Macromolecules Flashcards

0
Q

Definition of macromolecules

A

Large organics polymers built from monomers.

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1
Q

What are the 4 classes of macromolecules?

A
  1. Carbohydrates
  2. Lipids
  3. Proteins
  4. Nucleic acids.
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2
Q

Formation of macromolecules

A
  • Dehydration (condensation) reaction: 2 monomers connected by loss of water.
  • When taking in, must be broken down by hydrolysis.
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3
Q

Types of carbohydrates (3)

A
  • Monosaccharides
  • Disaccharides
  • Polysaccharides
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4
Q

Monosaccharides (6)

A
  • Contain C,H,O
  • Comprised of a carbonyl group & hydroxyl groups.
  • Carbon backbone varies from 3 to 7 (numbering starts with carbonyl group as lowest)
  • Found in ring structures in aqueous solutions
  • Produced by CO2, H2O & sunlight (photosynthesis)
  • Alpha/Beta glucose (same/diff. sides)
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5
Q

Disaccharides

A

Two monomers connected by a glycosidic linkage.
Examples:
Maltose = glucose + glucose
Sucrose = glucose + fructose

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6
Q

Polysaccharides

A
  • Few hundred/thousand monosaccharides linked together.
  • Energy storage
  • Structural support
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7
Q

Energy storing polysaccharides (2)

A
  • Starch: alpha glucose, helical polymer, found in plants.

- Glycogen: branched starch, found in animals

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8
Q

Structural support polysaccharides (2)

A
  • Cellulose: beta glucose, can’t be digested by animals (while starch can), since they lack enzyme to digest b-glycosidic linkages.
  • Chitin: exoskeleton of arthropods, the monosaccharides are amino sugars.
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9
Q

Lipid solubility

A

Insoluble in water, soluble in non polar solvents

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10
Q

3 groups of lipids

A

Fats (storage compound)
Phospholipids (major component of cell membranes)
Steroids (eg. cholesterol, hormones, and bile acids)

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11
Q

Structure of fats

A

Glycerol and a fatty acid (has a carboxylic)

Glycerol is a 3-carbon alcohol.

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12
Q

Structure of fatty acids (in fats)

A
  • Long hydrocarbon chain containing a carboxyl group at one end.
  • Associate with each other and not water.
  • Saturated/Unsaturated
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13
Q

Saturated/unsaturated fatty acid

A

Unsaturated: double bonds, can cause a kink in the backbone, do not pack tightly together (plant fats).
Saturated: no carbon-carbon double bonds, can pack tightly together, solid at room temperature (eg. animal fat)

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14
Q

Formation of fats

A
  • Condensation (dehydration) reaction.
  • Fatty acids linked to glycerol by an ester linkage.
  • Triglycerides: 3 fatty acids bonded to one glycerol.
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15
Q

Composition of phospholipids

A

Glycerol, 2 fatty acids, 1 phosphate group, and 1 additional polar group.

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16
Q

What is special about phospholipids?

A

Are amphipathic molecules: head group is hydrophilic, carbon chain is hydrophobic.
(make up cell membrane)

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17
Q

Phospholipids in water

A

Self assemble into aggregates (micelles), hydrophobic hydrocarbons chains shielded from water.

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18
Q

Phospholipids on cell surface

A

Form a lipid bilayer, hydrophilic head group in contact with aqueous environment, hydrophobic tails point towards each other (shielded)

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19
Q

Steroids

A
  • Characterized by a carbon skeleton consisting of four fused rings.
  • Cholesterol: cell membrane, starting compound for other steroids.
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20
Q

What do proteins consist of?

A

One or more polypeptide chains.

Polypeptides are polymers of amino acids (linked by peptide bonds)

21
Q

Functions of proteins (7)

A
  1. Structural support (collagen in animal connective tissue)
  2. Transport (hemoglobin, Na, K-ATPase)
  3. Hormonal (insulin-regulates glucose in the blood)
  4. Receptor (detect chemical signals released by other cells)
  5. Movements (actin and myosin)
  6. Defensive (antibodies)
  7. Enzymatic (accelerate chemical reactions in the body)
22
Q

Monomer of proteins

A

Amino acids (20), polymers of these are called polypeptides (a protein is composed of one or more of these)

23
Q

Structure of amino acids

A
  • Four components attached to central carbon atoms (alpha carbon)
  • Three ionic states: acidic, physiological, basic.
  • picture*
24
Q

Grouping of amino acids

A
  1. Hydrophobic: non-polar side chains

2. Hydrophilic: uncharged/polar. charged: acidic groups (often carboxylic groups), basic groups (amino groups)

25
Q

Making a polypeptide

A
  • Formed when amino acids are linked by a peptide bond.
  • Carboxyl group of one amino acid is linked to the amino group of another.
  • Condensation reaction: n-terminus, pep. bond, c-terminus.
26
Q

Characteristics of a polypeptide

A
  • Length: a few amino acids to thousands.
  • Each has a unique linear sequence of amino acids.
  • Each has a unique isoelectric point at which there is no charge.
  • NH2, COOH influence isoelectric point if they are in the R group.
27
Q

What are the four levels of protein structure?

