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2. PTE Academic Reading Practice: Fill in the Blanks (Dropdown) – The Structure of DNA [2025 Updated]
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August 2, 2025
![Boost your PTE Academic Reading score with this ultra-interactive Fill in the Blanks (Dropdown) practice on “The Structure of DNA.” Includes a step-by-step tutorial, authentic exam-level passage, instant answer keys, expert explanations, advanced vocabulary/phrases, and responsive exercises. Perfect for PTE Academic candidates aiming for high band scores in 2025 and beyond. Practice, learn, and master the latest PTE question types with LingExam! - PTE Academic Reading Practice: Fill in the Blanks (Dropdown) – The Structure of DNA [2025 Updated] - LingExam Language Academy - Lingexam.com](https://lingexam.com/wp-content/uploads/2025/08/Article-Thumbnail-10.jpg)
Fill in the Blanks (Dropdown) Questions (PTE Academic Reading Tutorial – The Structure of DNA)
What are Fill in the Blanks (Dropdown) Questions?
In this PTE Academic Reading question type, you’ll see a passage about a real scientific discovery, with several blanks. For each gap, you must select the best word or phrase from a dropdown menu so the text is grammatical and logical. This question type tests your vocabulary, grammar, and understanding of academic English—all skills you need for PTE Academic success!
In this PTE Academic Reading question type, you’ll see a passage about a real scientific discovery, with several blanks. For each gap, you must select the best word or phrase from a dropdown menu so the text is grammatical and logical. This question type tests your vocabulary, grammar, and understanding of academic English—all skills you need for PTE Academic success!
How to Answer Fill in the Blanks (Dropdown) – Step by Step
1
Skim the Passage for General Meaning:
Begin by reading the entire passage without focusing on the blanks. Notice the topic (“The Structure of DNA”), the main ideas, and the sequence of facts. Understanding the “big picture” prepares your brain to choose the right words later. Academic passages often build ideas logically—so knowing the flow helps you see where each detail fits.
Begin by reading the entire passage without focusing on the blanks. Notice the topic (“The Structure of DNA”), the main ideas, and the sequence of facts. Understanding the “big picture” prepares your brain to choose the right words later. Academic passages often build ideas logically—so knowing the flow helps you see where each detail fits.
2
Examine the Context Around Each Blank:
Focus on the sentences and phrases before and after every blank. Does the sentence require a noun, verb, adjective, or prepositional phrase? Context clues are everywhere: scientific writing follows strict grammar and collocation rules. Missing these cues is one of the biggest reasons test-takers lose points!
Focus on the sentences and phrases before and after every blank. Does the sentence require a noun, verb, adjective, or prepositional phrase? Context clues are everywhere: scientific writing follows strict grammar and collocation rules. Missing these cues is one of the biggest reasons test-takers lose points!
3
Predict the Word or Phrase Needed:
Before opening the dropdown, “hear” the sentence in your mind and guess what type of word should go in the gap. Should it be a scientific term, a process, a description, or a linking phrase? This step is crucial—it stops you from being distracted by tricky but incorrect options.
Before opening the dropdown, “hear” the sentence in your mind and guess what type of word should go in the gap. Should it be a scientific term, a process, a description, or a linking phrase? This step is crucial—it stops you from being distracted by tricky but incorrect options.
4
Open the Dropdown—Read Every Option Carefully:
Every dropdown contains distractors. These are words that look “almost right,” but don’t match the grammar, logic, or science of the sentence. Read every option fully before choosing. Sometimes, only one word “sounds right” both grammatically and in context.
Every dropdown contains distractors. These are words that look “almost right,” but don’t match the grammar, logic, or science of the sentence. Read every option fully before choosing. Sometimes, only one word “sounds right” both grammatically and in context.
5
Use Academic Logic and Scientific Knowledge:
Scientific texts are full of logic! If the passage describes a “structure,” expect technical words like “helix,” “strand,” or “base pairs.” If you see clues about function, look for action verbs or processes. PTE passages reward you for thinking like a scientist and applying general knowledge.
Scientific texts are full of logic! If the passage describes a “structure,” expect technical words like “helix,” “strand,” or “base pairs.” If you see clues about function, look for action verbs or processes. PTE passages reward you for thinking like a scientist and applying general knowledge.
