TOPIC 2.3 –
CARBOHYDRATES & LIPIDS
2.3 – A - Carbohydrates
IB BIO – 2.3
Understandings
Monosaccharides are single sugar molecules. Whey two link
together through condensation, they form disaccharide. These can
further link to form polysaccharides. Examples of each include:
U1: Monosacch.
monomers are
linked together
by condensation
reactions to form
disaccharides
and
polysaccharide
polymers.
Key Terms
Monnosaccharide
Monosaccharide
Disaccharide
Polysaccharide
Disaccharide
Glucose
Galactose
Fructose
Maltose
Lactose
Sucrose
Starch
Glycogen
Cellulose
Polysaccharide
asdf
3
IB BIO – 2.3
Sucrose
Guidance
Formed from glucose and fructose
4
G3: Sucrose,
lactose and
maltose should
be included as
examples of
disaccharides.
Maltose
Formed from two glucose monomers
Key Terms
Sucrose
Maltose
https://classconnection.s3.amazonaws.com/652/flashcards/729652/jpg/05_05disaccharidesynth-l1316447585157.jpg
IB BIO – 2.3
Lactose
Guidance
Formed from glucose and fructose
5
G3: Sucrose,
lactose and
maltose should
be included as
examples of
disaccharides.
Key Terms
Lactose
https://pavansmicroscope.files.wordpress.com/2013/08/lactose_etc.png
IB BIO – 2.3
Applications
Mono- and disaccharides can join in many ways, which results in a
wide variety of polysaccharides (aka carbohydrates).
6
A1: Structure
and function of
cellulose and
starch in plants
and glycogen in
humans.
Key Terms
Polysaccharides
Carbohydrates
http://cnx.org/resources/ff24547bd43194a91783d82f3b805b5c/219_Three_Important_Polysaccharides-01.jpg
IB BIO – 2.3
Applications
7
Cellulose is a polysaccharide made up of straight chains of betaglucose units. Hydrogen bonds form between the their –OH groups.
A1: Structure
and function of
cellulose and
starch in plants
and glycogen in
humans.
Key Terms
Cellulose
http://bio1151.nicerweb.com/Locked/media/ch05/05_08CelluloseArrange.jpg
IB BIO – 2.3
Applications
A1: Structure
and function of
cellulose and
starch in plants
and glycogen in
humans.
Cellulose chains group together and form microfibril bundles. These 8
have high tensile strength and make up the basis of cell walls.
This gives cell walls the
strength to withstand high
internal pressure.
Key Terms
Cellulose
http://bio1151.nicerweb.com/Locked/media/ch05/05_08CelluloseArrange.jpg
IB BIO – 2.3
Applications
9
Starch polysaccharides form when α–glucose molecules link
together. Glucose units are oriented in the same way and curve into
a helical structures.
A1: Structure
and function of
cellulose and
starch in plants
and glycogen in
humans.
Key Terms
Starch
https://s-media-cache-ak0.pinimg.com/736x/94/0f/dd/940fddb9760db10b42f50ae0590826b0.jpg
IB BIO – 2.3
Guidance
G1: The
structure of
starch should
include amylose
and
amylopectin.
Amylose and amylopectin are two types of starch synthesized by
plants. Their function is to store energy.
10
Amylopectin has branched
structures which helps in store
large amounts of energy
Amylose consists of a long
helical chain
Key Terms
Amylose
Amylopectin
http://tundra.cnx.rice.edu:8888/resources/ab0d06aaee4b01e29fa3f115bc25d92ddeb8f15e/Figure_03_02_06.jpg
IB BIO – 2.3
Applications
Glycogen is a polysaccharide produced in animals. It is similar
to a branched form of starch, which makes it more compact.
11
A1: Structure
and function of
cellulose and
starch in plants
and glycogen in
humans.
Key Terms
Glycogen
http://www.periodni.com/gallery/glycogen.png
IB BIO – 2.3
Applications
Just like starch in plants, glycogen stores glucose in cells with a high12
concentration. Its many branches gives easy access to glucose.
A1: Structure
and function of
cellulose and
starch in plants
and glycogen in
humans.
Key Terms
Glycogen
http://cnx.org/resources/ff24547bd43194a91783d82f3b805b5c/219_Three_Important_Polysaccharides-01.jpg
IB BIO – 2.3
Skills
S1: Use of
molecular
visualization
software to
compare
cellulose, starch
and glycogen.
Key Terms
Molecular Visualization
13
Computer imaging software can be used to compare the structure of
polysaccharides. Go to the links below:
•
Cellulose - http://www.biotopics.co.uk/jsmol/cellulose.html
•
Amylose – http://www.biotopics.co.uk/jsmol/amylose.html
•
Amylopectin - http://www.biotopics.co.uk/jsmol/amylopectin.html
•
Glycogen - http://www.biotopics.co.uk/jsmol/glycogen.html
2.3 – B - Lipids
IB BIO – 2.3
Understandings
U2: Fatty acids
can be
saturated,
monounsaturated or
polyunsaturated.
Key Terms
Fatty acids are the building blocks of lipids, there are two different 15
kinds: saturated and unsaturated.
•
Saturated fatty acids -
•
Unsaturated -
Fatty Acid
asdf
IB BIO – 2.3
Understandings
U2: Fatty acids
can be
saturated,
monounsaturated or
polyunsaturated.
Saturated fatty acids have the 16
maximum number of C-H
bonds. So they only have
single-covalent bonds and are
relatively linear.
Unsaturated fatty acids have
double covalent bonds which
affects their shape.
