BBCCT 105 Proteins Key Facts at a Glance
- Course code and title: BBCCT-105, Proteins
- Programme: B.Sc. (Honours) Biochemistry, BSCBCH
- Syllabus size: 4 blocks, 14 units
- Maximum marks and time: 70 marks in 3 hours
- Paired practical course: BBCCL-106 Proteins, 2 credits, 8 experiments
- Questions in this guess paper: 18 solved questions across 33 pages
- Diagrams drawn in the file: 7 labelled diagrams
- Past papers analysed: 4 sessions, December 2024 to June 2026
- Topics tracked session by session: 33
- Target sessions: December 2026 and June 2027 Term-End Examination
- Samples on this page: 5 full solved answers, 13 questions remain in the file
- Enquiry number: WhatsApp 9899436384
Key facts about IGNOU BBCCT 105 Proteins and the Unnati Educations guess paper built for the coming sessions
What the BBCCT 105 Guess Paper for Proteins Actually Contains
BBCCT 105 Solved Guess Paper is a 33 page question and answer file for IGNOU BBCCT-105 Proteins, holding 18 questions that recur across the Term-End papers, each answered in full from the IGNOU study material, with seven of them carrying a drawn and labelled diagram.
Proteins is not a subject you can write around. The examiner wants the exact figure, the exact count and the exact scientist. Write that the alpha helix has "about three and a half" residues per turn instead of 3.6 and the point is gone. Every number in this file is left as the book states it.
The 18 questions run across all four blocks and all 14 units. Thirteen are tagged HIGH priority, meaning the topic repeated across sessions or has been absent long enough to be due. Five are MEDIUM, held back as your backup set.
Students taking more than one biochemistry paper this session usually start from the wider IGNOU Solved Guess Paper collection and then pick up the individual codes they are actually sitting.
5 Sample Questions and Answers from the BBCCT 105 Solved Guess Paper
Five of the 18 questions are reproduced below in full, exactly as they appear in the file. Read them before you spend anything. The other 13 questions are in the paid file, and they follow this same shape without exception.
The five shown were picked to cover every answer type BBCCT-105 throws at you, an objective plus short notes question, two comparison answers with ready tables, a diagram answer, and a structure answer. If you can write in these four shapes, the paper holds no surprises.
Q1. (a) Fill in the blanks. (b) Write short notes on biologically active peptides, disulphide bond and osmotic shock.
(a) Fill in the blanks, with the reason behind each answer.
- A cell placed in a hypotonic solution becomes swollen. Water potential outside is lower than inside, so water flows in by endo-osmosis and the cell swells.
- In SDS gel electrophoresis molecules separate on the basis of molecular size and weight. SDS gives every chain a net negative charge, so only size decides the speed.
- Avidin has specific affinity for biotin. In affinity chromatography avidin is the ligand used to pull out biotin containing enzymes.
- A mass analyser measures the mass to charge (m/z) ratio. It never measures mass alone, and for multiply charged ions m/z is a fraction of the real mass.
- IgA immunoglobulin is found in tears and milk. IgA is the main antibody of external secretions such as saliva, tears and breast milk.
(b) (i) Biologically active peptides.
The book defines these as peptides that play key roles in physiological processes, acting as neurotransmitters, hormones and antibiotics.
- Oxytocin. Peptide hormone of nine amino acids, with a disulphide link between cysteine 1 and 6. Drives uterine contraction and milk production.
- Glutathione. Thiol tripeptide of cysteine, glutamic acid and glycine. A well known antioxidant that holds the cell redox balance.
- Insulin. Fifty-one amino acids, molecular weight 5808 daltons, an A chain and a B chain joined by disulphide bonds. Controls blood glucose.
- Bradykinin. Nine amino acid residues. A vasodilator and a diuretic factor.
- Gramicidin S. An antibiotic peptide, a cyclic decapeptide of two identical pentapeptides, active against bacteria and fungi.
(b) (ii) Disulphide bond.
A covalent bond, the disulphide bridge (-S-S-) produced by the sulphhydryl groups (-SH) of two cysteine residues.
- Formation. Two cysteine residues are oxidised, the two -SH groups join, and the pair becomes cystine.
- Reversible. Oxidation makes it and reduction breaks it, so it is a reversible covalent modification.
- Types. Intra-molecular within one protein such as ribonuclease, insulin and lysozyme. Inter-molecular between two proteins such as antibody chains.
- Role. It gives structural conformation and stability, and protein disulphide isomerases ensure the correct bonds form.
(b) (iii) Osmotic shock.
The method rests on osmosis, the diffusion of water across a semi-permeable membrane towards the side of higher solute concentration.
- Type. It is the third method of non-mechanical cell disruption.
- Hypertonic solution. Water leaves the cell and the cell shrinks. This is exo-osmosis.
- Isotonic solution. Solute and water are equal on both sides, so there is no net movement and no change in size.
- Hypotonic solution. Water enters, the cell swells and bursts, and this endo-osmosis releases the cell contents.
Conclusion. Objective questions test one sharp fact each, so learn the exact word. In short notes, open with the book definition, then give two or three crisp points.
