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daughter cells with the same genetic information as the parent cell, so somatic cells retain the genome originally present in the fertilised egg."},{"text":"They are produced by meiosis.","correct":false,"explanation":"Meiosis produces genetically varied haploid gametes rather than ordinary somatic cells. Most somatic cells arise by mitosis, which preserves the genetic information of the fertilised egg."},{"text":"They are produced by fertilisation.","correct":false,"explanation":"Fertilisation produces the initial diploid zygote but does not produce most somatic cells. These develop from the zygote through repeated mitotic cell divisions."},{"text":"They are produced by binary fission.","correct":false,"explanation":"Binary fission is the characteristic division process of prokaryotic cells. Eukaryotic somatic cells are produced by mitosis, which copies and distributes the chromosomes."}]},{"id":"5c3ab66f-242b-46d1-9087-e7a9c5d73c8e","cardType":"basic","points":2,"front":"Why can a neurone and a liver cell have the same DNA but different functions?","back":"They express different genes, producing different mRNA and proteins.","mcqOptions":[{"text":"They express different genes, producing different mRNA and proteins.","correct":true,"explanation":"Selective gene expression means each cell type transcribes and translates a different subset of its genes. The resulting proteins give neurones and liver cells different structures and functions."},{"text":"They express the same genes, producing identical mRNA and proteins.","correct":false,"explanation":"Identical gene expression would produce the same range of mRNA and proteins, so it would not explain specialisation. The cells differ because they express different genes."},{"text":"They contain different genes, producing different mRNA and proteins.","correct":false,"explanation":"Cell differentiation usually does not change which genes are present in the genome. Neurones and liver cells instead express different subsets of the same genes."},{"text":"They translate the same mRNA, producing different proteins and functions.","correct":false,"explanation":"A particular mRNA normally specifies the same amino acid sequence wherever it is translated. Different cell functions primarily result from expressing different genes and producing different mRNA molecules."}]},{"id":"28250973-59c9-4df5-b2c7-12bbc4d1a2cc","cardType":"basic","points":1,"front":"Why can’t mature mammalian red blood cells transcribe new genes?","back":"They have no nucleus.","mcqOptions":[{"text":"They have no nucleus.","correct":true,"explanation":"Mature mammalian red blood cells lose their nucleus during development. Without nuclear DNA and the transcription machinery associated with it, they cannot transcribe new genes."},{"text":"They have no ribosomes.","correct":false,"explanation":"Lacking ribosomes prevents translation, not transcription itself. Mature mammalian red blood cells cannot transcribe genes because they have expelled their nucleus and therefore lack nuclear DNA."},{"text":"They have no mitochondria.","correct":false,"explanation":"The absence of mitochondria prevents aerobic respiration but does not directly explain the loss of transcription. Transcription is impossible because mature red blood cells have no nucleus."},{"text":"They have no cell membrane.","correct":false,"explanation":"Mature red blood cells have a plasma membrane enclosing their cytoplasm. They cannot transcribe new genes because they lack a nucleus containing DNA, not because they lack a membrane."}]},{"id":"bbd1cb4b-d9f8-48b0-8f15-b9cb47b0e1b5","cardType":"cloze","points":null,"front":"A gene usually codes for a [ ], which folds to form a [ ].","back":"A gene usually codes for a polypeptide, which folds to form a protein.","mcqOptions":[{"text":"A gene usually codes for a polypeptide, which folds to form a protein.","correct":true,"explanation":"The nucleotide sequence of a gene determines the amino acid sequence of a polypeptide. Folding gives the polypeptide its specific three-dimensional shape, producing a functional protein."},{"text":"A gene usually codes for a protein, which folds to form a polypeptide.","correct":false,"explanation":"This reverses the relationship between the two terms. A gene specifies a polypeptide chain, and that chain folds into the three-dimensional structure of a protein."},{"text":"A gene usually codes for a nucleotide, which folds to form a protein.","correct":false,"explanation":"Nucleotides are the monomers that make up DNA and RNA, not the direct product specified by a protein-coding gene. The gene codes for a polypeptide that folds into a protein."