CHAP 1

• light microscope ca magnify up to 1000x
• electron microscope can magnify more than 200,000x
• micrograph is a photo taken through a microscope to show a magnified image of specimen.
• we cut a cell in 2 ways to view structures from different angles to build up a 3D picture of the cell.
• each living cell contains a living material called protoplasm. [contains cell membrane , cytoplasm and nucleus.][complex jelly like substance.chemical activities that allows the cell to grow and survive are carried out here.]
• cell membrane is made up of lipids and proteins. it is a partially permeable membrane and only allows some soluble substances to pass through + control movements of substances in and out of cell.
• cell Wall is made up of cellulose and is fully permeable and protects the cell from injuries as well as gives the plant a regular shape by preventing the cell from bursting.
• cytoplasm is a jelly like substance enclosed by the cell membrane where most activities occur. [contains organelles]
• nucleus contains genetic information in the form of chromosomes. it controls cell activities and is essential for cell division.
• chromosomes are made up of a molecule called DNA,coiled around proteins. hereditary information is stored inside DNA and controls cell activities.
• vacuoles is a fluid filled space enclosed by partially permeable membrane. it stores substances within the cell.
• plant cells have a large central vacuole which contains a liquid called cell sap which contains dissolved substances.[sugar]
• animal cells have small vacuoles that contains water/food substances [temporary]
• mitochondria is a small oval shape organelle that are bound by membrane and breakdowns glucose in the presence of oxygen to release energy for cell activities. > aerobic respiration.
• ribosomes have small round structures that are either attached to organelles within the cell or lie freely in the cytoplasm. they synthesise proteins in the cell.
• chloroplasts are oval structures containing chlorophyll. chlorophyll is essential for photosynthesis.
• red blood cells contains haemoglobin which binds to oxygen and transports it around the body. It has a circular biconcave shape which increases the surface area to volume ratio so that oxygen can diffuse in and out at a higher rate. [no nucleus to store more haemoglobin for transport of oxygen.
• muscle cell contains many nuclei and mitochondria. mitochondria to provide energy for contraction of muscle.

  
• root hair cell has a long and narrow extension to increase the surface area to volume ratio to absorb water and mineral salts at a higher rate.