Q5. (a) Describe the principle and applications of gel filtration chromatography with a suitable diagram. (b) Distinguish between gas chromatography and HPLC.
(a) Gel filtration chromatography.
The separation of molecules by molecular size and shape, using the sieve or filtration properties of porous materials.
- Set-up. A column of gel particles is held in equilibrium with a suitable mobile phase for the molecules being separated.
- Large molecules. They are completely excluded from the pores, so they move faster and reach the effluent first.
- Small molecules. They spread in and around the gel particles, so they pass through slowly and come out last.
- Procedure. Sample is loaded on top of a column 5 mm to 50 mm wide and 5 cm to 1 m high. Solvent is poured on top and fractions are collected in test tubes, each holding molecules of nearly the same size.
Applications. Purification of polysaccharides, proteins, enzymes, hormones, antibiotics and nucleic acids. Desalting of proteins and removal of phenol from nucleic acid preparations. Relative molecular mass determination and concentration of protein solutions. Protein binding studies.
(b) Gas chromatography versus HPLC.
| Feature | Gas chromatography | HPLC |
|---|---|---|
| Mobile phase | A carrier gas | A liquid solvent |
| Basis | Distribution or partition of solutes between stationary and mobile phase | Can adopt adsorption, partition, ion exchange and exclusion principles |
| Variants | Gas-solid and gas-liquid chromatography | Broadly liquid-liquid chromatography |
| Column | Long or coiled glass or metal, 1 to 3 m long, 0.25 mm to 50 mm wide | Straight stainless steel, 15 to 50 cm long, 1 to 4 mm wide |
| Pressure | Sample volatilised at temperature up to 200 degrees Celsius | Column withstands pressure up to 5.5 by 10 to the power 7 Pa |
| Resolution | Smaller the column diameter, higher the efficiency | Smaller the stationary phase particle, higher the resolution |
| Suitability | Suits volatile substances | Handles non-volatile compounds, unlike GC |
| Applications | Food adulteration, pesticide analysis, blood alcohol, plasma lipids, urinary steroids | Amino acids, proteins and peptides, drugs, antibiotics, steroids, dyes, environmental pollutants |
Conclusion. Gel filtration is the one chromatography where the biggest molecule leaves first. GC needs a volatile sample, while HPLC handles non-volatile samples under high pressure.
Q10. (a) Explain the different types of secondary structure present in proteins. (b) Distinguish between the alpha helix and the beta pleated sheet.
(a) Types of secondary structure.
Secondary structure means the local folded structures that form within a polypeptide through interactions between backbone atoms. Pauling and Corey identified two regular types, the alpha helix and the beta pleated sheet. Both are defined by hydrogen bonding patterns between main-chain peptide groups and are constrained to specific dihedral angle values on the Ramachandran plot.
Alpha helix.
- Shape. The most common secondary structure. Amino acids form a right-handed helix and each residue corresponds to a 100 degree turn.
- Dimensions. 3.6 residues per turn, translation of 1.5 angstrom along the axis, pitch of 5.4 angstrom, which is 1.5 multiplied by 3.6.
- Hydrogen bonding. The N-H group of one amino acid bonds with the C=O group four residues earlier, so residue i bonds to residue i+4.
- Proline. Absent from alpha helices. Its imino group cannot donate a hydrogen bond, which is why it is called a helix disruptor.
- Occurrence. Found in alpha keratin of skin, hair and nails.
Beta pleated sheet. Sheets consist of beta strands joined by at least two or three backbone hydrogen bonds into a generally twisted, pleated sheet. A strand is typically 3 to 10 amino acids long with the backbone almost fully extended. Strands sit parallel or anti-parallel, with side chains above and below the plane. Multiple sheets give strength to structural proteins such as silk fibroin, and higher-level association appears in the amyloidosis of Alzheimer's disease.
| Feature | Alpha helix | Beta pleated sheet |
|---|---|---|
| Occurrence | Most common secondary structure | Less common than the alpha helix |
| Shape | Right-handed helical structure | Twisted, pleated sheet of extended strands |
| Hydrogen bonding | Within the same chain, residue i to residue i+4 | Between adjacent strands, parallel or anti-parallel |
| Residues per turn | 3.6 residues per turn | Not applicable, strands are 3 to 10 amino acids long |
| Rise and spacing | Translation of 1.5 angstrom, pitch 5.4 angstrom | Pleating brings spacing to about 6 angstrom instead of 7.6 |
| Torsion angles | phi about minus 60 degrees, psi minus 45 to minus 50 degrees | Preferred angles near phi minus 135 degrees, psi 135 degrees |
| Side chains | Protrude outside the central core, seen as a helical wheel from the top | Protrude above and below the plane of the sheet |
| Proline | Absent, proline is a helix disruptor | Not restricted in the same way |
| Example | Alpha keratin of skin, hair and nails | Silk fibroin, amyloid fibrils in Alzheimer's disease |
Conclusion. Both structures are held only by backbone hydrogen bonds. The helix bonds inside one chain while the sheet bonds between strands, and that single difference explains every other difference in the table.
