Cell Compounds and Biological Molecules. Biology 12 Unit 2 Cell Compounds and Biological Molecules Inquiry into Life pages 20-44

Transcription

1 Cell Compounds and Biological Molecules Biology 12 Unit 2 Cell Compounds and Biological Molecules Inquiry into Life pages 20-44

2 Basic Chemistry Matter anything that has mass and volume Element comprises all matter, living or non-living Atom the smallest unit of matter to function in chemical reactions; composed of 3 subatomic particles Isotope atoms with the same atomic number but different atomic mass

3 Basic Chemistry Subatomic Particle Charge Relative Mass electron 1 0 proton +1 1 neutron no charge 1

4 Basic Chemistry atomic number C Carbon atomic mass element symbol element name

5 Basic Chemistry Isotopes are different forms of the same atom The only difference is the number of neutrons present Neutrons only add mass and do not change chemical properties Some isotopes are unstable and emit radiation radioactive isotope

6 Molecules vs Compounds A molecule is any chemical unit that contains more than 1 atom. They can contain the same atom or different atoms A compound is any chemical unit that contains more than 1 atom, but the atoms cannot be the same.

7 Ionic Compounds Ionic compounds are formed when a metal and a non-metal are attracted resulting in the transfer of electrons from metal to non-metal Ionic compounds require ions or charged atoms Ions can be positive or negative, but never neutral

8 Ionic Compounds Positive ions are metals and have lost electrons Negative ions are non-metals and have gained electrons

9 Ionic Compounds Because electrons are negative particles, having more electrons means the ion is more negative Fewer electrons means more positive

10 Ionic Compounds This represents electron shells 1st shell = 2 e2nd shell = 8 erd 3 shell = 8 e-

11 Ionic Compounds C

12 Ionic Compounds Remember, ionic bonds transfer outer shell electrons from the metal to the non-metal

13 Covalent Compounds Covalent reactions occur between two non-metals Electrons are shared in covalent compounds instead of transferred The shared outer shell electrons spend equal time between the two atoms

14 Covalent Compounds Each pair of electrons form a single covalent bond When two pairs of electrons are shared, they form a double bond When three pairs of electrons are shared, they form a triple bond The more bonds between atoms, the more difficult it is to separate them

15 Covalent Compounds Electrons in the overlapping regions are shared Each H shares 1 ewith the carbon

16 Covalent Compounds The hydrogens share their electron with each other, forming a molecule of hydrogen gas

17 Water

18 Water H O H

19 Water Water is a polar molecule Since oxygen has a larger nucleus, the shared electrons spend slightly more time near the oxygen nucleus than the hydrogen nuclei This differential in time gives water a slight + and charge at its poles

20 H O H

21 Water Polar covalent molecules form weak bonds between compounds called hydrogen bonds A hydrogen bond occurs when the slight positive charge of a bound hydrogen attracts the slight negative charge of a neighbouring atom It is represented by a dashed line

22 Water

23 Water

24 Properties of Water 1. Liquid at room temperature 2. Facilitates chemical reactions 3. Molecules are cohesive 4. Changes temperature slowly 5. Has a high heat of vapourization 6. Solid water is less dense than liquid water

25 Roles of Water in Living Organisms 1. Temperature Regulator 2. Lubricant 3. Solvent

26 Acids and Bases Water spontaneous breaks up into two component + ions, H and OH + Acids are compounds that release H when dissociated in water Bases are compounds that release OH when dissociated in water

27 Acids and Bases

28 Acids Strong acids are characterized by the amount of H + ions that dissociate The more complete the dissociation, the stronger the acid The more H + added to the water, the more acidic the solution

29 Bases Strong bases are characterized by the amount of OH ions that dissociate The more complete the dissociation, the stronger the base The more OH added to the water, the more basic the solution

30 ph Scale This scale is used to indicate the acidity or the alkalinity of a solution Values range from 0 14 The lower the value, the more acidic the solution The higher the value, the more basic the solution

31

32 ph Scale ph is a logarithmic scale: ph 1 is 10X more acidic than ph 2 ph 1 is 100X more acidic than ph 3 ph 2 is 1000X more acidic than ph 5 ph 8 is 10X more basic than ph 7 ph 12 is X more basic than ph 8 ph 14 is X more basic than ph 0!

