Unit 2: Introduction to Biology Molecules of Life NOTES Biology & PAP Biology

Name______Teacher______Subject-Period______Unit 2: Introduction to Biology – Molecules of Life – NOTES Biology & PAP Biology

Introduction to Biology: ( read Chapter 1 Section 1.2 )

Biology is the study of life. Living things are called organisms.

All organisms on Earth share certain characteristics. 1. Cells: All organisms (so all living things) are made of cells. 2. Need for energy: All organisms need a source of energy to carry out life processes. Energy is important for metabolism, which is all the chemical processes that build up or break down materials. 3. Response to environment: All organisms must react to their environment to survive. 4. Reproduction and development: Species must have the ability to produce new individuals passing on their DNA (genetic material) to their offspring. ALL organisms (from bacteria to plants to animals) have DNA.

All organisms have systems of related parts. All living things are made of cells. Cells are made up of molecules. Molecules are made of atoms. Atoms are made of protons, neutrons, and electrons.

Which is smaller? molecules or atoms? ______Which is bigger? Molecules or cells? ______

Chemistry of Life: ( read Ch. 2 ALL sections 2.1-2.5; however, section 2.2 and 2.3 are the most important; section 2.5 will be covered in more detail later this year )

Models We often represent very small structures or very large structures with idealized models or even symbols to make our study of science easier.

• Which of the 3 is the biggest in real life?

Model of a Cell In science, when looking at atoms, we oftenModel seen of thethem Earth drawn out DNAwith Model symbols and/or letters 1 • These 3 pictures are all models of a molecule of water.

We can simplify this even more by just writing the formula for the molecule without representing the bonds holding them together at all. + • The formula for water is H20 + – This means there are 2 hydrogen atoms (represented by the letter “H”) and one oxygen atom (represented by the letter “O”) – Note: we do not put a “1” with the oxygen because it is understood. Anything other than “1” we record. - • Water’s unique properties allow life to exist on earth. – Water is polar due to its regions of slight + (positive) and – (negative) charges. – Water has a high specific heat which helps regulate temperature in organisms. – Water exhibits cohesion and adhesion. – Water is often the solvent of many solutions. • Solvent—the substance that is present in the greater amount that dissolves another substance. • Solute—the substance that dissolves in a solvent. • Pure water has a neutral pH of 7. Rain water is slightly acidic with a typical pH of 5.6. – pH stands for pondus hydrogenii meaning “potential hydrogen” – pH scale measures the concentration of hydrogen ions in solutions; scale 0-14 • 0-6.9 is acidic • 7.0 is neutral • 7.1-14 is basic or alkaline – Most organisms, including humans, overall need to maintain a pH around neutral; however, certain organs and organelles inside our bodies operate at different pHs.

Insert pH scale pic

Bonds- • The force that holds two atoms together represented by a line between two letters or other symbol in a drawing of a molecule  Energy is needed to break bonds and is released when bonds are broken. Chapter 2, section 2.3 Carbon-based Molecules Circle the bonds

2 All living things are composed of the following basic elements: Remember “CHNOPS” – Carbon – Nitrogen – Phosphorous – Hydrogen – Oxygen – Sulfur

Inorganic vs. Organic • Inorganic molecules do not contain the element carbon – Water • Organic molecules contain the element carbon – Example: Carbohydrates, Lipids, Proteins, Nucleic Acid

– Exception: carbon dioxide (CO2) and carbon monoxide (CO) Monomer vs. Polymer • Monomer – Mono = one, mero = part – A molecule that can bind to other molecules to form a polymer • Polymer – Poly = many, meros = parts – A large molecule that contains many molecules – A large molecule made of smaller, molecules of the same type (monomers) linked together. • A protein (the polymer) is made of many amino acids (monomers) • Think of a monomer like a puzzle piece and a polymer is like the whole puzzle.