6
Watch for Collocations and Fixed Phrases:
Science and academic English have “set phrases”—like “double helix,” “carry genetic information,” or “form a backbone.” If you spot half of a set phrase, try to complete it with a collocation from the dropdown. Knowing these expressions makes you sound (and score!) like an advanced reader.
Science and academic English have “set phrases”—like “double helix,” “carry genetic information,” or “form a backbone.” If you spot half of a set phrase, try to complete it with a collocation from the dropdown. Knowing these expressions makes you sound (and score!) like an advanced reader.
7
Test Your Choices by Reading the Sentence Aloud:
After selecting an option, re-read the sentence in your mind (or quietly aloud). Does the sentence flow? Is the grammar natural? If anything “sounds wrong,” check for a better option. Many errors in PTE come from skipping this simple “double-check.”
After selecting an option, re-read the sentence in your mind (or quietly aloud). Does the sentence flow? Is the grammar natural? If anything “sounds wrong,” check for a better option. Many errors in PTE come from skipping this simple “double-check.”
8
Be Careful with Tricky Distractors:
Some options fit grammatically but not logically (or scientifically). Don’t be fooled by words that are “nearly correct”—think about the actual meaning the passage needs. Double-check all similar options, especially technical terms!
Some options fit grammatically but not logically (or scientifically). Don’t be fooled by words that are “nearly correct”—think about the actual meaning the passage needs. Double-check all similar options, especially technical terms!
9
Review All Your Answers for Consistency:
When all blanks are filled, read the passage again from start to finish. Does it make sense from an academic/scientific viewpoint? Do all terms match the scientific style of the text? Editing your work is a pro skill—and it’s essential on the real PTE!
When all blanks are filled, read the passage again from start to finish. Does it make sense from an academic/scientific viewpoint? Do all terms match the scientific style of the text? Editing your work is a pro skill—and it’s essential on the real PTE!
10
Check for Academic Style and Submit:
Before submitting, make sure you’ve filled every blank, each choice matches the grammar, and the passage “sounds” academic. The PTE system will only accept your first submission, so confidence matters. Take a deep breath—and trust your preparation!
Before submitting, make sure you’ve filled every blank, each choice matches the grammar, and the passage “sounds” academic. The PTE system will only accept your first submission, so confidence matters. Take a deep breath—and trust your preparation!
11
Always Review the Answer Key—Learn from Explanations:
After the task, carefully read the answer explanations. Understand why each answer is correct—focus on context, collocations, and grammar. Every review helps you spot patterns, avoid past mistakes, and improve your reading skills for future exams!
After the task, carefully read the answer explanations. Understand why each answer is correct—focus on context, collocations, and grammar. Every review helps you spot patterns, avoid past mistakes, and improve your reading skills for future exams!
Example: Mini Fill in the Blanks (Dropdown) Task
Passage:
The shape of DNA is called a . This structure allows it to genetic information.
Options for blank 1: [double helix, twisted ladder, single strand]
Options for blank 2: [carry, destroy, replace]
Correct Answers: (1) double helix, (2) carry
Why? “Double helix” is the technical term for DNA’s shape; “carry” fits the scientific function of DNA.
The shape of DNA is called a . This structure allows it to genetic information.
Options for blank 1: [double helix, twisted ladder, single strand]
Options for blank 2: [carry, destroy, replace]
Correct Answers: (1) double helix, (2) carry
Why? “Double helix” is the technical term for DNA’s shape; “carry” fits the scientific function of DNA.
Practice: Fill in the Blanks (Dropdown) – The Structure of DNA
Instructions: Read the academic passage below about The Structure of DNA. Several words or phrases are missing.
For each blank, click the dropdown and select the best answer. Choose the option that makes the passage grammatically correct and logical.
Each word/phrase can only be used once. Not all options are needed.
For each blank, click the dropdown and select the best answer. Choose the option that makes the passage grammatically correct and logical.
Each word/phrase can only be used once. Not all options are needed.
Fill in the Blanks Passage:
Deoxyribonucleic acid (DNA) is the molecule that genetic instructions in all living organisms. Its structure was first described by Watson and Crick in 1953, who revealed that DNA exists as a —two long strands coiled around each other.
