Bio unit 2 Flashcards

Question

non polar

Answer 1

hydrophobic equally sahred

Answer 2

weakest pull from the center

Answer 3

Definition: The variable part of an amino acid that gives it its unique properties. Every amino acid has: -Amino group (–NH₂) -Carboxyl group (–COOH) -Hydrogen (H) -R-group (side chain) → this is what differs between amino acid

Answer 4

🌊 Hydrophilic: The molecule can mix with or dissolve in water. polar 🛑 Hydrophobic: The molecule does not dissolve in water; instead it clumps together to avoid water. nonpolar

Answer 5

✅ Quick Summary -Acids: donate H⁺ → pH < 7 -Bases: accept H⁺ / give OH⁻ → pH > 7 -1 pH change = 10× H⁺ difference -Buffers: stabilize pH Acids -Definition: Donate H⁺ ions (protons) in solution -pH range: 0–6.9 -Example: HCl (stomach acid), vinegar Bases -Definition: Accept H⁺ ions or produce OH⁻ ions -pH range: 7.1–14 -Example: Ammonia (NH₃), baking soda -pH Scale -Range: 0–14 (logarithmic) -Neutral: pH 7 (pure water) -Rule: 1 pH unit = 10× difference in H⁺ concentration -Ex: pH 5 has 10× more H⁺ than pH 6, 100× more than pH 7 Buffers -Definition: Substances that resist pH changes -How: Absorb excess H⁺ or release H⁺ when low -Purpose: Maintain homeostasis (stable pH) -Example: Blood buffer system → keeps blood ~pH 7.4

Answer 6

🌟 Definition Organic molecules are compounds that contain carbon (C) bonded to hydrogen (H) (often also O, N, P, or S). They are the building blocks of life, forming the structure and function of all living things. 🔹 Carbon can form 4 bonds, allowing it to build large, complex molecules. ✅ Quick Mnemonic Recap: Carbs = 🍞 Quick energy. - C, H, O (1:2:1) - Quick energy, short-term storage, plant structure (cell walls) - Glucose, starch, glycogen, cellulose Lipids = 🥑 Long-term energy + membranes - C, H (sometimes P) - Long-term energy, insulation, cell membranes, hormones - Fats, oils, phospholipids, steroids Proteins = 💪 Cell workers (enzymes, transport, defense) - C, H, O, N (sometimes S) - Structure, enzymes, transport, defense - Enzymes, hemoglobin, keratin, antibodies Nucleic Acids = 📖 Instructions for life (DNA, RNA, ATP) - C, H, O, N, P - Store and transmit genetic information - DNA, RNA, ATP

Answer 7

✅Quick Summary: Carbon = 4 bonds; hydrocarbons = nonpolar, hydrophobic. -Valence # of carbon: 4 → forms 4 covalent bonds → backbone of life (chains, rings, branched structures). -Importance: Enables variety of biomolecules: carbs, lipids, proteins, nucleic acids. -Hydrocarbon: Molecule made of only C + H (e.g., methane CH₄, fatty acid tails, gasoline). -Polarity: Nonpolar → hydrophobic (water-fearing). -Why hydrophobic: C–H bonds share electrons equally; water is polar → “like dissolves like” → hydrocarbons don’t mix with water (oil separates).

Answer 8

Hydroxyl group (-OH) Structure: R–OH Special: Polar (because O is highly electronegative). Forms hydrogen bonds. Effect: Makes molecules hydrophilic. Found in alcohols (ethanol). 2. Carbonyl group (C=O) Structure: Aldehyde → R–CHO (carbonyl at end) Ketone → R–CO–R (carbonyl in middle) Special: Polar; makes molecules more reactive. Effect: Hydrophilic; important in sugars (glucose, fructose). 3. Carboxyl group (-COOH) Structure: R–C(=O)–OH Special: Acts as an acid → can donate H⁺. Effect: Polar, hydrophilic, common in amino acids & fatty acids. 4. Amino group (-NH₂) Structure: R–NH₂ (sometimes protonated as R–NH₃⁺) Special: Acts as a base → can pick up H⁺. Effect: Polar, hydrophilic, found in amino acids. 5. Phosphate group (-PO₄²⁻) Structure: R–O–PO₃²⁻ (one O bonded to carbon backbone) Special: Negatively charged, very polar. Stores & transfers energy (ATP, DNA backbone). Effect: Hydrophilic, reactive, key in energy transfer. 6. Methyl group (-CH₃) Structure: R–CH₃ Special: Nonpolar, does not form hydrogen bonds. Effect: Hydrophobic. Often used as a tag (DNA methylation → gene regulation). ✅ Summary Hydrophilic groups (polar): Hydroxyl, Carbonyl, Carboxyl, Amino, Phosphate. Hydrophobic group (nonpolar): Methyl (-CH₃).

