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GCSE Biology


Master GCSE Biology with our interactive study cards designed for effective learning. These flashcards use proven spaced repetition techniques to help you memorize key concepts, definitions, and facts. Perfect for students, professionals, and lifelong learners seeking to improve knowledge retention and ace exams through active recall practice.


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What is a cell?

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Answer:

The basic unit of all living organisms

What is the difference between prokaryotic and eukaryotic cells?

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Answer:

Prokaryotic cells have no nucleus; eukaryotic cells have a nucleus

Name three structures found in plant cells but not animal cells

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Answer:

Cell wall and chloroplasts and permanent vacuole

What is the function of the nucleus?

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Answer:

Controls cell activities and contains genetic material

What is the function of mitochondria?

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Answer:

Site of aerobic respiration and releases energy

What is the function of chloroplasts?

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Answer:

Site of photosynthesis in plant cells

What is the function of ribosomes?

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Answer:

Site of protein synthesis

What is the cell membrane?

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Answer:

Controls what enters and leaves the cell

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What is diffusion?

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Answer:

Movement of particles from high to low concentration

What is osmosis?

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Answer:

Movement of water through a partially permeable membrane

What is active transport?

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Movement of substances against concentration gradient using energy

What factors affect diffusion rate?

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Answer:

Concentration gradient and temperature and surface area

What is a tissue?

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Answer:

A group of similar cells working together

What is an organ?

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Answer:

A group of tissues working together

What is an organ system?

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Answer:

A group of organs working together

Name the levels of organization in living things

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Answer:

Cell and tissue and organ and organ system and organism

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What is the equation for photosynthesis?

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Answer:

Carbon dioxide + water → glucose + oxygen

Where does photosynthesis occur?

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Answer:

In chloroplasts in plant cells

What are the limiting factors of photosynthesis?

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Answer:

Light intensity and carbon dioxide concentration and temperature

How do you test a leaf for starch?

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Answer:

Use iodine solution which turns blue-black if starch is present

What is cellular respiration?

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Answer:

Process that releases energy from glucose

What is the equation for aerobic respiration?

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Answer:

Glucose + oxygen → carbon dioxide + water + energy

What is anaerobic respiration?

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Answer:

Respiration without oxygen

What is the equation for anaerobic respiration in animals?

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Answer:

Glucose → lactic acid + energy

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What is the equation for anaerobic respiration in plants?

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Answer:

Glucose → ethanol + carbon dioxide + energy

What is oxygen debt?

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Answer:

Extra oxygen needed after exercise to remove lactic acid

What is the circulatory system?

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Answer:

System that transports substances around the body

What are the components of blood?

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Answer:

Red blood cells and white blood cells and platelets and plasma

What is the function of red blood cells?

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Answer:

Transport oxygen around the body

What is the function of white blood cells?

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Answer:

Fight infection and disease

What is the function of platelets?

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Answer:

Help blood clot at wounds

What is the function of plasma?

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Answer:

Transports dissolved substances in blood

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What is the structure of the heart?

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Answer:

Four chambers with two atria and two ventricles

What is the function of arteries?

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Answer:

Carry blood away from the heart at high pressure

What is the function of veins?

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Answer:

Carry blood back to the heart at low pressure

What is the function of capillaries?

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Answer:

Allow exchange of substances between blood and tissues

What is the digestive system?

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Answer:

System that breaks down food into smaller molecules

What is mechanical digestion?

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Answer:

Physical breakdown of food by teeth and stomach churning

What is chemical digestion?

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Answer:

Breakdown of food by enzymes

What are enzymes?

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Answer:

Biological catalysts that speed up chemical reactions

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What is the optimum temperature for human enzymes?

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Answer:

About 37 degrees Celsius

What happens to enzymes at high temperatures?

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Answer:

They denature and lose their shape

What is the function of amylase?

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Answer:

Breaks down starch into sugars

What is the function of protease?

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Answer:

Breaks down proteins into amino acids

What is the function of lipase?

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Answer:

Breaks down fats into fatty acids and glycerol

Where is bile produced?

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Answer:

In the liver

What is the function of bile?

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Answer:

Neutralizes stomach acid and emulsifies fats

What is the small intestine adapted for?

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Answer:

Absorption of nutrients into the blood

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Name three adaptations of the small intestine

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Answer:

Villi and microvilli and good blood supply

What is the respiratory system?

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Answer:

System that exchanges gases between body and environment

What is the pathway air takes into the lungs?

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Answer:

Nose/mouth → trachea → bronchi → bronchioles → alveoli

What are alveoli?

