Chemical reactions inside cells How do Cells Function? Chemical reactions inside cells

For example: A cake can be broken down into its basic units. What are cells made of? The smallest unit of life is the cell. All matter can be broken down into basic substances called elements. Elements can be broken down to smaller units called atoms. Therefore, the smallest unit of all matter, including life, are atoms. For example: A cake can be broken down into its basic units.

All Matter is Made of Elements There are about 100 different elements on Earth.

Elements are Built of Atoms All elements can be broken down into their basic units, atoms.

What are cells made of? Oxygen 65.0% Carbon 18.5% Hydrogen 9.5% Of all the elements, only 25 are necessary for life. And of those, only 6 make up 99% of the human body. Oxygen 65.0% Carbon 18.5% Hydrogen 9.5% Nitrogen 3.3% Calcium 1.5% Phosphorus 1.0% Other 19 1.2%

What are cells made of? This is another way of thinking about the organization of living things.

Atoms from different elements join together to form compounds What are cells made of? Atoms from different elements join together to form compounds Compounds

What are cells made of? Atoms join together to form compounds Water is a compound A water molecule is made when 2 hydrogen atoms join 1 oxygen atom

What are cells made of? The activities taking place inside cells involve the interaction of molecules and atoms These interactions, called chemical reactions, will produce energy Cells use chemical energy for life activities

Click a link, or here to move on What are cells made of? Cells are made of thousands of molecules The four main types of large molecules that make up atoms are: Carbohydrates Lipids Proteins Nucleic acids All these molecules share one characteristic – carbon atoms. Click a link, or here to move on

What are cells made of? Carbohydrates: Provide the cell with energy Simple carbs are sugars made from Carbon, Oxygen, and Hydrogen Simple sugars link into long chains to form complex carbs, such as: starch, cellulose, and glycogen Starch and cellulose are made by plant cells Animals get their energy by eating plants or other animals that eat plants Click here to return

What are cells made of? Lipids: fatty acids glycerol Are the fats, oils, and waxes found in living things Simple lipids are made of atoms from Carbon, Oxygen, and Hydrogen Can be used by cells for energy and for making structures Common lipids consist of a molecule called glycerol bonded to long chains of carbon and hydrogen atoms An extremely important property of lipids is that they cannot mix with water fatty acids glycerol Click here to return

What are cells made of? Proteins: Are made of smaller molecules called amino acids Contain atoms from the elements Carbon, Oxygen, Hydrogen, Nitrogen and sometimes Sulfur Cells use amino acids to build proteins needed for cell functions Many types of protein: Enzymes are proteins that control chemical reactions in cells Some support growth and repair living matter Some proteins in blood fight infections Some proteins in blood deliver oxygen Some transport materials in and out of the cell Click here to return

What are cells made of? Nucleic Acids: Are the molecules that hold the instructions for the maintenance, growth, and reproduction of a cell There are 2 types: DNA – provides the information used by the cell for making proteins RNA – produce the proteins in the cytoplasm Are made from Carbon, Oxygen, Hydrogen, Nitrogen, and Phosphorus Have subunits called nucleotides Click here to return

What are cells made of? Water: All the chemical reactions inside the cell take place in water Water inside the cell makes up 46% of your body’s mass Water outside the cell (in body fluids) accounts for 23% of body mass Water is polar, meaning it has a slight positive charge Because water is polar, many substances dissolve in water Most lipids do not dissolve in water

Question? The cell membrane controls what enters a cell. It is made of a double layer of lipids. What is one major property of lipids that you think helps the cell membrane do its job? How do you think that property helps the cell membrane?

Answer Lipids are large molecules which make up the fats, oils and waxes in living things. As such, a major property of lipids is that they cannot mix with water. Because the cell membrane is made of a double layer of lipids that have a water loving head and a water hating tail, lipids help separate the inside of the cell from the outside by keeping substances from entering freely. The polar quality of lipids and water makes this possible.

- the energy stored in the bonds between atoms of every molecule How do cells use energy? Cells need a constant supply of energy Animal cells get energy from food Plant cells get energy from sunlight All cells use chemical energy - the energy stored in the bonds between atoms of every molecule Glucose is a major source of energy for all cells

- a light-absorbing pigment that traps the energy in sunlight How do cells use energy? Photosynthesis is the process plants use to change the energy in sunlight into the chemical energy in glucose Photosynthesis takes place in plant cells that have chloroplasts Chloroplasts contain chlorophyll - a light-absorbing pigment that traps the energy in sunlight

How do cells use energy? Chloroplast

Some Cells Capture Light Energy Photosynthesis involves a series of steps: The starting materials are carbon dioxide and water. Plants get carbon dioxide from the air and water from the soil. The process begins when those material enter the plants chloroplasts. Chlorophyll captures energy from sunlight, and uses it to change carbon dioxide and water into new products. The products are oxygen and sugars such as glucose. The plant releases most of the oxygen to the air and keeps the glucose for energy. Photosynthesis Diagram

Photosynthesis Carbon Dioxide (6CO2) Water (6H2O) Light Energy Glucose (C6H12O6) Oxygen (6O2)

How do cells release energy? Glucose and other sugars are cell food, the power source for cell activities in almost all living things Chemical energy is stored in the bonds of sugars When a sugar molecule is broken down, a usable form of energy is released Cells release energy in two basic processes: cellular respiration and fermentation

How do cells release energy? Cellular Respiration is the process cells use to release the energy stored in sugars such as glucose Oxygen is used to release the energy Cellular respiration takes place in the mitochondria Both plant cells and animal cells release energy through cellular respiration Some of the energy is transferred to other molecules, which carry the energy to where it’s needed in the cell The rest of the energy is released as heat

How do cells release energy? Mitochondria

How do cells release energy? Cellular Respiration involves a series of steps: The starting materials are sugars – such as glucose – and oxygen. The process begins when glucose is broken down into smaller molecules that move into the mitochondria. At the same time oxygen enters the mitochondria. The smaller molecules are broken down further releasing hydrogen. Hydrogen combines with oxygen to form water. The products are energy, carbon dioxide, and water. Cellular Respiration Diagram

Cellular Respiration Glucose (C6H12O6) Oxygen (6O2) Carbon Dioxide Water (6H2O) Chemical Energy

How do cells release energy? Fermentation is the process by which cells release energy without oxygen When glucose is broken down into smaller molecules a small amount of energy is released Without oxygen cellular respiration cannot happen Instead of entering the mitochondria, the small molecules that carry the energy stay in the cytoplasm There are two main types of fermentation: alcoholic and lactic acid

How do cells release energy? Fermentation is the process by which cells release energy without oxygen In both kinds of fermentation sugars are broken down into smaller molecules Without oxygen, the reactions produce either alcohol and carbon dioxide or lactic acid Common foods we eat involve these processes.

Alcoholic Fermentation Bread is made by mixing flour, milk, sugar and yeast. Yeast uses fermentation to convert the sugar into alcohol and carbon dioxide.

Lactic Acid Fermentation yogurt cheese Some bacteria convert the sugar in milk into lactic acid. Lactic acid causes milk to partially solidify, producing the creamy texture of yogurt. If fermentation continues long enough milk solidifies into cheese.

Fermentation Cellular Respiration