Answer 9

polypeptide chain

Answer 10

lots of hydrocarbons

Answer 11

monoscrhdies, olisaxrdies, polycasrchdes

Answer 12

one starand runs 5-3 and the other 3-5

Answer 13

startch is found in plants glycogen is found in anamilas

Answer 14

cellulose plant cell walls structure startch in plant cekks energy storage

Answer 15

phospahte group, nitrogen base, 5 carbon pentose suagr

Answer 16

n termnious c termnious

Answer 17

cellouse found in oknats chtin in anmils

Answer 18

protiens can be amphipathic

Answer 19

pyridamine single six mebered ring

Answer 20

C–H bonds are relatively nonpolar → electrons are shared fairly equally. Because of this, they store a lot of chemical (potential) energy. Breaking these bonds (e.g., during cellular respiration) releases a large amount of energy.

Answer 21

A phosphodiester linkage. Formed between the phosphate group of one nucleotide and the 3′ hydroxyl (-OH) group of another. Results from a dehydration synthesis reaction (water released). Creates the sugar-phosphate backbone of DNA and RNA, giving them structural stability.

Answer 22

portens that act as infections diease casuing agents

Answer 23

a type of lipid with 4 carbon rings

Answer 24

What is a glycosidic linkage? It’s just the glue (a covalent bond) that holds two sugars (monosaccharides) together. How is it formed? Imagine two sugars holding hands. Each sugar “drops something” to connect: One sugar drops an H (hydrogen). The other drops an OH (hydroxyl). Together, those make H₂O (water), which gets released. Now the two sugars are linked by a covalent bond → that bond is the glycosidic linkage.

Answer 25

fats- caontain fatty acid steriods- no fatty acids phisplipds- cpntain faty acids waxx- contain fatty acids

Answer 26

glyercol at core phosophate group, 2 fatty acod tails, jpined by ester linkage tails are hydrohobc hydrophic head

Answer 27

scietnts figured out that the pyrine pyrmaide fit just right

Answer 28

Oligosaccharides = “short chains of sugars” (a few monosaccharides linked by glycosidic bonds). When these sugar chains are attached to proteins, you get a glycoprotein. Think of it like this: The protein = the worker (does jobs in the membrane). The oligosaccharide chain = the worker’s ID badge.

Answer 29

Monomer = small building block molecule. Polymer = large molecule made of repeating monomers. Linking reaction = dehydration reaction or condensation reaction → water is removed when the bond forms. Breaking reaction = hydrolysis → water is added to break the bond.

Answer 30

4 parts: Amino group (–NH₂) Carboxyl group (–COOH) Hydrogen atom (–H) R group (side chain, variable) 2 ways to write: Structural formula (shows atoms and bonds in detail). Generalized formula (simplified, highlights core groups + “R” placeholder).

Answer 31

monomer: amino acids → polymer: polypeptides/proteins

Answer 32

Nucleic acids (DNA/RNA) → monomer: nucleotides → polymer: nucleic acids

Answer 33

Carbohydrates → monomer: monosaccharides → polymer: polysaccharides

Answer 34

Proteins → amino acids joined by peptide bonds

Answer 35

Nucleic acids → nucleotides joined by phosphodiester bonds

Answer 36

Carbohydrates → monosaccharides joined by glycosidic bonds

Answer 37

Lipids → fatty acids + glycerol joined by ester bonds

Answer 38

Amphipathic = having both hydrophobic (nonpolar) and hydrophilic (polar/charged) regions. Significance: Allows proteins to fold correctly, embed in membranes, and interact with both water and lipids. Connection to amino acids: Each amino acid’s R group (side chain) determines whether it’s hydrophobic or hydrophilic → the mix of these in a protein makes it amphipathic.

