CELL PROCESSESChemistry of Life, Cell Transport, & Cell Energy

What is everything composed of?• Everything around you is made of matter and energy.

• Matter: anything that has mass and takes up space.

• Energy: anything that brings about change.

What are atoms?• All matter is made up of atoms.

• Center of an atom is its nucleus, which contains protons and neutrons.

• Outside of the nucleus are the electrons, which are involved in chemical reactions.

What are elements?• Elements: structure only made up of one type of atom.• Cannot be broken down into simpler form by ordinary

chemical reactions.• Arranged in a chart known as the periodic table of the

elements.• All living things are made up of a combination of

different elements.

What elements are in your body?

What are compounds?• Compounds are made up of two or more elements in exact proportions.

• Compounds have different properties from the elements they are made from.

• Compounds are composed of molecules.• Molecule: a group of atoms held together by the energy of chemical bonds.

• Molecular Compounds form when different atoms share their outer-most electrons and bond together.

What are ionic compounds?• Ions: electrically charged atoms, positive or negative.• Ions of opposite charges attract to one another to form

electrically neutral compounds, known as ionic compounds.

• Example: NaCl (salt)

What are Mixtures?• Mixture: combination of substances in which individual

substances keep their own properties.• Solution: mixture in which 2 or more substances are mixed evenly.• Suspension: forms when a liquid or gas has another substances

evenly spread throughout it.

What are organic compounds?• Organic compounds contain carbon and hydrogen

and are associate with living/once living things.• Carbohydrates: supply energy for cell processes• Lipids: store and release large amounts of energy• Proteins: are the building blocks of many structures• Amino Acids: smaller molecules that make up proteins• Enzymes: proteins that regulate nearly all chemical

reactions in cells• Nucleic acids: store important coded information in

cells

Why is water important?• Living things are composed of more than 50% water and

depend on it to survive.• All chemical reactions in living things take place in water

solutions.• Most living things use water to transport materials

through their bodies.

How do cells get the materials they need to do work?• Materials move in and out of the cell through the cell

membrane. • Water and oxygen can cross the membrane through a

process known as diffusion. • The cell membrane is semipermeable, meaning that it

only allows certain substances to pass through it.

What are diffusion & osmosis?• Diffusion is the movement of particles from areas of high

concentration to areas of low concentration.• Osmosis is the diffusion of water of water through a

membrane.

How do small particles enter/leave the cell?• Smaller particles, such as sugars, can cross the cell membrane through protein channels.

• Passive Transport: the movement of particles from areas of high to low concentration through the cell membrane without using energy.• Examples: diffusion and osmosis

• Active Transport: the movement of particles from areas of low concentration to high concentration. This process requires ENERGY.

Materials moving into the cell…

How do large particles enter/leave a cell?

• Endocytosis: process that occurs when a cell surrounds a large particle and encloses it in a vesicle (a sac formed from a piece of the cell membrane) to bring the particle into the cell.

• Exocytosis: process that occurs when a cell uses a vesicle to move a particle from inside the cell to outside a cell.

• Both of these processes require energy from the cell.

Endocytosis & Exocytosis

Are endocytosis and exocytosis examples of active or passive transport?

Are diffusion and osmosis examples of active or passive transport?

How do plants make food?• The major source of energy for life on earth is the sun.• Plants use Carbon Dioxide, water, and the sun’s energy to

make their own food through photosynthesis.• Photosynthesis occurs in the chloroplasts.• Plants make glucose (a simple sugar) as their food

source and expel oxygen as a waste.

How do organisms obtain energy by eating food?• Cellular Respiration: cells use oxygen to break down food

• Takes place in the mitochondria• To get energy, cells must break down glucose.• During cellular respiration, glucose is broken down into carbon

dioxide and water.• ENERGY is released and stored in a molecule called ATP.• Essentially, cellular respiration is the opposite of photosynthesis!

How do organisms obtain energy by eating food?• Fermentation: food is broken down without oxygen.• Used by some bacteria and fungi.• Cells in other organisms may use fermentation when

oxygen isn’t available for cellular respiration.• Example: muscle building, lactic acid formation

The total of all chemical reactions in an organism is called metabolism.