SCIENCE GATEWAYBiological Systems and Life

Processes REVIEW AND PRACTICE

BIOLOGY

Life

What does it mean to be alive?

Biological Systems

Homeostasis

ENERGY/MATTERTRANSFORMATIONS

RESPIRATION AND PHOTOSYNTHESIS

– Process by which plants and animals obtain energy from foods

– Organisms break down food into smaller molecules, which combine with oxygen

– Energy stored in sugars (glucose) is released as ATP

RESPIRATION

Process occurs in two phases:1. Glycolosis: breakdown of

glucose into pyruvic acid• Occurs in cytoplasm in

eukaryotes2. Oxidation of pyruvic acid to

carbon dioxide and water• Occurs in mitochondria

RESPIRATION

After the breakdown of glucose, waste products, such as CO2 and water, leave through cell membrane

RESPIRATION

RESPIRATION

– Chemical reactions produce the nucleotide, ATP

– ATP stores energy– Energy is released

from ATP when needed

– ATP is used for all the energy-consuming activities of the cell

RESPIRATION

OVERALL REACTIONRespiration

C6H12O6 + 6O2 → 6CO2 + 6H2O + energyGlucose Oxygen Carbon Dioxide Water

Similar to combustion reaction (burning)

PHOTOSYNTHESIS 6CO2 + 6H2O + energy → C6H12O6 + 6O2

• Process of producing food in plants

• Chloroplasts (cells) use energy from the sun to produce glucose

• Uses CO2 and water

• Releases oxygen as waste

PHOTOSYNTHESISLight Reaction• Chlorophyll traps the

energy available in sunlight

• ATP is produced– ATP stores energy for cell

processes• Water is split into hydrogen

and oxygen• Some oxygen is used in

respiration• A great deal of oxygen is

released to the environment

Dark Reaction• CO2 and other chemicals

combine to form glucose, using energy from ATP

• Some of the glucose produced is used in respiration

• Some glucose is used for growth

• Excess glucose is stored in roots, stems and leaves of plants

RELATIONSHIP BETWEENPHOTOSYNTHESIS AND RESPIRATION

Respiration• ALL plants and animals

carry on respiration• Uses oxygen• Releases water and CO2

Photosynthesis• Plants with chlorophyll

carry on photosynthesis• Produces oxygen• Uses water and CO2

LIFE FUNCTIONS

BASIC LIFE FUNCTIONS

• All living organisms need to perform certain functions to remain alive

• Living organisms contain systems designed to carry out these essential functions

BASIC LIFE FUNCTIONS

Six basic functions:

D Digestion

R Respiration

R Reproduction

R Response

E Excretion

G Growth

BASIC LIFE FUNCTIONS

DIGESTION• The process of

changing food into a usable form to provide energy

RESPIRATION• The process of using

food• Breaking down stored

food and combining it with oxygen to provide energy

• The exchange of gases to produce food and energy

BASIC LIFE FUNCTIONS

REPRODUCTION• The process by

which new organisms (offspring) are produced

BASIC LIFE FUNCTIONS

RESPONSE• How organisms react to changes in

their surroundings

BASIC LIFE FUNCTIONS

BASIC LIFE FUNCTIONS

EXCRETION• The process by which the body gets rid

of liquid waste• The lungs, kidneys, and skin function to

excrete waste produces created by the body

BASIC LIFE FUNCTIONS

GROWTH• The repair and

production of new and larger cells within a living organism

TO BE LIVING

• An organism must perform all life functions to be considered living

• However, these life functions may be carried out in different ways

BACTERIA • Prokaryotic organisms

– Single-celled organisms that lack a nucleus• Identified by shape, type of cell wall, movement, and the

ways in which they obtain energy• Most reproduce by binary fission, creating two identical

cells• May participate in conjugation

– Genes move from one cell to another

ARE VIRUSES ALIVE?

Not considered alive by many biologists• Not composed of

cells• Not able to reproduce

independently; must use host cell

• Infect living cells• Can make copies of

themselves• Made of a DNA or

RNA core surrounded by protein coat

HIV Virus

WWHHHEEE!!!!

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