IGCSE biology
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IGCSE biology - Leaderboard
IGCSE biology - Details
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| 🇬🇧 | 🇬🇧 |
| MRS GREN | Movement as an action by an organism Respiration as the chemical reactions realise energy Sensitivity to detect and respond to changes in environment Growth as a permanent increase in size Reproduction that makes more of the same kind of organism Excretion as the removal of waste products Nutrition, taking in materials for energy, growth and development |
| NA | NA |
| Principal dietary source and importance of fibre | Helps the movement of food in the alimentary canal, cabbage |
| Principal dietary source and importance of fibre | Helps the movement of food in the alimentary canal, cabbage |
| Plant cell | Plant cell |
| Animal cell | Animal cell |
| Principal dietary source and importance of fibre | Helps the movement of food in the alimentary canal, cabbage |
| Bacteria cell | Bacteria cell |
| Function of the cell wall | Gives shape to cells, stops cells from bursting when they fill with water, allows water and dissolved substances to pass through freely |
| Function of the cell membrane | Controls movement of other substances into and out of the cell, keeps contents of the cell inside, forms a barrier between the cell and its surroundings |
| Function of the nucleus | Controls all activities in the cell, controls how cells develop |
| Function of the cytoplasm | Place where chemical reactions take place (like respiration and making proteins for the cell) |
| Function of the vacuole | Stores salts and sugars, full of water to maintain shape and firmness of cell |
| Function of the chloroplasts | Stores starch, produce energy through photosynthesis and oxygen-release processes, site of photosynthesis |
| How are new cells produced | Division of existing cells |
| Ciliated cells function | Movement of mucus in the trachea and bronchi |
| Palisade mesophyll cells function | Contains lots of chloroplasts, close to where the light is so max amount of light hits the leaf, for photosynthesis |
| Root hair cells function | Allows the plant to absorb more water |
| Red blood cells function | Carry oxygen from the lungs and deliver it throughout our body |
| Sperm and egg cells (gametes) function | Carry out fertilization in sexually reproducible organisms, reproduction |
| Neurones function | Conduction of electrical impluses |
| Cell | Building blocks, muscle cells contract and relax |
| Tissue | Similar cells working together in the same way, cardiac muscle tissue is made of muscle cells that contract and relax together |
| Organ | Group of tissues working together, your heart is made of muscle and other tissues and pumps blood around your body |
| Organ system | A group of organs working together, your heart and blood vessels make up your circulatory system which carries blood around your body |
| Organism | An individual living species, which exhibits all the properties of life |
| Diffusion | Net movement of particles from a region of their higher concentration to a region of their lower concentration, down a concentration gradient, as a result of their random movement |
| Where does energy for diffusion come from | Kinetic energy of random movement of molecules and ions |
| Magnification calculation | Magnification = image size ÷ actual size |
| Importance of diffusion of gases and solutes in living organisms | Allows them to gain the useful substances they require to obtain energy and grow, and lets them get rid of waste products, allows for gas exchange |
| Conversion between mm and µm | 1mm = 1000 µm |
| How does surface area influence diffusion | As the surface area of the membrane increases, the rate of diffusion also increases, as there is more space for molecules to diffuse across the membrane |
| How does temperature influence diffusion | Molecules move faster and collide more often as the temperature increases, diffusion is faster at warmer temps |
| How does concentration gradient influence diffusion | Higher the concentration the higher diffusion rates |
| How does distance influence diffusion | The greater the distance that a substance must travel, the slower the rate of diffusion |
| Role of water | Solvent in organisms |
| How does water move in and out of cells | Osmosis, through the cell membrane |
| How are plants supported | By the pressure of water inside the cells pressing outwards on the cell wall |
| Osmosis | The net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane |
| The importance of water potential and osmosis in the uptake and loss of water by organisms | If the water would only diffuse out or into the cell, it would shrink or burst, nutrients and minerals are diffused along with the water. |
| Active transport | The movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration (against the concentration gradient) using energy from respiration |
| Importance of active transport | A process for movement of molecules or ions across membranes, including ion uptake by root hairs |