Answer 39

N-terminus = end of a polypeptide with a free amino group (–NH₂). C-terminus = end of a polypeptide with a free carboxyl group (–COOH). Recognition: N-terminus always has the –NH₂ group exposed. C-terminus always has the –COOH group exposed. By convention, amino acid sequences are written from N → C terminus.

Answer 40

Primary → linear sequence of amino acids (peptide bonds). Secondary → local folding into α-helices or β-sheets (H-bonds). Tertiary → overall 3D shape of one polypeptide (interactions among R groups). Quaternary → multiple polypeptides combining into one functional protein. HbS mutation: In the primary structure, a single amino acid changes (glutamic acid → valine). Effect: Valine is hydrophobic → causes hemoglobin to stick together abnormally. Result: Hemoglobin forms long fibers → red blood cells become sickle-shaped, less flexible, and can block blood vessels.

Answer 41

DNA carries the instructions for the amino acid sequence of proteins. RNA (mRNA) delivers the instructions to the ribosome, where proteins are built. If there is a mutation in DNA, the RNA copy carries that error → the wrong amino acid may be placed in the protein. Sickle cell example: DNA mutation → wrong codon in mRNA → valine instead of glutamic acid in hemoglobin → defective protein → sickled red blood cells.

Answer 42

Structure → Function: A protein’s specific 3D shape (from its amino acid sequence + folding) determines how it interacts with other molecules → this shape gives it its function. Denatured protein: When heat, pH, or chemicals disrupt folding, the protein loses its shape → can no longer perform its function. Prion: Misfolded protein that can cause other proteins of the same type to misfold. Occurrence & Effect: Arise spontaneously, by mutation, or via infection. Cause protein aggregates that damage cells → lead to diseases like mad cow disease, Creutzfeldt-Jakob, etc.

Answer 43

Nucleotide parts: Phosphate group (–PO₄) Pentose sugar (5-carbon sugar) Nitrogenous base (A, T/U, C, G) Recognition: Look for phosphate + sugar + base. Difference: Ribonucleotide (RNA) → sugar = ribose (–OH on 2’ carbon) Deoxyribonucleotide (DNA) → sugar = deoxyribose (–H on 2’ carbon, missing one oxygen)

Answer 44

DNA → stores genetic information. RNA → carries instructions from DNA to make proteins; also involved in protein synthesis (mRNA, tRNA, rRNA). Pyrimidines (PY-CUT) → single-ring structure → Cytosine (C), Uracil (U), Thymine (T) Purines (Pure As Gold) → double-ring structure → Adenine (A), Guanine (G) Base pairing: A ↔ T (DNA) or A ↔ U (RNA) G ↔ C

Answer 45

A nucleotide has 1 phosphate functional group as part of its basic structure. That phosphate can be linked to others to form di- or triphosphates (like ATP, ADP), but a single nucleotide monomer only has one phosphate.

Answer 46

ATP (adenosine triphosphate) is a nucleotide with three phosphate groups. The phosphate bonds (especially the last two) store high-energy → breaking them releases energy for cellular work. ATP links the concepts of nucleotides, phosphate groups, and energy transfer: Adenine → nitrogenous base Ribose → sugar Three phosphates → energy storage/release

Answer 47

H bonds in base pairing: Adenine (A) – Thymine (T) → 2 hydrogen bonds Guanine (G) – Cytosine (C) → 3 hydrogen bonds 5’ and 3’ ends: DNA strands have directionality: 5’ end = phosphate group attached to the 5’ carbon of the sugar 3’ end = hydroxyl (–OH) attached to the 3’ carbon of the sugar DNA is read 5’ → 3’ because DNA polymerase adds nucleotides to the 3’ end, synthesizing the new strand in that direction. Antiparallel: the two DNA strands run opposite directions (one 5’→3’, the other 3’→5’). This orientation allows proper base pairing and replication.

