Biology flash cards (AQA)

What is a cell?

The smallest unit of life, which can perform all life processes.

What is the function of the nucleus?

The nucleus controls the cell's activities and contains genetic material.

What are organelles?

Specialized structures within a cell that perform specific functions.

What is osmosis?

The diffusion of water molecules through a partially permeable membrane.

What is homeostasis?

The process by which a stable internal environment is maintained in an organism.

Define biodiversity.

The variety of life and ecosystems in a given area.

What is a prokaryotic cell?

A simple, unicellular organism without a nucleus, like bacteria.

What is a eukaryotic cell?

A complex cell with a nucleus and organelles, found in plants and animals.

What is chlorophyll?

A green pigment in plants that absorbs light energy for photosynthesis.

What are the stages of the cell cycle?

Interphase, mitosis, and cytokinesis.

What is the role of ribosomes?

Sites of protein synthesis in cells.

Define natural selection.

The process where organisms better adapted to their environment tend to survive and produce more offspring.

What is a mutation?

A change in the DNA sequence that can lead to variations in traits.

What is the function of mitochondria?

The powerhouse of the cell, where energy (ATP) is produced.

What is the role of the cell membrane?

It regulates the movement of substances in and out of the cell.

Define ecosystem.

A community of living organisms and their physical environment interacting together.

What is a food chain?

A linear sequence of organisms where energy is transferred from one to another.

What is a food web?

A complex network of interconnected food chains in an ecosystem.

What is genetic engineering?

The manipulation of an organism's DNA to alter its characteristics.

What are antigens?

Molecules on the surface of pathogens that trigger immune responses.

What is the difference between aerobic and anaerobic respiration?

Aerobic respiration uses oxygen to produce energy; anaerobic respiration does not and produces less energy.

Define biodiversity hotspot.

A region with a significant amount of biodiversity that is threatened by human activity.

What are producers in an ecosystem?

Organisms that produce their own food, mainly through photosynthesis.

What are consumers in an ecosystem?

Organisms that obtain energy by consuming other organisms.

What is ecological succession?

The gradual process of change in species composition in a given area.

Define trophic level.

Each step in a food chain or food web that represents a different level of energy transfer.

What is a cardiovascular system?

A system responsible for the flow of blood, nutrients, hormones, and oxygen to and from cells.

What is the role of white blood cells?

To defend the body against infectious disease and foreign materials.

What is the function of red blood cells?

To transport oxygen from the lungs to the body's tissues and carry carbon dioxide back to the lungs.

Define enzyme specificity.

The concept that each enzyme only catalyzes a specific reaction or type of reaction.

What is the process of fertilization?

The fusion of male and female gametes to form a zygote.

What are dominant and recessive alleles?

A dominant allele masks the effect of a recessive allele in the phenotype.

What is genetic drift?

Random changes in allele frequencies in a population over time.

What is carrying capacity?

The maximum population size that an environment can sustain indefinitely.

What is ecological niche?

The role and position a species has in its environment.

What is the role of the enzyme amylase?

To catalyze the breakdown of starch into sugars.

What is an antibiotic?

A substance that kills or inhibits the growth of bacteria.

What is the role of chloroplasts in plant cells?

To conduct photosynthesis by converting light energy into chemical energy.

Define habitat.

The natural environment in which a species lives.

What is an ecosystem service?

The benefits provided by ecosystems to humans, like clean water and air.

Define photosynthesis equation.

6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

What is a keystone species?

A species that has a disproportionately large effect on its environment relative to its abundance.

What is the concept of biomagnification?

The increasing concentration of toxins in organisms higher up the food chain.

What are adaptive traits?

Heritable traits that enhance an organism's ability to survive and reproduce.

What is reproductive isolation?

A mechanism that prevents different species from interbreeding.

What is a phenotype?

The physical and observable characteristics of an organism.

Define genotype.

The genetic constitution of an individual organism.

What is speciation?

The formation of new and distinct species in the course of evolution.

What role do decomposers play in an ecosystem?

They break down dead organic matter, returning nutrients to the soil.

What are the primary functions of the immune system?

To identify and protect the body against pathogens.

What is a carbohydrate?

Organic compounds made of carbon, hydrogen, and oxygen, primarily serving as energy sources.

