Chapter 2- The chemical composition of cells

Cell Environments All cells exist in a very watery environment. Eg blood, water etc Extracellular fluid As the plasma membrane is semi- permeable the extracellular fluid is critical for all cells. External environment For unicellular organisms the extracellular fluid is the extracellular environment it lives in. It can’t control the extracellular fluid, it can only move to a different environment. Internal environment Because multicellular organisms are part of a larger organisation they are able to have an extra barrier against the external environment. This creates an internal environment that can be controlled. More or less independent of external environment Intracellular fluid The environment within a cell.

 Regulated so that cells can function at their optimum levels ◦ Aspects regulated: -ion concentration -temperature -pH -Nutrients, water and waste levels and removal What happens when the above aspects are not regulated? Some of the major bodily systems are involved in this regulation process: Respiration Digestion Circulation Plants and Animals

 Compounds are organized into 2 types: ◦ Organic compounds – These are complex chemical compounds which contain Carbon and Hydrogen. ◦ Inorganic compounds- These are all non-organic compounds. e.g. water, oxygen, nitrogen.

Water- most organisms are % water  Surface tension  Heat capacity  Cohesiveness Oxygen and carbon dioxide  Oxygen is needed for cells to release energy from food molecules  Carbon is the key molecule in organic molecules. Nitrogen  Nitrogen is needed to make proteins. Minerals  Are needed for the structural part of cells, the body and in enzymes and vitamins

Carbohydrates  Important source of energy  Made of carbon, hydrogen and oxygen Lipids  fats and oils important for energy stores and some structures. Proteins  Vital for all sorts of functions! Nucleic Acid  Genetic material for all organisms Vitamins  Required for normal functioning.

 These are really big molecules that make up 99% of most organisms.  These are:  LIPIDS  CARBOHYDRATES  PROTEINS  NUCLEIC ACID

 Biomacromolecules are made up of subunits; meaning they are made of smaller parts that can be broken down or built up. The smaller parts are called subunits. Why do you think they need to be built up or broken down?  Lipids are made of a glycerol and 3 fatty acids  Carbohydrates are made of glucose chains  Proteins are made of amino acid chains  Nucleic acids are made of nucleotide chains

The most important functions of lipids Storage of energy The plasma membrane is made up of lipids.

 Most lipids are made of fatty acids tails and one glycerol.  Lipids can either be saturated or unsaturated. Saturated Fats Coconut oil Butter Beef Pork Cheese Saturated Fats Coconut oil Butter Beef Pork Cheese Unsaturated fats Olive oil Peanut oil Almonds Sunflower oil Corn oil Fish Mayonnaise Margarines Unsaturated fats Olive oil Peanut oil Almonds Sunflower oil Corn oil Fish Mayonnaise Margarines

 Special types of lipids, that have a phosphate head and 2 fatty acid tails.  The phosphate head is hydrophillic (water loving) and the fatty acid tails are hydrophobic (water hating)

The plasma membrane separates the cells internal environment from the external environment. Controls the movement of substances into and out of the cell. The membrane that surrounds cell organelles controls the movement of substances into and out of different organelles.

Lipids are important components of membranes. Lipids are the fluid part of the membrane. Cholesterols give flexibility when cold and stability when hot.

 Fats are needed in our diet for the absorption of many vitamins.

 Proteins are made up of subunits called amino acids. There are 20 different types of amino acids. Different combinations can made different types of proteins. AA CLASSFUNCTION Catalytic proteinsCatalytic proteins (enzymes) control and regulate chemical reactions in the cell Structural proteinsProteins provide support and shape the cell. They are components of many structures. Mobility proteinsProteins are involved in the movement of cells. Regulatory proteinsProteins regulate the movement of substances across the plasma membrane, act as signals between cells, are components of the immune response.

Keratin and Collogen

 Catalasts- meaning they speed up chemical reactions! Enzymes break things down or build things up. e.com/watch?v=CZ D5xsOKres

 These are made up of sugar chain. They can be 1 sugar – monosaccharide, 2 sugar- disaccharide or longer – polysaccharide.  Carbohydrates are the biggest source of energy.  Cells break down carbs into glucose and use it to make ATP.

 The mitochondria is the site where carbohydrates or glucose is used to make ATP. It is the power supply of the cell. WHAT IS THIS PROCESS CALLED?

TRANSPORTATION

 Folded membranes and tubules within the cytoplasm.  2 kinds of endoplasmic reticulum rough ER and smooth ER. ▪ Rough ER is caused by the ribosome being present on the surface Proteins produced by the ribosomes enter the ER and are then transported about the cell, they are finally exported out of the cell.

 Recieves protein products via the ER. Protein products are modified and stored in this structure before they are placed in vesicles for transport to the plasma membrane and released from the cell.

 DNA and RNA  They are information molecules. The hold the instructions for everything that is made by an organism’s body.  The DNA is located in the Nucleus of a eukaryotic cell. Why?

 Complete a DNA model.

 Water is the main liquid in your body because: ◦ It doesn’t boil at low temperatures or freeze at higher temperatures. ◦ It keeps the temperature stable enough for chemical reactions. ◦ It has a high surface tension meaning all the molecules stick together this allows cells to hold their shape by being filled up with water. Water is INCOMPRESSIBLE!

 Pigments in animal and plant cells provide the colours in the world around us. Chlorophyll

WHERE DOES THE ENERGY COME FROM?

 All cells use a form of energy called ATP.  Adenosine Triphosphate is when this molecule is fully loaded with energy.  Adenosine Diphosphate is when it is not fully loaded with energy.

 ATP is made from glucose in a process called CELLULAR RESPIRATION. Glucose Cellular respiration ATP

 Autotrophs make their own glucose from sunlight. They undergo a process called photosynthesis (some bacteria undergo chemosynthesis instead).

Heterotrophs get their energy from...

 BOTH Autotrophs and Heterotrophs must undergo cellular respiration to make ATP!

Aerobic respiration Occurs in the MITOCHONDRIA Anaerobic respiration LACTIC ACID STITCH

 20 Questions! Chapter 1 and 2