Biology paper 1 topics

• amylase enzyme breaks down starch
• iodine turns from orange to a blue/black colour when starch is detected
• lipids are broken down into glycerol and fatty acids
• starch is broken down into sugars and starch
• Large molecules such as proteins and lipids are broken down by digestive enzymes
• large molecules are broken down so that they can be absorbed into the bloodstream via the intestine
• the small intestine has villi which increase surface area, allowing more absorption
• villi have microvilli which further increases surface area
• proteins are broken down into amino acids by proteases in the stomach and small intestine
• the equation for total magnification without the lenses is total magnification= eyepiece lens magnification x objective lens magnification
• total magnification with lenses = image size/object size
• electron microscopes have a higher resolution and a higher magnification
• electron microscopes are better than light microscopes because they can see smaller details
• a rise in temperature causes an enzyme's bonds to break and the active site to change shape
• enzymes work best at their optimum temperature, which varies between different types of enzymes
• amylase is another name for carbohydrase
• a substrate is the molecule changed in a reaction by a reaction
• enzymes only work with one type of substrate. This is called the lock and key mechansim
• after mitosis, genetically identical diploid cells are formed
• to tell mitosis has occurred you will be able to see x shaped chromosomes in the nucleus
• stem cells are able to divide by mitosis to produce more stem cells, which can differentiate into specialised cells
• the risks of using stem cells include tumour development, rejection and infection
• stem cells have the potential to cure some diseases
• adult stem cells aren't as versatile as embryonic stem cells
• sexual reproduction uses mitosis to produce genetically different offspring
• the 4 stages of mitosis are prophase, metaphase, anaphase, and telophase
• to investigate osmosis put potatoes in different concentrations of sucrose solution to see the effect different water concentrations have on them
• to find the percentage change in mass do

  final mass - initial mass / initial mass x 100
• undifferentiated cells are stem cells
• stem cells are found in bone marrow and early embryos
• concentrated means there is more solvent that solute (water)
• active transport is the movement of molecules from a low concentration to a high concentration across a cell membrane against a concentration gradient
• active transport requires energy
• diffusion is a passive process where particles move from an area of high concentration to an area of low concentration
• cell differentiation is the process by which a cell becomes specialised for its job
• cell elongation is when a plant cell expands, making the cell bigger and forcing the cell to grow upwards
• during mitosis, in the step of anaphase, spindle fibres pull the chromosomes apart and the chromosomes are pulled to opposite sides of the cell
• during mitosis, in the step telophase,membranes form around the chromosomes to create nuclei- the nucleus has divided
• the difference between meiosis and mitosis is that meiosis doesnt produce identical cells
• meiosis occurs in the reproductive organs of animals