Q15. (a) Draw the oxygen binding curves of myoglobin and haemoglobin and discuss the factors affecting the oxygen dissociation curve. (b) Discuss the Bohr effect and the mechanism of chloride shift.
Appeared in all four sessions analysed, December 2024 through June 2026.
(a) Oxygen binding curves.
An oxygen binding curve plots fractional saturation against oxygen concentration, with partial pressure standing in for concentration.
- Myoglobin. The curve rises sharply and is hyperbolic. Half-saturation, P50, is at 2 torr, showing high oxygen affinity.
- Haemoglobin. The curve is S-shaped, therefore sigmoid. Its P50 is 26 torr, showing weaker binding than myoglobin.
- Cooperativity. Binding of oxygen at one site increases binding at the remaining unoccupied sites.
- Meaning of P50. The partial pressure at which Mb or Hb is 50 percent saturated, the conventional measure of affinity.
- Shifts. A right shift means reduced affinity, so more oxygen reaches the tissues. A left shift means increased affinity.
Factors affecting the dissociation curve. A rise in temperature shifts the curve right and lowers affinity. A fall in pH shifts it right, depending on histidine 146 of the beta subunit and histidine 122 of the alpha subunit. Carbon dioxide forms carbaminohaemoglobin, which stabilises the deoxygenated state and shifts the curve right. A rise in 2,3-bisphosphoglycerate also shifts it right, since BPG binds deoxyhaemoglobin in the central cavity and forms stabilising salt bridges.
(b) Bohr effect.
First described in 1904 by the Danish physiologist Christian Bohr.
- What it explains. Oxygen uptake in the lungs and release in the tissue, regulated by carbon dioxide, hydrogen ions and oxygen partial pressure.
- In the tissues. Carbon dioxide partial pressure is higher. Carbonic anhydrase converts it to carbonic acid, which ionises to hydrogen and bicarbonate ions, and the hydrogen ion lowers the oxygen affinity of haemoglobin.
- Buffering. De-oxyhaemoglobin is a weaker acid, so it binds excess hydrogen ions and limits the fall in pH.
- In the lungs. The process reverses, hydrogen joins bicarbonate to form carbonic acid, which splits into carbon dioxide and water, and the lungs expel it.
- Two names. The combined effect of carbon dioxide and hydrogen ions is the classical Bohr effect, while the hydrogen ion effect alone is the Bohr effect.
Chloride shift. Also called the Hamburger phenomenon, this is the exchange of bicarbonate and chloride across the red blood cell membrane. Carbonic anhydrase makes carbonic acid, which splits into bicarbonate and hydrogen ions, lowering intracellular carbon dioxide partial pressure so more diffuses in.
Cell membranes block charged ions, but red cells swap bicarbonate for chloride using the anion exchanger. Chloride is therefore lower in systemic venous blood than in arterial blood, and the whole exchange reverses in the lungs.
Conclusion. The sigmoid curve is what makes haemoglobin a delivery van rather than a storage tank. Bohr effect and chloride shift are the chemistry that moves the curve where the body needs it.
Q17. (a) Describe the general structure of an immunoglobulin with a labelled diagram. (b) Distinguish between IgM and IgG.
(a) General structure of an immunoglobulin.
Whatever the class, all immunoglobulins are Y-shaped proteins made of four peptide chains, two heavy and two light.
- Papain digestion. Digesting immunoglobulin with papain gives three roughly equal fragments. Two keep the power to bind antigen and are the Fab fragments. The third cannot bind antigen but is crystallisable, so it is the Fc fragment.
- Y shape. The arms of the Y are the Fab fragments and the tail is the Fc fragment. Arms bind antigen, the tail binds cells or activates complement.
- Light chain. About 214 amino acids in two domains, constant at the C-terminal end and variable at the N-terminal end. Types are kappa and lambda, only 35 percent homologous, and 65 percent of human immunoglobulin molecules carry kappa.
- Heavy chain. About 445 amino acids, one variable domain and three constant domains. Classes are defined by the heavy chain, gamma for IgG, alpha for IgA, mu for IgM, epsilon for IgE and delta for IgD.
- Variable regions. Variation is largely restricted to three hyper-variable regions, the complementarity-determining regions. Each is 6 to 10 residues long and shapes the antigen-binding site.
- Constant regions. CH1 with CL stabilises the antigen-binding site, CH2 is the complement activation site and CH3 the phagocytic cell binding site.
- Hinge region. About 12 amino acids between CH1 and CH2. Hydrophilic residues make it accessible to proteolytic enzymes, proline residues give the Fab fragment rotational freedom, and it holds all the inter-chain disulphide bonds.
| Feature | Immunoglobulin G | Immunoglobulin M |
|---|---|---|
| Basic form | A dimer of two disulphide-linked heterodimers | A pentamer of five, very rarely six, subunits |
| Molecular weight | Average 160 kDa | Subunits of 180 kDa give a heavy 900 kDa structure |
| Heavy chain | Gamma chains | Mu chains |
| Valency | Two antigen-binding sites | Valency of ten, binding 10 epitopes at a time |
| J-chain | Not present | Subunits joined at the Fc fragment by a cysteine-rich 15 kDa J-chain |
| Abundance | Most abundant in serum, about 80 percent of antibodies | Very low concentrations in intercellular tissue fluids |
| Diffusion | Small size lets it leave blood vessels and protect tissue spaces and body surfaces | Large size prevents easy diffusion across membranes |
| Immune response | Four human subclasses, differing in gamma chain constant region and interchain disulphide bonds | The first immunoglobulin class produced in the primary immune response |
Conclusion. Every antibody is the same Y with four chains, and only the heavy chain changes the class. IgG is the small, plentiful one and IgM is the large, first-responder one.
