PBEP Flashcards

Question

What role does denitrification play in the nitrogen cycle?

Answer 1

Denitrification is the process by which bacteria convert nitrates (NO₃⁻) back into nitrogen gas (N₂), returning nitrogen to the atmosphere and completing the nitrogen cycle.

Answer 2

Ammonification is the conversion of organic nitrogen in dead plants and animals or their waste products into ammonia (NH₃) or ammonium (NH₄⁺) by decomposers, replenishing the nitrogen in the soil.

Answer 3

Nitrogen is an essential element for the synthesis of amino acids, proteins, and nucleic acids, making it vital for plant growth and animal nutrition.

Answer 4

Carbon fixation occurs during photosynthesis when plants convert atmospheric carbon dioxide (CO₂) into organic compounds like glucose, storing energy in the form of carbon.

Answer 5

During respiration, organisms break down glucose to release energy, producing carbon dioxide (CO₂) as a by-product, which is released back into the atmosphere.

Answer 6

Decomposers break down dead organic material, releasing carbon back into the atmosphere as CO₂ or into the soil as organic carbon compounds.

Answer 7

Through consumption, carbon is transferred as organic compounds from plants (producers) to herbivores (primary consumers) and then to higher trophic levels (secondary and tertiary consumers).

Answer 8

Oceans act as a major carbon sink, absorbing large amounts of carbon dioxide from the atmosphere, which is then stored in water or in marine organisms like plankton and coral reefs.

Answer 9

The combustion of fossil fuels releases stored carbon (in the form of CO₂) back into the atmosphere, increasing atmospheric carbon levels and contributing to global warming.

Answer 10

Photosynthesis removes carbon dioxide from the atmosphere and incorporates it into plant tissues, effectively reducing atmospheric CO₂ levels.

Answer 11

Evaporation is the process by which water is heated by the sun and changes from a liquid to a gas, rising into the atmosphere as water vapor.

Answer 12

Condensation is the process by which water vapor cools and changes back into liquid water, forming clouds or fog.

Answer 13

Precipitation occurs when condensed water in the atmosphere becomes too heavy to stay suspended and falls to Earth as rain, snow, sleet, or hail.

Answer 14

Infiltration is the process by which water enters the soil after precipitation, replenishing groundwater supplies and influencing soil moisture levels.

Answer 15

Transpiration is the process by which water is absorbed by plant roots and then released as water vapor through small openings in leaves, contributing to atmospheric moisture.

Answer 16

Runoff is the flow of water across the land surface, typically after heavy rain, which can lead to the movement of water into rivers, lakes, or oceans.

Answer 17

Groundwater, stored in aquifers beneath the Earth's surface, can return to the surface through springs or wells, contributing to water availability for ecosystems and human use.

Answer 18

The hydrological cycle regulates atmospheric moisture, influencing weather patterns such as cloud formation, precipitation, and temperature, and plays a key role in global climate systems.

Answer 19

The water table is the boundary between saturated and unsaturated ground, indicating the level at which groundwater is found. It can fluctuate based on seasonal precipitation and infiltration rates.

Answer 20

Plate tectonics is the theory that the Earth's outer shell, called the lithosphere, is divided into several large and small plates that float on the semi-molten asthenosphere beneath them. Their movement causes geological processes like earthquakes, volcanic eruptions, and the creation of mountain ranges.

Answer 21

Tectonic plates are made up of the Earth's lithosphere, which includes the crust and the upper part of the mantle. These plates are rigid and move on the more fluid asthenosphere below them.

Answer 22

Oceanic plates are thinner, denser, and primarily composed of basalt rock, while continental plates are thicker, less dense, and primarily made of granite rock.

Answer 23

At convergent plate boundaries, two plates collide, leading to the formation of mountain ranges, volcanic activity, or earthquakes. In cases where one plate is oceanic and the other is continental, the denser oceanic plate is forced beneath the continental plate in a process called subduction.

Answer 24

At divergent plate boundaries, two plates move away from each other, creating space for magma to rise and form new crust. This is commonly seen at mid-ocean ridges, like the Mid-Atlantic Ridge.

