Download Key Idea #11 - Mona Shores Blogs

Key Idea #14

Cells in all multicellular organisms are specialized to
take in nutrients, which they use to provide energy for
the work that cells do and to make the materials that
cells or organisms need.
http://library.thinkquest.org/C004535/media/cell_membrane.gif
Chemical Compounds in Cells
Nutrients taken in by the cell provide materials to
 build cell organelles
 build specialized molecules used by the
organisms, including:
–
–
–
–
carbohydrates
lipids (fats)
proteins
nucleic acids: DNA and RNA

In plants, water and
carbon dioxide are
taken in by the
plant and used to
produce
carbohydrates,
proteins and fats
(lipids).
Carbohydrates




are energy-rich compounds
made of the elements
carbon, hydrogen, and
oxygen.
are an important part of cell
membranes and cell walls.
include sugars found in
fruits and some vegetables.
include starches found in
potatoes, corn, rice, and
wheat bread which your
body breaks down into
glucose (a sugar).
Proteins





are large organic molecules
made of carbon, hydrogen,
oxygen, nitrogen and sulfur.
are found in foods such as
meats, eggs, fish, nuts and
beans.
form parts of cell membranes.
make up many of the
organelles found in cells.
are used by cells in your body
to build body parts such as
hair and nails.
ldenicola.wordpress.com
publications.nigms.nih.gov
Fats (Lipids)

are energy-rich compounds
made of carbon, hydrogen,
and oxygen.
 include fats, oils, and waxes
found in seeds.
–
–
–
–

Peanuts, almonds walnuts (fat)
Sunflower (fats)
Olive (oil)
avocado (oil)
include cholesterol.
– an important part of animal cell
membranes
– Meat, cheese, and eggs are all
high in cholesterol.
FYI
The jojoba (Simmondsia
chinensis), a native shrub of
the southwestern United
States produces seeds and
liquid wax.
The white, solid wax is
produced by hydrogenation of
the unsaturated liquid wax.
Hydrogenation is the process
that involves the addition of
hydrogen to the fatty acids
under heat and pressure.
Nucleic Acids


are very large organic
molecules made of
carbon, oxygen,
hydrogen, nitrogen, and
phosphorus.
contain the instructions
needed to carry out life.
– DNA:
• genetic material that
contains the information
that is passed from
parent to offspring
– RNA:
• important for protein
production
• found in the cytoplasm
and nucleus
Plants are multicellular organisms that produce
their own food.

Plants use energy
from light to make
sugar molecules from
the atoms of carbon
dioxide and water.
 Plants use these
sugars along with
minerals from the soil
to form fats, proteins,
and carbohydrates.
 Fats, proteins and
carbohydrates can be
used immediately,
incorporated into the
cells of a plant as the
plant grows, or stored
for later use.
Water

helps cells keep their
size and shape.
 is important because
most chemical
reactions in cells
require water.
botany.thismia.com
Cell Membrane



acts as a gatekeeper
is selectively permeable and controls what
substances can enter or leave the cell
is permeable to oxygen, water, and carbon dioxide
– (they can pass through it)

is not permeable to some large molecules and salts
– (they can’t pass through it)
Substances that can move into and out of a
cell use one of three methods:

diffusion
 osmosis
 active transport
Diffusion – Molecules in Motion

Diffusion is the
main method by
which small
molecules move
from an area of
higher
concentration to
an area of lower
concentration.
Diffusion occurs when

molecules bump
into each other
and eventually
spread out evenly
throughout an
area.
Diffusion and Osmosis
Osmosis

is the diffusion of only
water molecules
through a selectively
permeable membrane.
 is important to cells
because they can’t
function properly without
adequate water.
Note: Only water molecules
pass through the cell membrane
during osmosis.
http://www.biologycorner.com/resources/osmosis.gif

Active transport uses
the cell’s energy (ATP)
to help nutrients enter
the cell that can’t pass
through the cell
membrane by diffusion.
Active Transport
Active transport examples:
 Engulfing

Transport proteins in the cell membrane pick
up molecules outside the cell and carry them
inside.
http://www.nicksnowden.net/images/Membranes_and_Transport/endocytosis.gif ; phschool.com.jpg