That is 5 of the 18. The other 13 questions, covering cell disruption, subcellular fractionation, precipitation and dialysis, the remaining chromatography types, electrophoresis, protein sequencing, mass spectrometry, the Ramachandran plot, protein folding, bioinformatics, structural proteins, haemoglobin disorders and muscle contraction, are in the full file.
BBCCT 105 Topic Frequency Table, December 2024 to June 2026
Thirty-three BBCCT-105 topics were tracked across four sessions, and only two of them appeared in all four papers. A yes means the topic was asked in that session. The last column is our reading for the coming sessions, and that is the column worth slowing down on.
| Topic | Dec 24 | Jun 25 | Dec 25 | Jun 26 | Priority | Our read for the next paper |
|---|---|---|---|---|---|---|
| Cell disruption methods | Yes | Yes | Yes | No | HIGH | Three in a row then a miss, which usually signals a return. Learn sonication, osmotic shock and detergents. |
| Homogenisation versus ultrasonication | No | Yes | Yes | No | HIGH | Always asked as a differentiate question, so keep the eight-row table ready rather than prose. |
| Centrifugation and subcellular fractionation | No | Yes | No | Yes | HIGH | Strict alternate pattern. Spin speeds and times are the marks, not the description. |
| Ammonium sulphate precipitation | Yes | No | No | No | MEDIUM | Quiet for three sessions. Comes as a 3.5 mark short note, so prepare it at note length only. |
| Dialysis | No | Yes | No | No | MEDIUM | One appearance. The membrane cut-off range of 5 to 50 kDa is the detail examiners look for. |
| Lyophilisation | No | No | Yes | No | MEDIUM | Recent single appearance. Sublimation as the principle, freeze drying as the other name. |
| Paper and thin layer chromatography | No | No | Yes | No | MEDIUM | The Rf value definition carries the mark here, not the apparatus list. |
| Ion exchange chromatography | No | No | Yes | No | MEDIUM | Cation exchanger negative, anion exchanger positive. Get that one line right and the rest follows. |
| Gel filtration chromatography | Yes | No | No | Yes | HIGH | Alternate pattern and a diagram question. Largest molecule leaves first is the fact that gets tested. |
| Gas chromatography and HPLC | No | Yes | No | Yes | HIGH | Usually the second half of the gel filtration question. Table it, do not narrate it. |
| SDS-PAGE and gel electrophoresis | Yes | Yes | Yes | Yes | HIGH | Four from four, the most reliable topic in the paper. Urea, SDS and mercaptoethanol each break a different bond. |
| Isoelectric focusing and 2-D electrophoresis | Yes | No | Yes | No | HIGH | Alternates with a clean rhythm. Two independent properties is the phrase that earns the mark. |
| Protein sequencing, Sanger and Edman | No | Yes | Yes | Yes | HIGH | Three straight. Sanger labels only the N-terminal, Edman cycles residue by residue. |
| Endopeptidases and exopeptidases | No | Yes | Yes | No | MEDIUM | Trypsin after Arg and Lys, chymotrypsin after bulky aromatics. Specificity is what is marked. |
| Disulphide bonds, formation and identification | Yes | No | No | Yes | HIGH | Alternates, and appears as both a short note and a four-step illustration question. |
| Mass spectrometry principle and components | Yes | Yes | Yes | No | HIGH | Three in a row then absent, so it is due. The block diagram has five boxes, draw all five. |
| Tandem mass spectrometry | No | No | No | Yes | MEDIUM | New entrant in the most recent paper. Two spectrometers with a fragmentation step between. |
| Secondary structure, helix versus sheet | Yes | No | Yes | No | HIGH | December pattern so far. The numbers 3.6, 1.5 and 5.4 must be exact. |
| Ramachandran plot | No | Yes | No | Yes | HIGH | June pattern so far and always with a diagram. Ramachandran, 1963, is the attribution to name. |
| X-ray crystallography and NMR | Yes | No | Yes | Yes | HIGH | Three of four. X-ray needs a crystal, NMR works in solution, that contrast is the whole answer. |
| Protein folding defects and Alzheimer's | Yes | No | Yes | No | HIGH | Three probable reasons, then the amyloid-beta peptide of 40 to 42 residues. Both halves get asked. |
| Chaperones | Yes | No | No | Yes | HIGH | Usually the second half of the misfolding question. Six functions, list them numbered. |
| Denaturation and renaturation | No | No | No | Yes | MEDIUM | Fresh in June 2026. Trypsin denaturing at 80 to 90 degrees and recovering at 37 is the example. |
| Biological databases | Yes | No | Yes | No | HIGH | Primary versus secondary versus composite. Two named examples of each, every time. |
| Bioinformatics applications and in-silico tools | No | Yes | No | Yes | HIGH | PyMol and Jmol are the two tools the book names. Learn what each one actually does. |
| Functional diversity of proteins | No | Yes | No | Yes | HIGH | Six functions with one example each. Sucrase splitting sucrose is the book's bio-catalysis example. |
| Fibrous versus globular proteins | Yes | Yes | Yes | Yes | HIGH | Four from four. Keratin and actin structure always rides along with the comparison. |
