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Intro to Biology & Biochemistry

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1 Intro to Biology & Biochemistry

2 Biology - study of living things Organism– complete, individual living thing

3 Characteristics of Living Things
1. All organisms are made of cells - these are the basic building blocks (smallest unit that can carry on the activities of life) unicellular – organism composed of a single cell (bacteria)         multicellular– more than 1 cell (humans)

4 2. Organisms are highly organized – the basic difference between organisms is the way they synthesize raw materials– cells are like miniature factories.  Living things are based on a universal genetic code.

5 3. Organisms use energy – the ultimate source of energy is sunlight – Plants typically store excess energy as oils while animals typically store excess energy as fats Metabolism– sum of chemical building up (anabolism) & breaking down (catabolism)

6 4. Organisms grow & develop – growth is increasing in size while development is maturation.

7 5. Organisms have a life span (average length of life) & all organisms maintain a stable internal environment – this is called homeostasis. 

8 6. Organisms reproduce– this is necessary for the continued existence of the species.  In sexual reproduction, 2 cells from different parents unite to produce the first cell of the new organism (offspring & parents have different traits).  In asexual reproduction, the new organism has a single parent (offspring & parents have the same traits).

9 7. Organisms respond to a stimulus - this is any condition to which an organism can react; the resulting action is called a response; irritability refers to the ability to respond to stimuli

10 8. Organisms adjust to their environment– one must adapt to survive – any change in an organism that makes it better suited to its environment is an adaptive response.  Variation refers to a set of differences among individuals – sometimes these variations may give the organism an edge over others.  Any kind of organism can change, or evolve over time.

11 The Scientific Method – a logical, organized method of study
1. State the problem 2. Collect information (use all available sources – library, internet, magazines, interviews)

12 3. Formulate a hypothesis – a statement that can be tested
3. Formulate a hypothesis – a statement that can be tested.  It should be short, definitive, & positive.

13 4. Experiment. This involves testing the hypothesis
4. Experiment.  This involves testing the hypothesis.  A variable is a condition that changes in the experiment.  Independent variables may be controlled by the experimenter.  These belong on the x-axis of a graph. 

14 Dependent variables are typically the results
Dependent variables are typically the results.  These belong on the y-axis of a graph.  A controlled experiment is one in which there is only 1 experimental variable (all of the conditions are alike except for the one being tested).  The experimental group is exposed to the experimental variable while the control group is not.  In scientific experiments, only one variable is changed at a time. 


16 5. Make & record observations
5. Make & record observations.  This includes data, statistics, graphs, etc. Quantitative observations involve numbers – counting or measuring objects.  Qualitative observations involve characteristics that can’t be counted – ex. = color, texture, etc.

17 6. Draw a conclusion.  This may or may not support the original hypothesis.

18 Redi’s Experiment with Spontaneous Generation

19 Spallanzani’s Experiment

20 Pasteur’s Experiment

21 A scientific law explains how an event occurs while a scientific theory explains why an event occurs.  It is a well-tested explanation that unifies a broad range of observations.  An inference is a logical interpretation based on prior knowledge & experience. 

22 Examples Observations The dog’s tail is wagging
The man is riding a bicycle The Braves are leading the wild card Inferences The dog’s tail is wagging because he is excited. The man is riding a bicycle because his car won’t start. The Braves are leading the wild card because they are playing well right now.

23 Observation vs. Inference
Statement Observation Inference X Object A is round and orange. X Object A is a basketball. X Object C is round and black and white. X Object C is larger than Object B. X Object B is smooth. X Object B is a table-tennis ball. X X Each object is used in a different sport.

24 Observation vs. Inference

25 Microscopes are used to study cells
Microscopes are used to study cells.  Magnification refers to the ability to make an image larger.  Resolution refers to the ability to show details clearly.  As magnification increases, resolution typically decreases.

26 Types of Microscopes 1.  Compound light- uses light passing through 1 or more lenses to produce an image – produce magnified images by focusing visible light rays -  (we use these at school) – Magnification = multiplying the magnifications of the lenses

27 2.  Electron microscopes - these produce magnified images by focusing beams of electrons
a.  Transmission e- microscopes – produces a stream of electrons that passes through a specimen – thinly sliced, then stained – used to view internal structure – magnifies up to 200,000x

28 b.  Scanning e- microscopes – beam of electrons reveals surface details of images – gives 3-D appearance –specimens are coated with metal -  magnifies up to 100,000x

29 BIOCHEMISTRY Atoms - are the building blocks of matter – They are made of protons (positive charge), electrons (negative charge), & neutrons (no charge). Because the number of protons equals the number of electrons, atoms have a neutral charge.  The protons & neutrons make up the nucleus of an atom. 


31 Elements - are pure substances that are made of only 1 type of atom
Elements - are pure substances that are made of only 1 type of atom.  Molecules - are the smallest particles that can have a stable, independent existence – they are typically joined by covalent bonds. Compounds - are groups of atoms held together in definite proportions by chemical bonds Isotopes - are atoms of the same element that differ in the number of neutrons they contain – they still have the same number of protons.

32 Isotopes

33 Chemical Bonds All atoms strive for a stable octet
1) Covalent bonds- when atoms share electrons – these are very strong; Example = O2, H2O 2)  Ionic - molecules have opposite charges & transfer electrons – these dissociate in water ; Example = NaCl


35 Ionic Bonding

3)  Hydrogen bonds- weak bonds – can’t form with long distances – these link molecules rather than atoms; Example = between the bases of DNA 4)Van der Waals forces - slight attraction that develops between the oppositely charged regions of nearby molecules  - holds molecules together

37 Organic compounds are made by living things & contain the element carbon. Inorganic compounds are not made by living things. The elements that are crucial for life are C HOPKINS Ca Fe. The elements that are considered macromolecules are CHOPSN.