},{"text":"A gene usually codes for a polypeptide, which folds to form a mRNA.","correct":false,"explanation":"mRNA is produced by transcription before the polypeptide is synthesised, so it is not formed by polypeptide folding. A polypeptide folds to form a protein."}]},{"id":"e9085702-5222-40e7-a0e1-2658d4cfde12","cardType":"cloze","points":null,"front":"[ ] makes an mRNA copy of a gene; [ ] uses mRNA to make a polypeptide.","back":"Transcription makes an mRNA copy of a gene; translation uses mRNA to make a polypeptide.","mcqOptions":[{"text":"Transcription makes an mRNA copy of a gene; translation uses mRNA to make a polypeptide.","correct":true,"explanation":"During transcription, RNA polymerase uses the DNA template to produce mRNA. During translation, ribosomes read the mRNA codons and join amino acids into a polypeptide."},{"text":"Translation makes an mRNA copy of a gene; transcription uses mRNA to make a polypeptide.","correct":false,"explanation":"This swaps the two stages of gene expression. Transcription copies the DNA sequence into mRNA, while translation reads that mRNA to assemble a polypeptide."},{"text":"Replication makes an mRNA copy of a gene; translation uses mRNA to make a polypeptide.","correct":false,"explanation":"Replication copies DNA to produce more DNA rather than mRNA. Transcription makes the mRNA copy, and translation then uses that mRNA to produce a polypeptide."},{"text":"Transcription makes an mRNA copy of a gene; replication uses mRNA to make a polypeptide.","correct":false,"explanation":"Replication uses DNA as a template to copy the genome and does not assemble amino acids. Translation uses mRNA at a ribosome to make a polypeptide."}]},{"id":"627a5a28-906b-432f-91d4-e9e06791972a","cardType":"cloze","points":null,"front":"The set of proteins made by a cell is its [ ].","back":"The set of proteins made by a cell is its proteome.","mcqOptions":[{"text":"proteome","correct":true,"explanation":"The proteome is the complete set of proteins expressed by a cell at a particular time. It can change as gene expression and environmental conditions change."},{"text":"genome","correct":false,"explanation":"The genome is the complete set of genetic material in a cell, not the proteins being produced. The set of proteins made by a cell is its proteome."},{"text":"transcriptome","correct":false,"explanation":"The transcriptome is the complete set of RNA transcripts produced by a cell. The corresponding set of proteins made through translation is called the proteome."},{"text":"metabolome","correct":false,"explanation":"The metabolome consists of the small molecules and metabolic intermediates present in a cell. The complete set of proteins produced by the cell is its proteome."}]},{"id":"2f253646-adf1-4c1e-aef1-f07014e99b39","cardType":"basic","points":1,"front":"In ciliated epithelial cells, what do tubulin proteins form?","back":"Microtubules inside cilia.","mcqOptions":[{"text":"Microtubules inside cilia.","correct":true,"explanation":"Tubulin subunits polymerise to form microtubules. These microtubules are arranged within each cilium to create the axoneme that supports and enables ciliary movement."},{"text":"Microfilaments inside cilia.","correct":false,"explanation":"Microfilaments are primarily made from actin rather than tubulin. In cilia, tubulin forms the microtubules of the internal axoneme."},{"text":"Intermediate filaments inside cilia.","correct":false,"explanation":"Intermediate filaments are built from proteins such as keratins, not tubulin, and provide mechanical strength elsewhere in cells. Tubulin forms microtubules inside cilia."},{"text":"Microtubules inside microvilli.","correct":false,"explanation":"This confuses cilia with microvilli. Microvilli are supported mainly by actin microfilaments, whereas tubulin forms the microtubules arranged inside cilia."}]},{"id":"cb705d81-f33e-4a98-a19e-a4ae67d27644","cardType":"basic","points":2,"front":"How do dynein proteins help cilia beat?","back":"They use ATP to produce bending movements.","mcqOptions":[{"text":"They use ATP to produce bending movements.","correct":true,"explanation":"Dynein is a motor protein that hydrolyses ATP and moves adjacent microtubule doublets relative to one another. Structural links convert this sliding into ciliary bending."},{"text":"They use GTP to produce bending movements.","correct":false,"explanation":"GTP is associated with tubulin polymerisation, making it a tempting confusion with microtubule formation. Dynein hydrolyses ATP to drive the movements that bend cilia."},{"text":"They use ATP to produce straightening movements.","correct":false,"explanation":"Dynein-driven sliding between neighbouring microtubules is constrained and converted into bending, not simple straightening. ATP supplies the energy for these bending movements."