| Oxygen binding and dissociation curves | No | Yes | Yes | Yes | HIGH | Three straight and a diagram question. Draw both curves on one axis with P50 marked. |
| Bohr effect and chloride shift | Yes | No | Yes | No | HIGH | Alternating and often a standalone note. Christian Bohr, 1904, and the Hamburger phenomenon. |
| Myoglobin versus haemoglobin | No | No | Yes | Yes | HIGH | Two in a row and rising. One chain against four chains explains every row of the table. |
| Haemoglobin disorders | Yes | No | No | Yes | HIGH | Sickle cell changes quality, thalassaemia reduces quantity. That framing answers both halves. |
| Immunoglobulin structure and classes | Yes | Yes | No | Yes | HIGH | Three of four and always with a labelled Y diagram. Mark Fab, Fc, hinge and both chain types. |
| Muscle contraction, sliding filament | Yes | Yes | Yes | No | HIGH | Three in a row then a miss, so it is overdue. The A band stays constant is the marked point. |
BBCCT 105 Proteins Exam Pattern and Marking Scheme
The BBCCT-105 Term-End paper carries 70 marks and runs for 3 hours, and the paper is printed bilingually in English and Hindi. Those three facts have held across every paper we have seen, and the marks and duration are printed on the official IGNOU BBCCT-105 Proteins question paper hosted by the university.
The number of questions you must attempt has not held steady, and this is worth knowing before you walk in. The official December 2021 paper printed "attempt any seven questions" at 10 marks each. The recent sessions our file is built from work to five questions of 14 marks each. Either way the total is 70, so read the instruction line first and divide your three hours accordingly.
What has stayed constant is the internal shape of a 14 mark question. It arrives as 7 plus 7, or as four short notes of 3.5 marks each, or as "explain any two of the following". No word limit is printed, so the marks are your only guide to length.
| Answer type | Marks | Word target | Time to allot | What the answer must carry |
|---|---|---|---|---|
| Half of a split question | 7 | About 250 words | 15 to 18 minutes | Quoted definition, four to six numbered points, diagram if the question says illustrate |
| Short note | 3.5 | About 130 words | 7 to 8 minutes | Definition plus three or four crisp points, nothing padded |
| Objective, fill in the blanks | 1 each | One word | Under a minute each | The exact term only, since a near-miss word scores zero |
| Differentiate or distinguish | 7 | Table form | 15 minutes | A table with at least six rows, each row naming its basis of comparison |
| Illustrate or draw | 7 | Diagram plus 200 words | 18 to 20 minutes | A labelled figure, because an unlabelled one earns almost nothing |
One habit separates a pass from a first division in this paper. Objective questions test one word each, so learn the exact term rather than the idea around it. A vague answer on a one-mark blank scores nothing at all, while the same effort spent on precision scores full.
The Seven Diagrams Every BBCCT 105 Proteins Answer Needs
Seven questions in BBCCT-105 carry a diagram, and an unlabelled figure earns almost nothing. This is the single largest avoidable loss in the subject, because students who know the theory still draw a rough sketch, skip the labels and hand over half the marks.
The file draws all seven, labelled, at a size you can copy into an answer book in three or four minutes. Below is what each one has to show for the examiner to award it in full.
| Diagram | Question it belongs to | Labels that must appear |
|---|---|---|
| Subcellular fractionation flowchart | Stages of subcellular fractionation | Every spin speed and time, from 1,000 g through to 150,000 g, and the fraction dropped at each step |
| Gel filtration column | Principle of gel filtration chromatography | Four stages showing large molecules excluded from the pores and leaving the column first |
| Mass spectrometer block diagram | Components of mass spectrometry | Sample inlet, ion source, mass analyser, detector and data system, in that order |
| Ramachandran plot | Role of the Ramachandran plot in structure determination | Phi on the x-axis, psi on the y-axis, both allowed regions marked with their angle values |
| Oxygen binding curves | Myoglobin and haemoglobin oxygen binding | Hyperbolic and sigmoid curves on one axis, P50 of 2 torr and 26 torr both marked |
| Immunoglobulin structure | General structure of an immunoglobulin | Two heavy and two light chains, Fab arms, Fc tail, hinge region and the disulphide bonds |
| Sarcomere | Sliding filament model of muscle contraction | Z line, A band, I band, H zone and M line, drawn twice for relaxed and contracted states |
BBCCT 105 Proteins Syllabus, All 4 Blocks and 14 Units
BBCCT-105 Proteins is built from 4 blocks holding 14 units in total. The table maps each unit against the topics the examiner has actually drawn from it and where that unit lands in our guess paper. The course structure is verifiable on eGyanKosh, the official IGNOU repository.
