AQA GCSE Combined Science Flashcards

Flashcards for AQA GCSE Combined Science Unit 4 & Unit 2

Photosynthesis

A chemical reaction in plants converting carbon dioxide and water into glucose and oxygen using light energy.

Chlorophyll

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

Endothermic Reaction

A reaction that requires energy to be absorbed, like photosynthesis.

Chloroplasts

Small organelles found in plant cells where photosynthesis takes place.

Stomata

Pores on the leaves of plants where carbon dioxide enters via diffusion.

Xylem

Plant tissue that transports water from the roots to the cells carrying out photosynthesis.

Limiting Factor

A factor that limits the rate of photosynthesis when in short supply (e.g., light, temperature, carbon dioxide).

Denatured Enzymes

Enzymes that have lost their shape and function due to high temperatures (above 45°C).

Inverse Square Law

The intensity of light is inversely proportional to the square of the distance from the source.

Respiration

The chemical reaction in living cells that releases energy for living functions and processes.

Mitochondria

Organelles inside cells where aerobic respiration occurs.

Exothermic Reaction

A reaction that releases energy to the surroundings, like respiration.

Aerobic Respiration

Respiration using oxygen, producing carbon dioxide, water, and energy (ATP).

Anaerobic Respiration

Respiration without using oxygen, producing less energy than aerobic respiration.

Fermentation

Anaerobic respiration in plants and yeast, producing ethanol and carbon dioxide.

Oxygen Debt

The amount of oxygen required by the body to convert built-up lactic acid back into glucose after anaerobic respiration.

Metabolism

The combination of all the reactions in a cell or in the body.

Differentiation

The process by which a cell changes to become a specialized cell.

Prokaryotic Cell

A cell that does not have a true nucleus (e.g., bacterial cell).

Eukaryotic Cell

A cell that has a true nucleus (e.g., animal or plant cell).

Osmosis

The movement of water molecules across a partially permeable membrane from a region of higher concentration to a region of lower concentration.

Active Transport

The movement of substances against the concentration gradient, requiring energy from respiration.

Chromosome

A structure in the nucleus of a cell containing DNA, organized in pairs in human cells.

Mitosis

Cell division process where DNA is copied and replicated before the cell divides.

Stem Cells

Undifferentiated cells that have the potential to turn into any kind of cell.

Meristem

The area of plant stem cells.

Diffusion

The spreading out of particles from an area of higher concentration to an area of lower concentration.

Gas Exchange

The process by which oxygen and carbon dioxide are exchanged in the lungs via the alveoli.

Alveoli

Small air sacs in the lungs where gas exchange takes place.

Villi

Small projections in the small intestine that increase the surface area to absorb more digested food.

Stomata

Pores on the underside of leaves that control gas exchange and water loss by the use of guard cells.

Gills

Organs in fish with a large surface area for gas exchange.

Pathogens

Microorganisms that enter the body and cause communicable diseases.

Bacteria

Small cells that reproduce quickly and produce toxins that damage cells and tissues.

Viruses

Small pathogens that replicate inside a host cell before bursting out to infect other cells.

Protists

Eukaryotic microorganisms, some of which are parasites and carried by a vector.

Fungi

Microorganisms that include single-celled organisms and those with hyphae that penetrate skin and plant surfaces.

Antibiotics

Drugs that kill bacteria but are ineffective against viruses.

Vaccination

Injection of a dead or weakened version of a pathogen to stimulate antibody production.

Antibodies

Proteins produced by white blood cells that lock onto antigens on pathogens.

Antigens

Molecules on the surface of pathogens that trigger an immune response.

Phagocytosis

The process by which white blood cells engulf and digest pathogens.

Tumor

Uncontrolled growth cells.

Coronary Heart Disease

A condition resulting from blockages in the coronary arteries.

Plasma

The liquid component of blood that transports blood cells, nutrients, and waste products.

Xylem

Vessels which transport water through the plant.

Pholem

Vessels which transport food such as dissolved sugars and glucose from photosynthesis.

Enzyme

Biological catalyst; enzymes speed up chemical reactions without being changed or used up.

Amylase

Enzyme which is the reactant for starch.

