w2 slides fc Flashcards

Question

How do prions cause disease? (A) Prions induce abnormal protein folding, leading to aggregates. (B) Prions directly damage DNA. (C) Prions function as enzymes that break down proteins. (D) Prions stimulate excessive protein translation.

Answer 1

Answer: (A) (Prions misfold normal proteins, forming aggregates seen in diseases like CJD and mad cow disease.)

Answer 2

Answer: (A) (SDS-PAGE separates proteins by molecular weight.)

Answer 3

Answer: (A) (Cryo-EM is a powerful technique for structural biology.)

Answer 4

the r group is variable and determines the type of amino acid

Answer 5

-nonpolar amino acid -depending on where the protein ends up, oxidation conditions in the cell will favour forming disulfide bonds -SH: forms strong covalent bonds -reducing conditions in the cell will favour disulfide bonds being broken --> SH bonds -cell controls whether disulfide bridges are formed or broken

Answer 6

Peptide bonds -carboxyl group reacting with amino group to make peptide bond and water

Answer 7

take AA and make peptide bond and join it to another AA = residue --AA part of protein --numbered from AMINO end (starts there)

Answer 8

secondary structure -R groups NOT involved in forming this structure

Answer 9

-H-bonding between carbonyl oxygen (C=O) of 1 aa and amide hydrogen (N-H) of aa in neighboring strand -R groups not involved but they alternately project up and down -polypeptide arrows always pointing TWD carboxyl terminus

Answer 10

-stacked beta sheets -part of neurogenerative diseases

Answer 11

carbonyl oxygen, amide hydrogen in peptide backbone

Answer 12

4 AA's apart and within the SAME segment of polypeptide chain

Answer 13

between AA's in different segments or strands of polypeptide chain

Answer 14

-has to be amphipathic (type of alpha helix) to form a coiled coil --(amphipathic: both hydrophobic and hydrophilic areas in SAME molecule) -hydrophobic force will push R groups (?)

Answer 15

3D overall structure of a protein held tg by: -hydrophobic interactions -non-covalent bonds -covalent disulfide bonds -water pushes side groups into middle of molecule

Answer 16

1) proteins generally fold into the conformation that's MOST energetically favourable 2) proteins will fold into the shape dictated by their AA sequence, but CHAPERONE proteins help make the process more efficient and reliable

Answer 17

-aids in folding -if it folds incorrectly... ---won't be able to correct itself

Answer 18

-specialized for different functions -portion of a protein that has its own tertiary structure, often functioning in semi-independent manner -eukaryotic proteins often have 2 or more domains connected by intrinsically DISORDERED sequence (flexible part of polypeptide) -domains important for the evolution of proteins

Answer 19

1) hemoglobin protein formed from separate subunits: 2a, 2B 2) each subunit= separate pp (held by noncovalent bonds) 3) sickle cell anemia is caused by a mutation in the B subunit -hemoglobin can't carry oxygen and changes RBC shape to a sickle cell

Answer 20

-non-enzymatic, multi-domain proteins that organize and coordinate signaling pathways by bringing together multiple interacting proteins -serve as molecular platforms that control signal transduction, structural organization, and intracellular communication

Answer 21

-study of proteins --protein-protein interactions, regulation and their position within a pathway -location within a cell or tissue

Answer 22

Imagine a protein like a LEGO set: 🟩 Primary Structure → The individual LEGO pieces 🟦 Secondary Structure → How those pieces snap together (walls, bridges) 🟥 Tertiary Structure → How the entire LEGO set looks when complete 🟨 Quaternary Structure → How multiple LEGO sets combine into a giant castle

Answer 23

Amino acids are categorized as: Nonpolar (hydrophobic) → Think oil, avoids water (e.g., valine, leucine) Polar uncharged → Loves water but doesn’t carry a charge (e.g., serine)

Answer 24

Primary Structure: The Blueprint (Amino Acid Sequence) Secondary Structure: Local Folding (Alpha Helices & Beta Sheets) -these structures are stabilized by hydrogen bonds between atoms in the protein backbone Alpha helix (spiral staircase)→ Found in hair, keratin -Beta sheet (folded paper) 📄 → Found in silk, spider webs -Exam Tip: Beta sheets can be parallel or anti-parallel. Tertiary Structure: 3D Folding (Functional Shape!) Now the protein gets its final functional shape, stabilized by: ✅ Hydrogen bonds (weak but important) ✅ Ionic bonds (salt bridges) ✅ Hydrophobic interactions (water-fearing amino acids clump together) ✅ Disulfide bonds (covalent "bridges" by cysteine) 💡 Key Concept: Chaperone proteins help proteins fold correctly! Without them, misfolded proteins can cause diseases like Alzheimer’s. 🟨 Quaternary Structure: When Multiple Proteins Work Together Some proteins work alone, but others team up into giant molecular machines. Example: 🩸 Hemoglobin → 4 protein subunits work together to carry oxygen in blood! 🚨 Exam Tip: Sickle cell anemia happens due to one mutation in hemoglobin, causing red blood cells to become rigid and sickle-shaped.

Answer 25

1️⃣ Protein function depends on its 3D shape, which depends on the amino acid sequence! 2️⃣ Misfolded proteins = disease (e.g., Alzheimer’s, sickle cell anemia). 3️⃣ Peptide bonds hold amino acids together, but hydrogen, ionic, and disulfide bonds shape the protein. 4️⃣ Chaperones help proteins fold correctly. 5️⃣ Proteins can work alone or as giant molecular machines (e.g., hemoglobin).

Answer 26

Hydrogen bond ✅