Chapter 2- Chemical Basis Of Life Flashcards
Matter
Anything that takes up space and has mass
Electricity
The flow of electrons (energy)
Mass
A measure of the amount of matter an object contains
Stays the same regardless if changes in the objects position
Weight
The measure of how strongly an object is pulled by earths gravity and it varies with distance from earths center
Trace elements
Elements required by life in very minute quantities
Ultratrace elements
Element required by organisms in extremely minute quantities but are TOXIC at high levels (arsenic- Ar)
Compound
A pure substance composed of 2+ different elements combined in a fixed ratio (✔️molecule)
Ex: NaCl (sodium chloride)
Molecule
2+ atoms
Atom
Smallest possible unit of matter that retains chemical/physical properties of its element
Atoms of the same element share similar chemical properties
Subatomic particles
Neutrons, Protons, electrons
Electrostatic charge
✔️Two opposites attract each other
✔️Positive attracts negative
What is unique about hydrogen
It has only one electron and one proton, NO neutrons
Atomic nucleus
Where protons and neutrons are found; where mass of entire atoms is measured
Mass of 1 proton, one neutron= 1 Dalton
Where are electrons located
Orbit around the nucleus; held together by electrostatic attraction to positively charged nucleus
Mass so small, it’s not used to calculate atomic mass
Atomic number
DETERMINES the atom (unique to each)
Number of protons in an atom
All atoms of an element have the same atomic number (subscripts to the of the elements written symbol)
Mass number
Number of protons and neutrons in an atom (one of each has mass of approx 1 dalton)
Superscript to left or an elements symbol
Octet rule
1st shell- max 2 electrons
2nd shell- max 8 electrons
3rd shell- max 8 electrons
In what shell do electrons have most energy
The further out the shell, the more energy the electrons have because they aren’t being pulled into positively charged nucleus as strongly
Chemical reactions always go to the _________________? energy state
Chemical reactions always go to the LOWEST energy state
Inert
NOT reactive
Outermost shell is naturally full; ALL gasses (noble gasses)
Isotopes
Atoms of an element that have the same atomic number but different mass number
Different number of NEUTRONS
Under natural conditions, elements occur as mixtures of isotopes
Different isotopes of the same element react chemically in the ____________ way.
Different isotopes of the same element react chemically in the SAME way.
Radioactive isotope
Unstable isotope in which the nucleus spontaneously decays emitting subatomic particles and/or energy as radioactivity
Fixed half-life
What are two biological applications of radioactive isotopes
- Dating geological strata (layers) and fossils
2. Radioactive tracers
Radioactive tracers
Trace steps of biochemical reaction or to determine the location of a particular substance within organism
Useful bc they chemically react like the stable isotopes and are easily detected at low concentrations
Diagnose disease
Cause or cure cancer
Octet rule
Rule that valence shell is complete when it contains 8 electrons
Chemical bond
Attractions that hold molecules together
Covalent bond
✔️Strongest bond
✔️Chemical bonds formed by sharing s pair of valence electrons
Carbon and silicon have 4 valence electrons, what is this called?
Tetravalent
Valence
Bonding capacity of an atom which is the number of covalent bonds that must be formed to complete the outer shell
Electronegative atom
The personality of some atoms to be attracted to electrons and pull them close to them!!
EX: N2 and O2 !!!!!!
Dipole
Uneven distribution of the charge in a molecule
Hydrogen bond
✔️Weak bond
✔️form between molecules or diff parts of a large molecule
✔️Bond formed by the charge attraction when HYDROGEN is COVALENTLY bonded to an ELECTRONEGATIVE atom and is attracted to another electronegative atom
✔️indicated by dotted line in structural formula
Why is DNA hard to unravel?
Bc it has ALOT of weak hydrogen bonds which are strong when together bc there are so many
How many hydrogen bonds can a water molecule form with neighboring water molecules?
4
What holds DNA together?
