IB Biology HL IA examples

How does different concentrations (1%, 2%, 3%) of Carbon Dioxide affect the rate of photosynthesis of the plant Hydrilla verticillata, as measured by a UV-Vis Spectrometer at 615 nm?

How does the pH of the milk (pH 4.5 ,5.5, 6,5, 7.5, 8.5) affect the hydrolysis of lactose 15 minutes after adding lactase, measured by the final concentration of glucose using refractometry?

How does varying ethanol concentration (10%, 20%, 40%, 60%, 80%) affect the percentage increase (%) in dry casein mass from skim milk when combined with lemon juice, as measured by gravimetric analysis, compared to lemon juice alone?

To what extent does the daily application of 30 mL of aqueous caffeine solutions at different concentrations (0, 30, 60, 90, 120 mg/L), in the presence and absence of CaCl2 (5 mL/L), affect the apical stem length of Raphanus Sativus over 10 days?

To what extent does the incubation temperature (20°C, 30°C, 40°C, 50°C, and 60°C) affect the soluble protein concentration of lentil (Lens culinaris) extracts as determined by the Biuret test and measured using colourimetry?

How does the concentration of Nigella sativa extract (0% (control), 10%, 20%, 30%, 40%, 50%) affect the percentage of amylase inhibition in starch digestion, as recorded by the color change in the iodine test, confirmed by Benedict’s test and the absorbance reading from the colorimeter at 470 nm?

To what extent do mortality rates by Malaria (P. falciparum), per 100,000 people, in African regions (Barbados, Oklahoma, Bungoma, Gambia, Edo, Sierra Leone, Oyo) sampled between 1980 and 2008, correlate with the predicted relative fitness of haemoglobin variant A homozygotes (HbAA) calculated from allele frequencies in populations at the rs344 locus?

To what extent does the mass of green tea (Camellia sinensis) leaves (1g, 1.5g, 2g, 2.5g, and 3g), affect the rate of amylase-catalyzed starch hydrolysis, measured by the change in absorbance of starch-iodine complex using a spectrophotometer at 615nm over 10 minutes?

How does the pH of a hydrogen peroxide solution (ranging from 2.0 to 12.0) affect the rate of oxygen production (%) by catalase extracted from yeast, measured using an oxygen probe in Logger Pro?

How do different plant proteases (Bromelain, Papain, Actinidin, Mango Serine protease) affect the rate of gelatin proteolysis (g/h), measured as the mass loss of gelatin (g) over 4 hours?

How does varying soil pH (4.0, 5.0, 6.0, 7.0, 8.0) affect the overall length (bottommost root meristem to uppermost apical meristem) in millimetres, of watercress (Nasturtium officinale) plants over 15 days?

What is the effect of different amoxicillin concentrations (0g/L, 0.5 g/L, 1 g/L, 2 g/L, 3 g/L, 4 g/L) on Hordeum vulgare radicle length?

How does varying the type of carbohydrate substrate (glucose, fructose, sucrose, lactose, maltose) affect the efficiency of respiration in Saccharomyces cerevisiae, as measured through the increase in carbon dioxide gas concentration (ppm) over 180 seconds?

To what extent do different naturally antibacterial plant extracts (black pepper (Piper nigrum), garlic (Allium sativum), turmeric (Curcuma longa), rosemary (Salvia Rosmarinus), paprika (Capsicum annuum)), each at a standardised concentration of 10%, affect the proliferation of Escherichia coli (E. coli K-12 strain) in 10cm3 of 13.0g/L nutrient broth incubated at 37.0°C for 24 hours, as measured by changes in optical density (OD600) using mass spectrophotometry in absorbance units (Au)?

To what extent does increasing concentrations of H2SO4 /Sulfuric acid (0M, 0.01M, 0.02M, 0.03M, 0.04M) impact growth (germination and post germination included) in mung beans (Vigna Radiata) in soil as measured by overall increase in mass (± 0.01 grams) over a span for 48 hours at standard room temperature and pressure?

How does increasing the length of shortwave ultraviolet (UV) light exposure (0s, 45s, 90s, 135s, 180s, 225s, 270s, 315s) affect inoculated K-12 Escherichia coli culture’s growth as measured by number of perceivable colony-forming units (CFUs)?

How does the time elapsed after juicing (0, 15, 30, 45, and 60 minutes) affect the concentration of ascorbic acid in Citrus x Sinensis (sweet orange) juice, determined by the amount of DCPIP required to decolourise?

What effect does altering concentration (0.0%, 0.5%, 1.0%, 1.5%, 2.0%) of 12.4: 2.7: 6.2 NPK Plant fertiliser have on final dry mass of Viola odorata plants?

How does the reaction time in a color-changing human benchmark test (milliseconds averaged over multiple trials) differ in trained male Homo Sapien basketball athletes (aged 16-18) on reaction time in comparison to male untrained athletes (aged 16-18)?