Read the last column before you plan your revision. Block 1 and Block 4 between them have fed more than half the questions across the four sessions, while several Block 1 technique units surface only as 3.5 mark short notes. Knowing which unit produces a full 7 mark half and which produces a note changes how long you spend on each.
| Block | Unit | Topic area of the unit | What the examiner has drawn from it | In our guess paper |
|---|---|---|---|---|
| Block 1 Isolation and purification of proteins | 1 | Proteins and peptides, basic properties | Characteristics of proteins, isoelectric point, denaturation and renaturation, biologically active peptides | Q1 and Q2, as a short note and a 7 mark half |
| Block 1 Isolation and purification of proteins | 2 | Cell disruption and subcellular fractionation | Homogenisation versus ultrasonication, osmotic shock, the spin ladder from 1,000 g to 150,000 g | Q2 and Q3, with the fractionation flowchart |
| Block 1 Isolation and purification of proteins | 3 | Precipitation and concentration techniques | Ammonium sulphate salting out, dialysis, solvent fractionation, lyophilisation | Q4, four short notes at 3.5 marks each |
| Block 1 Isolation and purification of proteins | 4 | Chromatographic techniques | Gel filtration, paper, ion exchange, affinity and reverse phase chromatography, GC versus HPLC | Q5 and Q6, one diagram answer and one notes set |
| Block 2 Characterisation and analysis of proteins | 5 | Electrophoresis of proteins | SDS-PAGE principle, stacking and separating gels, isoelectric focusing, 2-D electrophoresis | Q7, full 14 mark answer |
| Block 2 Characterisation and analysis of proteins | 6 | Protein sequencing | Sanger's method with FDNB, Edman degradation cycles, endopeptidases and exopeptidases, disulphide bond identification | Q8, and the disulphide short note in Q1 |
| Block 2 Characterisation and analysis of proteins | 7 | Mass spectrometry | Ion source, analyser and detector, tandem mass spectrometry, five application areas | Q9, with the block diagram |
| Block 3 Protein structure, folding and bioinformatics | 8 | Secondary structure of proteins | Alpha helix and beta pleated sheet geometry, hydrogen bonding patterns, proline as helix disruptor | Q10, with the comparison table |
| Block 3 Protein structure, folding and bioinformatics | 9 | Structure determination techniques | Ramachandran plot and torsion angles, applications of X-ray crystallography and NMR | Q11, with the plot drawn |
| Block 3 Protein structure, folding and bioinformatics | 10 | Protein folding | Three reasons for misfolding, amyloid-beta and Alzheimer's disease, chaperones and chaperonins | Q12, full 14 mark answer |
| Block 3 Protein structure, folding and bioinformatics | 11 | Bioinformatics and biological databases | Primary, secondary, composite and structural databases, applications of bioinformatics, PyMol and Jmol | Q13, full 14 mark answer |
| Block 4 Protein function | 12 | Functional diversity of proteins | Six protein functions, transport channels versus carriers, fibrous versus globular, keratin and actin | Q14, full 14 mark answer |
| Block 4 Protein function | 13 | Oxygen transport proteins | Binding curves and P50, cooperativity, Bohr effect, chloride shift, sickle cell and thalassaemias | Q15 and Q16, one with curves drawn |
| Block 4 Protein function | 14 | Immunoglobulins and contractile proteins | Y structure and Fab and Fc fragments, IgG versus IgM, sarcomere and the cross-bridge cycle | Q17 and Q18, both diagram answers |
Anyone still reading the units rather than revising them should keep the book open alongside the answers. Our BBCCT 105 Study Material section follows the same block and unit order as the table above, so the two can be used side by side without hunting for the right page.
BBCCL 106 Practical File Index for BBCCT 105 Proteins Students
BBCCT-105 is the theory course and has no practical file of its own, but every BSCBCH student taking it also sits BBCCL-106 Proteins, a 2 credit laboratory course of eight experiments. The two run together, and the lab manual is built directly on the units you study in BBCCT-105.
Because students keep asking which experiments the file has to cover, here is the index straight from the IGNOU Biochemistry discipline page for BBCCL-106. Notice how closely it tracks the theory. Four of the eight experiments come straight out of the same units this guess paper covers.
| No. | Experiment | What you actually do | Theory unit it rests on |
|---|---|---|---|
| 1 | Estimation of protein by UV absorbance | Read absorbance at 280 nm and use the aromatic residue content to estimate concentration | Unit 1, protein properties |
| 2 | Estimation of protein by the Biuret method | Develop the violet copper complex with peptide bonds and read against a standard curve | Unit 1, protein properties |
| 3 | Estimation of protein by the Lowry method | Combine the Biuret reaction with Folin reagent for a more sensitive reading | Unit 1, protein properties |
| 4 | Estimation of protein by the Bradford method | Use Coomassie dye binding, the quickest of the four estimation methods | Unit 1, protein properties |
| 5 | Isolation of casein from milk by the isoelectric pH method | Drop milk to the isoelectric pH of casein so the protein loses charge and precipitates | Unit 1, isoelectric point |
| 6 | Ammonium sulphate fractionation of serum proteins | Salt out serum proteins in stages to concentrate the sample after extraction | Unit 3, precipitation techniques |
| 7 | Separation of serum proteins by paper electrophoresis | Resolve serum into its protein bands on a paper strip under an applied field | Unit 5, electrophoresis |
| 8 | Separation of proteins by SDS-PAGE | Run a denatured sample through stacking and separating gels and read the band pattern | Unit 5, electrophoresis |
There is a practical benefit in this overlap. Writing the theory answer on ammonium sulphate precipitation or on SDS-PAGE means you already have the principle section of two lab records written. Prepare them once and use them twice.
