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Carbohydrates and Lipids
Honors Biology
•
The sugar in your soda and the
starch and fiber in your bread, fruit
and vegetables are all
carbohydrates.
•
You consume more carbohydrates
than any other organic biomolecule.
•
A carbohydrate is an organic
macromolecule.
•
QUESTION: Do you remember what
ORGANIC means???
•
QUESTION: Do you remember a synonym
for “macromolecule?”
•
Carbohydrates are composed of carbon,
hydrogen and oxygen in a 1:2:1 ratio.
•Short-term
energy storage
•Fiber
In Plants
In Animals
•Energy storage
•Structure of Cell Wall
Carbohydrate
Formula:
C6H12O6
Notice the ratio of 1:2:1 for
carbon, hydrogen and oxygen
atoms.
C2H4O2
C3H4O5
C3H6O3
CH4O2
C6H12O6
C36H72O36
Notice the ratio of 1:2:1?
For every one carbon there are
two hydrogens and one oxygen!
1.
2.
3.
Short-term energy storage in animals (glycogen)
Used to create energy (glucose) in all organisms
Plant cell walls (cellulose) and plant energy
storage (starch)
What is dietary fiber?
Parts of a plant that we eat but cannot
digest. Fiber acts like a broom in our gut,
cleaning out decaying food particles.
Celery, popcorn, and whole wheat are high
in fiber
•
All carbohydrates can be categorized by
size
•
Three main sizes of carbohydrates—
•
•
•
Monosaccharides (“one sugar”)
Disaccharides (“two sugars”)
Polysaccharides (“many sugars”)
Building block of all carbohydrates
•It is also called a single or simple
sugar.
•Six-sided, diamond-like shape
Glucose
•Polysaccharides are composed of
hundreds or thousands of
monosaccharide molecules bound
together.
Glucose is the primary energy
source for most organisms.
•Energy is stored in the chemical bonds
of the glucose molecule.
•The energy is released during cellular
respiration in organisms.
Thousands of glucose molecules make up the
starches found in the foods you eat.
“two sugars”
Sucrose
Sugar
Glucose
+
Fructose
Monosaccharides
•
Polysaccharides are made of long chains of
glucose molecules.
•
Glycogen and starch are broken down into
glucose molecules during digestion
•
The glucose molecules then go to your cells
where they are broken down to release energy
during cellular respiration.
•
Glucose molecules are
created by plants during
photosynthesis. The
glucose molecules are
bound together in long
chains to make starch.
•
Starch, a polysaccharide,
is stored in plants until the
plant needs to use it. When
you eat starchy foods, like
potatoes, you break the
starch down into glucose.
•
Your body will bind
glucose molecules
together to make
glycogen. Glycogen,
a polysaccharide, is
stored in your
muscles and liver
for later use by you!
Grains
Starch
Energy storage in plants!
Carbs stored
in muscles
Glycogen
Energy storage in you!
•
Ever wonder why
plants have stiff and
rigid stems and
leaves? Every plant
cell is surrounded by
a rigid cell wall made
of cellulose.
Cellulose is a tough
polysaccharide that
most organisms
cannot digest. The
chemical bonds in
cellulose make it
hard to digest.
Cellulose
Structure in plant cell walls!
1.
What is the C:H:O ratio found in all
carbohydrates?
2.
True or false: Glycogen is used to store energy in
plants.
3.
True or false: Starch is a source of dietary fiber
4.
True or false: Glucose is a disaccharide
5.
True or false: Polysaccharides are composed of
two monosaccharides bound together

Nonpolar, organic molecules

Composed of hydrogen (H), carbon
(C), and oxygen (O)

Lipids consist of two types of
molecules - glycerol & fatty acids

Glycerol
- an alcohol
- Serves as
backbone of the
molecule

3 Fatty acids
Long hydrocarbon chains

All lipids are insoluble in water
Lipids are a more efficient energy storage system than
carbohydrates – become FAT STORAGE
Energy stored in bonds of lipids – fats store 2.5 times as
much energy per unit as carbs

Major component of cell membrane
Cell membrane = Phospholipid bilayer

Phospholipids have a hydrophyllic
end and a hydrophobic end
“Hydrophobic” – water fearing
“Hydrophillic” – water loving
These ends give the membrane many of its
properties!!!
1.
2.
3.
4.
Would it be more efficient to store energy
as glycogen or as fat? Why???
Why are lipids considered an organic
molecule?
What does it mean to be hydrophobic?
What is the name of the lipid that makes up
the cell membrane?


Saturated fats have long chains with no
double-bonds
Unsaturated fats have double bonds
between hydrogen and carbon
Triglycerides:

composed of 3
molecules of
fatty acids and
1 molecule of
glycerol


Oils - lipids that are
liquid at room
temperature
Fats - lipids that are
solid at room
temperature

Waxes – lipid that gives many
substances a waterproofing cover
Examples:
surface of plant leaves, ear wax

Steroids – lipids that cause changes
within an organism
Examples:
nerve tissue,plant poisons, hormones, and venoms