To what extent the effect of Bromelain enzyme of Pineapple (Ananas comosus) in different stages of ripeness (Extremely underripe, Underripe, Ripe, Slightly overripe, Extremely overripe) on the weight of Gelatine blocks?

What is the effect of increasing the concentration of jasmine tea leaves (Jasminum officinale and Camellia sinensis) (0.00%, 0.20%, 0.40%, 0.60%, 0.80%, 1.00% w/v) on the enzymatic breakdown of starch via amylase over five minutes as determined by the percentage change in absorbance value (%) of yellow (565 nm) using a colourimeter?

What are the vitamin C levels in 50mL of freshly pressed juice from oranges, apples, and tomatoes, and how does it compare to the vitamin C levels in 50mL of juice from concentrates made from the same fruits?

To what extent does the temperature of storage (21°C, 7°C, -18°C) for a 10 hour period of fruit Malus domestica and Prunus domestica affect the enzymatic activity of catalase (volume of O2 produced in milliliters after 7 minutes) from the decomposition of 3% Hydrogen peroxide solution?

How does altering robusta coffee concentrations (0%, 1%, 2%, 3%, 4%) affect the rate of fermentation in Saccharomyces cerevisiae, measured by CO₂ production in parts per million (ppm) over 5 minutes?

How varying amounts (2–3.16 g) of sucrose or glucose - fructose mix affect yeast fermentation, measured by dough volume increase (mL) after baking?

How does the pH of an amylase solution affect the rate of reaction in the breakdown of starch?

Is there a correlation between light intensity and the height of Euphorbia amygdaloides (wood spurge) in Wildwood, Kent?

How do different dietary patterns (Vegetarian, Vegan, Mediterranean diet) correlate with the prevalence of being underweight in the European region?

How do beverages containing caffeine (coffee, celsius, green tea, coke and water (as control) affect heart rate (BPM) using self-measured pulse rates (BPM) over a fixed time period?

How does increasing pH levels ( 3, 4, 5, 6, and 7) affect the fermentation rate (ppm) of yeast (Saccharomyces cerevisiae) when reacting in a 10% sucrose (C12H22O11) solution?

Effects of different concentrations of Amoxicillin (0.00M, 0.02M, 0.04M, 0.06M, 0.08M, 0.10M ) on the growth of Phaseolus vulgaris as measured by the shoot length in millimeters (± 0.1) using 30 cm ruler ( ± 0.05) for 15 days.

How do varying concentrations of sodium phosphate (0.0M, 0.2M, 0.4M, 0.6M, 0.8M, 1.0M) affect the growth rate (mm/day) of Trigonella foenum-graecum (Fenugreek) over 13 days?

What is the relationship between different concentrations of honey (0%, 5%, 10%, 20%, 30%) and the inhibition of Rhizopus stolonifer growth, as measured by the diameter of the Inhibition Zone?

To what extent do 10μL (±0.2) samples of 5 different plant-based protein sources (Phaseolus vulgaris L (kidney bean), Arachis hypogaea (peanuts), Triticum aestivum (wheat flour), Vigna radiata (green grams), and Persea americana (avocado)) vary in branched-chain amino acid (BCAA) concentration, measured by thin layer chromatography (TLC) and analysed using the Hue, Saturation, Lightness (HSL) colour model?

How changing the concentration(0.010g/100g of soil, 0.050g/100g of soil, 0.150g/100g of soil, 0.500g/100g of soil, 1.000g/100g of soil,) of microplastics in soil affects the concentration of chlorophyll a and b in Common Oats (Avena sativa) calculated through the measurement of the absorbance of the chlorophyll extract at 645 nm and 663 nm from a spectrophotometer.

How does varying soil acidity affect the growth rate of the plant height of Raphanus sativus in a mesocosm environment?

Does the storage method of Musa acuminata (common banana) affect the speed of their browning process, measured by the time the skin turns brown completely and calculating the volume of brown spotting on the inside (pulp)?

What is the effect of increasing temperature (10°C, 30°C, 50°C, 70°C, and 90°C) on the antioxidant capacity of Citrus sinensis (Orange) to reduce free radicals by measuring percentage of light absorbance change in 1,1-diphenyl-1-picrylhydrazyl (DPPH) at 517nm after 15 seconds?

How has climate change affected the distribution of the monarch butterfly (Danaus plexippus) over time in North America from the years 1990-2020 ?

How does varying concentrations of lead (II) nitrate (0.00M, 0.20M, 0.40M, 0.60M, 0.80M, and 1.00M (±0.01M)) affect the photosynthetic activity of Elodea canadensis plant measured by the volume of oxygen production in ml (±0.1) using a 25.0 ml (±0.1 ml) gas syringe for a period of 30 minutes (±0.1 s)?