38 Water is the most important inorganic compound for living things
Water is the most important inorganic compound for living things.  Most cellular activities take place in its presence.  Water is a neutral molecule (positive charges balance the negative charges).  Water is a polar molecule because there is an uneven distribution of electrons between the oxygen & hydrogen atoms.  Drawing:

39 Characteristics of water:
1.  High heat capacity (this means it can absorb & release great amounts of heat before changing its temperature) 2.  Cohesion (this means it clings to itself – this creates surface tension) 3.  Adhesion (this means it clings to other molecules – this creates capillary action)

40 4.  Water ionizes (when the covalent bonds break, a hydrogen ion and a hydroxide ion are produced) 5.  Universal solvent (this is because it is a polar molecule)

41 A mixture is a material composed of 2 or more elements or compounds that are physically mixed together but not chemically combined.  The 2 parts of a solution are the solute (the substance being dissolved) & the solvent (the substance in which it is dissolved).

42 ACIDS & BASES Acid - any compound that forms hydrogen ions when dissolved in water – proton donors, electron acceptors, increase {H+}, turns litmus paper red, found below 7 on the pH scale; Example = sulfuric acid

43 Base - any compound that forms hydroxide ions when dissolved in water – turns litmus paper blue, found above 7 on the pH scale; Example = bleach

44 The pH scale’s range is from 0 - 14. Neutral is 7
The pH scale’s range is from   Neutral is 7.  The pH scale is a logarithmic scale meaning it increases or decreases in powers of 10.

45 ORGANIC COMPOUNDS Carbon is the backbone of all organic molecules.  It can bond with other Carbons to form rings or chains.  Carbon prefers to have 4 bonds. Monomers are basic units that repeat themselves.  When 2 or more of these combine, a new compound is formed called a polymer.

46 A condensation reaction is the process of joining monomers to build polymers.  In the process, 2 hydrogens, and 1 oxygen are released & these form water.

47 A hydrolysis reaction is the process of breaking down polymers into monomers.  Water is necessary for this reaction to occur.

48 There are 4 Classes of Organic Compounds.
1)Carbohydrates 2)Lipids 3)Proteins 4) Nucleic Acids

49 CARBOHYDRATES Living things use carbs as their main source of energy -contain the elements C, H, & O in a ratio of 1:2:1, meaning that if there are 6 Carbon atoms, there will be 12 hydrogen atoms & 6 oxygen atoms - examples of carbohydrates are starches, sugars, & glycogen - they are mainly used as structural or energy storage molecules

50 Monosaccharides - are sugars that can’t be hydrolyzed into smaller units - examples are glucose, galactose, fructose - Their formula is C6H12O6. They are all isomers of each other (they have the same chemical formula but different structural formulas)

51 sucrose = glucose + fructose lactose = glucose + galactose
Disaccharides - result from the condensation of 2 monosaccharides Examples are sucrose = glucose + fructose                   lactose  = glucose + galactose maltose = glucose + glucose Polysaccharides ’s of sugars combined; examples are starch, glycgen & cellulose Sugar Sweetness fructose 173% sucrose 100% glucose 74% maltose 33% galactose lactose 16%

52 LIPIDS - examples are fats, oils, & waxes - they contain the elements C, H, & O and consist of the monomers glycerol + 3 fatty acids - all are insoluble in water because they are nonpolar compounds - they are used for the storage of energy & in hormone/steroid synthesis

53 Saturated fats contain all single bonds & are difficult for the body to break down. Unsaturated fats contain more double bonds & are easier for the body to attack.  These are healthier for the body.  These fats can be made saturated by hydrogenation such as in Crisco (trans fats).  Lipases are enzymes that break down fats & oils. Lipids are essential for the body for cell membranes, cushioning, hormone synthesis.


55 PROTEINS - the basic building blocks for the body - they contain the elements C, H, O, N, & sometimes S- they are made of monomers known as amino acids - polypeptides are long chains of amino acids - proteins are held together by peptide bonds

56 The 2 classes of proteins are 1) Structural - these make hair, nails, ligaments, & tendons; &
2) Dynamic - these make things happens & include enzymes & hemoglobin Proteins have a native configuration – this is their original shape.  Most proteins that are denatured cannot be annealed.

57 Enzymes are proteins that act as catalysts(speed reactions)
Enzymes are proteins that act as catalysts(speed reactions).  They lower the activation energy but are not used up in the reaction.  They are specific (think key & lock).  The substrate is what the enzyme acts on.  The active site is where the enzyme & substrate come into contact. Coenzymes help enzymes bind to the substrate (vitamins).  Inhibitors slow or stop enzyme activity by either blocking the active site or distorting the enzyme’s shape.



60 NUCLEIC ACIDS - these carry instructions for cellular activities – they store hereditary info to make protein - nucleic acids are made from the monomers of nucleotides- these are made of 1) a nitrogen base (adenine, thymine, guanine, uracil, & cytosine), 2) a 5-C sugar, & 3) a phosphate group.

61 The 2 nucleic acids are DNA & RNA
The 2 nucleic acids are DNA & RNA. DNA is found in the nucleus & records instructions.  RNA is found in the nucleus & cytoplasm & reads instructions & carries them out.

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