},{"text":"They use ATP to assemble tubulin fibres.","correct":false,"explanation":"Dynein moves along existing microtubules rather than assembling tubulin fibres. It hydrolyses ATP to generate relative microtubule sliding, which produces bending movements in cilia."}]},{"id":"735d56a6-4a53-4d5b-a817-6b124b0b2bad","cardType":"basic","points":2,"front":"Why does high expression of respiratory enzyme genes help ciliated epithelial cells?","back":"It supplies more ATP for ciliary movement.","mcqOptions":[{"text":"It supplies more ATP for ciliary movement.","correct":true,"explanation":"Cilia require ATP to power the motor proteins that produce their beating movement, so increased respiratory enzyme expression supports the high energy demand of ciliated epithelial cells."},{"text":"It supplies more DNA for ciliary movement.","correct":false,"explanation":"DNA stores genetic information and does not directly power ciliary beating. The correct answer is more ATP, produced through respiration and used by motor proteins in the cilia."},{"text":"It supplies more glucose for ciliary movement.","correct":false,"explanation":"Glucose is a respiratory substrate rather than the immediate energy source for ciliary movement. High respiratory enzyme expression increases ATP production, which powers the cilia."},{"text":"It supplies more oxygen for ciliary movement.","correct":false,"explanation":"Oxygen is needed for aerobic respiration but does not directly drive ciliary movement. The relevant product is ATP, which provides energy for the cilia’s motor proteins."}]},{"id":"54fde50d-aeda-469a-a599-e33eab37aac7","cardType":"cloze","points":null,"front":"Differential gene expression can mean different cells express different [ ], or the same genes at different [ ].","back":"Differential gene expression can mean different cells express different genes, or the same genes at different rates.","mcqOptions":[{"text":"Differential gene expression can mean different cells express different genes, or the same genes at different rates.","correct":true,"explanation":"Cells can differ by switching particular genes on or off, or by transcribing the same gene at different rates. Both mechanisms produce different amounts of gene products."},{"text":"Differential gene expression can mean different cells express different alleles, or the same genes at different rates.","correct":false,"explanation":"Most specialised cells contain the same alleles, but regulate which genes are expressed. The correct term is genes, referring to different genes being active in different cells."},{"text":"Differential gene expression can mean different cells express different genes, or the same genes at different frequencies.","correct":false,"explanation":"The expected measure is transcription rate, not frequency. Differential expression involves different genes being expressed or the same genes being transcribed at different rates."},{"text":"Differential gene expression can mean different cells express different proteins, or the same genes at different rates.","correct":false,"explanation":"Different protein outputs can result from differential expression, but the definition concerns which genes are expressed. The correct first term is genes, not proteins."}]},{"id":"2b191117-def0-43b6-b2a5-25d4bef2fffa","cardType":"basic","points":2,"front":"What happens to unused genes in most specialised cells?","back":"They remain in the DNA, but are not transcribed or only weakly transcribed.","mcqOptions":[{"text":"They remain in the DNA, but are not transcribed or only weakly transcribed.","correct":true,"explanation":"Specialisation usually changes gene expression rather than removing genes. Unneeded genes remain in the cell’s DNA but are switched off or transcribed at a very low rate."},{"text":"They are removed from the DNA, so they cannot be transcribed.","correct":false,"explanation":"Specialised cells generally retain the same genome as other body cells. Unused genes are usually not deleted; they remain in DNA and are switched off or weakly transcribed."},{"text":"They remain in the DNA, but are translated instead of transcribed.","correct":false,"explanation":"Translation produces proteins from mRNA, whereas unused genes are regulated at transcription. They remain in the DNA but are not transcribed or are transcribed only weakly."},{"text":"They are converted into RNA, but are not translated or only weakly translated.","correct":false,"explanation":"Genes are DNA sequences and are not normally converted permanently into RNA. The correct description is that they remain in DNA and transcription is reduced or absent."