Weak hydrogen bonds
adenine—-> thymine
cytosine—> guanine
Ion
A charged atom or molecule
Ionic bond
✔️Formed by the electrostatic attraction (positive—>neg.) after the complete transfer of an electron from a donor atom to an acceptor. (Acceptors attract electrons bc electronegative)
✔️strong bonds in crystals not in water (salt dissolves in water bc ionic bonds dissociate into ions
Chemical reactions
Making and breaking chemical bonds leading to changes in composition of matter; reactants—> products
Matter cannot be created nor destroyed
The relative concentration of reactants and products affects the reaction rate. The higher the concentration the ____________
….greater probability of a reaction
Completion in chemical reaction
All reactants are converted to products. (Majority are reversible)
Chemical equilibrium
The RATE of the forward reaction (speed/time) equals the RATE (speed/time) of the reverse reaction
Dynamic- reactions continuing in both directions.
Relative concentrations of reactants/products stay the same
Homogenous
Particles in a mixture are all spread out throughout; mixed together
Dissociation of water molecules
Occasionally, the hydrogen atom that is shared in a hydrogen bond between two water molecules, shifts from the oxygen atom to which its covalently bonded to the unshared orbitals of the oxygen atom to which its hydrogen bonded
H2O—–> OH+H
What would happen if you took protein (slightly negative charge) and dumped it in acid?
The H+ ions (protons) will all pull the electrons toward them changing the shape of protein thus affecting its function
DENATURED ENZYME
When does the #H+ = #OH-?
At equilibrium (pure water)
Brackets indicate
Molar concentration
[H+] + [OH-] = ?
M?
1/10,000,000
M= 10-7 M
Acid
Substances that increase the [H+] of a solution; also removed [OH-] bc it combines with H+ to form H2O
Caustic
Either extremely acidic or extremely alkaline; will burn you
Base
Substances that reduce the relative H+ of a solution; may alternately increase OH-
LEO the lion says GER stands for ?
Lose electrons= oxidation
Gain electrons= reduction
Anything that breaks down into a positive and a negative
Salt
Substance formed by the reaction between an acid and a base
[H+][OH-]= ?
1.0 * 10-14
In what pH range are most biological fluids?
6 to 8
Each pH unit represents a ________ difference (logarithmic scale)
Tenfold
Slight change in pH= large change in actual [H+]
Buffers
Minimizing wide fluctuations in pH to help organisms maintain the Psh of body fluids within the narrow range necessary for life
Prevents sudden changes in pH
Ex: Bicarbonate (buffer in blood)
How do buffers work?
They either donate H+ to the solution when they have been depleted or accept H+ from the solution when they are i know excess
Polymer
Large molecule consisting of many identical or similar subunits connected together
Ex: protein consists of many amino acids
Monomer
Subunit or building block molecule of a polymer
Ex: amino acids are the monomers of the polymer protein
Macromolecule
Large organic (carbon-containing) polymer
What are the four classes of macromolecules in living organisms
Carbohydrates
Lipids
Proteins
Nucleic acid (DNA,RNA, and ATP)
Polymerization reactions
Chemical reactions that link 2+ small molecules to form molecules with repeating structural units (making a polymer)
Condensation reactions
Mose polymerization reactions in living things !!!!
(Anabolism) Monomers are covalently linked, producing net removal of a water molecule for each covalent linkage
One monomer loses OH and another loses H
Requires energy
Hydrolysis
(Catabolism)
A reactions process that breaks (splits) covalent bonds between monomers by the addition of water molecules
Hydrogen fro water bonds with one monomer and remaining OH from water bonds with adjacent monomer
Ex: digestive enzymes catalyze hydrolysis reactions which BREAK APART large food molecules into monomers that can be absorbed into the bloodstream
Carbohydrates
Organic (must have carbons and hydrogen to be organic) molecules made of sugars and their polymers
Monosaccharides
Simple sugars that are monomers or building block molecules in CARBOHYDRATES
CH2O
Major nutrients for cells ; glucose is most common
Where do carbs store energy
In their chemical bonds and it is harvested by cellular respiration
How do we get energy out of glucose?
