Chemistry-only: match natural polymers to their monomers
| English | 中文 | Pinyin |
|---|---|---|
| glucose/ˈɡluːkəʊs/ | 葡萄糖 | pú táo táng |
| natural polymer | 天然聚合物 | tiān rán jù hé wù |
What would explain this observation?
- Starch and cellulose both use glucose 葡萄糖 building blocks, but one stores carbohydrate and the other supports plant cell walls. The identity of the monomer alone does not determine the complete polymer structure.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- Natural polymers 天然聚合物 include proteins, starch, cellulose and DNA. Proteins are made from amino acids; starch and cellulose are made from glucose monomers; DNA chains are made from nucleotides. Natural means produced in biological systems, not a promise that a substance is safe, edible or rapidly biodegradable. Each family can contain very large molecules assembled from many smaller building blocks.
- natural polymer: A polymer produced in a biological system; glucose: The simple sugar identified as the monomer type for starch and cellulose in this course.
Which statement correctly matches these natural polymers to monomers?
Proteins can use different amino acids in the same chain, with sequence and folding contributing to their functions. Starch and cellulose use glucose but differ in how their building blocks are joined and arranged, producing different properties. Starch stores carbohydrate in plants; cellulose gives strength to plant cell walls. The required Chemistry comparison is monomer identity and polymer recognition, not memorising advanced alpha/beta linkage names or complete structural formulae of carbohydrates.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Proteins can use different amino acids in the same chain, with sequence and folding contributing to their functions. Starch and cellulose use glucose but differ in how their building blocks are joined and arranged, producing different properties. Starch stores carbohydrate in plants; cellulose gives strength to plant cell walls. The required Chemistry comparison is monomer identity and polymer recognition, not memorising advanced alpha/beta linkage names or complete structural formulae of carbohydrates.
- Sort labelled structure or identity cards into monomer/polymer pairs, then justify each match aloud using the building-block evidence. Place starch and cellulose in separate polymer groups even though their glucose cards match. If using a teacher-approved starch observation with iodine, record the actual sample and observed colour; a result for starch does not identify every glucose-containing polymer. Keep practical observations, structural inferences and biological-use statements in separate columns.
Which two habits make the investigation or model in this case more defensible?
Sort labelled structure or identity cards into monomer/polymer pairs, then justify each match aloud using the building-block evidence. Place starch and cellulose in separate polymer groups even though their glucose cards match. If using a teacher-approved starch observation with iodine, record the actual sample and observed colour; a result for starch does not identify every glucose-containing polymer. Keep practical observations, structural inferences and biological-use statements in separate columns.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: a simplified chain diagram labels 15 glucose-derived units in a cellulose segment and 12 in a starch segment. The total is 15+12=27 glucose-derived units. This counts the supplied model units, not free glucose dissolved in either sample. If the protein model beside them has 20 amino-acid residues, those residues must not be added to a glucose-unit count just because all three diagrams represent polymers.
Two supplied carbohydrate chain models contain 18 and 14 glucose-derived units. Count their total units. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Two supplied carbohydrate chain models contain 18 and 14 glucose-derived units. Count their total units.
The result is 32 units. Known: a simplified chain diagram labels 15 glucose-derived units in a cellulose segment and 12 in a starch segment. The total is 15+12=27 glucose-derived units. This counts the supplied model units, not free glucose dissolved in either sample. If the protein model beside them has 20 amino-acid residues, those residues must not be added to a glucose-unit count just because all three diagrams represent polymers.
Check the conclusion and its limits
- Do not say cellulose has different monomers merely because its properties differ from starch, or that all proteins contain only glycine. A polymer’s monomer type and arrangement are separate evidence. Common-tier recognition of amino-acid protein monomers does not require the HT condensation mechanism, and common-tier DNA recognition does not require an invented written practical examination.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Starch and cellulose must have identical properties because both use glucose monomers. This claim is false: Do not say cellulose has different monomers merely because its properties differ from starch, or that all proteins contain only glycine. A polymer’s monomer type and arrangement are separate evidence. Common-tier recognition of amino-acid protein monomers does not require the HT condensation mechanism, and common-tier DNA recognition does not require an invented written practical examination.
Chemistry-only: match natural polymers to their monomers: Proteins can use different amino acids in the same chain, with sequence and folding contributing to their functions. Starch and cellulose use glucose but differ in how their building blocks are joined and arranged, producing different properties. Starch stores carbohydrate in plants; cellulose gives strength to plant cell walls. The required Chemistry comparison is monomer identity and polymer recognition, not memorising advanced alpha/beta linkage names or complete structural formulae of carbohydrates.
Starch and cellulose must have identical properties because both use glucose monomers.
Do not say cellulose has different monomers merely because its properties differ from starch, or that all proteins contain only glycine. A polymer’s monomer type and arrangement are separate evidence. Common-tier recognition of amino-acid protein monomers does not require the HT condensation mechanism, and common-tier DNA recognition does not require an invented written practical examination.
A polymer produced in a biological system: write the technical term.
natural polymer means A polymer produced in a biological system.