}]},{"id":"d958aa8a-dcad-4d49-8316-2486c28e532a","cardType":"basic","points":1,"front":"Why are housekeeping genes expressed in almost all cells?","back":"They are needed for basic cell survival.","mcqOptions":[{"text":"They are needed for basic cell survival.","correct":true,"explanation":"Housekeeping genes produce proteins required for essential processes such as respiration, DNA maintenance and protein synthesis, so nearly all living cells need them to remain functional."},{"text":"They are needed for cell division only.","correct":false,"explanation":"Many housekeeping genes support cells whether or not they are dividing. They are expressed widely because they provide functions essential for basic cell survival."},{"text":"They are needed for specialised cell movement.","correct":false,"explanation":"Movement is important only in certain specialised cells, such as muscle or ciliated cells. Housekeeping genes are expressed broadly because they support basic survival in almost all cells."},{"text":"They are needed for producing antibodies.","correct":false,"explanation":"Antibody production is a specialised function of B lymphocytes, not a universal cellular requirement. Housekeeping genes are expressed widely because they maintain basic cell survival."}]},{"id":"909c19af-28db-4758-b339-79aba3c5f303","cardType":"basic","points":1,"front":"What binds at a promoter to begin transcription?","back":"RNA polymerase and other proteins.","mcqOptions":[{"text":"RNA polymerase and other proteins.","correct":true,"explanation":"RNA polymerase binds at the promoter, often with assistance from other proteins, positioning it so transcription can begin at the correct point on the DNA."},{"text":"DNA polymerase and other proteins.","correct":false,"explanation":"DNA polymerase copies DNA during replication, not transcription. RNA polymerase binds at the promoter to begin making an RNA transcript."},{"text":"Ribosomes and other proteins.","correct":false,"explanation":"Ribosomes translate mRNA into polypeptides and do not bind promoters. Transcription begins when RNA polymerase and associated proteins bind at the promoter."},{"text":"Restriction enzymes and other proteins.","correct":false,"explanation":"Restriction enzymes cut DNA at particular recognition sequences and do not initiate transcription. RNA polymerase binds at the promoter to start RNA synthesis."}]},{"id":"08809e02-76c2-4ff0-ad63-1434be24df78","cardType":"cloze","points":null,"front":"Some transcription factors increase transcription by helping [ ] bind; others reduce transcription by making DNA less [ ].","back":"Some transcription factors increase transcription by helping RNA polymerase bind; others reduce transcription by making DNA less accessible.","mcqOptions":[{"text":"Some transcription factors increase transcription by helping RNA polymerase bind; others reduce transcription by making DNA less accessible.","correct":true,"explanation":"Activator transcription factors can help RNA polymerase bind to a promoter, while repressor effects may reduce access to DNA, preventing transcription machinery from reaching the gene."},{"text":"Some transcription factors increase transcription by helping ribosomes bind; others reduce transcription by making DNA less accessible.","correct":false,"explanation":"Ribosomes bind mRNA during translation, not DNA during transcription. RNA polymerase must bind at the promoter, while reduced DNA accessibility can inhibit transcription."},{"text":"Some transcription factors increase transcription by helping RNA polymerase bind; others reduce transcription by making DNA less stable.","correct":false,"explanation":"DNA stability is not the key access mechanism described here. The correct term is accessible: tightly associated DNA is harder for transcription machinery to reach."},{"text":"Some transcription factors increase transcription by helping DNA polymerase bind; others reduce transcription by making DNA less accessible.","correct":false,"explanation":"DNA polymerase functions in DNA replication, whereas RNA polymerase carries out transcription. Activators assist RNA polymerase binding and reduced accessibility limits transcription."}]},{"id":"d42243be-d348-4ac8-8be7-9ae3d75e7fb4","cardType":"cloze","points":null,"front":"Eukaryotic DNA is wrapped around [ ] to form [ ].","back":"Eukaryotic DNA is wrapped around histones to form chromatin.","mcqOptions":[{"text":"Eukaryotic DNA is wrapped around histones to form chromatin.","correct":true,"explanation":"Histone proteins act as spools around which eukaryotic DNA winds. The resulting DNA-protein complex is chromatin, which helps package the long DNA molecules inside the nucleus."