Key concepts

• Animal cells have a cell membrane, nucleus, cytoplasm, mitochondria and ribosomes.

  
• Plant cells have a cell wall, cell membrane, nucleus, cytoplasm, mitochondria, chloroplasts, ribosomes and a permanent vacuole.

  
• Microscopes are made from a stage, slide, mirror, eye piece lens, objective lens, coarse focusing wheel and a fine focusing wheel.
• estimating size - TIA

  image x actual size = total magnification
• Total magnification - TOE

  eyepiece lens x objective lens = total magnification
• Enzyme activity can be effected by temperature, ph and substrate concentration.
• As temperature increases so dose the chance of substrate molecules slotting into an active site which increases the rate of reactions.

  Optimum temperature is the point at which enzymes work the fastest.
• A sperm cell has -

  A streamlined shape to move faster.

  A store of mitochondria to provide it with energy to swim

  A small vacuole with enzymes to break down the eggs jelly coat.
• An egg cell has -

  A jelly coat to protect the egg, it hardens after fertilisation to ensure only one egg fuses.

  A store of nutrients to provide energy for an embryo to grow and develop.
• In the process of digestion the substrate attaches to the active site due to the complementary shape which breaks it down and turns it into a smaller product.

  
• An acrosome is an organelle in the tip of a sperm that contains enzymes which digest the egg cells membrane
• An active sight is a specific region on an enzyme where the substrate binds and the reaction takes place
• Active transport is the movement of substances across a semi-permeable membrane from a low concentration to a higher concentration, with the use of energy from respiration
• Benedict's is used to test for sugars, if sugar is present it turns from blue to an orange/red
• Biurets is used to test for protein, if protein is present it turns from blue to purple
• Calorimetry is a method Used to measure the heat transfer in a chemical reaction
• Carbohydrates are large molecules synthesised from simple sugars
• A cell membrane is a partially permeable barrier that surrounds the cell
• A cell wall is an outer layer made of cellulose that strengthens the plant cells structure
• Chloroplasts are organelles for the site of photosynthesis
• Chromosomes are long coiled molecules of DNA that carry genetic information in the form of genes
• Cilia are hair-like structures found on epithelial cells which waft substances across the surface of tissue in a singular diredition
• Ciliated epithelial cells waft to bacteria trapped by mucus into the stomach, where it is killed by the acid
• When an enzyme is denatured, its active sight experiences a permanent change in shape which prevents it from binding with the substrate
• diffusion is the net movement of particles across a semi-permeable membrane from a high concentration to a low concentration
• A diploid cell contains two copies of each chromosome
• electron microscopes-

  Use beams of electrons to produce images of specimen

  Have a greater magnification and resolution
• Enzymes are biological catalysts that speed up the rate of reactions in living organisms without being used up
• Eukaryotic cells are cells found in plant and animals that contain a nucleus
• Flagella’s are hair-like structures on bacterial cells that are used for movement
• Haploid cells contain a singular copy of each chromosome
• Iodine is used to test for starch, if starch is present it turns from yellow to blue/black
• Light microscopes-

  Use a series of lenses to magnify the visible light reflecting a specimen

  Have lower magnification and resolution
• Lipase is an enzyme that breaks down lipids into fatty acids and glycerol
• Lipids are large molecules synthesised from fatty acids and glycerol
• Mitochondria is an organelle specialised as the site of respiration
• Nucleolus is an organelle found in most eukaryotic cells that contains the genetic material and controls the cell’s activities
• Osmosis is the net diffusion of water molecules across a semi-permeable membrane from a high water concentration to a low water concentration
• Plasmids are loops of DNA found in the cytoplasm of prokaryotic cells
• Prokaryotic cells are cells found in bacteria that do not contain a nucleus