Key concepts biology

• Animal cell has a nucleus which stores the cell's genetic information, a cell membrane that controls what enters and exits the cell, mitochondria responsible for respiration to produce energy, ribosomes to make essential proteins, and cytoplasm where chemical reactions happen.
• Plant cell has a cell wall for extra strength and protection, a vacuole to store cell sap, and chloroplasts for photosynthesis.
• Bacteria cell has a flagellum for movement, plasmid loops for extra loops of DNA, and a flagellum for movement.
• Cells can be categorized into prokaryotic cells which are smaller, simpler, and have no nucleus, and eukaryotic cells which are bigger, more complex, and have a nucleus.
• Cells go through a process of differentiation when they switch particular genes on or off to develop characteristics and become specialized.
• Sperm and egg cell are specialized cells, known as gametes, with a haploid nucleus, and the egg cell has lots of nutrients in its cytoplasm.
• The sperm cell has an axon filled with enzymes to help break down the egg cell, and underneath the head, it has lots of mitochondria for energy.
• Ciliated epithelial cell is a specialized cell adapted to have a hair-like structure called cilia, typically lining organs to help move substances along.
• Microscopes include light microscope invented in the 1500s which works by passing beams of light through the specimen, and electron microscope invented in the 1930s which works by passing beams of electrons through the specimen.
• Enzymes are biological catalysts made by living things, and the word catalyst means they speed up reactions.
• Enzyme is a molecule, not a living thing, and it has the substrate which is the thing the enzyme is reacting with and the active site on the enzyme which is the place where the reaction happens.
• Enzymes are highly specific and can only catalyze one reaction and one type of substrate.
• Enzymes need specific conditions to work, such as a certain temperature and pH.
• Enzymes cannot die but instead denature if the conditions are not optimal.
• Enzyme activity can be increased by increasing the substrate concentration.
• To test for reducing sugars, the Benedict's reagent test is used, where a positive result forms a colored precipitate.
• To test for proteins, the burette test is used, where a positive result results in a purple color.
• To test for lipids, the emulsion test is used, where a positive result results in a milky water.
• To test for starch, the iodine test is used, where a positive result results in a blue-black color.
• Calorimetry is a process used to determine the energy in food by measuring the change in temperature of a food when it is alight.
• Diffusion is the movement of particles from a higher to low concentration, such as spraying air freshener and having it diffuse out into the surroundings.
• Active transport is the movement of particles from a low concentration to a higher concentration, this process does require energy.
• Osmosis is the overall movement of water molecules from a high to low concentration through a partially permeable membrane.