cell biology

• light microscopes were developed in the mid 17th century and use a light beam
• light microscopes are relatively cheap and easy to use, but they have limited magnification and resolution
• electron microscopes were invented in 1930 and it uses a beam of electron
• electron microscopes magnify around x2000000, are expensive and must be kept in a pressure controlled room
• nucleus controls the all activity in the cell
• cell membrane controls the passage of substances in and out of the cell
• cytoplasm is liquid gel where most chemical reactions take place
• mitrochondria is where respiration takes place
• ribosomes is where protein synthesis takes place
• chloroplasts absorb light for photosynthesis
• permanent vacuole keeps the cell rigid to support the plant
• diffusion is the spreading out of particles from a higher concentration to a lower concentration along a concentration gradient
• affecting factors of diffusion include, concentration, surface area, temperature
• osmosis is the movement of water from a dilute solution to a more concentrated solution through a partially permeable membrane
• active transport is the movement of substances from a lower concentration to a higher concentration which requires energy
• in mitosis the chromosomes replicate themselves and create two genetically identically daughter cells
• mitosis makes new cells for, growth and repair, repairing damaged tissue, asexual reproduction
• stem cells are undifferentiated cells
• stem cells can be found in human embryos, umbilical cord, some organ and tissues
• adult stem cells are found in bone marrow but can only differentiate into certain types of cells
• stem cells are useful in treating conditions where cells are damaged, such as diabetes and paralysis
• plant stem cells are found in meristems
• eukaryotic cells are animal cells, plant cells, fungi, they all contain a nucleus
• prokaryotic cells are bateria cells and dont contain a nucleus
• bacteria cells contain, a cytoplasm, ribosomes, plasmid, flagella, pili, capsule