Each strand is composed of repeating units called , which consist of a phosphate group, a sugar molecule, and a nitrogenous base. The two strands are held together by between complementary bases, forming what is known as base pairs.
The sequence of bases along the DNA strand determines the for building proteins. DNA’s structure allows it to accurately, ensuring that genetic information is faithfully passed on during cell division.
The forms the exterior of the molecule, giving stability to the helix. Advances in molecular biology have shown that even small changes in DNA’s sequence, called , can have significant effects on an organism’s characteristics and health.
Each strand is composed of repeating units called , which consist of a phosphate group, a sugar molecule, and a nitrogenous base. The two strands are held together by between complementary bases, forming what is known as base pairs.
The sequence of bases along the DNA strand determines the for building proteins. DNA’s structure allows it to accurately, ensuring that genetic information is faithfully passed on during cell division.
The forms the exterior of the molecule, giving stability to the helix. Advances in molecular biology have shown that even small changes in DNA’s sequence, called , can have significant effects on an organism’s characteristics and health.
encodes
double helix
nucleotides
hydrogen bonds
genetic code
replicate
sugar-phosphate backbone
mutations
translates
imitates
linear chain
triple strand
enzymes
carbohydrates
ionic bonds
peptide bonds
cell membrane
energy supply
decompose
mutate
lipid bilayer
amino acid chain
reactions
regulations
Answer Key & Step-by-Step Explanation
Master this PTE Academic Fill in the Blanks (Dropdown) passage about DNA! Read the detailed logic, vocabulary, grammar, collocations, and scientific clues for every blank. These explanations will strengthen your exam skills for complex academic reading and word choice.
1st Blank:
encodes (Deoxyribonucleic acid (DNA) is the molecule that encodes genetic instructions...)
The verb “encodes” is the precise scientific word for what DNA does—it “encodes” (stores, represents, and transmits) the genetic information required by living organisms.
In this context, “translates” means changing something into another form (like translating a language), which doesn’t fit. “Imitates” means to copy the actions of something else, which also does not fit DNA’s function here.
The grammar clue is that the sentence needs a verb that matches “genetic instructions” as the object.
Academic texts in biology use “encode” as a technical term for the molecular representation of genetic data.
Students sometimes choose “translates” because DNA is involved in translation (in protein synthesis), but here the sentence is about storing, not translating.
Collocation tip: “encodes genetic information/instructions” is a classic phrase in molecular biology.
“Encodes” emphasizes that DNA is a code—a chemical sequence that holds and passes on data.
Scientific context and the direct object (“genetic instructions”) require the most precise verb.
This blank tests your academic vocabulary and understanding of the logic of scientific processes.
Always pick the answer that fits both technical meaning and sentence structure.
2nd Blank:
double helix (...DNA exists as a double helix—two long strands coiled around each other.)
“Double helix” is the universally accepted term for the shape of the DNA molecule: two strands twisted together in a spiral, resembling a ladder that’s been twisted.
“Linear chain” and “triple strand” are scientific distractors. DNA is never described as “triple strand”; “linear chain” describes some RNA or protein structures, not DNA’s iconic form.
The phrase “coiled around each other” strongly supports the selection of “double helix.”
Academic and exam texts often rely on precise technical vocabulary—“double helix” is a must-know for biology.
Grammar note: only a noun phrase describing a shape/structure fits after “exists as a.”
Visual imagery in scientific reading—think of Watson and Crick’s famous model—helps anchor the right answer.
Collocation tip: “double helix structure,” “the DNA double helix.”
“Triple strand” would suggest three intertwined strands, which is incorrect for standard DNA.
This blank tests your ability to match detailed scientific description with the correct technical term.
Context and background knowledge in science are rewarded here.
3rd Blank:
nucleotides (Each strand is composed of repeating units called nucleotides...)
“Nucleotides” are the monomer units that make up each DNA strand; each contains a sugar, phosphate, and a nitrogenous base.
“Enzymes” are proteins that catalyze biochemical reactions, not structural units of DNA. “Carbohydrates” are sugars and related molecules—again, incorrect here.
The phrase “repeating units called ___” is common in academic science texts, and “nucleotides” is the only precise answer.
