Learn: Phys & PathoPhys Exam 1 | Quizlet

Nucleotide

Composed of a nitrogen base, pentose sugar (5C), and phosphate group

Nucleoside

A nitrogenous base + sugar

Essential amino acids

Amino acids that must come from the diet

Non-essential amino acids

Amino acids that are naturally produced by the body

Conditionally essential amino acid

An amino acid that requires the presence of an essential amino acid to be made

Animal amino acids vs plant amino acids

Amino acid ratios in animals are very similar to ours, making animals a better source of amino acids than plants

Monosaccharides

Simple sugar units that are the main source of energy for the body (ex, glucose)

Disaccharides

Carbohydrates used to transport monosaccharides

Oligosaccharides

Carbohydrates composed of 3-14 sugar units, used for glycosylation

Polysaccharides / Complex carbohydrates

Carbohydrates with 14+ sugar units (made of homo or hetero sugars) used for storage (starch in plants, glycogen in humans)

Fatty acids

Composed of a free, hydrophobic hydrocarbon chain and a carboxylic acid, typically containing 16-18 carbons

Structural elements of DNA and RNA

C, O, H, N, and P

Purines in DNA and RNA

Adenine, guanine, and hypoxanthine

Pyrimidines in DNA and RNA

Cytosine, thymine, and uracil

Hypoxanthine

A modified purine (inosine) that is present in tRNA

Deoxyribose vs Ribose

Deoxyribose (found in DNA) has an H at the C2 position, while ribose (found in RNA) has an OH at C2

DNA backbone bond

Phosphodiester bonds

DNA complementary base pairing

Strands are antiparallel, held together by hydrogen bonds (A = T, and G-C which has three hydrogen bonds)

Grooves of DNA

Minor and major grooves that allow for proteins to bind

Mature mRNA components

A 5' guanine cap, a 3' polyA tail, and introns removed

5' guanine cap

Has an extra methyl group and is put on backwards; not recognized by enzymes, tells the ribosome where to start translation

3' poly A tail

Composed of ~250 Adenines; broken down slowly, and once reached, tells the cell the mRNA has replicated enough and can be destroyed

Non-functional protein structures

Primary (amino acid sequence) and secondary (held together by hydrogen bonds, alpha helices/beta sheets)

Functional protein structures

Tertiary (three-dimensional) and quaternary (three-dimensional made of multiple subunits)

Protein secretory pathway

Proteins are made in the endoplasmic reticulum (ER) and can stay there or go to the Golgi apparatus (GA), lysosome, plasma membrane, or be excreted via a secretory vessel

Phosphorylation

Reversible (transient) addition of a phosphate group to serine, threonine, or tyrosine to change shape and function

Lipidation

Attaches a lipid, such as a fatty acid, to a protein chain to bind the protein to the cell membrane

Glycosylation

Attaches a sugar, usually to an "N" or "O" atom in an amino acid side chain, sticking the sugar outwards to make the molecule more soluble

Ubiquitination

Addition of 4-7 ubiquitin molecules to a lysine residue of a target protein, marking it for destruction

Acetylation

Reversible (transient) addition of an acetyl group to the N terminal of a protein to increase stability, changing shape and function

Methylation of proteins

Post-translational modification occurring if only one carbon is added

Disulfide bonds

Covalently links the "S" atoms of two different cysteine residues to stabilize protein structures

Phospholipids:

Amphipathic lipids (both hydrophilic and hydrophobic) that make up the cell membrane and form the lipid bilayer

Cholesterol

A flat lipid that integrates into the cell membrane to control fluidity (making it rigid when warm, loose when cold), and acts as a precursor for steroids and vitamin D

Triglycerides

Lipids important for fat storage and transport

Chylomicrons

Lipoproteins that move fat from the small intestine through the lymphatic system and bloodstream into tissues

Capillary lipid breakdown

Lipids are converted to fatty acids and glycerol in capillaries

VLDL and LDL relationship

The liver produces VLDL, which becomes LDL as it loses triglycerides

HDL

Lipoprotein that "eats" cholesterol and is destroyed

Structural function of carbohydrates

Glycosylation (attaching oligosaccharide chains to proteins to make them stick outwards and increase solubility)

Structural roles in the cell membrane

Phospholipids form the bilayer, cholesterol maintains integrity/fluidity, carbohydrates do glycosylation, and proteins act as channels/receptors

Lipidation function

Anchors proteins in place within the membrane

Nucleotide functions

Coordinate genetic storage, replication, and protein expression (DNA/RNA)

Lipid signaling pathway

Phospholipids release arachidonic acid, which is converted via COX and lipoxygenase pathways to create inflammatory and anti-inflammatory molecules

Premier brain fuel

Glucose (carbohydrates) provides 99% of fuel for the brain

RBC energy source

Glucose provides 100% of fuel for red blood cells (RBCs)

Glucose metabolism destinations

Metabolized via glycolysis to create acetyl CoA, or stored as glycogen

Fatty acid energy production

Undergoes beta-oxidation to yield acetyl CoA

Ketone bodies

Produced from excess acetyl CoA during starvation or diabetic states; can cause ketoacidosis

Ketone brain fuel proportion

Ketones provide 1% of brain fuel, primarily in the form of beta-hydroxybutyrate