How This BBCCT 105 Guess Paper Was Built from Four Past Papers
Four consecutive Term-End papers were read, December 2024 through June 2026, every topic was recorded session by session, and the 18 questions were selected from that record. Four sessions, not five or six. We would rather say so than round the number up.
That matters for how you read the frequency table. With four columns, a topic appearing twice is already a fifty percent hit rate, so the thresholds are tighter than they would be on a six-paper run. HIGH here means four appearances, three in a row, a clean alternating rhythm, or a recent gap after a run.
The June 2026 paper sits in the analysis rather than the target. It has already been conducted, so it is evidence, not a prediction. That is why the file is aimed at December 2026 and June 2027.
If you want to run the same check yourself, work through the IGNOU Previous Year Question Paper set for this code and tally the topics against the units. That tallying is the work this file saves you.
Answers were then written from the IGNOU study material itself, not from summary blogs. Where the book quotes a definition, the quotation stays. Where the book gives six functions or seven steps, the count stays exact, because the examiner marks against that count.
Full List of 18 Questions in the BBCCT 105 Guess Paper
All 18 questions in the file are listed below, with the 5 shown on this page marked as samples. Nothing is held back from the list itself, so you know exactly what you are getting before you enquire.
- Fill in the blanks and short notes on active peptides, disulphide bond and osmotic shock. Sample shown above
- Characteristics of proteins, and homogenisation versus ultrasonication.
- Stages of subcellular fractionation, with diagram, plus the principle of centrifugation.
- Short notes on ammonium sulphate precipitation, dialysis, solvent fractionation and lyophilisation.
- Gel filtration chromatography with diagram, and gas chromatography versus HPLC. Sample shown above
- Short notes on paper, ion exchange, affinity and reverse phase chromatography.
- Principle and applications of SDS-PAGE, and 2-D gel electrophoresis.
- Protein sequencing by Sanger and Edman, peptidase types and disulphide bond identification.
- Mass spectrometry with block diagram, tandem mass spectrometry and five applications.
- Types of secondary structure, and alpha helix versus beta pleated sheet. Sample shown above
- Ramachandran plot with diagram, and applications of X-ray crystallography and NMR.
- Three reasons for protein misfolding, Alzheimer's disease, and the role of chaperones.
- Biological databases and their classification, bioinformatics applications and in-silico tools.
- Functional diversity of proteins, and fibrous versus globular proteins with keratin and actin.
- Oxygen binding curves with diagram, Bohr effect and chloride shift. Sample shown above
- Myoglobin versus haemoglobin, sickle cell disease and thalassaemias.
- General structure of an immunoglobulin with diagram, and IgM versus IgG. Sample shown above
- Sliding filament model with diagram, and the role of calcium and ATP in muscle contraction.
Five are open on this page and 13 are in the paid file. Question 1 deserves a separate mention, because it is the objective and short notes question, and it is the only place in the paper where a single correct word is worth a full mark.
Which IGNOU Programme the BBCCT 105 Guess Paper Is Meant For
BBCCT-105 Proteins is a core course of the IGNOU B.Sc. (Honours) Biochemistry programme, BSCBCH. It is a theory course paired with the BBCCL-106 laboratory course, and the Term-End paper is the same for every student registered under this code.
It suits four groups in particular. Students sitting BBCCT-105 for the first time with a few weeks left. Students carrying this paper as a back from an earlier session. Students who have finished all 14 units but cannot judge what to leave out. And students whose theory is sound but who lose marks on unlabelled diagrams and rounded-off numbers.
Learners preparing several biochemistry codes in one session usually take the BSCBCH Guess Paper bundle instead of buying codes one at a time, since the answer shape carries across the core courses and the 7 plus 7 structure is common to them.
This file will not suit you if you want the whole study material rewritten, or if you are after assignment answers. It is built for the written examination and nothing else.
How to Use the BBCCT 105 Guess Paper in Your Last Ten Days
Ten days is enough for BBCCT-105 if you work by diagram and priority rather than page by page. The plan below is what our counsellors hand to students who arrive with a fortnight left and nothing started.
- Days 1 and 2. The diagram questions only. All seven, drawn by hand, labelled, timed at four minutes each. Repeat until you can draw the sarcomere and the mass spectrometer block from memory.
- Days 3 and 4. The four-from-four and three-in-a-row topics, SDS-PAGE, fibrous versus globular, protein sequencing and oxygen binding. Write each once in full.