33 Buffers and ph A buffer is a chemical that keeps ph within certain limits Buffers resist changes in ph by absorbing excess hydrogen and hydroxide ions Buffers in human blood are carbonic acid and bicarbonate ions

34 Organic Molecules Characterized by the presence of carbon and hydrogen

35 Organic Molecules

36 Organic Molecules Carbon molecules can link to other carbon molecules forming a hydrocarbon molecule

37 Organic Molecules Functional groups can be added to hydrocarbons to impart certain characteristics Two important functional groups are: carboxyl (COOH) amine (NH3)

38 Carbohydrates

39 Carbohydrates Short-term energy storage Structural molecule in plants and bacteria Cell membrane communication

40 Carbohydrates Monosaccharides are simple carbohydrates that can be characterized by having 5 or 6 carbons (pentose and hexose) Common monosaccharides are: glucose fructose galactose

41 Carbohydrates Disaccharides are links of two monosaccharides (di meaning two and mono meaning one) Common disaccharides: sucrose lactose maltose

42 Carbohydrates Polysaccharides contain many monosaccharides linked together Polysaccharides are considered polymers A polymer is a long chain of monomers A monomer is a single unit

43 Carbohydrates monomer polymers

44 Carbohydrates Polysaccharides are formed through a process called condensation synthesis synthesis = making of condensation = releases water

45 Carbohydrates Breaking apart polysaccharides involves a process called hydrolysis hydro means water lysis means to break apart Hydrolysis reactions break down polysaccharides by adding water

46 Carbohydrates monomers polymer + H2O is.html

47 Carbohydrates Starch and glycogen store glucose in plants and animals Starch is a polymer of glucose with few side branches GLYCOGEN is similar to starch except it is highly branched

48 Carbohydrates Cellulose is found only in plants The glucose molecules are linked differently than in glycogen and starch This linkage causes the greater strength of this molecule

49

50 Lipids Lipids are the greatest energy source in biological molecules carbohydrates = 17 kj/g proteins = 17 kj/g lipids = 38 kj/g However, most lipids are not used as energy stores

51 Lipids Lipids have different structures and functions: long-term energy storage steroids (sex hormones) membrane components What links all lipids is that they are all insoluble in water

52 Lipids Fats and oils usually of animal origin and is solid at room temperature Fats have two functions: long term energy storage insulation and cushioning

53 Lipids Fats and oils form when one glycerol molecule react with three fatty acid molecules Sometimes called trigylcerides

54 Lipids Emulsification is the process of mixing fat with water Elmulsifiers are made of a polar molecules (polar head and nonpolar tail)

55 Lipids polar head nonpolar tail Fat globule Emulsifier (bile) (soap)

56 Fat Emulsification

57 Fatty Acids A fatty acid is a hydrocarbon chain that ends with the acidic group -COOH

58 Saturated Fatty Acids Saturated fatty acids have no double bonds between carbon atoms, and it is saturated, or full of, all the hydrogens that can fit Saturated fatty acids are solid at room temperature Animal fats are often saturated

59 Unsaturated Fatty Acids Unsaturated fatty acids have double bonds somewhere within the carbon chain, often causing kinks in the chain They occur where the carbon does not have two hydrogens attached to it Unsaturated fatty acids are liquid at room temperature Plant fats are often unsaturated

60 Phospholipids Phospholipids are polar molecules containing a phosphate or a phosphate/nitrogen group attached to the lipid tail They are found in cell membranes and will spontaneously form a bilayer with hydrophobic tails facing in and hydrophilic heads facing out

