Topic 2: Chemical Level of Organization part 1 Flashcards
Describe the structure of an atom
Nucleus contains;
protons; (p+), positive charge; = atomic number
neutrons; neutral charge (n0)
Orbiting the nucleus:
electrons (e-): negative charge
Atoms are….
electrically neutral – the number of electrons and protons is equal
Neutrons may not be equal to these (isotopes).
ex; H, C, N, O
Ions
if an atom loses or gains an electron, it is no longer neutral and becomes an ion
anion
atom gains an electron and becomes a negative ion
cation
atom loses electrons and becomes a positive ion
List some imp. ions (electrolytes):
Calcium: Ca2+ Sodium: Na+ Potassium: K+ Hydrogen: H+ Chloride: Cl
Chemical Bonds
Bond (hold) atoms together to form molecules
Ionic bonds
(ions formed) - atom to atom transfer of electrons
What type of bond is NaCl in? What happens to it in water?
ex of an ionic bond
Na loses one electron = Na+
Cl gains one electron = Cl-
the positive (Na+) and negative (Cl-) ions attract forming the bond
in H2O NaCl dissociates (dissolves/separates/ionizes) into ions: Na+, Cl-
Covalent bonds
- sharing electrons between atoms
e. g. O2
These-_________allow the formation of _______ which may be-___________
These chemical bonds allow the formation of chemical compounds which may be
organic or inorganic:
Organic substances
covalently bonded carbon (C) atoms
e.g. carbohydrates, proteins, lipids and nucleic acids
inorganic substances
– usually lack C atoms
e.g. water (H2O), NaCl, O2
List the exception of inorganic compounds which contain carbon atoms:
H2CO3 (Carbonic Acid)
HCO3 - (Bicarbonate)
CO2 (Carbon Dioxide)
CO (Carbon Monoxide)
ALL CONTAIN 1 CARBON SO CAN’T MAKE COVALENT BONDS
Water
(inorganic)
Most abundant substance in cells
2 hydrogen (H) atoms and 1 Oxygen (O)
polar molecule; oxygen has a greater affinity for electrons so they spend more time there
Many reactions in the body take place in H2O because it is a universal solvent
Transports chemicals e.g. O2, nutrients
Maintains body temperature (~37°C)
polar molecules
unequal sharing of electrons leads to a slight charge difference
Acids and Bases
can be organic OR inorganic
Acids
dissociate in H2O releasing H+ ions
- ↑[H+] =↓pH (high hydrogen ion concentrations indicate a low or acidic pH)
- e.g. hydrochloric acid (HCl) in H2O—–> H+ +Cl
ex- citric and acetic acid= organic HCl and sulfuric acid= inorganic
atom
basic building block of matter
Bases
substances that bind free H+ ions in H2O
• ↓ [H+ ] =↑pH (low hydrogen ion concentrations indicate a high pH)
• e.g. 1: NaOH in H2O—-> Na+ + OH- (hydroxyl ion)
then OH- (base, removes free H+ decreasing concentration) + H+ —> H2O (neutralization)
e.g. 2: HCO3 (bicarbonate) + H+ —-> H2CO3 (carbonic acid)
• OH- and HCO3
- act as bases by binding to the free H+ ions
pH Scale
a measure of the [H+ ] of free H+ in solution
Basic—-> Acidic ↑[H+]
0-7; acidic
7; neutral
7-14; basic
e.g. pH of blood = 7.35- 7.45
Carbohydrates
consist of C,H, and O
formula: (CH20)n [n =#]
What are the functions of Carbs?
