Chapter 2 Molecular Interactions Flashcards
Define an Atom
The smallest unit of matter is the element or ATOM
Atoms are the primary “building blocks”
What were the three primary components that make up an atom?
Protons, Neutrons and electrons
What is inside of the nucleus of an atom
Contains protons and neutrons.
The exception is hydrogen
Where are the electrons located?
Electrons occupy orbitals or shells outside the nucleus
What are the components that determine the nature of an atom?
Atomic mass: which is the sum of protons and neutrons in an atom
Atomic number: number of protons in an atom
What is an Isotope?
It’s a different atom of the same element. E.g. Carbon isotopes: 12C, 13C, and 14C
Isotopes have the same atomic number because the number of protons does not change. Isotopes differ in the number of NEUTRONS found in the nucleus.
How are Atoms Joined to others?
By three major types of bonds:
Covalent bonds
Ionic bonds
Hydrogen bonds
Van der Waals forces
Define Covalent bonds?
Arise when two atoms share an electron, this sharing of electron completes the outer shells of each and stabilizes the atoms
In non-polar covalent molecules, the atoms __________ __________ electrons?
In non-polar covalent molecules, the atoms EQUALLY SHARE electrons
E.g. Is methane
In polar covalent molecules, what type of sharing is taking place between electrons?
In polar covalent molecules, UNEQUAL sharing of electrons
E.g. Water
When electrons are shared unequally what happens between the atoms?
The stronger attraction for electrons develops a slightly negative charge (-)
The weaker atom with a weaker attraction for electrons develops a slightly positive charge
These are called polar molecules because they have positive and negative ends or poles?
Define Ionic Bonds?
Ionic bonds occur when valence electrons are transferred from on atom to another, forming charged ions
What are the two charged ions that are formed from transferring valence electrons?
Cation (+ charged)
Anion (- charged)
When molecules of opposite charges come close enough the charged ions attract. E.g. Na+ and Cl-
What is the easiest way to disrupt ionic bonds?
They are easily disrupted by water, as the ions interact with water molecules.
What type of bonds are Hydrogen bonds?
They are weak interactions between hydrogen and a nearby oxygen, or nitrogen or fluorine atom.
It’s a weak attractive force!
No electrons are gained, lost, or shared in a hydrogen bond
What Molecules are Associated with life called?
Molecules that contribute to life function are often called “Organic molecules”
What are organic molecules made of? Usually?
Usually made up of Carbon, hydrogen, and oxygen
What are the 4 major groups of organic molecules that are necessary for life function?
Carbohydrates
Lipids
Proteins
Nucleotides
What are carbohydrates primary functions?
Carbohydrates are often used as fuel sources
Carbohydrates can also combine with other macromolecules and thus serve a structural function
What are the 3 major carbohydrate groupings (based on structure)?
Monosaccharides (single sugar) e.g. Glucose, Galactose, Fructose
Dissacharides (two sugars combined) e.g. Lactose (Galactose+Glucose), Sucrose (Glucose+Fructose)
Polysaccharides (multiple sugars) e.g. Starches, glycogen
What are 4 different types of Lipids:
Triglycerides
Phospholipids
Cholesterol and its Derivatives
Eicosanoids
What is the common thing amount triglycerides?
Insolubility in water and they contain carbon, oxygen, and hydrogen
What is the common name for triglycerides and what is their structure made up of?
Also called FAT
Made up of a glycerol backbone and three fatty acids
Fatty acids in which carbons are joined with single covalent bonds are called?
Fatty acids that have either double or triple covalent bonds that exist in the fatty acid are called?
Saturated
Unsaturated
Phospholipids have similar structures to triglycerides. What are the similarities and differences?
Similar- Glycerol backbone
Different - two fatty acids
Different - The phosphate head is polar and hydrophilic and loves to interact with water.
What is the major functions of phospholipids?
Membrane structural component (in the plasma membrane, some organelles, and nuclear envelope
Fat emulsification during digestion
What is the major make up of the fatty acid tail of phospholipids?
The tail of the phospholipids is the non-polar (hydrophobic) portion.
Define Cholesterol?
Cholesterol is a lipid-related molecule containing three six-carbon rings and one five-carbon ring.
What is the job of cholesterol?
Cell membrane component
Bile salts are synthesized from cholesterol
Steroid hormones are synthesized from cholesterol
*steroids are derivatives of cholesterol
Define Eicosanoids?
It’s another group of lipids that are local signal molecules.
What is the basic structure of Eicosanoids?
Fatty acids with cyclic hydrocarbon group
All contain an open five-carbon ring and two tails
What are the major Eicosanoids?
Prostaglandins
Leukotrienes
Thromboxanes
What are the building blocks of Proteins?
Proteins are polymers of amino acids.
Where do amino acids come from and what are their properties?
Amino acids are encoded by our DNA
Each amino acid contains an amino group (NH2) and a carboxyl group (COOH)
How do amino acids differ from each other?
How do amino acid link together?
Amino acids differ according to the structures of the functional groups(R)
Amino acids link together via peptide bonds between the COOH and the amino group by a dehydration synthesis rxn
What are the functions of proteins?
The provide structure Act as enzymes Antibodies Signal Molecules Cell Membrane Receptors
What are the 4 structures of peptides and proteins?
Primary Structure- amino acid chain
Secondary structure- alpha - helix and beta strands that form sheets
Tertiary Structure - proteins three-dimensional shape (fibrous proteins collagen, and globular proteins)
Quaternary Structure- Multiple subunits combine with non-covalent bonds e.g. Hemoglobin 4 subunits.
How is a primary structure formed?
Encoded by an individual’s genetic expression
How are secondary structures formed
Induced by weak bonding within a polypeptide chain
- hydrogen bonds
- Van der Waals
How are tertiary structures formed and stabilized?
They are 3-D structures that are formed and stabilized by weak bonds between functional groups
They are also stabilized by stron covalent bods between sulfide residues
How are Tertiary structures denatured?
Heat and pH
Quaternary Structure is known as?
Multi-subunit association
What are combination molecules?
Many proteins can be combined with other macromolecules
Glycoproteins contain:
Carbohydrates
Lipoproteins contain:
Lipids
A Nucleic Acid is composed of?
Nitrogenous base - Purines & Pyrimidines
Sugar - either Ribose, or Deoxyribose
One to three phosphate groups
Define Purines:
They are two-ringed structures
- Adenine
- Guanine
Define Pyrimidines
They are single-ringed structure
- Cytosine
- Thymine (DNA)
- Uracil (RNA)
What bases form base pairs in DNA and RNA?
What types of bonds are formed?
Guanine forms a triple hydrogen bond with cytosine in DNA
Adenine forms a double hydrogen bond with Thymine in DNA
Adenine forms a double hydrogen bond with Uracil in RNA
What are the components of a Nucleotide?
A nucleotide consists of (1) one or more phosphate groups, (2) a 5-carbon sugar, and (3) a carbon-nitrogen ring structure called a nitrogenous base.
Describe Deoxyribonucleic Acid DNA
Contains genetic code
The sugar base is a deoxyribose
It has 4 bases that make up the double helix, which are bonded with H-bonds
G-C
A-T
Define and explain Ribonucleic Acid (RNA)
Consists of Ribose sugar
It’s single stranded
Has 4 bases:
G-C
A-U
What are the three types of RNA
- mRNA (messenger RNA)
- tRNA (transfer RNA)
- rRNA (ribosomal RNA)
