Science lessons 3 and 4

Lesson 3- moving cellular material

Cell membrane: (gatekeeper)

The boundary between the cells and it controls the movement of substances in and out of the cell. It is semi permeable. Substances can go into the membrane in different ways depending on the chemical and physical properties of the cell.

Semi permeable- let's some substances into the cell.

Passive transport:

The movement of substances through the membrane, doesn't use the cells energy. Passive transport is dependent on the amount of the substance that's on either side of the membrane.

Ex- of more oxygen outside of the cell it wil move into the cell until there's no equal amount on both sides of the membrane.

Types of passive transport:

Diffusion:

Movement of substances from an area of higher concentration to lower concentration. Diffusion will continue until there is equal amount on both sides of the membrane and equilibrium occurs.

Equilibrium- until it's equal

Osmosis:

Diffusion of water through the cell membrane from a higher concentration to lower concentration (moved with concentration gradient) the semi permeable cell membrane allows allows water to pass through until equilibrium.

Concentration gradient- move from a higher to lower concentration.

Facilitated diffusion:

When molecules pass through the membrane with the help of special proteins called transport proteins. It does not require energy.

transport proteins;

Carrier proteins- Carry molecules like glucose- the pump

Channel proteins- Form pores (holes) like a tunnel- through membranes that allow molecules to pass through.

Active transport:

The movement of substances through the cell membrane using the cells energy. This is when the substance will go from a lower concentration to a higher concentration. (Against the concentration gradient) this allows the cell to take in nutrients that might be in a lower concentration in the area surrounding the cell inside the cell and waste molecules can the cell through active transport.

Endocytosis:

The process when a cell takes in a substance by surrounding it with the cell membrane. Cells can use endocytosis for different purposes like taking in bacteria.

Exocytosis:

The process when a cells vesicle fuses with the cell membrane and releases a substance outside of the cell when it's too big. Proteins and others leave the cell through this process.

Lesson 4- cells and Energy

Cellular respiration:

A series of chemical reactions that converts molecules in food into a usable type of energy called ATP. Takes place in the cytoplasm and mitochondria.

ATP-

An energy compound that your cells can use.

Glycolysis:

1st step of cellular respiration where glucose is broken down into smaller molecules. This chemical reaction uses some ATP to make ATP.

Chemical reaction in the mitochondria:

2nd step of cellular respiration in the mitochondria for eukaryotic cells (this is because the mitochondria has a membrane and prokaryotic cells don't have any membrane bound organelles.) This requires oxygen. The smaller molecules were broken down more producing large amounts of ATP. 2 waste products are water and carbon dioxide are produced in this step.

Cellular respiration equation:

C6H12O6 + O2 = CO2 + H2O + ATP

Fermentation:

A chemical reaction that all cells can use to obtain energy levels are low. Because there is no oxygen less ATP is made than cellular respiration. This is done in the cytoplasm.

Types of fermentation:

Lactic acid fermentation:

This type of fermentation happens when glucose is made into ATP and a waste product called lactic acid is made. Muscle cells in people can use lactic acid fermentation to get energy during exercise.

Alcohol fermentation:

Some types of bacteria and yeast make ATP in a process alcohol fermentation instead of making lactic acid it makes an alcohol called ethanol and Co2 and ATP.

Photosynthesis:

A series of chemical reactions that converts sunlight energy and h2o and co2 into glucose and o2. Light energy is absorbed by the chlorophyll. Takes place in the Chloroplast.

In Chloroplast:

This chemical reaction takes place in plants and some unicellular organisms in the Chloroplast when they need to make glucose.

Photosynthesis equation:

Co2 + h2o + sunlight = C6H12O6 + O2

Cellular respiration and photosynthesis cycle combined.

How does this all work together?

First a plant takes in h2o and co2 and sunlight. In the Chloroplast it converts that into glucose and o2. The mitochondria in a plant and animal cell takes in that o2 and glucose (animals eat glucose and plants make glucose in Photosynthesis) produces ATP and co2 and h2o. Then the process repeats.