Unit 1 Flashcards
What are the properties of life
- order
- sensitivity or response to the environment
- reproduction
- adaptation
- growth and development
- regulation
- homeostasis
- energy processing
- evolution
What are two examples of regulation?
- nutrient transport
- blood flow
- Carrying oxygen
- Removing wastes: The excretory system (e.g., kidneys) regulates waste removal to maintain chemical balance.
- Cooling the body: The integumentary system (skin) and circulatory system regulate temperature through sweating and blood flow adjustments.
What are carbohydrates, and what are their main functions?
Carbohydrates are macromolecules composed of carbon, hydrogen, and oxygen. They serve as a vital energy source (short-term energy) and provide structural support in organisms, such as cellulose in plants and chitin in arthropods.
What are examples of carbohydrates and their roles?
Examples include:
Glucose: Short-term energy source.
Cellulose: Structural support in plant cell walls.
Chitin: Forms exoskeletons of insects and arthropods.
Starch/Glycogen: Energy storage in plants and animals.
What are the key differences between saturated and unsaturated lipids?
Saturated lipids 🍟:
No double bonds in hydrocarbon chains
Tend to form solids at room temperature
Unsaturated lipids 🥑:
At least one double bond in hydrocarbon chains
Tend to stay liquid at room temperature
Describe the structure of a phospholipid and its relevance to cell membranes.
Phospholipids have a polar (hydrophilic) head and nonpolar (hydrophobic) tails
Head: “water-loving”, faces outward in cell membranes
Tails: “water-fearing”, face inward in cell membranes
This structure allows phospholipids to form bilayers in cell membranes
How do phospholipids arrange themselves in cell membranes?
Form a bilayer structure
Hydrophilic heads face outward (toward aqueous environments)
Hydrophobic tails face inward (away from water)
Result: Hydrophobic middle layer sandwiched between two hydrophilic outer layers
This arrangement creates a stable membrane structure
What defines the primary structure of a protein?
The linear sequence of amino acids in a polypeptide chain.
Held together by covalent peptide bonds.
Determines all subsequent levels of protein structure.
What forms the secondary structure of a protein, and what are its key features?
Local folding into alpha-helices or beta-pleated sheets.
Stabilized by hydrogen bonds between the backbone’s amine and carboxyl groups.
Provides mechanical stability to the polypeptide.
What interactions stabilize the tertiary structure of a protein?
The three-dimensional shape formed by folding due to R-group interactions, including:
Hydrogen bonds
Ionic bonds
Disulfide bridges
Hydrophobic interactions.
Determines the protein’s specific function (e.g., enzyme active sites).
When does a protein have quaternary structure, and what stabilizes it?
Arises when multiple polypeptide chains (subunits) interact.
Stabilized by similar forces as tertiary structure (e.g., hydrogen bonds, ionic bonds).
Example: Hemoglobin (4 subunits).
What is denaturation, and how does it affect protein function?
Denaturation is the disruption of a protein’s structure (secondary, tertiary, or quaternary) due to factors like heat, pH changes, or chemicals.
Results in loss of shape and biological function (e.g., enzymes lose catalytic activity).
Summarize the four levels of protein structure.
Primary Structure: Sequence of amino acids (peptide bonds).
Secondary Structure: Local folding into alpha-helices or beta-sheets (hydrogen bonds).
Tertiary Structure: 3D shape from R-group interactions (functional shape).
Quaternary Structure: Assembly of multiple polypeptide chains.
How does a mutation in the primary structure affect higher protein levels?
Primary structure (amino acid sequence) determines all higher structures.
A single substitution (e.g., sickle cell anemia: Glu → Val in hemoglobin β-chain) disrupts hydrogen bonding, folding, and function46.
Altered sequence → changed secondary/tertiary structure → potential loss of function.
What happens if a mutation disrupts secondary structure?
Secondary structures (α-helices, β-sheets) rely on hydrogen bonds between backbone groups.
Mutations can:
Break hydrogen bonds → collapse helices/sheets.
Example: Loss of α-helix stability reduces mechanical support for the polypeptide9.
How do mutations in R-groups affect tertiary structure?
Tertiary structure depends on R-group interactions (e.g., disulfide bridges, hydrophobic interactions).
Mutations can:
Disrupt bonds → misfolded 3D shape.
Example: Cysteine → non-cysteine mutation breaks disulfide bonds, destabilizing the protein910.
Draw out structure of DNA
https://library.fiveable.me/ap-bio/unit-1/review/study-guide/NgY7RbUFacBqXbbzx601 (end)
How do mutations affect quaternary structure?
Quaternary structure involves interactions between multiple polypeptides.
Mutations can:
Prevent subunit assembly (e.g., defective hemoglobin tetramer in sickle cell anemia)4.
Alter binding sites → disrupt protein complexes (e.g., antibody-antigen binding)3.
How do structural changes from mutations affect function?
Loss of function: Misfolded proteins (e.g., enzymes lose catalytic sites)6.
Gain of function: Rarely, new interactions arise (e.g., evolutionary adaptation)13.
Example: A single mutation switches IgG-binding (4β+α fold) to albumin-binding (3-α fold)3.
How do mutations cause denaturation?
Mutations weaken stabilizing interactions (e.g., hydrophobic cores, ionic bonds).
Result: Protein unfolds → loses function610.
Example: Heat/pH changes disrupt weak bonds, but mutations can mimic this permanently.
Key Exam Tips
Key Exam Tips
Case Study: Sickle cell anemia (Glu6Val in hemoglobin) → hydrophobic interactions → deformed RBCs4.
Vocabulary:
Conservative mutation: Similar amino acid → minimal structural change.
Non-conservative mutation: Drastic amino acid change → major structural/functional disruption10.
FRQ Focus: Explain how a mutation’s location (e.g., active site vs. non-critical region) determines impact15.
What are nucleic acids, and what elements compose them?
Definition: Polymers (DNA/RNA) storing genetic information.
Elements: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P).
Monomer: Nucleotide (sugar + phosphate + nitrogenous base).
What three components make up a nucleotide?
5-carbon sugar: Ribose (RNA) or deoxyribose (DNA).
Phosphate group: Links nucleotides via phosphodiester bonds.
Nitrogenous base:
DNA: Adenine (A), Thymine (T), Cytosine (C), Guanine (G).
RNA: Uracil (U) replaces Thymine.
Compare DNA and RNA.
https://www.perplexity.ai/search/make-me-fully-understand-induc-Z2rCZK_JSIGTLHdGitdb_g
