Cellular Functions All the different parts of the cell are important to the life of the cell. Cellular activities require energy. All cells are able to release energy from complex molecules. The energy in a sugar molecule is released by the mitochondria in small steps. After a cell has taken in energy-rich molecules, the molecules are used by the mitochondria and energy is released.

Metabolism Metabolism is the sum of all the chemical reactions in a in a cell or organism. Important molecules, like sugar, are processed and energy is transformed to ATP and waste materials. Not all energy is used immediately. Some cells, for example, those in green plants that contain chloroplasts, store energy in complex molecules such as sugars.

Homeostasis and Transport Atoms, molecules and small particles are in constant motion. Molecules tend to move from an area where they are more concentrated to an area where they are less concentrated, until their concentration is the same everywhere. The concentrations of molecules at various points between the high and low areas form what is called the concentration gradient. Molecules are said to move down the concentration gradient.

There are two types of cellular transport units: ___________________________

Passive transport Passive Transport = movement of substances from an area of high concentration to low concentration across the cell membrane without any input of energy by the cell

Types of passive transport Diffusion = movement of molecules from high to low Diffusion = movement of molecules from high to low Driven by the concentration gradient Driven by the concentration gradient Molecules spread out evenly till dynamic equilibrium is reached Molecules spread out evenly till dynamic equilibrium is reached

Water and food coloring

Osmosis= Movement of water molecules from areas of high concentration to low concentration (diffusion of water)

A solution may be one of the following: (compared to a cell) hypotonic solution: lower concentration of solute, a lot of water hypotonic solution: lower concentration of solute, a lot of water hypertonic solution: higher concentration of solute, less water hypertonic solution: higher concentration of solute, less water isotonic solution: same concentration of water and solute isotonic solution: same concentration of water and solute

- Plasmolysis = cells shrink when turgor pressure is lost - the reason plants wilt

- Cytolysis = cell bursts due to water entering the cell

Facilitated Diffusion = move molecules across the cell membrane through carrier/transport proteins are specific for the type of molecule they help diffuse are specific for the type of molecule they help diffuse

Facilitated Diffusion (Open Channels)

Facilitated Diffusion (Proteins Change Shape)

Diffusion vs. Facilitated Diffusion Diffusion Facilitated Diffusion Diffusion Facilitated Diffusion

Facilitated diffusion Facilitated diffusion

REVIEW The diffusion of water is called the osmosis. Molecules move across a semipermeable membrane, from an area of high concentration to low concentration. The diffusion of water is called the osmosis. Molecules move across a semipermeable membrane, from an area of high concentration to low concentration.

Hypertonic: If concentration of water is higher inside the cell, water diffuses out of the cell and the cell will shrink. Hypertonic: If concentration of water is higher inside the cell, water diffuses out of the cell and the cell will shrink. Salt solution Salt solution Plasmolysis is a loss of turgor pressure and the cell will shrink. Plasmolysis is a loss of turgor pressure and the cell will shrink.

Hypotonic: If concentration of water is higher outside the cell, water diffuses into the cell and the cell will expand (burst). Hypotonic: If concentration of water is higher outside the cell, water diffuses into the cell and the cell will expand (burst). Provides the plant cell with turgor pressure. Provides the plant cell with turgor pressure. In an animal cell, it may result in cytolysis (bursting of the cell) In an animal cell, it may result in cytolysis (bursting of the cell) Contractile vacuoles are used to remove excess water in protozoa. Animals use lungs and kidneys. Contractile vacuoles are used to remove excess water in protozoa. Animals use lungs and kidneys.