biology cells across a membrane

• plant cells contain a cell wall, vacuole, chloroplast, nucleus, cytoplasm, cell membrane, and mitochondria
• animal cells contain a nucleus, mitochondria, cytoplasm, and a cell membrane
• in aminal cells the cell wall, chloroplast and vacuole is NOT present
• functions of the cell;
• • cell membrane - controls substances entering and leaving the cell
• cytoplasm - where most chemical reactions take place
• nucleus - carries genetic information and controls activities of the cell
• cell wall- supports cells structure
• chloroplast- absorbs light for photosynthesis
• vacuole- filled with sap, helps maintain cell shape
• mitochondria- where aerobic respiration takes place, breaks down food into energy
• red blood cells- contain hemoglobin which carries oxygen around the body. biconcave shape to maximize surface area to absorb oxygen. thin membrane so gases can easily diffuse in and out.
• sperm cell- fertilizes egg and cells to create life. adaptions; long tail for the sperm to swim to the egg
• white blood cell-immune response fights pathogens
• • tissues- groups of similar cells with similar functions that work together to perform specific functions
• organs - several tissues performing specific functions
• organ system-a number of organs working together to carry out specific functions
• diffusion - the movement of particles from a high concentration to a low concentration
• change in diffusion; TEMPERATURE increase increases the diffusion rate as it increases the energy particles have. CONCENTRATION- The greater the difference in concentration the faster the rate of diffusion. PRESSURE- when high-pressure molecules quickly move from an area of high pressure to low.
• • substances enter and leave the cell through cell membranes. small molecules can easily pass through the cell membrane while larger molecules can't as the pores are too small. the cell membrane is selectively permeable
• selectively permeable membrane- only allows certain molecules though
• osmosis- the diffusion of water molecules from an area of high concentration to low concentration through a selectively permeable membrane.
• TURGID cell - when the concentration of water on the outside is higher than the concentration of the water inside water moves through the selectively permeable membrane by osmosis. the cell gets BIGGER and becomes TURGID.
• FLACCID-when the concentration of water inside is higher than the concentration of water outside. water moves out of the cell through the selectively permeable membrane by osmosis. the cell gets smaller and becomes flaccid.
• active transport - the movement of particles from a low to a high concentration using energy from respiration.
• enzymes- catalysts that speed up reactions. they are proteins
• properties of enzymes; they are proteins, they speed up rates of chemical reactions, work best at optimum temperature and PH
• optimum temperature- the temperature at which the enzyme is most active and the reaction is the fastest.