The Lego bricks of life – BBS1001
Table of contents
...................................................................................................................................................................... 1
Case 1 Sugar and Fats ..................................................................................................................... 2
case 2 the most beautiful experiment in biology ............................................................................................ 6
case 3 lost in translation .............................................................................................................................. 10
Case 5 the inside of the cell.......................................................................................................................... 16
Proteins (lecture part)........................................................................................................................................18
Case 6 Where do the proteins end up?......................................................................................................... 20
Case 7: a little tale from long, long ago......................................................................................................... 25
Case 8: Ossobucco........................................................................................................................................ 28
Virtual microscopy; cells and tissues..................................................................................................................31
Case 9- What language do cells speak?......................................................................................................... 34
Case 10: the truth between cats and dogs.................................................................................................... 38
Case 11: Comparing species, nucleotide sequences and amino acid sequences.............................................41
Case 12: Listen to what Mendel had to say!.................................................................................................. 44
Case 13: A fictitious scientific debate............................................................................................................ 47
1
, Case 1 Sugar and Fats
What are fats and what is their function?
Fatty acids have numerous of functions:
insulation of vital organs (fatty
tissue layer)
energy storage and metabolism >
the burning of fats releases
9kcal/g! In comparison to for
example carbohydrates, only
4kcal/g
components in cell membranes
(lipids) > lipids have a hydrophobic
and hydrophilic site and therefore
are acquainted with keeping
aqueous substances out of the internal system, to regulate osmotic values.
> the polar regions are a lot smaller than the nonpolar regions
gene regulator > primary messengers (steroids) and secondary messengers, for
instance prostaglandins and thromboxane’s mediate the hormonal response
CH3 – (CH2)n CH2 – CH2 – COOH > common form of an mono-fatty acid
> fatty acids have one methyl group and one carboxyl group, in between there are carbon
atoms (mostly differing from 11 to 22 atoms)
> In daily consumption most fats occur in a triglyceride form, existing from a glycerol ‘base’
connected with an ester linkage to three (or less) fatty acids. These are large molecules that
are difficult to break down
What kinds of fats exist?
> There are many, many types of fats.
This all has to do with molecule structure
and order of different atoms. But in
general there are 2 types of fatty acids,
namely:
1. Saturated fatty acids: lack double
bonds between carbon atoms,
maximum amount of hydrogen
atoms. Solid form in room
temperature (animal fats)
2. Unsaturated fatty acids: minimum
of one double bond between
carbon atoms not maximum
amount of hydrogen atoms as a
result of double bonds.
Besides this cis and trans isomers occur, meaning that fatty acids have a different
‘3d’ structure, what therefore has a great impact on the effectiveness of enzymes and
on the processing of these fats. Trans fatty acids are in general less flexible and
therefore more difficult to break down by the body.
2
, What fats are healthy and which ones are not?
The most important fatty acid to remember is TFA- Trans Fatty Acid,
TFA’s are industrially synthesized by a different form of ‘harding’, instead this is only a partial
harding, in comparison to the ‘fully’ harding process in which no trans fatty acids are formed.
TFA’s are as said before the result of an incomplete hardening. This is to enhance the shelf
life and structure of the products it is going to be used in, e.g. margarine and pastry
> TFA’s mostly occur in dairy products and meat (excluding skim meat and semi-skimmed
milk, these are recommended for your daily intake), however the European Law made up a
new rule implying 100 grams of fat shouldn’t contain more than 2 grams of TFA, why?
! Companies aren’t restricted to put TFA’s on nutrition labels, therefore you should look out
for the word; partially hydrogenated (this simply means TFA is present)
LDL Cholesterol and HDL Cholesterol correlation to TFA
Trans fatty acids are proven to enlarge LDL (low density lipoprotein) cholesterol levels,
cholesterol is a fatty substance that doesn’t dissolve well in water. When LDL Cholesterol
levels rise, the liver will start to release cholesterol to the body. This LDL cholesterol will then
start to build up in the arteries (especially those with a slippery surface). Eventually such a
thick ‘plague’ will have formed resulting in
a blockage. This can have severe
consequences for the heart. Because of the
blockage red blood cells (and other blood
cells) won’t be able to pass anymore,
resulting in those cells dying and not
reaching their destination (the heart for
example). This results in for instance a
heart stroke, for the heart not receiving
enough oxygen. Besides this TFA’s also
tend to diminish HDL (high density
lipoprotein) Cholesterol Levels. HDL
Cholesterol ‘cleans’ up the residual LDL
cholesterol, so the higher this level the
healthier a person will be. If the
concentration of HDL cholesterol drops,
LDL cholesterol won’t be broken down as
fast and will get the chance to form
plague in the arteries. (TFA’s = heart and coronary disease).