- Day 5. All the comparison tables. IgG versus IgM, GC versus HPLC, helix versus sheet, homogenisation versus sonication, myoglobin versus haemoglobin. Six rows minimum on each.
- Day 6. The short notes set. Ammonium sulphate, dialysis, solvent fractionation, lyophilisation, and the four chromatography notes. Each at 130 words, no longer.
- Day 7. Numbers day. 3.6 residues per turn, 1.5 angstrom, 5.4 angstrom pitch, 153 amino acids in myoglobin, P50 of 2 and 26 torr, 5808 daltons for insulin. Write them out until they are automatic.
- Day 8. The MEDIUM backups, tandem mass spectrometry, denaturation and renaturation, endopeptidases and exopeptidases. One read each, points only.
- Day 9. Definitions revision. Read only the quoted definition boxes and the conclusions across all 18 answers.
- Day 10. One full mock in three hours, no book, diagrams drawn properly. Then check your word counts against the marking bands.
One warning worth repeating. Do not spend this fortnight on Rf value lists, solvent ratios or the full amino acid sequence of insulin. Two entries from any table is plenty, and the time saved goes into the diagrams, where the marks actually sit.
How to Get the Complete BBCCT 105 Solved Guess Paper
Message 9899436384 on WhatsApp with the code BBCCT-105 and the file reaches you the same day. There is no account to create and no form to fill. Send the code, confirm the session you are appearing in, and you receive the complete 33 page file with all 18 solved answers and all seven diagrams.
You have already read 5 of those answers in full on this page. The remaining 13 arrive in the same format, same quoted definitions, same numbered structure, same tables, same drawn figures. Nothing here is a trimmed version of what you receive.
If you are unsure whether BBCCT-105 is the right code for your registration, send your enrolment number and programme in the same message and we will check it before anything else happens.
FAQs on the BBCCT 105 Guess Paper and Proteins
How many questions does the BBCCT 105 Solved Guess Paper contain?
Eighteen questions with complete answers, running to 33 pages. Five of those answers are printed in full on this page as samples, and the other 13 sit in the file. Thirteen questions are tagged HIGH priority and five are MEDIUM, based on how often each topic appeared across the four sessions analysed. The five samples cover four different answer types.
Which sessions is the BBCCT 105 guess paper prepared for?
It targets the December 2026 and June 2027 Term-End Examinations of BBCCT-105 Proteins. IGNOU holds Term-End papers in June and December only. The June 2026 paper was already conducted before this file was made, so it sits in the analysis as evidence rather than being treated as a target session. The frequency table on this page shows all four sessions side by side.
What is the exam pattern of BBCCT 105 Proteins?
The paper carries 70 marks and runs three hours, printed in English and Hindi. The number of questions to attempt has varied. The official December 2021 paper asked for any seven at 10 marks each, while recent sessions work to five questions of 14 marks. Read the printed instruction line before you begin, since the total stays at 70 either way.
How many previous year papers were analysed for this BBCCT 105 guess paper?
Four consecutive Term-End papers, December 2024, June 2025, December 2025 and June 2026. Every topic in those papers was recorded session by session, producing the 33 topic frequency table on this page. We say four rather than five because four is what we actually had in hand, and rounding it up would weaken every frequency claim made here.
Does the BBCCT 105 Proteins guess paper include diagrams?
Yes, seven labelled diagrams. They cover subcellular fractionation, gel filtration, the mass spectrometer block diagram, the Ramachandran plot, oxygen binding curves, immunoglobulin structure and the sarcomere. Each one is drawn at a size you can reproduce in an answer book in about four minutes, with every label the examiner expects. An unlabelled figure earns almost nothing in this paper.
Does BBCCT 105 Proteins have a practical file or laboratory course?
BBCCT-105 itself is a theory course with no practical file. The paired laboratory course is BBCCL-106 Proteins, worth 2 credits and made up of eight experiments, from protein estimation by four methods through to SDS-PAGE. The full experiment index appears in the practical section on this page, and four of those eight experiments rest on units this guess paper already covers.
Which programme and courses include the BBCCT 105 course?
BBCCT-105 is a core theory course of the IGNOU B.Sc. (Honours) Biochemistry programme, BSCBCH, offered by the School of Sciences. It is studied alongside its laboratory course BBCCL-106. The Term-End paper is identical for every student registered under this code in a given session, so check your registration slip if you are unsure which code applies to you.
Are the BBCCT 105 answers written from the IGNOU book or other sources?
They come from the IGNOU BBCCT-105 study material itself, Blocks 1 to 4 and Units 1 to 14. Quoted definitions stay in the book's own wording, and exact figures are left as printed, 3.6 residues per turn, 153 amino acids, a P50 of 26 torr. Rounding those numbers off loses marks, so we never do it.
How do I get the complete BBCCT 105 guess paper with all answers?
Send a WhatsApp message to 9899436384 with the code BBCCT-105 and the session you are appearing in. The complete file with all 18 solved answers and seven diagrams is shared the same day. If you are unsure the code matches your registration, include your enrolment number and we will verify it first. Message from the number you want the file on.