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GCSE Cell Biology
GCSE Cell Biology (Topic 1 AQA Combined Science) Flashcards
Question | Answer |
---|---|
Nucleus | Contains genetic material |
Mitochondria | Where most of the reactions for aerobic respiration take place |
Cell membrane | Controls what goes in and out |
Ribosomes | Where proteins are made |
Cytoplasm | Where most of the chemical reactions take place |
Cell Wall | Made of cellulose - strengthens the cell |
Chloroplasts | Where photosynthesis occurs |
Permanent vacuole | Contains cell sap |
Animal cell contains... | Mitochondria, cell membrane, nucleus, cytoplasm and ribosomes |
Plant cell contains | Mitochondria, cell membrane, nucleus, cytoplasm, ribosomes, chloroplasts, permanent vacuole and cell wall |
Two differences between prokaryotic cells and eukaryotic cells | Prokayrotic cells are tiny compared to eukaryotic AND they don't have a true nucleus |
Are bacterial cells prokayrotic or eukaryotic? | Prokaryotic |
Bacterial cells contain... | Cell wall, plasmid, cell membrane and DNA loop floating in cytoplasm |
Magnification equation | Magnification = Image size/real size |
Two differences between electron and light microscopes | Electron microscopes have a higher magnification and resolution than light microscopes |
Chromosomes | Coiled up lengths of DNA molecules which carry genes. |
Where a chromosomes found? | In the nucleus, and theyre normally in pairs in body cells |
Cell cycle | A series of stages in which cells divide to produce new cells |
Before a cell divides, it does three things... | Grows in size, Increases the amount of subcellular structures and duplicates its DNA |
Mitosis | the stage of the cell cycle when the cell divides |
What happens during mitosis? | The cell's DNA doubles... One set of chromosomes is pulled to each end of the cell... The cytoplasm and cell membranes divide... Two identical cells are formed |
Binary fission | the simple cell division process by which bacterial cells replicate |
Cell differentiation | The process by which a cell changes to become specialised for its job |
Sperm cells | Reproduction - long tail and streamlined head for swimming to the egg |
Nerve cells | Rapid signalling - Long to cover a large distance and branched to form a network of connections |
Xylem and phloem cells | Transporting substances - Xylem cells are hollow and phloem cells have few subcellular structures SO substances can easily flow through |
Muscle cells | Contraction - Long so they have space to contract, and lots of mitochondria for energy |
Root hair cell | Absorbing water and minerals - Large surface area for absorbing water and mineral ions from the soil |
Diffusion | the spreading out of particles from an area of higher concentration to an area of lower concentration down a concentration gradient |
Three factors that increase the rate of diffusion across a cell membrane | A high concentration gradient A high temperature A large surface area |
Osmosis | The movement of water molecules across a partially membrane from a region of higher water concentration to a region of lower water concentration |
Active transport | The movement of a substance against the concentration gradient. It requires energy from respiration |
What does Active transport allow? | Mineral ions to be absorbed from the soil into root hair cells And glucose to be absorbed into the bloodstream from the gut |
Do single-celled organisms have a large or small SA:V ratio and what does this mean? | Large SO enough substances can pass across outer surface to meet needs of organism |
Do multicellular organisms have a large of small SA:V ratio and what does this mean? | Small SO many cells too far away from outer surface to get substances in and out this way |