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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

complexity.

Through time:

Unicellular multicellular

Division of labor (compartmentalization)

Prokaryote (uncompartmentalized eukaryote

compartmentalized)- presence of organelles

Individuals----populations-----species-----higher taxa------

populations-------communities

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LEVELS OF ORGANIZATION:

PROTONS NEUTRONS

ELECTRONS

ATOMS BIOSPHERE

MOLECULES BIOMES

SIMPLE

COMPOUNDS

ECOSYSTEMS

COMPLEX

ORGANIC

COMPOUNDS

COMMUNITIES

BIOMOLECULES POPULATIONS

ORGANELLES ORGANISMS

CELLS ORGAN SYSTEMS

TISSUES ORGANS

Copyright © The McGraw-Hill Companies, Inc.

6. Life adjusts to a changing environment.Ecosystem is where the abiotic and biotic components interact in an exchange of matter & energy

creates

made up ofmay be

carry

out

Ecosystem

consist of

Energy Matter

lost as

Heat

radiated to

space

is

Always

eventually

recycled

results in

used to make new organic compounds

except that captured for photosynthesis by

Decomposers Consumers Producers

Niche

(way to live)

Habitat

(place to live)

modify

eaten by

shapes

made up of

carry out

made up of

Communities

Populations

Species

is composed of

Abiotic

(nonliving)

components

Biotic

(living)

components

broken

down by

is

Always

dispersed or

degraded

heat released

A concept map of ecosystem

components & relationships (CCS 2003) Climate change in Asia

• Scope: 16 countries from India to Phils. (1.6 B people)

• Water: Melting of Himalayan glaciers, causing floods

• Agriculture: Decline in rice yields due to increased

temperature

• Coastal Zones: Rising sea levels by 1 meter

• Health: Spread of malaria, dengue fever, schistosomiasis

• Adaptations: Several million people will be displaced; new

crops will be introduced to replace faltering rice

production.

• Frequent episodes of El Nino and La Nina

• Scope: 16 countries from India to Phils. (1.6 B people)

• Water: Melting of Himalayan glaciers, causing floods

• Agriculture: Decline in rice yields due to increased

temperature

• Coastal Zones: Rising sea levels by 1 meter

• Health: Spread of malaria, dengue fever, schistosomiasis

• Adaptations: Several million people will be displaced; new

crops will be introduced to replace faltering rice

production.

• Frequent episodes of El Nino and La Nina