A technical reading clue: “phosphate group, a sugar molecule, and a nitrogenous base” is the textbook definition of a nucleotide.
Knowing the structure of DNA is basic to molecular biology and is tested in all major academic English and science exams.
Collocation: “nucleotide sequence,” “chain of nucleotides.”
Grammatically, the noun “nucleotides” fits perfectly as the object of “composed of.”
You should always check that your answer matches both the grammatical structure and the scientific content.
This blank rewards deep content knowledge and careful analysis of definitions in context.
4th Blank:
hydrogen bonds (The two strands are held together by hydrogen bonds...)
“Hydrogen bonds” are weak chemical bonds that form between specific pairs of bases in the DNA helix, providing just enough strength for stability but also flexibility for replication and repair.
“Ionic bonds” and “peptide bonds” are common distractors: ionic bonds form between charged atoms, and peptide bonds join amino acids in proteins, not DNA bases.
The phrase “held together by ___ between complementary bases” is classic for describing DNA’s structure.
A science exam tip: always match the bonding type with the molecular structure. Only “hydrogen bonds” occur between DNA strands.
The word “complementary” is a key clue, since A pairs with T, and C with G, held by hydrogen bonds.
Grammar: a plural noun fits (“by ___”), matching the structure of the sentence and scientific conventions.
Academic context expects the technical precision of “hydrogen bonds” here.
Students often confuse these chemical bond types; knowing their usage is key for academic reading.
Collocation: “hydrogen bonds between base pairs.”
This blank tests both deep science and advanced English collocations.
5th Blank:
genetic code (The sequence of bases along the DNA strand determines the genetic code...)
The “genetic code” refers to the information encoded in the order of DNA bases, which is used to build proteins during gene expression.
“Cell membrane” and “energy supply” are unrelated here—those are biological structures or concepts that don’t connect with the base sequence’s function.
The phrase “sequence of bases determines the ___ for building proteins” is a classic definition of the genetic code in academic science.
Collocation: “genetic code” is nearly always used in this context; “code for proteins,” “decode the genetic code.”
Grammar: only a noun describing information fits after “determines the ___ for building proteins.”
Students must match scientific logic—DNA’s function is to store and transmit the genetic code, not physical structures.
Precise academic reading means choosing not just “any” correct word, but the best technical answer.
This blank rewards both vocabulary knowledge and understanding of molecular biology principles.
6th Blank:
replicate (DNA’s structure allows it to replicate accurately...)
“Replicate” means to make an exact copy of something. The key biological feature of DNA is its ability to replicate itself during cell division, ensuring faithful inheritance of genetic information.
“Decompose” means to break down or rot, and “mutate” means to change, but the sentence focuses on copying, not breaking or altering DNA.
The word “accurately” in the sentence is a clue: DNA’s greatest strength is its precision in making copies.
Grammar: a verb is needed (“allows it to ___ accurately”).
Academic reading often requires recognizing that “replicate” is a technical word in genetics.
This blank checks whether you know both the scientific process and the exact language to describe it.
“Mutate” is a possible answer, but mutations are rare errors, not the normal function of DNA.
Collocation: “DNA replicates,” “accurate replication.”
This tests knowledge of scientific verbs, not just noun phrases.
7th Blank:
sugar-phosphate backbone (The sugar-phosphate backbone forms the exterior of the molecule...)
The “sugar-phosphate backbone” is the chain of alternating sugar and phosphate groups that form the “outside rails” of the DNA double helix, providing structure and stability.
“Lipid bilayer” refers to cell membranes; “amino acid chain” refers to proteins—these are intentionally tricky distractors.
Grammar: a noun phrase is required (“The ___ forms the exterior of the molecule...”).
Academic texts about DNA almost always use “sugar-phosphate backbone” for this part of the molecule.
This blank requires careful scientific reading—mixing up these biomolecules is a classic student error.
Collocation: “DNA backbone,” “sugar-phosphate backbone.”
Exam skills: always double-check that your answer fits both science content and English grammar.
8th Blank:
mutations (...small changes in DNA’s sequence, called mutations, can have significant effects...)
“Mutations” are any changes or errors in the DNA sequence; they can affect the structure, function, and inheritance of genetic traits, sometimes causing disease or variation.