| What happens during active transport | Protein carriers move molecules or ions across a membrane |
| Chemical elements that make up carbohydrates, fats and proteins | Carbon, hydrogen, and oxygen |
| What is starch made of | Glycogen and cellulose from glucose |
| What are proteins made of | Amino acids |
| What are fats and oils made of | Fatty acids and glycerol |
| Iodine test for starch | Changes from brown to a blue/black colour |
| Benedicts solution for reducing sugars | From blue to green/yellow if the amount is low and red if it is high |
| Chemical elements that make up fats | Carbon, hydrogen, and oxygen |
| Ethanol test for fats and oils | Milky white |
| DCPIP test for vitamin C | It changes from blue to red with acids but loses its colour in the presence of certain chemicals, one of which is ascorbic acid (vitamin C) |
| Structure of a DNA molecule | 2 strands coiled together, each strand contains bases, bonds between pairs of bases hold the strands together, bases always pair with each other (A&T, C&G) |
| Catalyst | A substance that increases the rate of a chemical reaction and is not changed by the reaction |
| Enzymes | Proteins that are involved in all metabolic reactions where they function as biological catalysts |
| Why enzymes are important to all living organisms | Without enzymes reactions simply would not occur or would run too slowly to sustain life, for example without enzymes digestion would be impossible |
| Lock and key model | Only a substrate molecule with a shape that fits into the active site will take part in the reaction catalysed by this enzyme |
| Photosynthesis | The process by which plants synthesise carbs from raw materials using energy from light |
| Word equation of photosynthesis | Carbon dioxide + water --> glucose + oxygen in the presences of light and chlorophyll |
| What does chlorophyll do | Chlorophyll transfers energy from light into energy in chemicals for the synthesis of carbohydrates |
| What is chorophyll | Green pigment that is found in chloroplasts |
| Why do plants store starch | Plants store starch as an energy store |
| Why do plants store cellulose | To build cell walls |
| Why do plants store glucose | Used in respiration to provide energy |
| Why do plants store sucrose | For transport in the phloem |
| Why do plants store nectar | To attract insects for pollination |
| Why do amino acids needs nitrate ions | Nitrate in plants is a source of nitrogen. It is required to make amino acid |
| Why does chlorophyll need magnesium ions | Regulate the activity of key photosynthetic enzymes |
| Why does photosynthesis need chlorophyll | To absorb the energy from light |
| Why does photosynthesis need light | Provides energy for the process |
| Why does photosynthesis need carbon dioxide | Diffuses into the leaves from the air |
| Balanced chemical equation for photosynthesis | 6CO2+6H2O→C6H12O6+6O2 |
| How leaves have adapted for photosynthesis | A large surface area to absorb light rays, a thin shape so gasses can diffuse in and out easily |
| Leaf diagram | Leaf diagram |
| Balanced diet | A diet consisting of a variety of different types of food and providing adequate amounts of the nutrients necessary for good health |
| Principal dietary source and importance of carbohydrates | Sugars, provide you with energy |
| Principal dietary source and importance of fats and oils | Long term energy store, good thermal insulators, butter |
| Principal dietary source and importance of proteins | Growth and repair, needed to make your own proteins, nuts |
| Principal dietary source and importance of vitamin C | Repair resistance to disease, citrus fruits |
| Principal dietary source and importance of vitamin D and calcium | Strengthens bones and teeth, milk |
| Principal dietary source and importance of iron | Formation of haemoglobin in red blood cells for transport of oxygen, eggs |
| Principal dietary source and importance of calcium | Strengthens bones and teeth, milk |
| Principal dietary source and importance of fibre | Helps the movement of food in the alimentary canal, cabbage |
| Importance of water | Needed for chemical reactions to take place |
| Cause of scurvy and rickets | Vitamin C deficency, vitamin D deficency |
| Digestive system | Digestive system |
| Cause of rickets | Vitamin D deficency |
| Ingestion | The processes of taking food, drink, or another substance into the body by swallowing or absorbing it |
| Digestion | The process of mechanically and enzymatically breaking down food into substances for absorption into the bloodstream |
| Absorption | The movement of nutrients from the intestines into the blood |
| Assimilation | Uptake and use of nutrients by cells |
| Egestion | The removal of undigested food from the body as faeces |
| Physical digestion | The breakdown of food into smaller pieces without chemical change to the food molecules |
| What does physical digestion do | Increases the surface area of food for the action of enzymes in chemical digestion |
| Tooth structure | Tooth structure |
| Function of the stomach in physical digestion | Release gastric juices that begin to break down all the food you've eaten |