Topic 2 - Chemical level of Organization Flashcards
describe the charge and location of electrons, protons, and neutrons in an atom
atom has a central nucleus containing: protons (P+) = positive, and neutrons (N0) = neutral that are tightly bound together. the entire mass is carrying 99.9% of the atom; fantastically dense!
orbiting the nucleus are the electrons (E-) = negative charge
electrons are electrically neutral: # of electrons = # of protons (# of neutrons may not be equal to these)
describe how a neutron is formed
if an atom loses or gains an electron it becomes an ion
- if an atom gains an electron it becomes a negative charge (anion)
- if an atom loses an electron it becomes a positive charge (cation)
there are 5 important ions (electrolytes)
compare and contrast ionic and covalent bonds
ionic bond: transfer of one or more electrons from one atom to the other.
covalent bond: sharing electrons between atoms
compare and contrast organic and inorganic substances. list the carbon containing exceptions considered to be inorganic
organic substances: covalently bonded carbon (C) atoms
e.g. carbohydrates, proteins, lipids and nucleic acids
inorganic substances: usually lack C
e.g. water (H2O), NaCl, O2
with the exception of these inorganic compounds containing C atoms:
- H2C03 (carbonic acid)
- HC03 (bicarbonate)
- CO2 (carbon dioxide)
- C0 (carbon monoxide)
describe water. describe what is meant by a polar versus a non-polar molecule
- water is inorganic
- most abundant substance in cells
- 2 hydrogen (H) atoms + 1 oxygen (O)
- polar molecules - unequal sharing of e- leads to a slight charge difference
- many reactions in body take place in or evolve H20
- transport chemicals e.g. O2, nutrients
- maintains body temp at 37 degrees celsius
Non-polar molecules: occur when electrons are shared equally between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out. this is because they do not have separate + and - poles of charge.
Polar molecules: occur when there is an electronegativity difference between the bonded atoms. unequal electron pair sharing
define the terms acid and base. give an example of each
Acids: disassociation in H20 releasing H+
↑(H+) =↓pH
hydrochloric acid (HCI) in H20 ⇒ H+ + Cl- releases
- hydrogen ions - proton donors
Base: substances that bind free H+ in H20
↓(H+)=↑pH
e.g. NaOH ⇒ Na+ + OH- and then OH- + H+ ⇒ H20
base cation hydroxyl ion
- proton acceptors - make up hydrogen ions
explain the pH scale
concentration of free H+ in solution basic⇒acidic↑(H+) 0 ⇒⇒⇒⇒⇒⇒⇒⇒⇒⇒⇒ 7.0 ⇒⇒⇒⇒⇒⇒⇒⇒⇒⇒⇒ 14 acidic neutral basic (alkaline) e.g. pH of blood is 7.35 - 7.45
what are the 5 important ions (electrolytes)
calcium: Ca++
sodium: Na+
potassium: K+
hydrogene: H+
chloride: Cl-
define the general structure of carbohydrates, lipids, proteins, and nucleic acids
- four major classes of biological macromolecules—large molecules necessary for life that are built from smaller organic molecules.
- macromolecules are made up of single units known as monomers that are joined by covalent bonds to form larger polymers.
Describe ATP and why it is important to cells
adenosine triphosphate
- energy stored in covalent bonds. powers cellular activities
- breaking bond releases immediately usable energy
- 3 PO4 + ribose + adenine (modified RNA nucleotide)
- ATP → ADP + Pi Adenosine diphosphate
inorganic phosphate
Define carbohydrates
Carbohydrates:
- consists of carbon (C), hydrogen (H), oxygen (O)
- formula: (CH2O) n (n = # of carbons in the sugar)
- function: source of energy for cells e.g. glucose (C6H12O6)
- cellular structures e.g. DNA + RNA
Monosaccharides:
- simple sugars
e. g. glucose, fructose, ribose, deoxyribose - basic building of basic carbohydrates
Disaccarides:
- 2 monosaccharides covalently bonded together
e. g. glycogen (animals), starch (plants)
Polysaccharides:
- many monosaccharides (basic building blocks) bonded together
define lipids
Lipids:
- consist of C, H, O (ratio different from carbohydrates)
- e.g. fats, oils, waxes, cholesterol, fatty acids (FA)
- insoluble in water (non-polar)
functions:
a) protect organs (padding)
b) component of cell membranes
c) source of stored energy
Types:
- Glycerides
- most common lipid in the body (diet)
- composed of two building blocks:
i) glycerol (backbone)
ii) fatty acids (FAs)
Naming:
glycerol + 1 FA = monoglyceride
glycerol + 2 FA = diglycerides
glycerol + 3 FA = triglycerides
- phospholipids:
3 building blocks - modified triglyceride
i) phosphate “head” group and polar-hydrophobic (water-soluble)
ii) glycerol back bone
iii) 2 FAs “tails” (hydrocarbon) non-polar and hydrophobic (water insoluble)
i.e. “diglyceride” with a phosphate head group
simple depiction: - cholesterol - found in cell membranes & used to synthesize steroids
- steroids - derived from cholesterol e.g. bile, salts, hormones such as (vitamin D, testosterone, estrogen etc.)
synthesis: process of combining two or more components to produce an entity
define synthesis
process of combining two or more components to produce an entity
define proteins
- consist of C,H,O,N,P and sometimes S (sulfer)
- functions:
a) structural materials e.g. collagen
b) enzymes, hormones, transporters
c) antibodies
d) source of energy (especially when carbs and lipids in low supply
naming:
i) amino acids (aa)
- building blocks for proteins
- each amino acid has its own name e.g. glycine
ii) dipeptides - 2 aa
iii) polypeptides - many aa (10 or more, 50 or more aa = protein)
iv) protein - 1 or more polypeptides, folded in the final shape
*can think as the 20 amino acids as a 20 letter “alphabet” used in specific combinations to form “words” (proteins)
Nucleic acids
- consists of C,H,O,N,P
- 2 forms:
DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)
2 major forms of molecules
- building blocks called nucleotides
- each nucleotide contains: PO4 (phosphate)
- monosaccharides (simple sugar)
- ribose in RNA or deoxyribose in DNA
- an organic base: five major varieties of nitrogen
containing bases contribute to the structure
i) adenine (A)
ii) thymine (T) - DNA only
iii) uracil (U) - RNA only
iv) cytosine (C)
v) guanine (G)
* adenine and guanine are purines
* cytosine, uracil, and thymine are pyrimidines
- structure: DNA deoxyribose - A,T,C,G bases bind to form a double stranded helix (twisted ladder)
- A to T are complementary bases
- G to C are complementary bases
alternating sugar and phosphate form “uprights”
bases form “rungs”
Functions:
- cellular reproduction
- used as a template to make RNA
- structure: RNA: PO4 - ribose - A,U,C,G bases bind to form single strand
- A to U
- G to C
Function: - protein synthesis
ATP: adenosine triphosphate
- energy stored in covalent bonds which powers cellular activities
structure: 3 PO4 (phosphate) + ribose + adenine
(modified RNA nucleotides)
“ ~ “ = high energy bond
breaking bond releases immediately usable energy
ATP - ADP + Pi
adenosine inorganic
diphosphate phosphate