},{"text":"Eukaryotic DNA is wrapped around ribosomes to form chromatin.","correct":false,"explanation":"Ribosomes make proteins from mRNA and do not package DNA. DNA is wrapped around histones, producing the DNA-protein material called chromatin."},{"text":"Eukaryotic DNA is wrapped around histones to form nucleotides.","correct":false,"explanation":"Nucleotides are the individual building blocks of DNA, not the packaged DNA structure. Histones organise DNA into chromatin."},{"text":"Eukaryotic DNA is wrapped around centrioles to form chromatin.","correct":false,"explanation":"Centrioles help organise the spindle during cell division and do not package nuclear DNA. Histones provide the protein spools that form chromatin with DNA."}]},{"id":"ea45ce56-9de2-43be-8c12-afa5dae4c548","cardType":"basic","points":2,"front":"How does tightly packed chromatin affect transcription?","back":"It reduces transcription because RNA polymerase cannot easily reach genes.","mcqOptions":[{"text":"It reduces transcription because RNA polymerase cannot easily reach genes.","correct":true,"explanation":"Tightly packed chromatin makes DNA less accessible. RNA polymerase and associated transcription factors cannot readily bind the genes, so transcription is reduced."},{"text":"It increases transcription because RNA polymerase binds more strongly to genes.","correct":false,"explanation":"Tightly packed chromatin generally prevents transcription machinery reaching DNA rather than strengthening its binding. Reduced packing makes genes more accessible and transcription more likely."},{"text":"It stops translation because ribosomes cannot reach genes.","correct":false,"explanation":"Ribosomes act on mRNA in the cytoplasm, not directly on genes. Tightly packed chromatin primarily reduces transcription by restricting RNA polymerase access to DNA."},{"text":"It increases replication because DNA is protected from enzymes.","correct":false,"explanation":"Dense chromatin can restrict access for replication machinery as well as transcription machinery, but it does not increase replication. The stated effect is reduced transcription."}]},{"id":"911dd281-bcdf-499c-8cee-dd0e9751fbae","cardType":"cloze","points":null,"front":"Epigenetic modifications affect [ ] without changing the DNA [ ].","back":"Epigenetic modifications affect gene expression without changing the DNA base sequence.","mcqOptions":[{"text":"Epigenetic modifications affect gene expression without changing the DNA base sequence.","correct":true,"explanation":"Epigenetic modifications alter which genes are active or expressed, while the order of DNA bases remains unchanged. This changes gene activity without changing the underlying genetic code."},{"text":"Epigenetic modifications affect gene expression without changing the DNA phosphate backbone.","correct":false,"explanation":"Epigenetic modifications do not usually alter the DNA base sequence; they regulate gene expression. The DNA backbone is not the feature whose sequence is changed."},{"text":"Epigenetic modifications affect gene expression without changing the DNA chromosome number.","correct":false,"explanation":"Epigenetic changes regulate gene expression rather than changing the number of chromosomes. Chromosome number is altered by events such as nondisjunction or changes in ploidy."},{"text":"Epigenetic modifications affect gene expression without changing the DNA amino acid sequence.","correct":false,"explanation":"Epigenetic modifications affect gene activity without changing the DNA base sequence. The amino acid sequence is a product of gene expression and may change only if protein production is altered."}]},{"id":"7f165895-e7f9-4912-af97-9f5182b5cd9b","cardType":"basic","points":1,"front":"What is the usual effect of adding methyl groups to DNA?","back":"Reduced transcription.","mcqOptions":[{"text":"Reduced transcription.","correct":true,"explanation":"Methyl groups commonly attach to DNA near promoter regions and make transcription less likely, often by preventing transcription factors or RNA polymerase from binding effectively."},{"text":"Increased transcription.","correct":false,"explanation":"Increased transcription is the opposite of the usual effect of DNA methylation. Methyl groups generally repress promoter activity, reducing transcription of the associated gene."},{"text":"Reduced RNA splicing.","correct":false,"explanation":"DNA methylation generally affects transcription, not the direct removal of introns from pre-mRNA. Splicing is controlled by the spliceosome and associated regulatory factors."},{"text":"Increased DNA replication.","correct":false,"explanation":"Methylation does not usually increase DNA replication. Its typical role is to reduce transcription by making gene promoters less accessible or recruiting repressing proteins."