Arteries

Vessels away from the heart.

Photosynthesis

A chemical reaction in plants converting carbon dioxide and water into glucose and oxygen using light energy.

Chlorophyll

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

Endothermic Reaction

A reaction that requires energy to be absorbed, like photosynthesis.

Chloroplasts

Small organelles found in plant cells where photosynthesis takes place.

Stomata

Pores on the leaves of plants where carbon dioxide enters via diffusion.

Xylem

Plant tissue that transports water from the roots to the cells carrying out photosynthesis.

Limiting Factor

A factor that limits the rate of photosynthesis when in short supply (e.g., light, temperature, carbon dioxide).

Denatured Enzymes

Enzymes that have lost their shape and function due to high temperatures (above 45°C).

Inverse Square Law

The intensity of light is inversely proportional to the square of the distance from the source.

Respiration

The chemical reaction in living cells that releases energy for living functions and processes.

Mitochondria

Organelles inside cells where aerobic respiration occurs.

Exothermic Reaction

A reaction that releases energy to the surroundings, like respiration.

Aerobic Respiration

Respiration using oxygen, producing carbon dioxide, water, and energy (ATP).

Anaerobic Respiration

Respiration without using oxygen, producing less energy than aerobic respiration.

Fermentation

Anaerobic respiration in plants and yeast, producing ethanol and carbon dioxide.

Oxygen Debt

The amount of oxygen required by the body to convert built-up lactic acid back into glucose after anaerobic respiration.

Metabolism

The combination of all the reactions in a cell or in the body.

Differentiation

The process by which a cell changes to become a specialized cell.

Prokaryotic Cell

A cell that does not have a true nucleus (e.g., bacterial cell).

Eukaryotic Cell

A cell that has a true nucleus (e.g., animal or plant cell).

Osmosis

The movement of water molecules across a partially permeable membrane from a region of higher concentration to a region of lower concentration.

Active Transport

The movement of substances against the concentration gradient, requiring energy from respiration.

Chromosome

A structure in the nucleus of a cell containing DNA, organized in pairs in human cells.

Mitosis

Cell division process where DNA is copied and replicated before the cell divides.

Stem Cells

Undifferentiated cells that have the potential to turn into any kind of cell.

Meristem

The area of plant stem cells.

Diffusion

The spreading out of particles from an area of higher concentration to an area of lower concentration.

Gas Exchange

The process by which oxygen and carbon dioxide are exchanged in the lungs via the alveoli.

Alveoli

Small air sacs in the lungs where gas exchange takes place.

Villi

Small projections in the small intestine that increase the surface area to absorb more digested food.

Stomata

Pores on the underside of leaves that control gas exchange and water loss by the use of guard cells.

Gills

Organs in fish with a large surface area for gas exchange.

Pathogens

Microorganisms that enter the body and cause communicable diseases.

Bacteria

Small cells that reproduce quickly and produce toxins that damage cells and tissues.

Viruses

Small pathogens that replicate inside a host cell before bursting out to infect other cells.

Protists

Eukaryotic microorganisms, some of which are parasites and carried by a vector.

Fungi

Microorganisms that include single-celled organisms and those with hyphae that penetrate skin and plant surfaces.

Antibiotics

Drugs that kill bacteria but are ineffective against viruses.

Vaccination

Injection of a dead or weakened version of a pathogen to stimulate antibody production.

Antibodies

Proteins produced by white blood cells that lock onto antigens on pathogens.

Antigens

Molecules on the surface of pathogens that trigger an immune response.

Phagocytosis

The process by which white blood cells engulf and digest pathogens.

Tumor

Uncontrolled growth cells.

Coronary Heart Disease

A condition resulting from blockages in the coronary arteries.

Plasma

The liquid component of blood that transports blood cells, nutrients, and waste products.

Xylem

Vessels which transport water through the plant.

Pholem

Vessels which transport food such as dissolved sugars and glucose from photosynthesis.

Enzyme

Biological catalyst; enzymes speed up chemical reactions without being changed or used up.

Amylase

Enzyme which is the reactant for starch.

Arteries

Vessels away from the heart.