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Answer:

Tiny air sacs where gas exchange occurs

Name three adaptations of alveoli for gas exchange

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Answer:

Large surface area and thin walls and good blood supply

What is inspiration?

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Answer:

Breathing in air to the lungs

What is expiration?

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Answer:

Breathing out air from the lungs

What happens to the diaphragm during inspiration?

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Answer:

It flattens and moves down

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What is the nervous system?

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Answer:

System that coordinates responses to stimuli

What is a stimulus?

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Answer:

A change in the environment

What is a response?

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Answer:

A reaction to a stimulus

What is the central nervous system?

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Answer:

Brain and spinal cord

What is the peripheral nervous system?

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Answer:

All nerves outside the brain and spinal cord

What is a reflex action?

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Answer:

Automatic response to a stimulus

What is the pathway of a reflex arc?

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Answer:

Receptor → sensory neuron → relay neuron → motor neuron → effector

What is the function of sensory neurons?

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Answer:

Carry impulses from receptors to CNS

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What is the function of motor neurons?

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Answer:

Carry impulses from CNS to effectors

What is a synapse?

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Answer:

Gap between two neurons

How do impulses cross synapses?

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Answer:

Chemical messengers called neurotransmitters

What is homeostasis?

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Answer:

Maintaining constant internal conditions

What is negative feedback?

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Answer:

Process that counteracts changes to maintain steady state

How is body temperature controlled?

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Answer:

By the hypothalamus in the brain

What happens when body temperature rises?

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Answer:

Sweating increases and blood vessels dilate

What happens when body temperature falls?

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Answer:

Shivering occurs and blood vessels constrict

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How is blood glucose controlled?

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Answer:

By insulin and glucagon hormones

What does insulin do?

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Answer:

Lowers blood glucose by converting glucose to glycogen

What does glucagon do?

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Answer:

Raises blood glucose by converting glycogen to glucose

What is Type 1 diabetes?

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Answer:

Condition where pancreas cannot produce insulin

What is the treatment for Type 1 diabetes?

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Answer:

Regular insulin injections

What are hormones?

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Answer:

Chemical messengers carried in the blood

Where are hormones produced?

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Answer:

In endocrine glands

What is the menstrual cycle?

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Answer:

Monthly cycle preparing female body for pregnancy

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What hormone causes egg release?

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Answer:

Luteinizing hormone (LH)

What is fertilization?

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Answer:

Fusion of male and female gametes

Where does fertilization occur?

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Answer:

In the fallopian tubes

What is a gamete?

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Answer:

A sex cell containing half the normal number of chromosomes

What are the male gametes called?

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Answer:

Sperm

What are the female gametes called?

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Answer:

Eggs or ova

What is mitosis?

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Answer:

Cell division producing two identical diploid cells

What is meiosis?

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Answer:

Cell division producing four genetically different haploid gametes

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What is DNA?

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Answer:

Chemical that carries genetic information

What is a gene?

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Answer:

A section of DNA that codes for a characteristic

What is an allele?

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Different versions of the same gene

What is a chromosome?

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Answer:

Structure containing DNA found in the nucleus

How many chromosomes do humans have?

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Answer:

46 chromosomes or 23 pairs

What is the difference between dominant and recessive alleles?

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Answer:

Dominant alleles are expressed when present; recessive only when homozygous

What is genotype?

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Answer:

The genetic makeup of an organism

What is phenotype?

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Answer:

The observable characteristics of an organism

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What is heterozygous?

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Answer:

Having two different alleles for a gene

What is homozygous?

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Answer:

Having two identical alleles for a gene

What is variation?

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Answer:

Differences between individuals

What causes genetic variation?

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Answer:

Sexual reproduction and mutations

What causes environmental variation?

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Answer:

Factors in the environment like diet and exercise

What is evolution?

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Answer:

Change in inherited characteristics over time

What is natural selection?

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Answer:

Process where organisms with advantageous traits survive and reproduce

What is adaptation?

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Answer:

Features that help organisms survive in their environment

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What is extinction?

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Answer:

When all members of a species die out

What is biodiversity?

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Answer:

The variety of living organisms in an ecosystem

What is an ecosystem?

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Answer:

All living and non-living factors in an environment

What is a habitat?

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Answer:

The place where an organism lives

What is a population?

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Answer:

All organisms of one species in a habitat

What is a community?

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Answer:

All organisms in a habitat

What do food chains show?

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Answer:

Transfer of energy between organisms

What is a producer?

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Answer:

Organism that makes its own food by photosynthesis

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What is a primary consumer?

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Answer:

Organism that eats producers

What is a secondary consumer?

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Answer:

Organism that eats primary consumers

What is a decomposer?

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Answer:

Organism that breaks down dead material

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