Answer 48

Similarities: Both are nucleic acids Both have phosphate, sugar, and nitrogenous bases Both store or transfer genetic information Differences: DNA has deoxyribose sugar; RNA has ribose. DNA is double-stranded; RNA is single-stranded. DNA uses thymine (T); RNA uses uracil (U). DNA stores genetic info long-term; RNA carries out short-term and functional roles. DNA is more stable; RNA is less stable. Chargaff’s rules: A = T and G = C in DNA %A + %T = %G + %C = 100% Explains complementary base pairing

Answer 49

Attributes of DNA’s double helix: Two antiparallel strands (5’→3’ opposite 3’→5’) complementary base pairing: A–T (2 H-bonds), G–C (3 H-bonds) Right-handed helix Sugar-phosphate backbone on outside, bases inside Major and minor grooves allow protein binding DNA replication: Semi-conservative: Each new DNA molecule has one old strand + one new strand Steps: Helicase unwinds the double helix DNA polymerase adds nucleotides to the 3’ end of the new strand Primase lays down RNA primers for starting replication Ligase seals gaps between Okazaki fragments on the lagging strand Replication occurs 5’ → 3’, with leading and lagging strands due to antiparallel orientation

Answer 50

Proteins can bind to DNA at specific sites (like promoters or enhancers). This controls gene expression by turning genes on or off. Examples: Transcription factors, repressors, polymerases. Proper DNA–protein interaction ensures genes are expressed at the right time, place, and level.

Answer 51

Helicase cuts, Primase starts, Polymerase builds, Ligase seals.” Helicase → unwinds the DNA double helix. single-strand binding proteins (SSBs) → stabilize unwound strands. Primase → lays down RNA primers to start replication. DNA polymerase → adds nucleotides to synthesize new DNA strands. Ligase → seals gaps between Okazaki fragments on the lagging strand. Topoisomerase → prevents DNA from supercoiling. Summary: Proteins are essential for unwinding, stabilizing, copying, and finishing DNA replication.

Answer 52

RNA can store genetic information like DNA. RNA can catalyze chemical reactions like proteins (ribozymes). This dual ability means RNA could replicate itself and perform cellular functions without proteins or DNA, making it a likely candidate for the first self-replicating life molecule.

Answer 53

Types of carbohydrates: Monosaccharides → single sugar units (glucose, fructose, galactose); sweet, soluble, basic building blocks. Disaccharides → two monosaccharides linked by a glycosidic bond (sucrose, lactose, maltose). Polysaccharides → many monosaccharides linked; can be: Storage → starch (plants), glycogen (animals) Structural → cellulose (plants), chitin (fungi/insects) General formula: CₙH₂ₙOₙ (roughly 1:2:1 ratio of C:H:O) Monosaccharide naming clues: Usually end in “-ose” (glucose, fructose, galactose) Often contain multiple –OH groups and a carbonyl group (aldehyde or ketone)

Answer 54

Glycoprotein = a protein covalently bonded to a short carbohydrate chain (oligosaccharide). Functions: Cell recognition & signaling → helps the immune system distinguish self vs. non-self. Protein stability & folding → carbohydrate can stabilize the protein structure. Membrane proteins → often found on cell surfaces, aiding communication and adhesion.

Answer 55

storage molecules α-glycosidic linkages → found in starch (plants) and glycogen (animals) Function: easily broken down for energy storage and release. structure β-glycosidic linkages → found in cellulose (plants) and chitin (fungi/insects) Function: form straight, rigid chains → good for structural support, harder to digest. Key idea: The type of linkage affects shape and digestibility → α = energy, β = structure.

Answer 56

Storage polysaccharides: Plants → starch Made of α-glucose, mostly helical chains Function: compact, easily broken down for energy. Animals → glycogen Made of α-glucose, highly branched Function: rapid energy release when needed. Structural polysaccharides: Plants → cellulose Made of β-glucose, straight chains with H-bonds between chains Function: strong, rigid, good for cell walls, not digestible by humans. fungi → chitin β-linked sugar with nitrogen groups Function: structural support in cell walls, exoskeletons of insects. Bacteria → peptidoglycan Sugar chains cross-linked by peptides Function: rigid cell wall, protects from osmotic pressure Relation to antibiotics: Antibiotics like penicillin target peptidoglycan synthesis, weakening bacterial cell walls. Humans don’t have peptidoglycan → antibiotics selectively kill bacteria without harming human cells.

Answer 57

Fatty acids are mostly hydrocarbon chains → highly reduced, with many C–H bonds. Carbohydrates have more C–O bonds, already partially oxidized. More C–H bonds → more electrons can be transferred during oxidation → more energy released per gram. Result: Fatty acids store more energy than carbohydrates for long-term energy storage.

