Biology 1 Chapter 5 (Lecture) Flashcards
Critically important molecules of all living things fall into 4 main classes:
1) CHO
2) Lipids
3) Proteins
4) Nucleic Acids
Macromolecules
1) CHO
2) Proteins
3) Nucleic Acids
Polymers
Long molecule consisiting of many similar or identical building blocks linked by covalent bonds.
Monomers
The building blocks of polymers; the repeating unit of smaller molecules.
Dehyrdation Reaction
A reaction in which two molecules are COVALENTLY BONDED to each other through the loss of a water molecule. (Also called a CONDENSATION REACTION)
Enzymes
Specialized macromolecules to speed up chemical reactions in cells. (Chemical agents that slectively speed reactions without being consumed by the reaction.)
Hydrolysis
Process that disassembles polymers. It is essentially the reverse of dehydration.
Carbohydrates include…
Sugars and polymers of sugars.
Monosaccharides
The simplest carbohydrates.
Disaccharides
Double sugars. Formed by covalent bonds (glycsidic linkage)
Trademark of Sugar
Carbonyl and multiple Hydroxyl groups
Glucose
The most important sugar and is an aldose.
Carbon skeleton
3-7 carbons long.
Glucose & Fructose
Examples of hexoses.
Diasscharides
Joined by glycosidic linkages which is a covalent bond formed by a dehydration reaction. (Most common diasscharide is sucrose [glucose & fructose])
Polysaccharides
Polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages.
Polysaccharides are important for…
1) Storage of sugar
2) Building material for structures that protect the cell or whole organism.
Storage Polysaccharides
1) Plants: Starch
2) Animals: Glycogen- Stored in liver & muscle cells. (Glycogen is polymer of glucose) (Our storage is depleted in 1 Day unless replenished by CHO)
Structural Polysaccharides
1) Cellulose
2) Chitin
Humans don’t have
***Cell Walls***
Cellulose
Polymer of glucose, but different glycoside linkages than in starch
- Major component of cell wall in plants
- Most abundant organic compund on earth
- Major constituent of Paper
- Only component of Cotton
- Few organisms possess enzymes that can digest cellulose
- Humans cannot digest cellulose
- Not a nutrient for humans, but part of a healthy diet
- Whole grains, veg, etc rich in celluluose
- “Insoluble fiber” on food packages is actually cellulose
- Some prokaryotes can digest cellulose
- Cows and termites have prokaryotes doing it for them.
Chitin
A structural polysaccharide
- Used by spiders, insects, etc to make their exoskeletons
- In cell wall of many fungi
- Used to make strong and flexible surgical thread
Lipids
- Not big enough to be considered macromolecules
- All share one important trait: mix poorly, if at all with water
- Three classes of lipids:
- Fats
- Phospholipids
- Steroids
Fats
Constructed from glycerol & 3 fatty acids
Triacylglycerol (aka griglyceride) is 3 fatty acid linked to one glycerol molecule
Two classifications: Saturated & Unsaturated
Have Ester Linkages
Saturated Fats
At room temperature are solid (e.g. butter) the molecule is fully saturated with hydrogen; there are no double bonds
Unsaturated Fats
At room temperature are liquid (veg oil) cannot pack together closely enough to solidify because of kinds in some of their fatty acids hydrocarbon chain; not saturated with H; therefore have one or more double bonds
Hydrogenated Vegetable Oil
Unsaturated fats have been synthetically to saturate fats by adding H (Ex: peanut butter & margarine); they are hydrogenated to prevent lipids from separating out in oil form.
Atherosclerosis
A diet rich in staurated fats can lead to this heart disease.
Major Function of Fats
- Energy storage in adipose cells for humans
- Cushions vital organs
- Insulates the body
Phospholipids
- Make up cell membranes
- 2 fatty acids attached to glycerol; third fatty acid attached to phospate group
- Hydrogen carbon tails: Hydrophobic- excluded from water
- Phosphate head is hydrophilic which attracts them to water.
Steriods
Lipids are charaterized by C skeleton of four fused rings.