a) Source of energy for cells
e. g. C6H12O6 (glucose)
b) Cellular structures
e. g. DNA + RNA
monosaccharides
(simple sugars)
e.g. glucose, fructose, ribose, deoxyribose
basic building blocks of other carbohydrates; monomers
disaccharides
2 monosaccharides covalently bonded together
e.g. glucose +fructose—> sucrose
polysaccharides
- many monosaccharides (basic building blocks) bonded together
e. g. glycogen (animals), starch (plants)
glycogen
glucose storage form in animals in liver and muscles
- MOST IS STORED AS LIPIDS
Lipids
C, H, O (ratio different from carbs)
e.g. fats, oils, waxes, fatty acids (FA)
Insoluble (nonpolar, hydrophobic) in water
- soluble in nonpolar solvents
List the functions of lipids
a) protect organs (padding)
b) build cell membranes
c) source of stored energy
List the different types of lipids:
a) Glycerides
b) Phospholipids
d) Cholesterol
e) Steroids
Glycerides
most common lipid in body and diet
composed of 2 building blocks:
i. glycerol (backbone)
ii. fatty acids (FAs)
monoglyceride
glycerol + 1 FA
diglyceride
glycerol + 2 FAs
triglyceride
glycerol + 3 FAs
Phospholipids
3 building blocks:
i. Phosphate “Head” Group (polar)
• hydrophillic (water soluble)
ii. Glycerol backbone and
iii. 2 FAs “tails” (non-polar)
• hydrophobic (water insoluble)
ie: diglyceride with a phosphate head group
Cholesterol
found in cell membranes and used to synthesize steroids
- imp for structural stability
Steroids
derived from cholesterol
e.g. bile salts, vitamin D, hormones (testosterone, estrogen, etc)
Proteins
consists of C, H, O, N, (also sometimes S)
e. g. collagen, albumin (most abundant protein in plasma
* workhorse of the cell
one or more polypeptides folded into its final shape
List the functions of Proteins:
a) structural materials
e. g. collagen
b) enzymes, hormones, transporters
c) antibodies
d) source of energy (especially when carbs & lipids in low supply)
* b/c proteins aren’t stored so if we are breaking them down then we start breaking down structural proteins
Amino acids
→ basic building blocks of all proteins
→ use the name of the aa itself e.g. glycine
dipeptides
two amino acids
polypeptides
many amino acids
Nucleic Acids
consists of C, H, O, N, P
2 forms:
a) DNA (deoxyribonucleic acid)
b) RNA (ribonucleic acid)
building blocks called nucleotides
What does each nucleotide contains?
a) PO4 - (phosphate)
b) monosaccharide (simple sugar)
ribose in RNA or deoxyribose in DNA
c) organic base: Adenine (A) Thymine (T) – DNA only Uracil (U) – RNA only Cytosine (C) Guanine (G)
DNA
PO4 - deoxyribose - A, T, C, or G
Bases bind to form double-stranded helix (twisted ladder)
→ A to T; 2 H bonds
→ G to C; 3 H bonds
alternating sugar and phosphate form “uprights”
bases “rungs
*stored within the nucleus
List the functions of DNA
→ cellular reproduction
→ used as a template to make RNA
RNA
PO4 - ribose - A, U, C, or G
single stranded
→ A to U
→ G to C
leaves nucleus
What is the function of RNA?
→ protein synthesis
Adenosine Triphosphate (ATP)
Energy stored in covalent bonds - powers cellular activities
*ORGANIC MOLECULE
Structure = 3 PO4 + ribose + adenine (modified RNA nucleotide)
in fig. 2.26 “~” = high energy bond
breaking bond creates immediately useable energy
ATP —–> ADP (adenosine diphosphate) + Pi (inorganic phosphate)
What level or organization are atoms and molecules at?
chemical level
Is the body only made of organic substances?
No also inorganic for ex water
Is water composed of 2 O and 1H atom?
No
H2
O1
As H+ concentration increases
a) pH increases
b) pH decreases
b) pH decreases
Are FA acids or lipids or both?
both
*ANYTHING WITH LIPID IN NAME IS ACID
Do Carbs and lipids contain N?
No
Do we have carbs in nucleic acids?
Yes; monosaccharides
An organic molecule could be
a) a molecule which has ionic bonds between carbon atoms
b) ATP
c) a molecule such as NaCl which ionizes in water
d) one that ionizes in water to release H+
e) b and d
e
Which is incorrect?
a) amino acids are the building blocks of proteins
b) a DNA molecule contains simple sugar a part of its structure
c) a triglyceride is composed of glycerol and 3 FA
d) disaccharides and lipids are present in the structure of collagen
e) glycogen is an example of a polysaccharide
d