Answer 25

Transform/conservative plate boundaries occur where two plates slide past each other horizontally, causing friction that leads to earthquakes. A well-known example is the San Andreas Fault in California.

Answer 26

Plate tectonics shapes landforms through processes like mountain building, earthquake formation, volcanic eruptions, and the creation of oceanic and continental features.

Answer 27

Clay soil consists of very fine particles that are tightly packed together, giving it a smooth texture when dry and a sticky feel when wet.

Answer 28

Clay soil has low permeability, meaning that water drains very slowly through it due to the small size of its particles.

Answer 29

Clay soil has a high nutrient-holding capacity because its fine particles provide a large surface area to retain nutrients and minerals.

Answer 30

Clay soil is generally fertile, as it retains nutrients well. However, its low permeability can lead to waterlogging, which may harm plant roots.

Answer 31

Clay soil can become compacted, reducing root growth, and it retains too much water, leading to potential waterlogging. This makes it harder for plants to grow in some cases.

Answer 32

Loam soil is a balanced mixture of sand, silt, and clay, making it the ideal soil type for most plants due to its optimal balance of drainage and moisture retention.

Answer 33

Loam soil has moderate permeability, allowing water to drain at a balanced rate while still retaining enough moisture for plant roots.

Answer 34

Loam soil has good nutrient-holding capacity, retaining nutrients while also preventing the leaching of vital minerals.

Answer 35

Loam soil is highly fertile, providing an ideal environment for plant growth because of its balance between water retention and drainage, as well as nutrient availability.

Answer 36

Sandy soil is composed of large, coarse particles. It has a gritty texture and drains water very quickly.

Answer 37

Sandy soil has high permeability, meaning water drains very quickly through it, which can result in the soil drying out faster.

Answer 38

Sandy soil has a low nutrient-holding capacity because its large particles allow nutrients to leach away quickly, making it less fertile.

Answer 39

Sandy soil is generally low in fertility due to its poor nutrient retention. However, it can be improved with organic matter and fertilisers to enhance plant growth.

Answer 40

Sandy soil dries out quickly, holds fewer nutrients, and may require more frequent irrigation and fertilisation for plant growth.

Answer 41

Silt soil consists of fine particles, smaller than sand but larger than clay. It feels soft and smooth when wet and powdery when dry.

Answer 42

Silt soil has moderate permeability, allowing it to retain moisture well while also draining excess water more effectively than clay soil.

Answer 43

Silt soil has a moderate ability to hold nutrients. Its fine particles allow for good nutrient retention, although it doesn't retain as much as clay soil.

Answer 44

Silt soil is moderately fertile, retaining moisture and nutrients, which makes it suitable for many plants. However, it can become compacted in wet conditions.

Answer 45

Silt soil can become compacted and prone to waterlogging, leading to poor aeration and root growth. It is also more susceptible to erosion if not properly managed.

Answer 46

The Haber Process is a chemical reaction used to synthesize ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) gases. It is an essential industrial process for producing fertilisers.

Answer 47

The reactants in the Haber Process are nitrogen (N₂), usually obtained from the air, and hydrogen (H₂), which is typically derived from natural gas (methane, CH₄).

Answer 48

The balanced chemical equation for the Haber Process is: N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g)

Answer 49

The Haber Process requires high temperature (about 450°C), high pressure (around 200 atmospheres), and the use of an iron catalyst to increase the rate of reaction.

Answer 50

The Haber Process allows for the mass production of ammonia, which is critical for agricultural fertilisers. However, it is energy-intensive, and there are ongoing efforts to make it more sustainable by improving efficiency and reducing carbon emissions.

Answer 51

The Haber Process requires large amounts of energy, typically from fossil fuels, contributing to CO₂ emissions. Additionally, excess fertiliser use can lead to water pollution and eutrophication.

Answer 52

Nitrogen is used in the Haber Process as a reactant, extracted from the air, where it makes up about 78% of the atmosphere. It combines with hydrogen to form ammonia.

Answer 53

Hydrogen is used in the Haber Process to combine with nitrogen to form ammonia. It is usually produced by reacting methane with steam in a process called steam reforming.

PBEP Flashcards

Weather, Rocks and cycles