Chapter 1 Biology GCSE

• Features in a animal cell include: cell membrane, cytoplasm, nucleus, mitochondria, ribosomes
• Features in a plant cell include cell wall, cell membrane, nucleus, mitochondria, ribosomes, cytoplasm, permanent vacuole, chloroplasts, chlorophyll.
• The purpose of the cell wall is to keep the plant rigid and maintain its shape.
• The purpose of the cell membrane is to allow chemicals in and out of the cell.
• The nucleus carries genetic material which is key for reproduction and it controls the cell's activities.
• The mitochondria is the site of aerobic respiration and is where most of the energy is released.
• Ribosomes are the site of proteinsynthesis: where protein is produced.
• The cytoplasm is a gel-like substance in which chemical reactions take place in.
• Chloroplasts are the site of photosynthesis and are the way that plants are able to make food for themselves.
• Chlorophyll is the green pigment inside chloroplasts, they absorb light to make food.
• The permanent vacuole is filled with cell sap that keeps the cell turgid.
• To find the magnification you must multiply the eyepiece lens magnification with the magnification of the microscope.
• To work out the magnification you must divide the image size by the actual size of the object.
• An electron microscope is better than the light microscope since you are able to see more with a higher resolution like ribosomes and mitochondria.
• The electron microscope is more expensive than the light one and therefore not used by many.
• Cell wall is made out of cellulose which makes the cell rigid and prevents the cell from bursting.
• Animal and plant cells are examples of a eukaryotic cells
• One difference between eukaryotic and prokaryotic cells is that in a eukaryotic cell there is an enclosed nucleus while in prokaryotic cells there are small ring/s of DNA called plasmids.
• Prokaryotic cells are smaller than eukaryotic cells at 0.2-2 micrometers,
• Although there is a cell wall in a prokaryotic cell there is no cellulose
• In a prokaryotic cell there may be a slime capsule too.
• In prokaryotic cells there are also flagella/flagellum which are protein strands which allow for movement.
• Nerve cells send electrical impulses to the brain and the body providing rapid communication,
• Some adaptations of nerve cells include: Lots of dendrites to make connections; long axons to carry one impulse to another; synapses that pass the impulses to other cells through transmitter chemicals; they contain a lot of mitochondria to provide energy for the creations of these chemicals.
• Sperm cells have: a streamlined head which makes protrusion easy; a long tail which helps the cell swim; a middle section filled with mitochondria for energy; a large nucleus carrying genetic material; acrosome in the head that stores digestive enzymes to make breaking the egg shell easy,
• Muscle cells have special proteins which slide over making the fibres contract; many mitochondria for energy; they store glycogen which can be broken down for cellular respiration.
• Mineral ions are moved into the root hair cell through active transport.
• The root hair cell has a large protrusion (root hair) which increases its surface area allowing for more water and mineral absorption; a large permanent vacuole which speeds up the movement of water by osmosis; many mitochondria which are needed to transfer energy which is needed for active transport of mineral ions into the root hair cell.
• Xylem cells move mineral ions and water from the roots to the highest leaves and stems.
• Xylem cells start off alive as a special chemical called lignin builds up in the cell, the cell then dies and leaves hollow tubes for mineral ions and water to pass through.
• The lignin in the xylem make the cell strong and able to withstand the pressure of water.
• Phloem cell carries food around the body of the cell made by photosynthesis.
• Phloem cells have a large sieve made from broken-down cells to allow for the movement of food molecules; mitochondria which are used to transfer energy for movement.
• Diffusion is the net movement of particles from an area of high concentration to low concentration.
• Diffusion happens since the particles bump around with each other which lead to them spreading out in random places.
• Diffusion is affected by the overall concentration gradient because the larger the gradient the faster the diffusion; the temperature; large surface area to volume ratio.
• Osmosis is the diffusion of water from a high concentration to a low concentration through a semi-permeable membrane.
• Osmosis may also be seen as the diffusion of a solute from a dilute solution to a concentrated solution through a semi-permeable membrane.
• Isotonic solution is when the concentration of the solution outside the cell is the same as the solution inside the cell
• Hypertonic solution is when the concentration of the solution outside the cell is higher than the solution inside the cell