Understanding how the cell works Micro life Understanding how the cell works

Advantages in Cell Structure Small size allows for EASY ACCESS for Nutrients and waste removal (Osmosis and Diffusion) Cells can become specialized to perform certain tasks Multicellular animals have better survival chance; (If you are single celled organism with cell flaw or cell damaged you die: Prokaryote/bacteria) In multicellular organisms cells can replaced when damaged: However, the more complex the organism the less “regeneration” Specialized Cells create more complex organisms and organs with better abilities: however, harder to repair when damaged and some can be not be repaired: Nerve, Brain cells in humans

2 Factors which limit cell’s size 1. Cell Volume- the space that the cells physically fills 2. Surface Area- area of the cell’s surface which interacts with the environment around the cell The ratio of cell’s S.A. to its volume is what limits the cell size The reason is that diffusion or osmosis will not work well when volume of cell out grows it’s S.A.

Cell Life Stages G 1 Stage S Stage G 2 Stage Cell increases in size Organelles double New Cytoplasm forms Cell functions Normally All Genetic Material is replicated Twin Chromosomes then form an attachment poit called a centromere Cell begins the process of Mitosis or cell Division Nucleus Disappears and Chromosomes become visible Centrioles appear and Spindle Fibers as well

Steps of Mitosis Interphase- nucleus disappears and chromosomes appear Prophase- Chromosomes move to center of cell; Centrioles move to opposite ends Metaphase- Spindle fibers attach to chromosomes in middle of cell Anaphase- Chromosomes are pulled toward opposite ends of cell (centrioles) Telophase- Chromosomes, centrioles, and spindle fibers disappear; nucleus reforms and cell splits its cytoplasm to make 2 new “daughter” cells (cytokinesis)

Cellular Respiration Use of Nutrients in a cell to provide energy for the cell to function

What is Diffusion Diffusion is how cell’s breathe Works through Cell Membrane- “Gatekeeper of the cell” Oxygen gas naturally want to go inside cell because cell contains a lower amount of oxygen inside: Carbon Dioxide naturally want to leave cell because of high levels of Carbon Dioxide inside cell and low amount outside

What is Osmosis? Natural flow of water across and through the cell membrane Allows for nutrients to enter and leave cell without using energy Energy then can be reserved for specialized functions/abilities

Passive Transport Requires no energy to move material throughout the cell Diffusion and Osmosis are forms of Passive Transport

Active Transport Energy is required to allow material enter the cell membrane . Nutrients that are not water dissolved in water must be brought in this way into the cell: Example would be an Amoeba engulfing its food (single celled organism) or the use of cilia to cause food to enter cell membrane for digestion in the vacuoles