61 Phospholipids Lecithin is a common phospholipid found in soybeans and eggs It is used to emulsify fats and is basis of mayonnaise, an emulsified fat

62 Steroids Steroids have the common stucture of 4 fused carbon rings

63 Steroids Steroids differ by their atom arrangement and the functional groups attached to them Cholesterol is an important component in the cell membrane, adding to rigidity as well as the starting point for sex hormones like estrogen and testosterone

64 Steroids Examples of common steroids: cholesterol estrogen (estradiol) testosterone cortisol vitamin D

65 Proteins Proteins have many functions, from movement to antibodies to enzymes to biological messengers Proteins are polymers of amino acids monomers

66 Proteins

67 Proteins The R group is what makes the 20 amino acids different from each other R groups can be as simple as a single hydrogen (glycine) or as complex as a double benzene ring (tryptophan)

68 Proteins

69 Proteins Amino acids combine through a peptide bond, which is a condensation synthesis reaction

70 Proteins A chain of amino acids is called a polypeptide

71 Proteins Four Levels of Organization (p. 39) primary structure the linear sequence of amino acids joined by peptide bonds secondary structure polypeptides form a 3-D shape hydrogen bonds between peptide bonds keep the shape

72 Proteins Tertiary Structure the final 3-D shape of proteins this shape is maintained by different covalent, ionic, and hydrogen bonds between R groups, including the covalent disulphide bond between 2 cysteine amino acids Quaternary Structure two or more polypeptides arranged together (mostly enzymes)

73 Proteins Protein structure is extremely important because structure is related to function If protein structure is changed (denatured) then the protein cannot function

74 Nucleic Acids Two types: Deoxyribonucleic Acid (DNA) Ribonucleic Acid (RNA) Both are polymers of nucleotides

75 Nucleotide

76 Nucleotides All nucleotides are composed of a sugar (either ribose or deoxyribose), a phosphate and a nitrogenous base There are five bases: Adenine Thymine (DNA only) Cytosine Guanine Uracil (RNA only)

77 Nucleotide Chains Nucleotides join via condensation synthesis the same process as joining monosaccharides and amino acids!

78 Nucleic Acids Nucleic acids form strands made up of a sugar-phosphate backbone Nitrogenous bases stick out of the sides

79 DNA DNA is double stranded, each twisting about the other

80

81 RNA RNA is a single strand of DNA There are three types: Messenger RNA (mrna) Ribosomal RNA (rrna) Transfer RNA (trna) We will look more into DNA at a later time.

82 ATP

83 ATP ATP (adenosine triphosphate) is composed of adenine (a nitrogenous base), a ribose 5-sided sugar and three phosphate groups. This structure is actually a modified nucleotide.

84 ATP ATP is the "energy currency" of the cell and is spent to drive chemical reactions Glucose is converted into ATP in the mitochondria via cellular respiration. Energy is derived from breaking the bond between phosphate 2 and 3, releasing energy stored in the bond.

85 ATP

86 ATP Breaking this bond results in the production of ADP or adenosine diphosphate and a phosphate group. These molecules can be recycled and used to produce more ATP in the mitochondria.

87 Quiz Quiz on Lipids, Proteins, Nucleic Acids, and ATP

88

89 This used to be Unit 6 Enzymes Textbook Ch 6

90 Metabolism Metabolism refers to the total of all chemical and physical reactions that occur in a cell Most of these activities are driven by ATP

91 Metabolism Metabolism is controlled by thyroxine, a hormone produced in the thyroid gland

92 Metabolism Thyroxine is made from the addition of iodine to the amino acid tyrosine Thyroxine stimulates all cells to produce more ATP through cellular respiration resulting in overall increase in metabolism

93 Metabolism The level of thyroxine in the blood is determined by a negative feedback loop which goes like this: Thyroxine levels drop causing hypothalamus to release TRH TRH acts on the anterior pituitary to release TSH TSH acts on the thyroid causing it to produce more thyroxine High levels of thyroxine cause the hypothalamus to stop TRH production and anterior pituitary to stop TSH production

