bio exam 2: Lipids & Nucleic Acids

Lipids

Fatty molecules made of C, H, and O that don't dissolve in water and don't form long repeating chains (polymers).

Glycerol

The 3-carbon backbone molecule that connects to fatty acids

Fatty Acid

A long chain of carbon and hydrogen with an acid group (−COOH−COOH) at one end

Triglyceride

The main type of body fat, made of 1 glycerol backbone attached to 3 fatty acid chains

Dehydration Synthesis

he chemical process that links glycerol to fatty acids by removing water molecules

Saturated Fat

A fat with only single bonds between carbons; packed with hydrogen, making it solid at room temperature (like butter)

Unsaturated Fat

A fat with one or more double bonds; liquid at room temperature (like plant oil)

Monounsaturated vs. Polyunsaturated

Monounsaturated has 1 double bond; polyunsaturated has 2 or more double bonds

Hydrogenation

Artificially adding hydrogen to unsaturated fats to make them more solid and last longer on store shelves

Trans-Fat

Unhealthy, fake fats created by partial hydrogenation; linear in shape, solid, and difficult for your body to break down (found in junk food)

Adipose Tissue

Body fat deposits that store energy, insulate against heat loss, and cushion internal organs

Eicosanoids

Fatty signaling molecules made from arachidonic acid that control blood clotting, pain, and inflammation

Thromboxanes

Help blood clot

Prostaglandins

Signal pain and trigger labor contractions

Leukotrienes

Coordinate the body’s immune response to injury

Cholesterol /Sterols

Ring-shaped lipids made by animals or eaten in food; used to build cell membranes, hormones, vitamin D, and bile salts

Steroid Hormones

Chemical messengers like testosterone, estrogen, and cortisol made from cholesterol

Bile Salts

Digestion-helping molecules made from cholesterol in the liver that break down (emulsify) big fat blobs into small droplets

Vitamin D

Made when sunlight hits cholesterol in the skin; needed to absorb calcium and phosphorus

Phospholipid

The main ingredient in cell membranes, made of a water-loving (polar) phosphate head and two water-fearing (nonpolar) fatty acid tails

Nucleic Acid

Large molecules (like DNA and RNA) built from nucleotide units that store and transfer genetic instructions to build proteins

Nucleotide

The monomer unit of nucleic acids, made of 3 parts: a phosphate group, a 5-carbon sugar, and a nitrogenous base

Phosphate Group

The negatively charged part of a nucleotide that gives DNA and RNA a overall negative charge

Deoxyribose vs. Ribose

Deoxyribose is the 5-carbon sugar in DNA; Ribose is the 5-carbon sugar in RNA

Purines

Double-ringed bases: Adenine and Guanine

Pyrimidines

Single-ringed bases: Cytosine, Thymine, and Uracil

Complementary Base Pairing

Bases match up specifically via hydrogen bonds: A pairs with T (or U in RNA), and G pairs with C

Antiparallel

The two strands of a DNA double helix run parallel to each other, but face in opposite directions

Phosphodiester Bond

The strong chemical bond linking the sugar of one nucleotide to the phosphate of the next, building the "backbone"

DNA

Double-stranded genetic blueprint containing A, T, G, and C

RNA

Single-stranded copy of genetic info containing A, U, G, and C

mRNA

Temporary copy of a gene used as a template to build a protein

tRNA

The truck that picks up and delivers specific amino acids to the ribosome

rRNA

The physical RNA helper that makes up the structure of a ribosome

ATP (adenosine triphosphate)

A specialized nucleotide carrying 3 phosphate groups that serves as the cell’s primary energy molecule