•
Monounsaturated – only one
double bond
•
Polyunsaturated – multiple
double bonds
Key Terms
Saturated
Unsaturated
Mono-/PolyUnsaturated
http://www.periodni.com/gallery/fatty_acids.png
IB BIO – 2.3
Understandings
The double bonds in unsaturated fats affects their overall shape.
•
Cis fatty acids have H’s on the same side of the double bond.
This bends the shape of the molecule.
•
Trans fatty acids have H’s on opposite sides of the double bond.
This results in an overall linear shape.
U3: Unsaturated
fatty acids can
be cis or trans
isomers.
Key Terms
17
Cis
Trans
http://www.nutrientsreview.com/wp-content/uploads/2014/12/Trans-cis-fatty-acid.jpg
IB BIO – 2.3
Understandings
18
Triglyceride molecules are the main component of fats and oils.
They are formed through condensation of 3 fatty acids and glycerol.
U4:
Triglycerides are
formed by
condensation
from three fatty
acids and one
glycerol.
Key Terms
Triglyceride
http://cnx.org/resources/4c57b4a7e7d8b5c8aeb90c67f774c20fed2bca54/220_Triglycerides-01.jpg
IB BIO – 2.3
Understandings
19
Triglyceride molecules are the main component of fats and oils.
They are formed through condensation of 3 fatty acids and glycerol.
U4:
Triglycerides are
formed by
condensation
from three fatty
acids and one
glycerol.
Key Terms
Triglyceride
http://cnx.org/resources/4c57b4a7e7d8b5c8aeb90c67f774c20fed2bca54/220_Triglycerides-01.jpg
IB BIO – 2.3
Applications
The lipids formed by fatty acids are more suitable or long-term
energy storage than carbohydrates. They are able to store any
more times energy in the same weight.
20
A3: Lipids are
more suitable
for long-term
energy storage
in humans than
carbohydrates.
Key Terms
They can also aid in heat insulation, which gives them a secondary
function useful for an organism.
http://www.medbio.info/Horn/Time%206/muscle26.gif
REVIEW
IB BIO – 2.3
1. Compare the properties of saturated and
unsaturated fatty acids.
2. Compare the structure of cis- and transunsaturated fatty acids.
3. Outline the formation of triglyceride.
4. Outline why lipids are more suitable for long-term
energy storage.
21
2.3 – C - Health
There have been many claims about the healfth effects of various 23
types of fat, especially in regards to Coronary Heart Disease (CHD).
INTRO
IB BIO – 2.3
http://4.bp.blogspot.com/-rivssLGQP5c/UaZHUPXYl_I/AAAAAAAABac/82k7sDAVBow/s1600/chd+awareness01.png
IB BIO – 2.3
Applications
A2: Scientific
evidence for
health risks of
trans fats and
saturated fatty
acids.
Coronary heart disease is a condition in which plaque builds up in
the coronary artery. This narrows the space avaible to carry
oxygenated blood to the heart’s tissues, which can result in heart
attack.
24
Key Terms
Coronary Heart
Disease
http://www.nhlbi.nih.gov/health/health-topics/topics/cad
IB BIO – 2.3
Applications
A2: Scientific
evidence for
health risks of
trans fats and
saturated fatty
acids.
Key Terms
Saturated fatty acids are found in foods such as dairy and meat. A 25
strong positive correlation has been shown between intake and CHD.
The correlation is
strong, but a causality
has not been proven.
Some populations
have diets rich in
saturated fatty acids
(Masai tribe), but
almost no CHD is
observed
http://3.bp.blogspot.com/-QNqfLwWXGas/T0_aFtG4qKI/AAAAAAAAABs/QNXGr23iHgY/s1600/cholesterol-heart-disease.jpg
IB BIO – 2.3
Applications
Trans fat consumption also shows a positive correlation with CHD. 26
Other risk factors for CHD proved negative, so it is likely that this
relationship is causal. Deceased patients have high trans-fat levels.
A2: Scientific
evidence for
health risks of
trans fats and
saturated fatty
acids.
Key Terms
http://sphweb.bumc.bu.edu/otlt/MPH-Modules/PH/PH709_Heart/DietaryFat-CHD.png
IB BIO – 2.3
Applications
A4: Evaluation of
evidence and the
methods used to
obtain the
evidence for
health claims
made about lipids.
Evaluating Claims
It is important to be able to analyze claims and the experimental
methods used to gather the associated data. Questions to ask:
Analysing results:
•
Is there correlation between
lipid initake and the rate of
disease?
Analysing method:
•
How large was survey size?
•
How even was the
sampling?
•
Are the differences between
CHD rates and lipid intakes
significant?
•
If the sampling was uneven,
were the results adjusted to
eliminate other factors?
•
Do statistical tests show
significant differences?
•
•
How variable is data?
Were the measurements of
lipid intake/CHD rates
reliable?
Key Terms
27
IB BIO – 2.3
Skills
S2: Determination
of body mass
index by
calculation or use
of a nomogram.
Key Terms
A nomogram is a type of chart28
that can be used to find BMI.
To use it:
•
Mark weight on the left
•
Mark height on the right
•
Connect the two values
The individuals body mass is
the indicated by the point that
the line crosses.
Nomogram
http://web.alfredstate.edu/ammanmj/nutrition/Nutr%20Package%20Update%2007/BMI%20nomogram.jpg
IB BIO – 2.3
Skills
S2: Determination
of body mass
index by
calculation or use
of a nomogram.
Practice
29
Using the nomogram, what is
the BMI of patient who weighs
130 kg and is 65 inches tall?
Answer: ~42
Key Terms
Nomogram
http://web.alfredstate.edu/ammanmj/nutrition/Nutr%20Package%20Update%2007/BMI%20nomogram.jpg