A

Primary, secondary, tertiary, & quaternary.

28
Q

Primary sequence of protein structure

A
  • Linear sequence of amino acids

- Determined by the DNA sequence

29
Q

Secondary sequence of protein structure

A

Spatial arrangement of amino acids close to each other, R group does not influence

  1. alpha helix: H-bonding between amino acid residues, located 4 places apart.
  2. beta-pleated sheets: two regions of the polypeptide chain lie parallel to each other, stabilized by H bonds between C=O & HN groups of the peptide backbone. side chains are not involved.
30
Q

Tertiary structure of proteins:

A
  • Irregular contortions of the polypeptide due to bonding of amino acid side chains.
  • Types of bonds that contribute to the tertiary structure:
    1. Weak interactions: H-bonds, ionic bonds between side chains (salt bridges), hydrophobic interaction between non polar side chains.
31
Q

Quaternary structure

A
  • When two or more polypeptides join to form a protein.
  • Held together by the same forces as tertiary.
  • Examples: collagen (3 helical polypeptides into a triple helix), hemoglobin (globular protein that is comprised of 4 subunits), NaATPase (integral membrane protein comprised of 2-3 subunits)
  • Denaturation
32
Q

Conditions that alter the conformation of a protein (5)

A
Temperature
pH
Salts
Detergents/organics solvents
Reduction agent
33
Q

Temperature affecting protein structure

A

Increase in temperature, increase in kinetic energy and peptide movement. This overcomes weak interactions that stabilize protein conformation.

34
Q

pH’s effects on the conformation of a protein.

A

Changes in the ionic state of ionizable side chains.

picture

35
Q

Effect of salts on protein configuration

A

Changes the ionic environment and disrupts the bonds.

36
Q

Effects of detergents/organic solvents on protein conformation

A

Hydrophobic, so disrupt hydrophobic interactions (flip inside out). Hydrophobic side chains move from the interior of the protein towards the outside (and hydrophilic does the opposite)

37
Q

Effects of reduction agents on protein conformation

A

They break disulfide bonds

38
Q

Types of polymers of nucleic acids (2)

A
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
39
Q

Deoxyribonucleic acid

A
  • Genetic material (passed on from one generation to the next)
  • Contains genes which code for protein synthesis
  • Double stranded
40
Q

Ribonucleic acid (RNA)

A
  • Function in the synthesis of proteins

- Single stranded

41
Q

Types of ribonucleic acid (RNA)

A
Ribosomal RNA (mRNA) 
Transfer RNA (tRNA)
Messenger RNA (mRNA)
42
Q

Structure of DNA & RNA

A

Polymers of nucleotides liked together by a phosphodiester bond.

43
Q

Nucleotides are comprised of (3)

A
  1. Nitrogen containing base (pyrimidine/purine)
  2. Pentose sugar
  3. Phosphate group
44
Q

Pyrimidines vs. purines

A
  • Pyrimidine: six-membered ring made of carbon & nitrogen. cytosine & thymine/uracil
  • Purine: five-membered ring fused to a six-membered ring. adenine & guanine.
45
Q

Pentose sugar

A

5 carbon backbone

  • RNA: ribose
  • DNA: deoxyribose (lacks an oxygen on carbon 2)
46
Q

DNA structure

A
  • Two polymers of deoxynucleotides, formed by linking phosphate of one nucleotide to sugar of the next.
  • Double helix: polyonucleotide chains oriented in an antiparallel fashion. Held together by H-bonds between bases on the two chains
47
Q

Base pairing

A
Adenine-Thymine/Uracil (2 H-bonds)
Guanine-Cytosine (3 H-bonds)
-The two strands are complimentary
-Sugar phosphate backbone forms the outside of helix
-Base pairs are in the center
48
Q

Prokaryotic vs. Eukaryotic

A

Both are double stranded

  • Prokaryotic: circular, smaller, not in a nucleus, less structured and folded.
  • Eukaryotic: linear, complex with large amount of proteins (forms chromatin)
49
Q

Chromatin

A

DNA wound around histones (small proteins, rich in positively charged amino acids arginine and lysine. bound tightly to negatively charged DNA)