94 Thyroxine Control Feedback Loop

95 Enzyme Enzymes are protein molecules with particular shapes (active sites) to bond with particular substrates Enzymes are catalysts for cellular reactions, bringing substrates together where they can react and form new substances /196646/lw03_enzymes_final.html

96 Substrate Substrates are molecules that react to produce new products with the help of an enzyme Reactions can be hydrolysis (breaking down) or synthesis (building) reactions

97 Coenzyme Coenzymes are smaller molecules that help enzymes function properly and are often contain vitamins

98 Activation Energy Activation energy refers to the amount of energy needed to make a reaction occur Enzymes reduce the activation energy needed

99 Lock and Key Model Enzymes are locks. Locks can only be opened by a specific key. Substrates are keys. They only work on a specific lock. Starch is the substrate, amylase is the enzyme Peptides are the substrates, peptidase is the enzyme Lipids are the substrates, lipase is the enzyme Lactose is the substrate, lactase is the enzyme

100 Factors Affecting Enzyme Action ph enzymes work at specific phs. Enzymes in the blood work at ph 7.4 while enzymes in the stomach work at ph 2.

101 Factors Affecting Enzyme Action Temperature Enzymes in our bodies work o efficiently at 37 C but their action starts to drop off dramatically after 40oC

102 Factors Affecting Enzyme Action Substrate Concentration The higher the concentration the more reactions that can occur up to a certain point

103 Factors Affecting Enzyme Action Competitive Inhibitors fight for active sites with the substrate and prevents them from binding. Enzyme Inhibition Products made by an enzymatic pathway prevent the binding of other substrates

104 Factors Affecting Enzyme Action

105 Factors Affecting Enzyme Action Heavy Metals Some metals act as enzyme cofactors (helps the enzyme function) but others (Hg and Pb) causes the enzymes to denature and no longer function

106 Factors Affecting Enzyme Action /196644/feedback_inhibition.html

107 Enzyme Inhibition Enzyme inhibition occurs when the enzyme cannot bind substrate molecules The purpose of this enzyme inhibition is to limit the amount of product made by the enzyme so levels do not rise too high

108 Enzyme Inhibition As product molecules are produced, their level or concentration will rise Eventually these product molecules will interfere or inhibit the enzymes producing them, by binding the active site on the enzyme or attaching to the enzyme in a manner that alters the active site on the enzyme.

109 Enzyme Inhibition When the product molecules are used up or their concentration lowers, the enzyme will no longer be inhibited by the product molecules The enzyme active site will be available to bind with substrate and make new product once again

110 Enzyme Inhibition Enzyme inhibition is controlled by a negative feedback loop

111 Enzymes Lab - Catalase Catalase is an enzyme found in liver and catalyzes the reaction decomposing hydrogen peroxide into oxygen and hydrogen

112 Enzymes Lab - Catalase In this lab, you will combine the reactants in the test tubes and record your observations When you are finished your observations, you will explain your observations with respect to the factors affecting enzyme action. The lab sheet is provided and all reactants are included

113 Summary Learn your basic chemistry Water is a polar molecule and is the universal solvent meaning lots of things can dissolve in it Acids and bases dissociate into different ions and their strength can be measured using the ph scale

114 Summary Organic molecules contain C and H Carbohydrates are composed of monosaccharides or polymers of them Lipids are composed of gylcerol and 3 fatty acids and form fats and oils, phospholids, and steroids

115 Summary Proteins are composed of polymers of amino acids called polypeptides There are 4 levels of protein organization Protein function is dependent on maintaining proper structure

116 Unit 2 Review Reread textbook pages Read section summaries on page 42 Answer all review questions on pages Define all keyterms on page 44 Use the website listed on page 44 for extra practice Test is on