Download The Study of Life

Unit #1 - Interdependence
What do living things need?
I. Studying Life
Biology – the study of
life (bios – “life”, -logy –
“study of”).
Biologist – someone who
uses scientific methods to
study living things.
A. Characteristics of Living Things
All living things share the following :
1. Are made up of units called cells.
Cell – a collection of living matter
enclosed by a barrier that separates
the cell from its surroundings.
-Cells are the basic/smallest units of
life.
Unicellular – single-celled organisms.
Multicellular – many-celled organisms.
Characteristics of Living Things
2. Can reproduce.
Sexual – 2 parents create
genetically different
offspring.
Asexual – one parent
produces a clone of itself.
3. Are based on a universal
genetic code : the
molecule DNA.
Characteristics of Living Things
4. Growth and development.
Metabolism – combination of
chemical reactions in which an
organism uses materials to
carry out life functions.
5. All obtain & use materials &
energy.
6. All respond to their
environment.
Stimulus – a signal to which
an organism responds; can
be internal or external.
Characteristics of Living Things
7. Maintain a stable
internal environment.
Homeostasis – process
by which an organism
keeps its internal
conditions fairly
constant in order to
survive.
8. In general, they
change over time.
B. Other Branches of Biology
1. Zoology – study of
animals.
2. Botany – study of
plants.
3. Paleontology – study
of ancient life.
C. 4 types of organic molecules in living things :
1. Carbohydrates – compounds
made up of carbon, hydrogen, &
oxygen atoms, usually in a ratio
of 1 :2 :1, ex : sugars, starches,
& cellulose.
**Living things use carbohydrates
as their main source of energy.**
-Energy for cell activities comes
from the immediate break-down of
sugars, such as glucose.
-Extra sugar is stored as complex
carbohydrates known as starches.
Lipids
2. Lipids – macromolecules
made mainly from carbon
& hydrogen atoms &
glycerol; includes fats, oils,
waxes, phospholipids, &
steroids.
-Used to store energy,
insulate, repel water, &
form membranes.
Nucleic Acids
3. Nucleic acids –
macromolecules
containing hydrogen,
oxygen, nitrogen,
carbon, & phosphorous.
-Contain genetic/hereditary
info.
-Are assembled from
nucleotides – monomers
of nucleic acids made up of a :
1. 5-carbon sugar
2. Phosphate group
3. Nitrogenous base.
2 Major Types of Nucleic Acids :
A. DNA – (deoxyribonucleic
acid) carries instructions
that control the activities
of a cell.
B. RNA – (ribonucleic acid)
uses those instructions
to make/build proteins.
Proteins
4. Proteins – macromolecules
that contain nitrogen, carbon,
hydrogen, & oxygen.
-Are made up of amino acids –
compounds with an amino
group (-NH2) on one end & a
carboxyl group (-COOH) on
the other end.
-Amino acids are the building
blocks of proteins.
-20 different amino acids are
used to build proteins. Different
combinations = different
proteins.
Each protein has a specific role, ex :
1. Control the rate of reactions
& regulate cell processes.
2. Form bones, muscles, &
hormones.
3. Transport substances in or
out of cells & fight disease :
antibodies.
Enzymes – proteins that help
control chemical reactions.
Can speed up reactions, ex :
Digestion.
D. Other nutrients needed by living things
Nutrients – substances in
food that provide the raw
materials and energy the body
needs for essential processes.
Nutrients are keep the body’s
cells functioning, growing,
and replicating.
-Are made up of chemical
elements including carbon,
oxygen, hydrogen, nitrogen,
and phosphorous.
Vitamins
1. Vitamins – chemical
compounds needed by
the body in small
amounts to strengthen
the immune system,
grow, and repair
damaged cells/tissues.
-Vitamins are supplied to
the body by a well
balanced diet.
Problems related to vitamin deficiency :
Vitamin A – Liver problems,
hair loss, rough skin.
Carrots are a good source.
Vitamin B2 – Eye problems
and cracking skin.
Vitamin B3 – Mental
problems, rash, and
diarrhea.
Vitamin C – Sore mouth,
bleeding gums, and bruises.
Vitamin D – Bowed legs,
rickets, & poor teeth.
Minerals
2. Minerals – chemical compounds
needed in small amounts to help form
important cell parts.
-Mineral deficiency can cause :
a. Iron – used for blood. Risk = Anemia,
which causes extreme fatigue & bruising.
b. Calcium – used for strong bones and
teeth. Risk = Osteoporosis later in life.
c. Magnesium – used for bones and teeth.
Risk = Severe muscle twitches that can
become very painful.
d. Iodine – used for making chemicals in the
thyroid (found in salt). Risk =
development of a goiter (abnormally
enlarged thyroid).
e. Sodium – (NaCl or salt) used for muscle
contractions and nerve messages.
Water
3. Water – fluid made up of
hydrogen and oxygen that
makes up approximately
50-60% of the human body.
How much water does the
average adult need?
Answer : 2 liters per day (8 glasses)
The body uses water to :
• Re-hydrate the body by
replenishing liquids.
• Flush out toxins.
• Control body temperature.