Fiches Biologie GCSE : 52 termes clés, pour Brainlag Flashcards et Anki

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Chaque réponse reprend mot pour mot une leçon gratuite de Brainlag Learn, où l'idée est expliquée en entier. Les organismes d'examen formulent certaines définitions autrement : compare avec ton programme.

Eukaryotic cells

Keep their genetic material (DNA) inside a nucleus. Animals, plants, fungi and protists are made of them.

Prokaryotic cells

Are bacteria. They are much smaller, about a tenth of the size of a typical animal cell, and have no nucleus

Nucleus

Holds the genetic material that controls the cell

Cytoplasm

A jelly where most chemical reactions happen

Cell membrane

Controls what goes in and out

Mitochondria

Where aerobic respiration releases energy

Ribosomes

Where proteins are made

Magnification

How many times bigger the image is than the real thing.

Resolution

How much detail you can see: the smallest gap between two points that still look like two points.

Stem cell

An undifferentiated cell that can divide to make more cells, which can differentiate.

Therapeutic cloning

An embryo is made with the patient's own genes, so the cells it gives are not rejected.

Chromosomes

Long molecules of DNA, each carrying many genes.

Mitosis

Mitosis is for growth, repair, replacing cells and asexual reproduction.

Diffusion

The net movement of particles from where they are more concentrated to where they are less concentrated.

Osmosis

The movement of water through a partially permeable membrane from a dilute solution to a more concentrated one.

Active transport

Moves substances against the concentration gradient, from dilute to concentrated, using energy from respiration.

Binary fission

One cell splits into two.

Population

All the organisms of one species in an area.

Community

All the populations of different species in that area.

Habitat

Where an organism lives.

Ecosystem

A community interacting with the non-living parts of its environment.

Interdependence

Species in a community depend on each other for food, shelter, pollination and seed dispersal

Abiotic factors

Are non-living: light intensity, temperature, moisture, soil pH and mineral content, wind, carbon dioxide for plants, oxygen for animals in water.

Biotic factors

Come from living things: the food available, new predators, new pathogens, and competition.

Extremophiles

Live in extreme conditions: very hot springs, high pressure on the sea floor, very salty lakes.

Homeostasis

Keeping internal conditions within set limits

Receptors

Detect a stimulus (a change inside or outside the body).

Effectors

(muscles or glands) carry out the response.

Central nervous system

The brain and the spinal cord.

Sensory neurone

Carries impulses from a receptor to the CNS

Relay neurone

Links neurones inside the CNS

Motor neurone

Carries impulses from the CNS to an effector

Synapse

Where two neurones meet there is a tiny gap

Reflex

An automatic, rapid response that does not involve the conscious part of the brain.

Pathogen

A microorganism that causes an infectious disease.

Communicable

They pass from one person (or plant) to another.

Phagocytosis

A phagocyte engulfs the pathogen and digests it

Antitoxins

These neutralise the toxins that bacteria release

Fertilisation

Two gametes join, so the full number is restored.

DNA

A polymer made of two strands twisted into a double helix.

Gene

A short section of DNA that codes for a particular sequence of amino acids, to make one protein.

Genome

All the genetic material of an organism.

Dominant

(capital letter, B) shows even if only one copy is present.

Recessive

(small letter, b) shows only if there are two copies.

Homozygous

Two identical alleles (BB or bb).

Heterozygous

Two different alleles (Bb).

Phenotype

The characteristic you see (black fur).

Tissue

A group of cells with a similar structure and function (muscle tissue, glandular tissue, epithelial tissue).

Organ

Different tissues working together on one job.

Organ system

Organs working together, such as the digestive system.

Bile

It is alkaline, so it neutralises stomach acid, and it emulsifies fat into tiny droplets

Chlorophyll

The green pigment in chloroplasts