Chemistry Lecture 5 Flashcards
Phospholipids:
- Structural components of cellular membranes.
- Amphipathic, containing both hydrophilic (polar) and hydrophobic (non-polar) regions.
- Composed of glycerol, two fatty acids, and a phosphate group.
- Form lipid bilayers in aqueous environments, facilitating selective permeability.
Steroids:
- Consist of four rings of carbon.
- Examples include cholesterol, estrogen, testosterone, and cortisol.
- Roles: structural integrity of cell membranes, hormone precursor, and regulation of metabolism.
- Insertion into plasma membranes alters fluidity and strengthens the membrane.
Eicosanoids:
- Oxidized derivatives of 20-carbon polyunsaturated fatty acids, such as arachidonic acid.
- Include prostaglandins (PGs) and leukotrienes (LTs).
- Functions: regulation of inflammatory responses, blood clotting, and bronchiole dilation.
- Commonly targeted by medications like aspirin and ibuprofen.
Other Lipids:
Carotenes: Precursors to vitamin A, found in vegetables like carrots.
Vitamin E: Tissue healing and antioxidant.
Vitamin K: Essential for blood clot formation.
Lipoproteins:Carriers of cholesterol and triglycerides in the bloodstream.
Lipoproteins:
Composed of fats (lipids) and proteins.
Transport cholesterol and triglycerides in the blood.
Types: HDL, LDL, VLDL, IDL, and chylomicrons.
HDL: “Good cholesterol” that removes cholesterol from the bloodstream.
LDL: “Bad cholesterol” that can deposit in arteries, leading to atherosclerosis.
VLDL: Another type of “bad cholesterol” that carries triglycerides.
IDL: Intermediate between VLDL and LDL.
Chylomicrons: Large lipoproteins that transport dietary fats through the blood.
Proteins:
Polymers made up of amino acid monomers.
Range from two to several thousand amino acids.
Essential for the structure, function, and regulation of cells and tissues.
Structural Proteins:
Roles: Key role in the formation and framework of different cells and tissues.
Example: Keratin in skin, hair, and nails.
Regulatory Proteins:
Roles: Function as key parts of the structure of hormones.
Examples: Insulin and glucagon.
Contractile Proteins:
Roles: Form filaments in muscles and cellular components, allowing muscles and cells to contract.
Examples: Actin and myosin in muscle cells.
Immunological Proteins:
Roles: Form key parts of immunological cells like white blood cells and antibodies.
Transport Proteins
Roles: Form key components of red blood cells and membrane structures of certain cells.
Example: Hemoglobin in red blood cells carries oxygen and carbon dioxide.
Catalytic Proteins (Enzymes
Roles: Lower activation energy and accelerate chemical reactions in the body.
Examples: Digestive enzymes like amylase, lipase, and protease.
Peptide Bonds:
- Formed by two amino acids joining together through dehydration synthesis.
- Covalent bonds between the amino group of one amino acid and the carboxyl group of another.
- Can be broken via hydrolysis reactions.
Primary Structure:
- Unique sequence of amino acids in a polypeptide chain.
- Determines the protein’s overall structure and function.
Secondary Structure:
- Repeated twisting of neighboring amino acids.
- Can form alpha-helices or beta-pleated sheets.
- Stabilized by hydrogen bonds.
Tertiary Structure
- 3D arrangement of the polypeptide chain.
- Results from interactions between R-groups (side chains).
- Stabilized by various forces including hydrogen bonds, ionic bonds, disulfide bonds, and hydrophobic interactions.
Quaternary Structure
- Arrangement of multiple polypeptide chains.
- Forms a complex with distinct functions.
- Stabilized by the same forces as tertiary structure.
Nucleic Acids:
- Biomolecules essential for storing and transmitting genetic information.
- Composed of nucleotide monomers.
- Include DNA and RNA.
Pentose Sugar:
- 5-carbon sugar that forms the backbone of nucleic acids.
- Deoxyribose in DNA and ribose in RNA.
Nitrogenous Bases
Heterocyclic bases that pair in DNA and RNA.
In DNA: Adenine, Thymine, Cytosine, Guanine.
In RNA: Adenine, Uracil, Cytosine, Guanine.
Base pairing: A-T (DNA), A-U (RNA), G-C (both).
Deoxyribonucleic Acid (DNA)
- Double-stranded helical molecule.
- Genetic material found in nearly all living organisms.
- Comprises nucleotides of deoxyribose sugar, phosphate group, and nitrogenous bases.
Ribonucleic Acid (RNA):
- Single-stranded molecule involved in various cellular processes.
- Comprises nucleotides of ribose sugar, phosphate group, and nitrogenous bases.
- Types: mRNA, tRNA, rRNA.
Adenosine Triphosphate (ATP)
- Energy currency of the cell.
- Comprised of adenine, ribose sugar, and three phosphate groups.
- High-energy bonds between phosphates store energy.
- Hydrolysis of ATP releases energy for cellular work.