“Reactions” and “regulations” are both distractors: chemical reactions happen in cells but are not sequence changes; regulation means controlling or adjusting a process, not changing DNA itself.
The phrase “small changes in DNA’s sequence” is a direct definition of “mutations” in all biology and genetics textbooks.
Collocation: “point mutation,” “genetic mutation.”
Grammatically, only a plural noun fits (“called ___”).
Science logic: only “mutations” have the lasting genetic effects described in the sentence.
Advanced reading skills are shown by linking definitions, collocations, and logical consequence in context.
Key Strategies for Fill in the Blanks (Dropdown) – Academic Reading:
1. Predict the meaning and grammar of the missing word before looking at dropdown options.
2. Match scientific logic, not just grammar. Technical terms and collocations are crucial for full marks.
3. Distractors are designed to “almost fit” but always break scientific or linguistic logic. Read carefully!
4. Review each answer by rereading the full passage for logical flow and technical correctness.
5. Study these explanations to master both the English and the science for top PTE Reading scores.
10 Hardest Words from the Passage & Questions
Master these advanced academic words from “The Structure of DNA” passage! Hover over each card for a glowing effect. Phonetics, patterns, and real exam usage included!
(Responsive and interactive—perfect for exam prep!)
encode
/ɪnˈkəʊd/ (BrE), /ɪnˈkoʊd/ (AmE)
Part of Speech:
verb
Word Pattern:
encode information, encode a message, encode genetic instructions
Definition:
To store, represent, or express information in a particular form, especially using a code or symbols.
Example:
DNA encodes all the genetic instructions for life. (It stores genetic data.)
Synonym: represent, store
Common Mistake: Using "encode" when "decode" (to interpret or read the code) is needed.
double helix
/ˌdʌb.əl ˈhiː.lɪks/ (BrE), /ˌdʌb.əl ˈhiː.lɪks/ (AmE)
Part of Speech:
noun
Word Pattern:
the DNA double helix, forms a double helix
Definition:
The spiral shape formed by two strands of DNA winding around each other.
Example:
Watson and Crick discovered the double helix structure of DNA. (DNA's shape.)
Synonym: spiral, coil (less precise)
Common Mistake: Writing "double helices" for the plural; "double helix" is singular.
nucleotide
/ˈnjuːkliəˌtaɪd/ (BrE), /ˈnuːkliəˌtaɪd/ (AmE)
Part of Speech:
noun
Word Pattern:
chain of nucleotides, nucleotide sequence
Definition:
The basic building block of DNA or RNA, consisting of a sugar, a phosphate, and a nitrogenous base.
Example:
Each nucleotide contains a base, a sugar, and a phosphate. (Basic unit of DNA.)
Synonym: (no simple synonym; sometimes called "building block")
Common Mistake: Confusing "nucleotide" with "nucleoside" (which lacks the phosphate group).
hydrogen bond
/ˈhaɪ.drɪ.dʒən bɒnd/ (BrE), /ˈhaɪ.drə.dʒən bɑːnd/ (AmE)
Part of Speech:
noun
Word Pattern:
form hydrogen bonds, held together by hydrogen bonds
Definition:
A weak chemical bond between a hydrogen atom and another atom, especially in DNA between base pairs.
Example:
The two DNA strands are held together by hydrogen bonds. (The strands “stick” via these bonds.)
Synonym: (no direct synonym in chemistry)
Common Mistake: Confusing "hydrogen bond" with "covalent" or "ionic" bonds.
genetic code
/dʒəˈnet.ɪk kəʊd/ (BrE), /dʒəˈnet.ɪk koʊd/ (AmE)
Part of Speech:
noun
Word Pattern:
carry the genetic code, code for proteins
Definition:
The set of rules by which information in DNA is used to build proteins in living things.
Example:
The genetic code is universal for almost all organisms. (All life “reads” DNA the same way.)
Synonym: (none; sometimes “DNA code” in non-academic texts)
Common Mistake: Using "genetic code" to refer to physical traits rather than the underlying DNA instructions.
replicate
/ˈreplɪkeɪt/ (BrE), /ˈrepləˌkeɪt/ (AmE)
Part of Speech:
verb
Word Pattern:
replicate itself, DNA replicates
Definition:
To make an exact copy or duplicate of something.