-
Cholesterol is the precursor from which other steroids are synthesized
- Synthesized in liver
- Many hormones including sex hormones are steroids which are produced from cholseterol
What is not a macromolecule?
Cholesterol
Proteins
50% dry mass of most cells
Enzymes are proteins.
A protein is one or more polypeptide each folded and coiled into a specific 3D structure.
Polypeptides
Polymers of amino acids. All proteins are constructed from the same set of 20 aminop acids.
Amino Acids
All have carboxyl group (COOH abd Amino Group)
- All amino acid used in protein are the same encantiomer (L form)
- Some are polar; some non polar
- Some acidic; some basic (this refers only to groups on the side chains)
Peptide bond
Covalent bonds formed by dehydration which link COOH group of one amino acid to the amino group (NH2) of the next to connect amino acids. (Peptide bonds link Amino Acid)
Functional Protein
Not just a polypeptide chain. It is one or more polypeptide precisely twisted, folded, and coiled into a molecule of unique shape. A polypeptide is not synonymous with a protein.
A protein specific structure determines how it…
Functions
Protein Structures
- Primary: Unique sequence of amino acids determined by its inherited genetic information
- Secondary: segments of polypeptide chain that are coiled and folded; there is a reaction between the backbone constituents
- Tertiary: overall shape resulting from interactions of side chains of the various amino acid groups.
- Quaternary: Overall protein structure that results from aggregation of polypeptide subunits.
Denatured
Protein unravels and loses its native shape due to a change in pH, salt concentration, temperature, or certain chemicals. A denatured protein is biologically inactive.
Excessively High Fevers
Can be fatal; proteins in the blood can denature at very high body temperature.
A slight change in primary struture
Can affect a protein’s structure and abilitty to function (one amino acid)
Sickle-Cell Disease
An inherited blood disorder, results from a single amino acid substitution in the protein hemoglobin.
Nucleic Acids
Two types: DNA and RNA which enable organisms to reproduce their components from one generation to the next.
DNA
Directions for its own replications; also directs mRNA synthesis.
- DNA is the gentic material that organisms inherit from their parents
- Each chromosome contains one long DNA molecule, usually carrying several hundred or more genes. DNA molecules are copied and passed along; in DNA is information that programs all the cell’s activites. Each gene along DNA molecules direct synthesis of mRNA
- mRNA driects production of polypeptides
- ***DNA→RNA→Proteins*** (flow of information in eukaryotic cells)
- Site of protein synthesis in the ribosome which are in the cytoplasm.
Struecture of Nucleic Acids
- Polynucleotides are polymers consisting of monomers called nucleotides.
- Each Nucleotide contains a nucleoside (Nitrogenous base and 5 carbon sugars) and a Phosphate Group.
- Nitrogenous Base
- Sugar: Ribose sugar in RNA; Deoxyribose sugar in DNA
Nitrogenous Bases
- DNA
- Adenosine
- Guanine
- Cytosine
- Thymine*
- RNA
- Adenosine
- Guanine
- Cytosine
- Uracil*
Nucleic Sugars
Ribose: RNA
Deoxyribose: DNA
DNA strand built in directionality along the sugar phophates backbone somewhat like a oneway street; along the backbone ther are appendages consisting of nitrogen bases. Gene’s meaning is encoded into specific sequence of DNA bases.
DNA Double Helix
- RNA has single polynucleotide chair
- DNA: 2 polynucleotide chains has a spiral forming a double helix
Watson & Crick
Proposed a double helix as a 3D structure DNA in 1954 to two sugar phosphate backbone that run in opposite 5’ → 3’ direction from each other
- Antiparallel- like divided highway
- Sugar phosphate backbone- outside of helix
- Nitrogen bases airs- in interior of the helix
- The two strands held together by H bonds between paired bases
A pairs with
T
G pairs with
C
5’ ACCTCCG 3’
3’ TGGAGGC 5’
The two strands are
Complemenary and perticable counter part of the other
Insoluble fiber
Cellulose
Starch
Plants
Glycogen
Animals
Thalildomide
Helps with nausea.
Caused birth defects in babies that the mother took this drug for morning sickness.
What has ester linkages
Fats
