IB Biology SL 2017: Experiments Paper 3 – Flashcards

The living specimen is enclosed in a sealed container Carbon dioxide production can be measured with a data logger or by pH changes if the specimen is immersed in water When an alkali is included to absorb CO2, oxygen consumption can be measured as a change in pressure within the system The pressure change can be detected with a data logger or via use of a U-tube manometer Factors which may affect respiration rates include temperature, hydration, light (plants), age and activity levels An increase in carbon dioxide levels or decrease in oxygen will indicate an increase in respiration

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A spirometer is a device that detects the changes in ventilation and presents the data on a digital display A more simplistic method involves breathing into a balloon and measuring the volume of air in a single breath The volume of air can be determined by submerging the balloon in water and measuring the volume displaced (1ml = 1cm3) Also can be measured via: Via simple observation (counting number of breaths per minute) Chest belt and pressure meter (recording the rise and fall of the chest) Spirometer (recording the volume of gas expelled per breath)

When it crosses the x axis Blot the potato Measure correct masses

A mixture is dissolved in a fluid (mobile phase) Passed through a static material (stationary phase) Components travel at different speeds, causing them to separate A retardation factor can then be calculated (Rf value = distance component travels ÷ distance solvent travels) Two of the most common techniques for separating photosynthetic pigments are: Paper chromatography - uses paper (cellulose) as the stationary bed Thin layer chromatography - uses a thin layer of absorbent (e.g. silica gel) which runs faster and has better separation

Bottom layer of pebbles, gravel or sand - for drainage Thin layer of activated charcoal - prevent mold and aerate the soil Thin cover of sphagnum moss (or use an organic coffee filter) to create a barrier between the lower layers and soil Final layer is the pre-moistened growing medium (i.e. potting mix) Choose plants that are both slow growing and thrive in a bit of humidity (e.g. most ferns, club moss, etc.) Inspect the plant thoroughly for any signs of disease or insects before introducing to the terrarium Maintaining appropriate conditions: Ensure the terrarium is placed in a location that provides a continuous source of light Locate the terrarium in a place that does not experience fluctuating temperature conditions (i.e. avoid direct sunlight) Do not initially over-water the plants - once the right humidity is established, a terrarium can go months without watering Occasional pruning may be required - however, as level of soil nutrients decrease, plant growth should slow down