Biology- Water Notes
The chemical structure of water makes it very important to biological
functions-the 3 atoms are in bent at an angle instead of a straight line
Water is made of 2 atoms of hydrogen covalently bonded (electrons shared) to 1 atom of oxygen
Covalent bond: molecule in which electrons are shared to become stable
Polarity- refers to “poles” = electrons are not distributed evenly making one side “more positive”
and the other side “more negative –
Because water is POLAR it can dissolve many other substances – the positive end pulls negative
particles, and the negative end pulls away positive particles
- “Like dissolves like”
-water is capable of dissolving polar and ionic substances
Ionic bond: bond that is formed by gaining or losing electrons and creating ions
The polarity also allows water molecules to be attracted to other water molecules- the bond between
water molecules is a HYDROGEN bond- a fairly weak bond that is easily broken
Cohesion and Adhesion
-cohesion – attractive force between particles of the same kind – like 2 between 2 water molecules
-seen in the surface tension of water – makes water seem to have a “skin”
-adhesion- attractive force between unlike substances like water molecule & the faucet
capillarity -The forces of cohesion and adhesion allow water molecules to move up through narrow
tubes against gravity
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Heating breaks the hydrogen bonds- temperature only rises after ALL the bonds between water
molecules are broken which allows it to absorb a lot of energy without raising the temperature
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The ability of water to absorb large amounts of heat allows an organism to keep cells at stable
temp when the temp in environment change
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Quiz
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https://b.socrative.com/teacher/#start-quiz/19303056
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Water – Liquid Awesome!!! https://www.youtube.com/watch?v=HVT3Y3_gHGg
3-2 Carbon Compounds – Element of Life!
Carbon has 4 valence electrons – so it can form 4 covalent bonds
It can form chains, rings or branched chains- and can bond with other carbon atoms
The fact it can form so many shapes is what is so important to biochemistry
Organic vs Inorganic Compounds
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Organic Compounds – Compounds of living origin – came from living
-they are not living, but come from living things
-Compounds that contain CARBON atoms bonded to other C, H, O, N
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Inorganic Compounds- Not of living origin – they are mineral based, but can also contain C such as
CO2
Functional Groups
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Functional Groups: clusters of atoms that influence the properties of molecules – main part may be
the same between compounds with the only difference being the functional group
Macromolecules
Macromolecules: BIG molecules that are created by joining together many smaller molecules
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Polymer: a macromolecule – made from many smaller repeating parts(poly = many; mer = parts)
Monomer: a single part that is repeated or put together many times to create a polymer (mono = one;
mer = part)
ATP – Adenosine Triphosphate
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Energy molecule of the cell – converted from glucose
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Energy from CARBS and FATS is broken down, O2 is breathed, together this allows the mitochondria to
create ATP to fuel your cell reactions
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Made of C,H,O,N,P
3-1 Molecules of Life (macromolecules)
4 Main Molecules of Life (Biomolecules)
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Carbohydrates
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Lipids
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Proteins
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Nucleic Acids
6 Essential Elements – CHONPS
Although there are about 25 different elements found in the body there are a main six:
C = Carbon, H = Hydrogen O = Oxygen N = Nitrogen P = Phosphorus S - Sulfur
Carbohydrates
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Organic compounds containing C,H,O
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Functions
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Energy storage
3 Types
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Monosaccharides
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Disaccharides
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Polysaccharides
Monosaccharides
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Simple sugars
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Made of 1 monomer of sugar
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Examples:
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Glucose- cell sugar
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-converted to ATP
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Fructose – fruit sugar
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Galactose – milk sugar
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Isomers: compounds with the same chemical formula but different structures – such as
glucose, fructose and galactose
Disaccharides
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Double Sugars
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Made of 2 monomers of sugar
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Examples:
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Sucrose – table sugar
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Lactose – milk sugar
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glucose + fructose
glucose + galactose
Maltose – malt sugar
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2 glucose
Polysaccharides
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Made of 3 or more monosaccharides
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Could be hundreds
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Examples:
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Glycogen – how animals store extra glucose “animal starch”
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Glucose is converted to glycogen & stored in the liver & muscles
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Starch – how plants store glucose
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Cellulose- found in cell walls of plants – most abundant organic molecule
