Transcript Cells - Tuckahoe Common School District

Cells
The Building
Blocks of Life
What are the Needs of Living
Things?
• In order to survive all living things need:
– Energy
– Food
– Water
– Oxygen
– Living space
– To maintain a proper temperature
Characteristics of Living Things
• All living things share characteristics,
they:
– Are made of cells
– Are able to move
– Perform complex chemical activities
– Are able to grow and develop
– Are able to respond to their environment
– Are able to reproduce
All living things are able to move
All living things perform
complex chemical activities
“building up and breaking
down”
• Metabolism is the sum total of all the
chemical reactions that occur in a living
thing.
– In humans these chemical reactions are
ingestion, digestion, respiration, and
excretion.
Ingestion
• Ingestion is taking in food to process.
Digestion
• Digestion is
the process of
breaking
down food
into simpler
substances.
Respiration
• Respiration is the process of taking in
oxygen and using it to produce energy.
Excretion
• Excretion is the process of getting rid
of waste material.
All living things are able to grow
and develop
• Life span is the
maximum
length of time
that an
organism is
expected to
live.
All living things are able to
respond to their environment
• A stimulus is
something that comes
from outside the
organism or from
within the organism
that triggers a
reaction.
Examples:
cold breeze
stomach growl
• A response is the
reaction that occurs
as a result of the
stimulus.
Examples:
goose bumps
eat food
All living things are able to
reproduce
“Like produces like”
• Sexual reproduction:
– Requires two parents
– Results in offspring that
show variations
• Asexual reproduction:
– Requires one parent
– Results in identical
offspring with no
variations
Both forms of reproduction give a chemical
“blueprint” to the next generation.
Cellular Reproduction
Egg and Sperm Cells Fertilization
Meiosis - Sexual Reproduction
Result is daughter cells with half the chromosomes
Mitosis – Asexual Reproduction
Result is two identical cells
What is Competition?
• Competition is the struggle among living
things to get the proper amounts of food,
water, oxygen and space.
• Competition plays an important role in
shaping a community.
How Do Living Things Maintain
Proper Temperature
• Homeostasis is the ability of an organism to
keep the conditions inside the body the same
even though external environmental
conditions change.
• Warm blooded animals maintain a constant
body temperature at all times.
– Examples are man and mammals
• Cold blooded animals have body
temperatures that change with the
environment.
– Examples are fish and reptiles
What Makes Up All Living Things?
“The Chemistry Of Life”
• All living things are made of elements and
compounds.
What is an Element?
• An element is a pure substance that can
not be broken down into any simpler
substances.
– Only 90 natural elements exist on earth.
– Only 11 elements are common in living things.
– 4 elements (carbon, nitrogen, oxygen and
hydrogen) make up 96% of the weight of the
human body.
What is a Compound?
• A compound is formed when 2 or more
elements join together chemically.
– Examples are: water H2O, and sugar C6H12O6
A water molecule is
an example of a
compound
There are 2 Types of Compounds
• Inorganic Compounds: are compounds that
do not contain carbon. (carbon dioxide, CO2, is
an exception)
– Examples: salt NaCl, Ammonia NH3, Rust Fe3O2
• Organic Compounds: are compounds that do
contain carbon; many are basic to life.
– There are many types of organic compounds
including: carbohydrates, fats, oils, proteins,
enzymes, and nucleic acids.
Organic Compounds Carbohydrates
• Carbohydrates are the main source of
energy for living things.
– Examples are sugar, starch (fruits, vegetables)
– Carbohydrates are made of carbon, hydrogen
and oxygen.
Carbohydrates
Organic Compounds –
Fats and Oils
• Fats and oils: known as “lipids” are
energy rich compounds.
– At room temperature fats are solid and oils
are liquid.
– Fats and oils are made of carbon, hydrogen
and oxygen.
Fats and Oils
Organic Compounds - Proteins
• Proteins are necessary for growth and
repair of the body.
• In addition to carbon, hydrogen and
oxygen, proteins are also made of
nitrogen (sometimes made of sulfur and
phosphorous).
– Amino acids are the building blocks of
proteins.
Proteins
Organic Compounds - Enzymes
• Enzymes are special proteins that
regulate chemical activities in the body.
• Enzymes act as catalysts.
– A catalyst is a substance that speeds up or
slows down a chemical reaction.
Enzymes
Organic Compounds –
Nucleic Acids
• Nucleic acids are the “blue prints” of life.
• They are large compounds that store
information that helps the body make the
proteins it needs.
– Example: DNA or deoxyribonucleic acid
Nucleic Acids
What Is Cell Specialization?
• In multicellular organisms, cells not
only complete its own life activities, but
also performs a function that
contributes to the life of the organism.
• Within multicellular organisms there is
division of labor or specialization.
– The work of keeping the organism alive is
divided up among different parts of the
organism.
Levels of Specialization
Cells combine to form
Tissues combine to form
Organs combine to form
Organ systems combine to form
Organism
More Specialization
Students combine to form
Classes combine to form
Grades combine to form
Schools combine to form
District
What are Tissues?
• Tissues are cells that are similar in
structure and function that combine
together.
– Example: bone cells form bone tissue
– Other examples: muscle tissue, nerve tissue,
connective tissue.
Bone Tissue and Muscle Tissue
What are Organs?
• Organs are groups of different tissues
that work together.
– Example: the heart is an organ made of
muscle tissues and blood tissue
– Other organs: brain, stomach, skin
Organs – Heart and Stomach
What are Organ Systems?
• Organ systems are a group of organs
working together to perform a specific
function for the organism.
– Examples: skeletal system, muscular system,
digestive system.
Organ Systems
What are Organisms?
• Organisms are an entire living thing that
carries out all the basic life functions.
– Examples: Humans, cat, fish, fly
Some Organisms