}]},{"id":"88cbe589-74e1-4384-82da-35ee38196e04","cardType":"basic","points":2,"front":"During development, how can signals cause cells to differentiate?","back":"Signals affect transcription factors, changing which genes are expressed.","mcqOptions":[{"text":"Signals affect transcription factors, changing which genes are expressed.","correct":true,"explanation":"Developmental signals can alter the activity of transcription factors. These factors bind regulatory DNA and change which genes are transcribed, producing different patterns of cell specialisation."},{"text":"Signals affect ribosome sequences, changing which genes are expressed.","correct":false,"explanation":"Signals can influence transcription factors, but they do not normally differentiate cells by changing the ribosome sequence. Ribosomes are cellular structures involved in translation."},{"text":"Signals affect amino acid sequences, changing which genes are expressed.","correct":false,"explanation":"Signals regulate gene expression through transcription factors and related pathways, not by changing the amino acid sequences of DNA. DNA contains nucleotide bases, not amino acids."},{"text":"Signals affect membrane thickness, changing which genes are expressed.","correct":false,"explanation":"Signals may affect membrane receptors during cell signalling, but differentiation occurs through altered gene expression controlled by transcription factors, not by changing membrane thickness."}]},{"id":"422cb98a-d0ad-4dd0-98d9-14c2c5f01b98","cardType":"basic","points":1,"front":"Which stem cell potency can form all cell types, including placenta?","back":"Totipotent.","mcqOptions":[{"text":"Totipotent.","correct":true,"explanation":"Totipotent stem cells can produce every type of body cell as well as extra-embryonic tissues such as the placenta, giving them the widest developmental potential."},{"text":"Pluripotent.","correct":false,"explanation":"Pluripotent cells can form many body cell types but generally cannot form all extra-embryonic tissues, so they do not have the full potential required here."},{"text":"Multipotent.","correct":false,"explanation":"Multipotent cells produce a restricted range of related cell types, such as different blood cells. They cannot form all body and extra-embryonic tissues."},{"text":"Unipotent.","correct":false,"explanation":"Unipotent cells can produce only one main cell type, so their developmental potential is far narrower than that needed to form all cell types and placenta."}]},{"id":"22d7c207-5634-45ce-85f3-45c5cc5ac8eb","cardType":"basic","points":1,"front":"Which stem cell potency can form many body cell types but not all extra-embryonic tissues?","back":"Pluripotent.","mcqOptions":[{"text":"Pluripotent.","correct":true,"explanation":"Pluripotent stem cells can differentiate into many types of body cell, but they generally cannot produce all extra-embryonic tissues such as the placenta."},{"text":"Totipotent.","correct":false,"explanation":"Totipotent cells have greater potential than described: they can form all body cell types and extra-embryonic tissues, including the placenta."},{"text":"Multipotent.","correct":false,"explanation":"Multipotent cells form only a limited range of related cell types, so they cannot generally produce many different body cell types across the whole organism."},{"text":"Unipotent.","correct":false,"explanation":"Unipotent cells are restricted to producing one cell type. They therefore have much less developmental potential than pluripotent cells."}]},{"id":"0137bab3-2ce1-4800-8dfd-0d93409c1fc7","cardType":"basic","points":1,"front":"Which stem cell potency forms a limited range of related cell types?","back":"Multipotent.","mcqOptions":[{"text":"Multipotent.","correct":true,"explanation":"Multipotent stem cells can differentiate into a restricted range of related cell types, such as the different cell types formed by a tissue-specific stem cell."},{"text":"Pluripotent.","correct":false,"explanation":"Pluripotent cells can form many different body cell types from across the organism, not merely a limited range of related cells."},{"text":"Totipotent.","correct":false,"explanation":"Totipotent cells have the broadest potency and can form all body cell types plus extra-embryonic tissues, rather than only related cell types."},{"text":"Unipotent.","correct":false,"explanation":"Unipotent cells form one main cell type, whereas multipotent cells can produce several related cell types. Confusing these terms underestimates multipotency."}]},{"id":"6af85257-6ffd-4703-a753-c06759809202","cardType":"basic","points":3,"front":"Why is high mRNA abundance useful but imperfect evidence for functional protein abundance?","back":"

High mRNA suggests high transcription.