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Gives strength and rigidity to plant cells
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Makes up about 50% of wood
Chitin – found in the shells of lobsters, crayfish, shrimp etc
Proteins
Proteins:
-Organic compounds made of C, H, O, N (and some of S in functional groups)
-Forms structures such as skin & muscles
- Enzymes are special proteins that act as catalysts
catalysts- speed up chemical reactions by lowering activation energy
- Also transport materials
-Monomers of proteins are AMINO ACIDS
Amino Acids
- Building blocks of proteins
- 20 amino acids to make all proteins
-DNA is the instructions to put the a.a.’s in the right order to make protein
Central carbon atom bonded to 4 functional groups:
Basic structure of an amino acid:
- single H atom
-Carboxyl group – COOH (carboxylic acid)
- An amino group – NH2
- R Group –
ALL amino acids are the same EXCEPT for
the R group- the difference in the R group gives them different shapes which gives
them different functions
Dipeptides and Polypeptides
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Dipeptide: 2 amino acids linked by a peptide bond
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Polypeptide: long chain of amino acids linked by peptide bond
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Peptide bond: Bond that links amino acids
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Proteins are made of 1 or more polypeptides – usually bend and folded upon themselves
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Shape of proteins can be affected by temperature and types of solvent
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Denatured proteins: Proteins that lose their 3-D structure (and their function) due to things such as
heat, pH, or chemicals
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Heat from cooking changes the protein in the egg from clear and runny to white and firm
Enzymes
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Enzymes: organic molecules that act as catalysts that speed up chemical reactions and reduce the
activation energy needed
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Enzyme reactions depend on a physical fit between the enzyme and its substrate
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Enzymes are special proteins
Substrate: the reactant that is being catalyzed, the molecule the enzyme attaches to
Enzyme & substrate fit together like lock and key –
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Attaches, slightly change shape, release the new products
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Enzyme is unchanged and can be used over and over
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Enzymes can be affected by temperature, pH – causing it to change shape and preventing the
reaction from occurring – called denaturing
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Lipids
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Lipids: Large, nonpolar organic molecules that do NOT dissolve in water
-like carbs, they are made of C, H, and O but with a higher ratio of carbon & hydrogen atoms to oxygen
-lipids store energy efficiently because they store more energy in the bonds between all the Carbon and
Hydrogen atoms than between the Carbon- Oxygen bonds
Functions:
- energy storage, insulation
-structure – cell membranes, hormones,
-lipids are polymers made of fatty acids as the monomer
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Fatty Acids
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Fatty acids: unbranched carbon chains that make up most lipids with a COOH (carboxyl) group on one
end
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Have 2 ends
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Hydrophobic tail (non-polar): repelled by water
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Hydrophilic head (polar):
attracted to water
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“saturated fatty acids” - each carbon atom is bonded to its maximum number of atoms – 4 – all single
bonds
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“unsaturated fatty acid: not all carbons are bonded to 4 atoms –
bond
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Saturated fat (all single bonds)
instead there is a double or triple
Unsaturated fat – has double or triple bond
Types of Lipids- based on structure
1. Triglycerides
2. Phospholipids
contain fatty acids
3. Wax
4. Steroids - does not contain fatty acids
Triglycerides
Triglycerides: 3 fatty acid molecules joined to one glycerol (-ol indicates alcohol)
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-Saturated triglycerides made of saturated fatty acids -have high melting points and solid at room temp
-examples: animal fat and shortening
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Unsaturated triglycerides made of unsaturated fatty acids are liquids at room temp
-examples : found in plant seeds and fruits –oils
Phospholipids
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Phospholipids: 2 fatty acid molecules joined to one glycerol
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Cell membrane is made of 2 layers of these with heads on the outside – and a “waterproof” center or
barrier between ( called the LIPID BILAYER)
Wax
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Wax: a structural lipid made of one long chain fatty acid joined to one long alcohol chain
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Very waterproof-
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forms protective outer covering of plants
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protects animals – earwax keeps microorganisms from the inner ear
Steroids
Steroids: Lipid that is not made of fatty acids but is made of 4 fused carbon rings with various
functional groups
-many animal hormones are steroids – testosterone
- cholesterol = human steroid needed by the body form nerve cells to function right
Nucleic Acids - CHONP
Nucleic acids – Large molecules that store information in the cell
Monomers are nucleotides
Uses 4 nitrogen bases as a code for the genetic instructions
2 kinds of Nucleic acids
- DNA (deoxyriboNucleic Acid) and RNA (riboNucleic Acid)
-DNA contains info essential to all cell activities such as cell division
Adenine, Thymine, Cytosine, Guanine ( A-T, C-G)
-RNA stores & transfers information needed to make proteins
RNA = Adenine, URACIL, Cytosine, Guanine (A-U, C
3 parts of a nucleotide
- 5 carbon sugar (ribose or deoxyribose)
- phosphate group
- nitrogen base (A, C, G, T) in DNA, (A,C,G,Uracil) in RNA