Define the term 'biome.'

A large geographical biotic unit, such as a desert, tundra, or forest.

What is a mutation rate?

The frequency at which mutations occur in a given DNA sequence.

What is community ecology?

The study of interactions among species in a community.

What is the role of fungi in ecosystems?

Decomposers that break down dead organic material, recycling nutrients.

What is a biotic factor?

A living component of an ecosystem that affects other organisms.

What is an abiotic factor?

A non-living component of an ecosystem that influences living organisms.

Define primary succession.

The process of community development on a previously uninhabited substrate.

Define secondary succession.

The process of community recovery after a disturbance that does not destroy the soil.

What is a nitrogen-fixing bacteria?

Bacteria that convert atmospheric nitrogen into a usable form for plants.

What is a symbiotic relationship?

A close interaction between two different species, where at least one benefits.

What is the role of the cell wall in plant cells?

To provide structural support and protection.

What is a vascular plant?

Plants that have specialized tissues for transporting water and nutrients.

Define chloroplasts location and function.

Chloroplasts are located in plant cells and are responsible for photosynthesis.

What are macro-nutrients for plants?

Essential nutrients required in large amounts, such as nitrogen, phosphorus, and potassium.

What are micro-nutrients for plants?

Nutrients required in smaller amounts, such as iron, zinc, and copper.

Define sympatric speciation.

The emergence of new species from a population that shares the same geographical area.

What is an invasive species?

A non-native species that disrupts local ecosystems.

What is the function of xylem?

To transport water and minerals from the roots to the rest of the plant.

What is the function of phloem?

To transport sugars and nutrients made during photosynthesis.

Define trophic cascade.

An ecological phenomenon triggered by the addition or removal of apex predators.

What factors affect enzyme activity?

Temperature, pH, and substrate concentration.

What is cellular respiration?

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

What are the roles of the kidneys?

To filter blood, remove waste, regulate electrolyte balance, and maintain blood pH.

Define the term 'ecosystem resiliency.'

The ability of an ecosystem to recover from disturbances.

What is genetic diversity?

The total number of genetic characteristics in the genetic makeup of a species.

Define ecological pyramid.

A graphical representation showing the biomasses or productivity at each trophic level.

What is a biogeochemical cycle?

The movement of elements and compounds through biological and geological processes.

What are the effects of pollution on ecosystems?

Pollution can harm organisms, reduce biodiversity, and disrupt ecosystem functioning.

What role do hormones play in organisms?

Chemical messengers that regulate physiological processes.

Define mutualism.

A type of symbiotic relationship where both species benefit.

What is commensalism?

A type of symbiotic relationship where one species benefits and the other is neither helped nor harmed.

What is parasitism?

A symbiotic relationship where one organism benefits at the expense of another.

Define the term 'population dynamics.'

The study of how populations change in size and composition over time.

What is an energy pyramid?

A graphical representation of energy flow in an ecosystem through different trophic levels.

What is the importance of wetlands?

Wetlands provide habitat, improve water quality, and mitigate flooding.

What is an ecological footprint?

A measure of human demand on Earth's ecosystems.

Define the term 'climate change.'

Significant and lasting changes in the Earth's climate, mainly caused by human activities.

What is the greenhouse effect?

The warming of Earth's surface due to trapped heat by greenhouse gases.

What is a carbon sink?

A natural system that absorbs more carbon dioxide than it releases.

Define eutrophication.

The process by which water bodies become overly enriched with nutrients, leading to excessive growth of algae.

What are sustainable practices in agriculture?

Farming methods that maintain productivity while minimizing environmental impact.

Define population ecology.

The study of populations in relation to their environment.

What is conservation biology?

A field of biology that focuses on the conservation of biodiversity.

What is an ecological niche?

The role and function of an organism or species within an ecosystem.

What is adaptive radiation?

The diversification of a group of organisms into forms filling different ecological niches.

What is a chromosome map?

A representation of the arrangement of genes on a chromosome.

What is DNA sequencing?

The process of determining the precise order of nucleotides in a DNA molecule.

What are stem cells?

Undifferentiated cells with the potential to develop into various cell types.

Define genetic counseling.

A process to evaluate and understand genetic risk factors for individuals or families.