Cellular FunctionsAll 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.

MetabolismMetabolism 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 TransportAtoms, 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:

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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

Driven by the concentration gradient

Molecules spread out evenly till dynamic equilibrium is reached

Examples of diffusion… Can you think of any?

https://www.youtube.com/watch?v=VY0mZUDvbH4&spfreload=10

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

hypertonic solution: higher concentration of solute, less water

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

Facilitated Diffusion (Open Channels)

Facilitated Diffusion (Proteins Change Shape)

Diffusion vs. Facilitated Diffusion

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.

Hypertonic: If concentration of water is higher inside the cell, water diffuses out of the cell and the cell will shrink.Salt solutionPlasmolysis 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). Provides the plant cell with turgor pressure.

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.