Cellular respiration
Glycosidic linkage
Covalent bond formed by a condensation reaction between two sugar monomers
Preferential order of utilization
Body’s favorite order of what macros to use first for energy
Carbs –> protein –> fat
Polysaccharides
Macromolecules that are polymers of a few hundred or thousand monosaccharides
Formed by linking monomers in enzyme-mediated condensation (joining by removing water) reactions
What’s the most common storage polysaccharide in animals?
Glycogen
Glucose polymer in animals stored in muscle and liver
Where is glycogen stored in humans?
The liver and muscles
Lipids
Diverse group of organic compounds that are insoluble in water (hydrophobic) but will dissolve in non polar (like dissolves like) solvents
What are the 3 important groups of lipids
Fats
Phospholipids
Steroids
What are fats composed of?
Glycerol- a three-carbon alcohol Fatty acid (carboxyl acid)- composer of a carboxyl group (COOH) head at one end and an attached hydrocarbon chain (tail)
Affinity
Attraction towards
Fats
(Tail)
Hydrocarbon chain (C-H) Hydrophobic and not water soluble
ester linkage
Bond formed between a hydroxyl group and a carboxyl group
Characteristics of fat:
✔️Insoluble to water
✔️variation among fat molecules is the fatty acid composition
✔️fatty acids in a fat may all be the same or some (all) may differ
✔️ vary in length
✔️ vary in number and location of carbon to carbon double bonds
Saturated fat
✔️No double bonds between carbons and fatty acid tail
✔️bonded to MAX number of hydrogens
✔️ solid at room temp
✔️most animal fats
Unsaturated fat
✔️one+ double bonds between carbons in fatty acid tail
✔️liquid at room temp
✔️plant fats
What are 4 useful functions of fats?
✔️energy storage (one gram stores twice as much energy as a gram of polysaccharide
✔️more compact fuel reservoir (store more energy for less weight than in plants)
✔️cushions vital organs (kidney)
✔️insulated against heat loss
Phospholipids
Compounds with molecular building blocks of glycerol, 2 fatty acids, one phosphate group, usually an additional small chemical group attached to the phosphate
How do phospholipids differ from fat?
The third carbon of glycerol is joined to a negatively charged phosphate group instead of another fatty acid
How is a cell membrane’s phospholipid bilayer set up?
Has two layers of phospholipids. Each have a hydrophilic head polar head and two hydrophobic fatty acid nonpolar tails. The heads are facing outward toward extra|intra cellular areas and tails are facing inward
Steroids
Lipids which have 4 fused carbon rings with various functional groups attached
Ex: cholesterol is important steroid
Cholesterol
Very important steroid
✔️adds stability to cell membrane (adds viscosity (thickness) to membrane)
✔️precursor to many other steroids (sex hormones etc)
Fluid- mosaic
Characteristic of cell membrane to move
Fluid- move all around
Mosaic- all different components
Protein
Polymer of amino acids
Structure of amino acids
Carboxyl end (COOH) and an amino acid end (NH2) as well as a variable R group
Peptide
2+ amino acids
Peptide bond
Formed between the amino group (NH2) of one amino acid to the carboxyl group (COOH) of the next
How many kinds of amino acids are use in protein structure?
20
What are the four levels of protein structure?
Primary structure
Secondary structure
Tertiary structure
Quaternary structure
Primary structure
The order of the amino acids in a peptide
Secondary structure
Coiled or FOLDED shape held together by hydrogen bonds
Tertiary structure
Further bending and folding
Quaternary structure
Between 2+ peptide chains
Will protein dissolve in water? Why/why not?
Yes bc proteins is polar and water is polar. Like dissolves like. The protein will bend on itself until is bonds with hydrogen in H2O
Protein conformation
✔️Overall protein shape
✔️Cannot function properly if shape is altered
Denatured protein
An unraveled or destroyed protein
Occurs when heat or changes in pH change protein shape
What are 6 functions of protein?
✔️structural components ✔️enzymes for catalysis ✔️communication ✔️membrane transport ✔️cell recognition/protection ✔️movement
