Living together – Food and Ecosystems

Photosynthesis

Process by which light energy is converted into chemical energy in plants and certain prokaryotes.

Chloroplasts

Organelles in plant cells where photosynthesis occurs

Light-dependent stage

First stage of photosynthesis where light energy is converted into chemical energy to produce ATP and NADPH.

Chlorophyll

Pigment in chloroplasts that absorbs light energy.

Light-independent stage

Second stage of photosynthesis where ATP and NADPH are used to convert carbon dioxide into glucose.

ATP

Adenosine triphosphate

NADPH

Nicotinamide adenine dinucleotide phosphate

Glucose

A carbohydrate produced during photosynthesis

Factors influencing photosynthesis rate

Concentration of carbon dioxide

Enzymes

Proteins that catalyze chemical reactions in living organisms.

Substrate

Molecule upon which an enzyme acts during a chemical reaction.

Active site

Region on an enzyme where the substrate binds and the reaction occurs.

Lock and key model

Concept describing the specificity of enzyme-substrate interactions.

Limiting factor

Factor that restricts the rate of photosynthesis when it's in short supply.

Inverse square law

Law stating that light intensity is inversely proportional to the square of the distance from the source.

Producers obtain materials

Various substances are taken up and released by photosynthetic organisms to sustain their processes.

Carbon dioxide (CO2) and water (H2O)

Essential molecules required for photosynthesis to occur in plants.

Mineral ions

Elements required for the construction of cell structures in plants.

Oxygen

Primary waste product released by plants during photosynthesis.

Diffusion

Passive process where gases move from areas of high concentration to low concentration.

Stomata

Pores on the undersides of leaves through which gases enter and exit plants.

Osmosis

Passive movement of water molecules across a partially permeable membrane from high to low concentration.

Root hair cells

Specialized cells in plant roots that uptake mineral ions from the soil through active transport.

Active transport

Process requiring energy where molecules move against their concentration gradient

Guard cells

Cells surrounding stomata that regulate their opening and closing to control gas exchange and water loss.

Phloem and xylem

Plant vascular tissues responsible for transporting nutrients, water, and sugars throughout the plant.

Transpiration

Loss of water vapor from the plant's surface due to evaporation, primarily from the leaves.

Transpiration pull

Mechanism by which water is drawn up the xylem due to cohesive forces between water molecules.

Environmental factors affecting water absorption

Light intensity, air movement, and temperature influence the rate of transpiration and consequently water absorption by plants.

Translocation

Process of moving sugars and amino acids through phloem channels from sources (where they're produced) to sinks (where they're stored or utilized).

Producers

Organisms that convert light energy to chemical energy to produce their own nutrients.

Consumers

Organisms that obtain their energy and biomass by feeding on other animals or plants.

Herbivores

Organisms that consume plants.

Carnivores

Organisms that consume animals.

Decomposers

Organisms responsible for breaking down decaying organic material (detritus).

Ecosystem

All living organisms and abiotic components (soil, rocks, water) interacting in a community.

Population

Organisms of the same species living together in one habitat.

Community

Populations of various species living together in one ecosystem.

Food chain

A diagram illustrating the order of energy transfer through feeding in an ecosystem.

Food web

A diagram showing how different food chains interact with each other.

Biomass

The total mass of living things in an ecosystem.

Pyramid of biomass

A graphical representation of the total biomass at each trophic level in a food chain.

Trophic level

The position of an organism in a food chain, food web, or pyramid of biomass.

Benedict's test used for

Identifying reducing sugars like fructose and glucose.

Result of a positive Benedict's test

Benedict's solution changes from blue to a brick-red precipitate.

Iodine test used for

Detecting the presence of starch.

Result of a positive iodine test

The solution changes color from yellow-brown to blue-black.

Sudan III test used for

Identifying lipids in a solution.

Result of a positive Sudan III test

A noticeable red layer forms on top of the solution.

Biuret test used for

Determining the presence of peptide bonds

Result of a positive biuret test

The solution containing proteins turns violet/purple.

Extracellular digestion

The process by which decomposers break down organic matter outside their cells using enzymes.

Factors influence the rate of decomposition

Temperature, oxygen presence, and water availability.

Carbon cycle

The movement of carbon atoms between the atmosphere and living organisms.

Role of plants in the carbon cycle

Plants absorb carbon dioxide during photosynthesis and release it during respiration and decomposition.

Water cycle

The continuous movement of water between the atmosphere, land, and oceans.

Role of decomposers in the nutrient cycle

Break down dead organisms to release nutrients back into the soil.