• Monomers are hooked together by chemical bonds • A Polymer can be broken back down into monomers – When using water to BREAK bonds • Hydrolysis (“hydro”- water, “lys”- to split) • A monomer can be linked together to form a polymer – When using water to LINK bonds • Dehydration (“de”- to remove, “hydro”- water)

Living things have four basic carbon compounds: 1. Carbohydrates we will study in Biology  Sugar, starch, cellulose 2. Proteins  Meat, fish, nuts, enzymes 3. Lipids  Fats, waxes, steroids, chlorophyll 4. Nucleic Acid  DNA or RNA These are the four general molecules Carbohydrates- NOTES 3 • Composed of CHO (Carbon, Hydrogen and Oxygen) in a 1:2:1 ratio • Examples: Sugar and Starch • Monomer is a monosaccharide • Carbohydrates provide energy – Most sugars end in “-ose”, fructose, glucose, sucrose, cellulose

• Glucose (C6H1206 )- – Is a carbohydrate – Is it a sugar or starch? sugar

– C6H1206 is the basic “fuel” in all living things, produced during photosynthesis – The pictures below are models of a molecule of glucose

Reading the Models: Notice the C’s for carbon connected in a ring that give the molecule its general shape. • Sometimes we simplify these models even more. • The third picture is a molecule of glucose, also, but the C’s have not been drawn to simplify it. • Everywhere that 2 lines (bonds) meet represents a carbon atom. • They are numbered 1-6 to help you see them. Carbohydrates can be either: 1. monosaccharide- a simple, single carbohydrate (monomer) examples: glucose or fructose 2. disaccharide- 2 monosaccharides put together (polymer) example: • Sucrose (table sugar) = 1 glucose + 1 fructose • Maltose (malt sugar) = 1 glucose + 1 glucose • Lactose (milk sugar) = 1 glucose + 1 galactose 3. polysaccharide - numerous monosaccharides (polymer) examples: starch, glycogen and cellulose  Starch—found in plant cells  Glycogen—how animals store carbs in muscles and liver  Cellulose—found in plant cell walls (humans CANNOT digest cellulose) Proteins- NOTES

• Composed of CHON (carbon, hydrogen, oxygen, nitrogen)

4 • Made of small units (monomers) called amino acids. There are 20 total amino acids that we need, our body can only make 12. From where do you think we get the other 8?

• Examples:

– Proteins make up muscle, skin and hair

– Hemoglobin (blood) is a protein that carries oxygenated blood

– Enzymes are proteins that speed of reactions in the body

– Antibodies in our immune system

• When trying to identify a protein look for:

– N-C-C “backbone”

• central Carbon

• the COOH

• the NH

– and the R

• Circle the components that make these amino acids (that make proteins)

CHALLENGE!

• Does the picture represent dehydration or hydrolysis?

Guess:

Correct:

Why? Lipids- NOTES

• Composed of CHO (carbon, hydrogen, oxygen)

• Monomer: 1 glycerol + 3 fatty acids “Fat E” (typically)

• Do not dissolve in water (“oil and water”)

• Provide long term energy storage 5 • Examples of lipids

– Fats: acts as an insulator

– Oils: some birds secrete oil to help them “waterproof” themselves

– Waxes: helps plants conserve water

– Steroid hormones: cholesterol, testosterone, estrogen

• Two types of lipids:

– Saturated fats

• The carbon bonds (where the carbon molecules meet) are single, no double bonds

• C-C-C-C-C-C-C-C

• animal fats like butter, cream, cheese

– Unsaturated:

• Some of the carbon bonds are double bonded (where two bonds hold the carbons together)

• C-C-C=C-C-C-C-C

• Plant fats like canola oil, olive oil

• Phospholipids- commonly found in the membrane of cells (more on this later!) Label:

Nucleic Acid- NOTES

• Nucleic Acids are large complex molecules containing genetic material

– Contain genetic information

• Made of monomers called nucleotides 6 – Nucleotide= sugar, phosphate group, and nitrogen base

– The monomers, put together, build the polymer DNA strand Two types of Nucleic Acids: 1. Deoxyribonucleic Acid- DNA 2. Ribonucleic - RNA • DNA carries instructions that regulate cells activities • RNA–uses information from DNA to make proteins

DNA and RNA Nucleotides have 3 parts: 1. Phosphate group 2. 5 carbon sugar (deoxyribose in DNA, ribose in RNA) 3. Nitrogen Base (Adenine, Thymine or Uracil, Guanine, Cytosine)

Label:

DNA RNA • Sugar- Deoxyribose • Sugar- Ribose • Double Stranded • Single Stranded • Nitrogen Bases- • Nitrogen Bases- – Adenine – Adenine – Thymine – Uracil – Guanine – Guanine – Cytosine – Cytosine

ATP ATP, or adenosine triphosphate, is a special type of nucleotide. ATP is the energy source used by cells for them to function. Food molecules are broken down and the energy is stored temporarily in ATP until it is needed by the cell for its cellular processes. ATP is made during cellular respiration, a process that takes place inside of cells.

C6H12O6 + 6O2  6H2O + 6CO2 + ATP energy