12/1/2008 1 BIOLOGY 3 LECTURE 1 ATTRIBUTES OF LIFE Objective: to recognize the unifying features of living things Unifying feature of life: 1. Living organisms are made up of bioelements. CHEMICAL PROPERTIES: ATOMS –BASIC UNITS OF MATTER are made up of Electron (-) , Proton (+), Neutron Atomic number : number of charged protons Atomic mass: weight of protons + neutrons (inside the nucleus) Maximum no. of protons: 92 Maximum no. of neutrons: 146 ELEMENT: any substance that cannot be broken down to any other substance by any ordinary chemical processes . There are 111 listed in the periodic table including carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. ISOTOPES –atoms with the same number of protons but different number of neutrons Eg. C 12 = 6P, 6N, 6E; C 13 = 6P, 7N, 6E ; C 14 = 6P, 8N, 6E RADIOACTIVE: unstable isotopes whose nucleus tend to break up into particles with lower atomic numbers IONS: atoms with an electrical charge due to excess electrons ACIDS: substances that release H+ BASES: substances with excess OH-and receives excess H+ OXIDATION: loss of electron or combination of compound with oxygen, producing heat and energy; REDUCTION: gain of electron REDOX reactions: transfer of electrons among atoms Ph: the basis of measurement of acidity of substances Ph 1 to 6.99 – acidic; Ph 7 – neutral; Ph 7.1 to 14 – basic Carbon skeleton of biomolecules: *sugar *DNA *amino acids/ protein *phospholipids *ATP These elements combine to form the biomolecules: carbohydrates (CHO) , lipids (CHO), protein (CHON), nucleic acids. I. CARBOHYDRATES 1. MONOSACCHARIDES a. Pentoses(5-C): ribose and deoxyribose b. Hexoses (6-C): i. Glucose - dextrose or grape sugar ii. Galactose – sugar in milk iii. Fructose – fruit sugar or levulose 2. DISSACCHARIDES a. Maltose (malt sugar) = glucose + glucose b. Lactose (milk sugar) = glucose + galactose c. Sucrose (cane or beet sugar) = glucose + fructose 3. POLYSACCHARIDES a. Starch – found in plants b. Cellulose – in the plant cell wall c. Glycogen – energy source of animals OH grou p optical isomers geometric isomers
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Transcript
12/1/2008
1
BIOLOGY 3
LECTURE 1
ATTRIBUTES OF LIFE
Objective: to recognize the unifying features of
living things
Unifying feature of life:
1. Living organisms are made up of bioelements.
CHEMICAL PROPERTIES: ATOMS – BASIC UNITS OF MATTER are made up of
Electron (-) , Proton (+), Neutron
Atomic number : number of charged protons
Atomic mass: weight of protons + neutrons (inside the nucleus)
Maximum no. of protons: 92 Maximum no. of neutrons: 146
ELEMENT: any substance that cannot be broken down to any other substance by
any ordinary chemical processes . There are 111 listed in the periodic table
including carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
ISOTOPES – atoms with the same number of protons but different number of
neutrons
Eg. C12 = 6P, 6N, 6E; C13 = 6P, 7N, 6E ; C14= 6P, 8N, 6E
RADIOACTIVE: unstable isotopes whose nucleus tend to break up into
particles with lower atomic numbers
IONS: atoms with an electrical charge due to excess electrons
ACIDS: substances that release H+
BASES: substances with excess OH- and receives excess H+
OXIDATION: loss of electron or combination of compound with
oxygen, producing heat and energy;
REDUCTION: gain of electron
REDOX reactions: transfer of electrons among atoms
Ph: the basis of measurement of acidity of substances
Ph 1 to 6.99 – acidic; Ph 7 – neutral; Ph 7.1 to 14 – basic
Carbon skeleton of biomolecules:
*sugar
*DNA
*amino acids/ protein
*phospholipids
*ATP
These elements combine to form the biomolecules:
carbohydrates (CHO) , lipids (CHO), protein (CHON), nucleic
acids.
I. CARBOHYDRATES
1. MONOSACCHARIDES
a. Pentoses(5-C): ribose and deoxyribose b. Hexoses (6-C):
i. Glucose - dextrose or grape sugar ii. Galactose – sugar in milk
iii. Fructose – fruit sugar or levulose
2. DISSACCHARIDES
a. Maltose (malt sugar) = glucose + glucose
b. Lactose (milk sugar) = glucose + galactose c. Sucrose (cane or beet sugar) = glucose + fructose
3. POLYSACCHARIDES
a. Starch – found in plants
b. Cellulose – in the plant cell wall c. Glycogen – energy source of animals
OH
grou
p
optical
isomers
geometric
isomers
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+
Starch - found in most plants
Chemistry of lipids:
Formation of polypeptides- condensation reactions:
two or more amino acids joined together
The primary structure of a protein is the sequence of amino acids
found in its polypeptide chain. This sequence determines its
properties and shape.
a)
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NUCLEIC ACIDS: DNA/RNANUCLEIC ACIDS: DNA/RNA
The Prism of Sennacherib
- about 700 b.c.
- Assyrian language
- 20,000 character
- 50kg
Single DNA molecule E.
coli
- 10 million characters
- 10 -10g
UracilUracil
ThymineThymine CytosineCytosine
2. Life is dependent on water.
Living things have fluids mad up of 90% water and 10% solutes
(organic and inorganic).
Eg. Cell cytoplasm, Vertebrate blood, Plant xylem sap
Biochemical reactions occur in the presence of water (the universal
solvent).
Photosynthesis: CO 2 + C6 H12 O6 + H2O + O2
WATER: the cradle of life; universal solvent;
75% of the earth’s surface,
67% to 70% of the human body;
90% of the plant cell
it has great fluidity that favors transport and
dissociation of materials (electrolytes)
its chemistry is controlled by its polarity with O- having
greater negativity with H+
Physical properties: has high surface tension
high specific heat – absorbs heat
ice formation – can solidify
cohesion – “stick together”
adhesion – stick to surfaces
3. Life occurs in the presence of coupled
cycling of nutrients.
Bioelements cycle from organic and inorganic states (and
vice versa).
Bioelements involved in the biogeochemical cycling:
*carbon cycle
*sulfur cycle
*nitrogen cycle
*hydrogen- oxygen cycle
*phosphate
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Components of the Biosphere
nutrient_cycling
4. Life occurs in the presence of a flow of energy.
Energy flow is unidirectional
Radiant energy�Chemical energy�Heat energy
Sun- the ultimate source of energy of the biosphere.
(PHOTOSYNTHESIS)
Chemical energy moves within the biosphere. (ASSIMILATION)
Heat energy is lost. (RESPIRATION)
The The The The
Energy Energy Energy Energy
FlowFlowFlowFlow
5. Life is orderly.
Large amounts of energy input is needed to maintain
orderliness (highly ordered state) of life.
Life is described as progression towards the increasing