Answer 58

Fats (Triglycerides) Glycerol + 3 fatty acids Function: long-term energy storage, insulation, cushioning Phospholipids Glycerol + 2 fatty acids + phosphate group Function: make up cell membranes, amphipathic (hydrophilic head, hydrophobic tails) Steroids 4 fused carbon rings (e.g., cholesterol, hormones) Function: signaling (hormones), membrane fluidity Waxes Long-chain fatty acids + long-chain alcohols Function: waterproofing, protective coating (plants, animals)

Answer 59

Fatty acid → long hydrocarbon chain with a carboxyl group (–COOH) at one end. Saturated vs. Unsaturated: Saturated → no double bonds, straight chains → pack tightly → solid at room temp (e.g., butter) Unsaturated → ≥1 double bond, kinked chains → don’t pack tightly → liquid at room temp (e.g., oil) Health: Saturated fats → raise LDL (“bad”) cholesterol → increase risk of heart disease Trans fats → artificially hydrogenated unsaturated fats → increase LDL and lower HDL, very unhealthy

Answer 60

Fat (triglyceride) → glycerol + 3 fatty acids (joined by ester bonds) → long-term energy storage. Steroid → 4 fused carbon rings (no fatty acids) → signaling (hormones) and membrane fluidity. Phospholipid → glycerol + 2 fatty acids + phosphate group → amphipathic: hydrophilic head, hydrophobic tails. Significance of amphipathic phospholipids: Form bilayers in cell membranes → hydrophobic tails face inward, hydrophilic heads face water. Creates a selective barrier that controls what enters/exits cells.

Answer 61

Saturated fatty acids → straight chains → pack tightly → membrane less fluid, less permeable Unsaturated fatty acids → kinked chains due to double bonds → looser packing → membrane more fluid, more permeable Key idea: Degree of saturation affects membrane flexibility, fluidity, and permeability, which is crucial for transport and cell function.

Answer 62

Structure: Two layers of phospholipids Hydrophilic heads face outward (toward water) Hydrophobic tails face inward (away from water) Function as a cell membrane: Selective barrier → controls what enters/exits the cell Fluidity allows membrane proteins to move and function Amphipathic nature enables self-assembly and repair of the membrane Forms a stable boundary between the cell’s internal environment and the external environment

Answer 63

Category: Enzymes are proteins (some RNAs can act as ribozymes). Function: Speed up chemical reactions by lowering activation energy without being consumed. Naming clue: Most end in “-ase” (e.g., lactase, polymerase). Parts & mechanism: Substrate: molecule(s) the enzyme acts on Active site: part of the enzyme where substrate binds Enzyme-substrate complex: temporary combination of enzyme + substrate Products: molecules formed after reaction Process: substrate binds → enzyme stabilizes transition state → reaction occurs → products released Activation energy (Ea): energy required to start a reaction Enzymes lower Ea, making reactions happen faster at lower temperatures Induced fit: enzyme changes shape slightly when substrate binds → optimizes interaction and catalysis

Answer 64

Molecules that work with enzymes: Cofactors: inorganic ions (e.g., Mg²⁺, Zn²⁺) required for activity Coenzymes: organic molecules (e.g., NAD⁺, FAD, vitamins) required for activity Types of enzyme regulation: Competitive inhibition: Molecule competes with substrate for the active site Can be overcome by increasing substrate concentration Allosteric regulation: Molecule binds elsewhere (allosteric site) → changes enzyme shape → affects activity Positive allosteric regulation: increases activity Negative allosteric regulation: decreases activity Feedback inhibition: End product of a pathway inhibits an earlier enzyme in the pathway Prevents overproduction of the product

Answer 65

R-CH3 nonpolar/hydrophobic

Answer 66

R-O-POs polar/hydriphlic

Answer 67

R-NH2 polar/hrdrophlic acts as a base

Answer 68

R-C(double bond O)-OH polar/hydrophlic acts as a acid

Answer 69

R-CHO: aldeyhde R-CO-R: keytsone polar/hydrophlic

Answer 70

R-O-H polar/hydrophlic

Bio unit 2 Flashcards

(94 cards)