Chapter 6 Section 3 p157163 Life Substances

1
Chapter 6 Section 3 (p157-163)Life Substances

• Biology Notes
• September 18

2
Catalyst

• Think about water, just regular water.
• List five things that are interesting about it.
• BE CREATIVE!!!

3
Objectives

• SWBAT relate waters unique features to polarity.
  
• SWBAT classify the variety of organic compounds.
• SWBAT compare the chemical structures of
  carbohydrates, lipids, proteins, and nucleic
  acids, and relate their importance to living
  things.

4
Water

• Most important compound in living organisms.
• Life processes occur in water.
• Water transports materials in organisms.
• Note
• 70 of your body is made up of water
• 2/3 of the molecules in your body are water
  molecules
• Your cells are filled with water

5
Water (H2O) is a polar molecule a molecule
that has a positive end and a negative end.
Negative end
Positive end
6
Amazing Properties of Water!!

• Because of its polarity
• Water has properties unlike any other molecule!

7
Properties of Water

• Water molecules attract ions
• Dissolves ionic and polar substances (salt, sugar
  etc).
• Water molecules attract other polar molecules
• Forms hydrogen bonds
• Cohesion Attraction b/w the same substance.
• Adhesion Attraction b/w different substances.

8
Properties of Water

• Water resists temperature changes
• Water heats slowly and retains heat longer
• Insulates cells, helps maintain homeostasis
• Water expands when it freezes
• Ice is less dense than water so it floats on top.

9
Carbon a primary building block of life.
10
Why is Carbon so Special?
11
Why is Carbon so Special?

• 4 outer electrons available for bonding
• Forms covalent bonds with
• Oxygen, Nitrogen, Phosphorous, Sulfur, Carbon
  etc.
• Ability to form variety of molecules
• Forms straight chains, branched chains, or rings.
  
• Can form single bonds, double bonds or triple
  bonds.
• Single bonds share 1 electron
• Double bonds share 2 electrons
• Triple bonds share 3 electrons
• Huge of compounds can be formed
• carbohydrates, lipids, proteins, and nucleic
  acids.

12
Why is Carbon so Special?
Ring
Straight and branched chains
13
Carbohydrates

• Carbohydrates are biomolecules
• Composed of 1 Carbon 2 Hydrogen 1 Oxygen
• Carbohydrates are an important source of energy
• Starch in plants
• Glycogen in animals
• Carbohydrates give plants structural support
• Cellulose

14
Carbohydrates

• Monosaccharide
• the simplest type of carbohydrate.
• Glucose main source of energy for cells
• Fructose found in fruits
• Galactose found in milk

15
Carbohydrates

• Glucose, fructose and galactose are isomers.
• C6H12O6
• Isomers
• molecules with same chemical formula but
  different structures

Glucose
Fructose
Galactose
16
Carbohydrates

• Disaccharides
• 2 monosaccharides combine in a condensation
  reaction
• Polysaccharides
• 3 or more monosaccharides
• Glycogen how animals store glucose
• Starch how plants store glucose
• Cellulose polysaccharide, structure in plants

17
Lipids

• Lipids are large biomolecules.
• Consist mostly of C,H,O (more than 2 Hydrogen 1
  Oxygen)
• Fats, oils, waxes and steroids are all lipids
• Lipids do not dissolve in water.
• Because they are nonpolar
• Lipids are best molecule for storing energy.
• b/c high ratio of carbon and hydrogen to oxygen

18
Lipids

• Lipids consist of fatty acids.
• Fatty acids are long chains of C and H.
• One end has a carboxyl group (-COOH)
• Carboxyl groups are polar, so they are attracted
  to water. This is called hydrophillic.
• One end has a hydrocarbon group (-CH3)
• Hydrocarbon is nonpolar so it is repelled from
  water. This is called hydrophobic.

19

• Fatty acids can be
• saturated or unsaturated
• Saturated fatty acids
• Only single bonds are present in the fatty acid
  chain.
• Unsaturated fatty acids
• Double bonds are present in the fatty acid chain

20
Fatty AcidsSaturated vs. Unsaturated
All Carbons form single bonds
Some Carbons form double bonds
21
Lipids

• Triglycerides
• 3 fatty acids attached to a molecule of
  glycerol.
• Saturated triglycerides are solid at room
  temperature
• ex. butter, red meat
• Unsaturated triglycerides are liquid at room
  temperature
• ex. vegetable oil

22
Is this triglyceride liquid or solid at room
temperature?
23
Proteins

• Proteins are large complex biomolecules.
• Contain C, H, O, N, sometimes S (contains NH2 and
  COOH)
• Come in a variety of shapes and sizes
• Proteins play an important role in the structure
  of organisms
• Hair, horns, nails, skin, muscle
• Proteins act as biological catalysts
• Helps speed reactions
• Enzymes

24
Proteins

• The basic building blocks of proteins are amino
  acids.
• 20 different amino acids
• The and sequence of amino acids determine
  protein size, shape and function.

25
Proteins

• Peptide Bonds
• Covalent bonds formed b/w amino acids.
• http//www.biotopics.co.uk/as/aminocon.html
• Polypeptide
• long chain of amino acids
• 3 dimensional shape determines function

26
Proteins

• Enzymes
• proteins that change the rate of a chemical
  reaction.
• involved in nearly all metabolic processes
• behavior determined by surroundings (temp. pH
  etc)
• Active Site
• a section of the enzyme shaped to fit a specific
  substrate
• Substrate
• reactant being catalyzed
• http//www.biotopics.co.uk/other/anenz.html
• enzyme remains unchanged, can be reused
• See Figure 6.23 on page 162

27
Nucleic Acids

• Nucleic Acids are complex biomolecules
• Consist of C, H, O, N, P arranged in 3 groups
• Nitrogenous base, Simple sugar, Phosphate group
• Made up of smaller subunits called nucleotides
• Nucleic Acids store cellular information
• DNA deoxyribonucleic acid
• determines characteristics, stores information
• RNA ribonucleic acid
• transfers info from nucleus to cytoplasm of cell
• can act as enzymes