Example:
DNA can replicate with great accuracy. (It makes a perfect copy.)
Synonym: copy, reproduce
Common Mistake: Using "replicate" when "mutate" is meant (opposite meanings in biology).
backbone
/ˈbækbəʊn/ (BrE), /ˈbækboʊn/ (AmE)
Part of Speech:
noun
Word Pattern:
sugar-phosphate backbone, the backbone of DNA
Definition:
The main structural part of something; in DNA, the alternating sugar and phosphate chain supporting the structure.
Example:
The sugar-phosphate backbone keeps DNA stable. (It gives the helix strength.)
Synonym: main support, foundation
Common Mistake: Using "backbone" for the whole DNA molecule, not just its structural support.
mutation
/mjuːˈteɪʃn/ (BrE), /mjuˈteɪʃn/ (AmE)
Part of Speech:
noun
Word Pattern:
genetic mutation, cause a mutation
Definition:
A change in the sequence of DNA that can affect traits or health.
Example:
A single mutation can lead to genetic disease. (One DNA change can be serious.)
Synonym: change, alteration (in genetics, “mutation” is preferred)
Common Mistake: Using "mutation" for intentional change; it’s usually random or accidental.
strand
/strænd/ (BrE), /strænd/ (AmE)
Part of Speech:
noun
Word Pattern:
DNA strand, single/double strand
Definition:
A thin length of something; in biology, a single chain of DNA or RNA.
Example:
Each DNA molecule has two strands. (Two “strings” twisted together.)
Synonym: chain, thread
Common Mistake: Using "strand" for “strand of hair”—the biological use is more technical.
complementary
/ˌkɒmplɪˈmentəri/ (BrE), /ˌkɑːmpləˈmentəri/ (AmE)
Part of Speech:
adjective
Word Pattern:
complementary base pairs, complementary strand
Definition:
Fitting together perfectly; in DNA, bases that pair (A with T, C with G).
Example:
Adenine is complementary to thymine. (A always pairs with T.)
Synonym: matching, paired
Common Mistake: Confusing "complementary" (matches) with "complimentary" (means “free” or giving praise).
10 Hardest Phrases & Expressions from the Passage & Questions
Unlock the most challenging scientific expressions! Each interactive card gives you phonetics, grammar, patterns, meaning, usage, synonyms, and common mistakes.
(Hover for a smooth blue glow—built for exam success!)
(Hover for a smooth blue glow—built for exam success!)
encodes genetic instructions
/ɪnˈkəʊdz dʒəˈnet.ɪk ɪnˈstrʌk.ʃənz/ (BrE), /ɪnˈkoʊdz dʒəˈnet.ɪk ɪnˈstrʌk.ʃənz/ (AmE)
Part of Speech:
verb + adjective + noun
Word Pattern:
encodes genetic instructions for, encodes instructions needed to
Definition:
Stores or represents the information required for life processes in DNA.
Example:
DNA encodes genetic instructions for cell function. (Stores life’s “blueprint.”)
Synonym: stores biological information
Common Mistake: Saying “writes” or “creates” instructions—DNA encodes them.
double helix structure
/ˌdʌb.əl ˈhiː.lɪks ˈstrʌk.tʃər/ (BrE), /ˌdʌb.əl ˈhiː.lɪks ˈstrʌk.tʃɚ/ (AmE)
Part of Speech:
noun phrase
Word Pattern:
the double helix structure of, forms a double helix structure
Definition:
The spiral, ladder-like shape formed by two winding DNA strands.
Example:
The double helix structure makes DNA stable. (Shape = strength.)
Synonym: spiral form
Common Mistake: Saying “double spiral structure” (not used in biology).
base pairs
/beɪs peəz/ (BrE), /beɪs perz/ (AmE)
Part of Speech:
noun (plural)
Word Pattern:
complementary base pairs, hydrogen bonds between base pairs
Definition:
Two nitrogenous bases from opposite DNA strands that bond together (A-T, C-G).
Example:
DNA contains millions of base pairs. (A-T and C-G “rungs.”)
