Biochem topics Flashcards
LIFE:
A living thing is essentially a “bag of chemicals” (a cell).
CARBON:
Carbon has 4 binding sites, meaning it can bond with 4 other elements. If 4 different elements bind to a single carbon atom, they can form different arrangements called isomers.
Isomer:
Molecules with the same composition but arranged differently (e.g., D and L forms).
Enzymes:
Molecules that perform work in living things, but only work with specific isomers.
HYDROGEN:
A key element associated with hydrogen bonds, which influence molecular shape and structure. Hydrogen is abundant in the universe as a gas.
OXYGEN:
A highly reactive element that bonds easily, including with other oxygen atoms.
HYDROCARBONS:
The simplest molecules, composed of carbon and hydrogen.
ALCOHOLS:
Molecules containing a hydroxyl group (-OH). The hydrocarbon part (R) determines the type of alcohol (e.g., ethanol, propanol, butanol).
ALDEHYDES:
Molecules with a carbonyl group bonded to a hydrogen. Many sugars, such as glucose, are aldehydes.
KETONES:
Molecules with a carbonyl group bonded to two R groups, without a hydrogen.
ESTERS:
Molecules formed by reacting an alcohol with an acid. Many food smells come from esters.
ETHERS:
Molecules with an oxygen atom bonded to two R groups. Ethers are vital for lipids, which are essential for cells.
CARBOXYLIC ACIDS:
Contain a carboxyl group made of a carbonyl and hydroxyl group. These acids are involved in many biological molecules and interactions.
ANHYDRIDES:
High-energy molecules like pyrophosphate. The prefix “pyro-“ means fire or energy. ATP is the most important anhydride.
NITROGEN:
Found in amino groups (-NH₂), nitrates (NO₃⁻), nitrites (NO₂⁻), and nitrogen gas (N₂), which makes up 80% of the atmosphere.
AMINO ACIDS:
The building blocks of proteins, with a carboxyl group, an amino group, and a variable R group. There are about 20 amino acids, and the L-isomers are predominant in living organisms.
SULFUR:
Rare in biological molecules but important when present, such as in sulfhydryl groups (-SH). Sulfur is found in amino acids like cysteine and methionine.
PHOSPHORUS:
Commonly found as phosphoric acid in DNA, RNA, and phospholipids. It’s a critical component of ATP, which provides energy.
CARBOHYDRATES:
Monosaccharides:
The simplest carbohydrates, with 3–7 carbon atoms (e.g., glucose).
Disaccharides:
Two monosaccharides joined together (e.g., lactose, sucrose, maltose).
Polysaccharides:
Long chains of monosaccharides used in cell walls and energy storage (e.g., starch, pectin, cellulose).
LIPIDS:
Fatty Acids:
Hydrocarbon chains with a carboxylic group.
Triglycerides:
Composed of glycerol and three fatty acids.
Phospholipids:
Lipids with hydrophilic heads and hydrophobic tails, forming bilayers in cell membranes.
Waxes:
Lipids with very long hydrocarbon chains.
NUCLEIC ACIDS:
Found in cells and viruses; include DNA and RNA.
Nucleoside:
A molecule made of a pentose sugar and a purine or pyrimidine.
Nucleotide:
A nucleoside with an added phosphate group.
DEOXYRIBONUCLEIC ACID (DNA):
Primary Structure:
The sequence of bases (~1,000 bases make up a gene).
Secondary Structure:
Double-stranded, with complementary base pairing (A-T, G-C).
Helix:
A double-stranded structure twisted into a helix (beta DNA).
Major Groove:
A larger groove where proteins may bind.
Minor Groove:
A smaller groove in the helix, also accessible to certain molecules but less commonly targeted than the major groove.
Z-DNA:
A zigzag form observed using X-ray diffraction.
RIBONUCLEIC ACID (RNA):
The product of transcription from DNA.
Primary Structure:
The linear base sequence.
Secondary Structure:
The 2D folding of RNA.
Tertiary Structure:
The 3D folding of RNA.
PROTEINS:
Made of amino acids linked by peptide bonds.
PROTEIN STRUCTURE:
Primary:
The sequence of amino acids.
Secondary:
Folding due to hydrogen bonds.
Tertiary:
Complex 3D folding caused by interactions like disulfide bonds.
Quaternary:
The combination of multiple polypeptide chains into a functional protein.
ENZYMES:
Globular proteins that act as biological catalysts.
Active Site:
The specific area where the substrate binds.
Cofactors:
Molecules that help enzymes function.
Apoenzyme:
The protein part of the enzyme.
Holoenzyme:
The enzyme with its cofactor.
Classification:
Enzymes are grouped by their functions, including oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.
ENVIRONMENTAL FACTORS:
Enzymes work best at temperatures of 40–50°C and a pH of 7–8. High temperatures or extreme pH can denature enzymes.
INHIBITORS:
Competitive:
Chemicals that resemble the substrate and bind to the active site. Reversible. BABY EATS CARROTS, M&M COME, BABY EATS M&M. TAKE AWAY M&M, BABY EATS CARROTS
Noncompetitive:
Bind to a different site on the enzyme and alter its shape. Reversible. BABY EATS CARROTS, SIBLING COME, POKES BABY. BABY STOP EATING AND STARTS FIGHTING
ALLOSTERIC PROTEINS:
Enzymes with additional regulatory sites that can increase or decrease activity.
Positive Effector:
Increases enzyme activity.
Negative Effector:
Decreases enzyme activity.
