NO NET CHARGE (0/NEUTRAL)</p> Signup and view all the answers

In an _____ solution, the zwitterion accepts a proton to form a ________ charged ion

<p>ACIDIC, POSITIVE (+)</p> Signup and view all the answers

In basic solution, the ____ of the zwitterion loses a proton, and a ________ species is formed

<p>NH3 (amino group), NEGATIVE (-)</p> Signup and view all the answers

The pH at which an amino acid exists primarily

<p>ISOELECTRICPOINT</p> Signup and view all the answers

At the isoelectric point, almost all amino acid molecules in a solution are present in their _________.

<p>ZWITTERION FORM</p> Signup and view all the answers

Chain of covalently linked amino acids

<p>PEPTIDES</p> Signup and view all the answers

Unbranched Chain of Amino Acids (Linear)

<p>PEPTIDES</p> Signup and view all the answers

contains 2 AAs

<p>DIPEPTIDE</p> Signup and view all the answers

3 AAs joined together in a chain

<p>TRIPEPTIDE</p> Signup and view all the answers

contain 10-20 AA residues

<p>OLIGOPEPTIDE</p> Signup and view all the answers

longer chain compared to Oligopeptide

<p>POLYPEPTIDE</p> Signup and view all the answers

A covalent bond between the carboxyl group of one amino acid and the amino group of another amino acid.

<p>PEPTIDE BOND</p> Signup and view all the answers

Link Amino Acids Together

<p>PEPTIDE BOND</p> Signup and view all the answers

N - terminal: end with the free _____ group

<p>AMINO</p> Signup and view all the answers

C - terminal: end with the free _______ group

<p>CARBOXYL</p> Signup and view all the answers

Portion of an amino acid structure that remains, after the release of H2O, when an amino acid participates in peptide bond formation as it becomes part of a peptide chain.

<p>AMINO ACID RESIDUES</p> Signup and view all the answers

Peptide Hormones

<p>Oxytocin, Vasopressin</p> Signup and view all the answers

Peptide Neurotransmitters

<p>Enkephalins</p> Signup and view all the answers

Peptide Antioxidants

<p>Glutathione</p> Signup and view all the answers

Regulates uterine contractions and lactations

Plays a role in simulating the flow of milk in a nursing mother

<p>OXYTOCIN</p> Signup and view all the answers

regulates the excretion of water by the kidneys

can also affect blood pressure

also known as Antidiuretic Hormone (ADH)

<p>VASOPRESSIN</p> Signup and view all the answers

are peptide neurotransmitters produced by the brain and bind at receptor sites within the brain

Help reduce pain

<p>ENKEPHALINS</p> Signup and view all the answers

Best known enkephalins

<p>METenkephalin: Tyr-GlyGly-Phe-Met LEUenkephalin: TyrGly- Gly-Phe-Leu</p> Signup and view all the answers

A tripeptide is present n high levels in most cells

Regulator of oxidation and reduction reaction

An antioxidant and protects cellular contents from oxidizing agents

<p>GLUTATHIONE</p> Signup and view all the answers

Study Notes

Proteins and Amino Acids

  • Proteins are the most abundant molecules in cells after water.
  • They are unbranched polymers composed of amino acids as monomer units.
  • Proteins are essential for synthesizing hormones, certain enzymes, and blood components.
  • They aid in tissue maintenance and repair.

Structure and Composition

  • Proteins consist of an amino group and a carboxyl group attached to the alpha carbon atom.
  • Alpha amino acids differentiate from one another through the nature of their side chains.
  • Non-polar amino acids are typically found in hydrophobic environments.
  • Polar neutral amino acids have side chains that are neither acidic nor basic.
  • Polar acidic amino acids contain one amino group and two carboxyl groups; their side chains bear a negative charge.
  • Polar basic amino acids consist of two amino groups and one carboxyl group, with positively charged side chains.

Essential Amino Acids

  • Essential amino acids cannot be synthesized by the body and must be obtained through diet.
  • They play vital roles in protein synthesis and overall health.
  • Basic amino acids include lysine, arginine, and histidine.
  • Ketogenic amino acids can be converted into ketone bodies.
  • Branched-chain amino acids such as leucine, isoleucine, and valine are crucial for muscle metabolism.

Chirality and Ionization

  • The alpha carbon of standard amino acids has four different groups attached, creating chirality, except in glycine where the R group is a hydrogen atom.
  • In neutral solutions, carboxyl groups tend to lose protons, leading to a negative charge, while amino groups gain protons, resulting in a positive charge.
  • Zwitterions have both a positive and a negative charge but are electrically neutral overall.

Isoelectric Point and Peptide Bonds

  • The isoelectric point is where the amino acid primarily exists in a neutral charged form.
  • Amino acids can form chains called polypeptides through peptide bonds, linking the carboxyl group of one amino acid to the amino group of another.
  • N-terminal refers to the free amino group, and C-terminal refers to the free carboxyl group of the peptide chain.

Peptide Functions

  • Peptides can function as hormones, neurotransmitters, and antioxidants.
  • Oxytocin regulates uterine contractions, lactation, and milk flow.
  • Antidiuretic Hormone (ADH) regulates water excretion by kidneys and can influence blood pressure.
  • Enkephalins, known as pain-reducing neurotransmitters, are tripeptides abundant in cells.
  • Certain peptides act as antioxidants, protecting cellular components from oxidative damage.

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Description

This quiz explores the fundamental nature of proteins, which are naturally occurring, unbranched polymers composed of amino acids. Test your understanding of their structure, function, and role in biological processes through a series of questions.

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