* Carbon Properties:
1- Carbon forms 4 covalent bonds.
Methane
Carbonyl
Carbon dioxide
Hydrocyanic acid
2- Carbon can bond to itself to form hydrocarbons.
Pentane (C5H12)
2 methyl butane (C5H12)
Isomers: Molecules that have same formula, but different structure.
3- Carbon forms rings.
Cyclo-hexane
Benzene
* Functional groups:
found in: alcohol & sugars
Found in: nucleic acid, fatty acids
& Amino acids
Found in: DNA, RNA, & ATP
Makes disulfide bridges.
important types of reactions:
1- Dehydration synthesis "Condensation"
Remove water, build molecules.
2- Hydrolysis:
Add water, Break molecules.
Carbohydrates
They contain the elements: Carbon, hydrogen, and oxygen, they supply quick energy.
H:O ratio is 2:1
a- Monosaccharides:
glucose
galactose
fructose
ribose "RNA sugar"
deoxyribose "DNA sugar"
* Importance of monosaccharides:
1- Glucose is the most common respiratory substance in cells.
2- Glucose is transported around the body in mammals.
3- They form disaccharides, and polysaccharides.
b- Disaccharides:
1- Maltose: found in malt, and beer.
Glucose + glucose
maltose + water
* It's the source of energy in germinating seeds.
2- Sucrose: table sugar.
Glucose + Fructose
sucrose + water
* It's the form in which sugars transported in plants phloem.
Milk sugar
Glucose + galactose
* It's found in mammals milk.
lactose + water
C- Polysaccharides:
Starch: plant food storage "in chloroplasts"
Glycogen: animal food storage "in liver and muscle cells"
Cellulose: Plant cell wall. "dietary fiber"
Chitin: Fungi cell wall and exoskeleton of arthropods.
Peptidoglycan: Bacterial cell wall.
Glycocalyx: Extracellular matrix.
Lignin: in xylem cell walls.
Lipids
* Contain C, H, and O. "less oxygen than in carbohydrates"
* They are insoluble in water.
* They are soluble in acetone and ether.
Glycerol + 3 fatty acids
Triglyceride "lipid" + 3 water
* fatty acids are formed of: Polar carboxyl group,
and non polar hydro-carbon chain.
* Saturated fatty acids:
They are solid at room temp.
They have hydrocarbon chains with single bonds only.
* Unsaturated fatty acids:
They are liquid at room temp.
They have hydrocarbon chains with at least one double bond.
Importance of lipids:
1- Energy Production and Storage:
they produce twice as much as energy produced from oxidation of the same amount
of carbohydrates pr proteins.
2- Insulation and Protection:
Thermal, electrical, and mechanical insulation.
3- Membranes Structure:
Phospholipids are found in membranes "cell membrane, ER membrane, nuclear
membrane". In phospholipids, one of the fatty acids is replaced by a phosphate
group.
It contributes to membrane fluidity.
4- Water proofing:
of skin.
5- Hormone Production
Cholesterol is a type of lipid needed to produce important steroid hormones in your
body. Estrogen, testosterone, progesterone and the active form of vitamin D are all
formed from cholesterol.
Proteins
* mainly for growth and maintenance.
* Contain C, H, O, and Nitrogen.
* They are polypeptide chains, built up from amino acid monomers and linked by
peptide bonds.
* Amino acids:
20 amino acids found in living organisms.
* Plants can synthesize all amino acids from products of photosynthesis and Nitrates
from soil.
* Animals can synthesize 12 amino acids only "Non-essential amino acids."
8 amino acids must be obtained from the diet "essential amino acids"
* Protein folding:
1- Primary structure: Linear sequence of amino acids.
2- Secondary structure: Hydrogen bonding with every 4th amino acid, to produce
alpha helix, or Beta pleated sheets.
3- tertiary structure: 3-D protein.
Molecules are held together by hydrogen bonds, Ionic bonds, covalent bonds, and
disulfide bonds between R groups.
4- Quaternary structure: Tertiary subunits.
ex: Hemoglobin.
* Protein mutation:
* Denaturation of proteins:
It involves disruption of the bonds that hold the tertiary structure, so proteins
changes in properties and function.
Caused by:
1- High temp. above 40 C
2- extremes of PH.
3- High concentration of salts.
4- presence of ions of heavy metals.
* Functions of proteins:
1- Found in cell membranes.
2- Enzymes "catalysts"
3- In muscle tissue "myosin"
4- Microtubules.
5- Microfilaments.
6- Structural protection "skin, hair, & nails"
7- Pigments "melanin, chlorophyll"
8- Hemoglobin "carries oxygen to cells"
Questions:
1- The glucose produced in tree leaves may be transported to the roots, where it is
typically converted and stored as
(A) Starch
(B) Lipids
(C) Proteins
(D) nucleic acid
(E) glycogen
2-
The molecule in the diagram above is a
(A) nucleotide
(B) lipid
(C) protein
(D) nucleic acid
(E) disaccharide
3- Monomers are linked together to form polymers in most proteins and
carbohydrates by which of the following?
(A) Dehydration reactions
(B) Hydrolysis
(C) Ionic bonds
(D) Hydrophobic interactions
(E) Hydrogen bonds
4- A gram of which of the following releases the most energy when oxidized?
(A) Amino acid
(B) Protein
(C) Nucleic acid
(D) Fat
(E) carbohydrates
(5) Which of the following is correct about the phospholipid shown above?
(A) Only I would be found in the middle of the lipid bilayer.
(B) Only II would be found in the middle of the lipid bilayer.
(C) Both I and II would be found in the middle of the lipid bilayer.
(D) II is hydrophilic.
(E) I and II are hydrophobic.
(6) Of the following elements, which is most abundant be weight in living organisms?
(A) Phosphorus
(B) Carbon
(C) Nitrogen
(D) Hydrogen
(E) Sulfur
(7) Proteins are degraded into a mixture of amino acids by
(A) osmosis
(B) phosphorylation
(C) hydrolysis
(D) oxidation
(E) synthesis
(8) Which of the following is a product of hydrolysis of glycogen?
(A) ENA
(B) Glucose
(C) Fats
(D) Amino acids
(E) Proteins
(9) On hot dry days, water absorbed from the soil moves rapidly through a tree, All
of the following characteristics of water provide for such movement EXCEPT:
(A) Water can adhere to many kinds of surfaces.
(B) Water is an effective solvent.
(C) Water molecules have both a slightly positive and a slightly negative charge.
(D) Water molecules have a strong attraction for each other.
(E) Water moves from areas of greater concentration to areas of lesser
concentration.
(10) The generalized structural formula pictured above represents which of the
following?
(A) A monosaccharide
(B) A glucose molecule
(C) A lipid
(D) An amino acid
(E) A fatty acid.