Synonym: paired bases
Common Mistake: Mixing up base pairs with “amino acids” (which build proteins).
sugar-phosphate backbone
/ˈʃʊɡə ˈfɒsfeɪt ˈbækbəʊn/ (BrE), /ˈʃʊɡər ˈfɑːsfeɪt ˈbækboʊn/ (AmE)
Part of Speech:
noun phrase
Word Pattern:
forms the sugar-phosphate backbone, DNA’s backbone
Definition:
The outer supporting structure of DNA, made of sugars and phosphates.
Example:
The sugar-phosphate backbone protects DNA’s core. (Acts as a shield.)
Synonym: structural support
Common Mistake: Using “lipid backbone”—lipids are not in DNA.
complementary bases
/ˌkɒmplɪˈmentəri ˈbeɪsɪz/ (BrE), /ˌkɑːmpləˈmentəri ˈbeɪsɪz/ (AmE)
Part of Speech:
adjective + noun
Word Pattern:
pair of complementary bases, complementary bases pair up
Definition:
Bases that always pair together in DNA (A with T, C with G).
Example:
Complementary bases keep the DNA code stable. (A “matches” T, C “matches” G.)
Synonym: matching bases
Common Mistake: Using “complimentary” (wrong spelling/meaning—means free/polite).
hydrogen bonds
/ˈhaɪ.drɪ.dʒən bɒndz/ (BrE), /ˈhaɪ.drə.dʒən bɑːndz/ (AmE)
Part of Speech:
noun (plural)
Word Pattern:
held by hydrogen bonds, break hydrogen bonds
Definition:
Weak chemical links between DNA base pairs holding the double helix together.
Example:
Heating DNA breaks the hydrogen bonds. (The strands “unzip.”)
Synonym: weak links, molecular bridges
Common Mistake: Saying “hydrogen bridge” (not a scientific term).
genetic code for proteins
/dʒəˈnet.ɪk kəʊd fə ˈprəʊtiːnz/ (BrE), /dʒəˈnet.ɪk koʊd fər ˈproʊtiːnz/ (AmE)
Part of Speech:
noun phrase
Word Pattern:
the genetic code for proteins, code for protein synthesis
Definition:
The DNA information used by cells to make proteins.
Example:
Changes in the genetic code for proteins can cause disease. (DNA “instructions” for building.)
Synonym: protein blueprint
Common Mistake: Saying “protein code”—the correct academic phrase is “genetic code for proteins.”
replicates accurately
/ˈreplɪkeɪts ˈækjərətli/ (BrE), /ˈrepləˌkeɪts ˈækjərətli/ (AmE)
Part of Speech:
verb + adverb
Word Pattern:
DNA replicates accurately, to replicate accurately
Definition:
Copies itself exactly, with very few errors.
Example:
DNA replicates accurately during cell division. (Copy is nearly perfect.)
Synonym: copies perfectly
Common Mistake: Writing “replicate correct”—“accurately” is the correct adverb.
sequence of bases
/ˈsiːkwəns əv ˈbeɪsɪz/ (BrE), /ˈsiːkwəns əv ˈbeɪsɪz/ (AmE)
Part of Speech:
noun phrase
Word Pattern:
sequence of bases, order of bases
Definition:
The specific order of nucleotides (A, T, C, G) in a DNA strand.
Example:
Each person’s sequence of bases is unique. (Our DNA order is one-of-a-kind.)
Synonym: order of nucleotides
Common Mistake: Using “sequences of base” (should be singular: “sequence of bases”).
cell division
/sel dɪˈvɪʒn/ (BrE & AmE)
Part of Speech:
noun phrase
Word Pattern:
during cell division, after cell division
Definition:
The biological process where a cell splits to form two new cells.
Example:
DNA is copied before cell division. (Each new cell gets a copy.)
Synonym: mitosis (in specific context)
Common Mistake: Using “division cell”—the correct phrase is “cell division.”
Interactive Exercise 1: Test Your DNA Vocabulary & Expressions!
Practice makes perfect! Choose the best answer for each question. After answering, get instant expert feedback and explanations. Try to score 10 out of 10!
Interactive Exercise 2: Deep Dive into DNA Words & Expressions
Challenge yourself! Choose the most accurate answer for each question. Get immediate feedback, see expert explanations, and review any mistakes to build your academic vocabulary mastery.
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