Translation, modification and breakdown also matter.

","mcqOptions":[{"text":"

High mRNA suggests high transcription.
Translation, modification and breakdown also matter.

","correct":true,"explanation":"A high mRNA level indicates active transcription, but protein abundance also depends on translation efficiency, post-translational modification and the rate at which the protein is broken down."},{"text":"

High mRNA guarantees high translation.
Transcription, modification and breakdown also matter.

","correct":false,"explanation":"mRNA abundance can suggest transcription, but it does not directly guarantee high translation. Protein modification and breakdown also affect the final functional protein abundance."},{"text":"

High mRNA suggests low transcription.
Translation, modification and breakdown also matter.

","correct":false,"explanation":"High mRNA is evidence of transcriptional activity, not proof that transcription is absent. Translation, modification and breakdown determine whether much functional protein accumulates."},{"text":"

High mRNA suggests high transcription.
Only translation matters afterwards.

","correct":false,"explanation":"Protein abundance is not determined only by translation. Transcription creates the mRNA, while modification and breakdown also influence the amount of functional protein present."}]},{"id":"3ce320eb-3d4f-4c6e-bda0-e0fe0d483b37","cardType":"basic","points":1,"front":"A gene has expression 48 units in cardiac muscle and 3 units in liver. What is the fold change?","back":"$$48 \\div 3 = \\mathbf{16}$ times higher.","mcqOptions":[{"text":"$$48 \\div 3 = \\mathbf{16}$ times higher.","correct":true,"explanation":"Fold change is calculated by dividing the cardiac muscle expression by the liver expression: $48 \\div 3 = 16$. Cardiac muscle therefore has 16 times higher expression."},{"text":"$$48 - 3 = \\mathbf{45}$ times higher.","correct":false,"explanation":"Subtracting the two expression values gives an absolute difference, not a fold change. Fold change requires division: $48 \\div 3 = 16$ times higher."},{"text":"$$48 + 3 = \\mathbf{51}$ times higher.","correct":false,"explanation":"Adding the expression values does not measure relative increase. The correct fold-change calculation divides cardiac muscle expression by liver expression: $48 \\div 3 = 16$."},{"text":"$$3 \\div 48 = \\mathbf{0.0625}$ times higher.","correct":false,"explanation":"Reversing the division gives the liver-to-cardiac ratio, approximately $0.0625$, rather than the cardiac-to-liver fold change. The required calculation is $48 \\div 3 = 16$."}]}]}],"examCountdown":{"examDate":"2027-06-07","paperLabel":"Paper 1"},"heading":"Differential gene expression and cell specialisation","title":"Differential gene expression and cell specialisation Flashcards","topbar":{"backHref":"/a-level/biology/edexcel/a/flashcards"},"topicSidebar":"$L38"}]}],"topicId":"9189379b-cdb9-5a07-ba96-c8e4c2fd305e","walled":"$L39"}],"$L3a","$L3b"]