Cada respuesta es palabra por palabra de una lección gratis de Brainlag Learn, donde se explica la idea completa. Los tribunales de examen redactan algunas definiciones de otra forma, así que compara la tuya con tu temario.
- 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