In this worksheet, we will practice explaining the effect of temperature, water content and oxygen on the rate at which organic material decomposes.
What biological molecules are used by decomposers to break down organic material?
The picture shows a selection of food products placed in airtight packaging. How does this help slow down the rate of decomposition?
- AThe microorganisms that carry out decomposition require a good supply of carbon dioxide, which has been removed.
- BThe microorganisms that carry out decomposition require a good supply of oxygen, which has been removed.
- CThe microorganisms that carry out decomposition require access to natural light, which has been removed.
- DThe microorganisms that carry out decomposition need to regulate their own body temperature, which is harder in airtight packaging.
Which of the following best explains why warmer temperatures allow faster decomposition?
- AA warmer temperature decreases the heat energy of the decomposers, so it reduces the rate of enzyme-controlled reactions.
- BA warmer temperature allows the decomposers to better regulate their body temperature, so they can act faster.
- CA warmer temperature provides more heat energy to increase the rate of enzyme-controlled reactions.
- DA warmer temperature increases the moisture content of the soil, which speeds up decomposition.
What biological process do decomposers carry out that requires oxygen to be available?
- BAerobic respiration
Which of the following conditions would not increase the rate of decomposition?
- AA moist environment
- BA warm environment
- CA good availability of oxygen
- DA cold environment
Some food waste was left to decompose in a dark, warm corner of a lab. After 12 days, the food waste decreased in mass by 8 grams. Calculate the rate of decay, in grams per day, giving your answer to two decimal places.
- A1.50 grams per day
- B0.67 grams per day
- C0.96 grams per day
- D0.7 grams per day
The graph shows the mass of an apple, in grams, compared to the days it was left in a compost bin. Which of the following conclusions is correct?
- AThe rate of decomposition in the first 15 days is slower than the rate in the last 15 days.
- BThe rate of decomposition in the first 15 days is faster than the rate in the last 15 days.
- CThere is no correlation between the time (days) and the rate of decomposition.
The graph shows how a mass of plant material changes as it is left to decompose. Calculate the rate of decomposition between days 0 and 10, in percent per day.