Hydrogenation
Carbon-carbon double bonds could change into a single bond when adding a catalyst and
hydrogen, this is done to convert liquid oils into solid ones. Removing double bonds has its
pro’s, since double bonds are sensitive to oxidation by the air and going rancid. Some of the
molecules will oxidize into aldehydes. Therefore, it is important to keep oils in a dark bottle
(UV catalyzes oxidation) and at a low temperature.
3
,What are sugars and what is their function?
Sugars, also known as carbohydrates, are the most present compounds in the plant world. It
has several crucial functions:
energy storage, in the form of glucose
stabilization, such as cellulose
important components connective tissue and even in
nucleic acids
> carbohydrate is derived from ‘a hydrate of a carbon’ with
formula; Cn(H2O)Mn
3 types of carbohydrates
monosaccharides, oligosaccharides (6
to 10 saccharides) and polysaccharides
(depends on number of simple
saccharides it contains)
if there is an aldehyde = aldose
if there is a keton= ketose
> during formation the OH of the
carbonyl will be either trapped above or
below→
When it’s up, it will be a beta-glucose,
and when it is down it will be alpha glucose
sucrose
Sucrose is the most abundant carbohydrate in the biological world, it is formed in a
condensation reaction between fructose and
glucose. When consuming sucrose, energy
won’t be available immediately, due to the
bond (keton) between fructose and glucose,
this must be hydrolyzed first. Afterwards the
liver will turn the fructose into glucose, and a
peak in blood sugar levels will be noticeable
(small)
lactose
Lactose is a disaccharide in dairy products, also human and animal milk. In digestion an
enzyme called lactase breaks down lactose in galactose and glucose.
4
,What happens to sugar inside the body?
As we know, some sugars can be very complex polysaccharides. So they need to undergo a
long complex process of breakdown. It all starts in
the mouth, our saliva contains an enzyme called
amylase, this breaks down cornstarch into smaller
pieces. In the stomach the amylase will denature
because of the low PH. In the small intestine, the
pancreas will add more pancreatic alpha-amylase
so that the polysaccharides will get broken down to
disaccharides. Disaccharides however are still too
large to pass our cell membranes, so in the
membrane of the small intestine are millions of
microvilli. They have been folded, to enlarge the
area of nutrient intake. On the surface of the
epithelial cells enzymes that can break down
disaccharides are present. So that monosaccharides will be created. Monosaccharides are
small enough to pass the villi. After this the monosaccharides will be transported via the
portal vein to the liver.
! Consuming monosaccharides will result in a fast sugar level rise, due to its fast intake!
Sugar levels regulation
Fructose will be directly made into glucose in the liver, as a fuel for the body. Glucose
however can be transformed into glycogen (depending on current sugar levels). If sugar is
needed glucagon will be produced and glycogen
will be broken down into glucose, for a fast sugar
level rise. When sugar levels are too high the liver
will release insulin, insulin will then turn glucose
into glycogen. When this mechanism doesn’t
function well you could have diabetes. The islets of
Langerhans are the most important part in the liver
in sugar level regulation. Alpha cells produce
glucagon and beta cells produce insulin.
nomenclature fats and carbohydrates
Fats
omega nomenclature
1. count amount of carbon atoms
2. count double bonds
3. count number when first double bond
occurs starting from CH3-group
Linoleic acid then has omega
nomenclature: 18:2(n-6)
5
, Carbohydrates
! the ending -ose means its a carbohydrate always add this!
1. Look if there is a
functional group
(aldehyde or keton),
pronoun -aldo or -keto
2. Count how many C-
atoms are present ->
mono, di ,tri, tetra,
penta, .. -ose
D and L configuration
dextrorotation and levorotation (right and
left), D and L configuration refers to the
lowest chiral carbon in the Fischer
projection. OH to the right is D-
configuration and OH to the left is L-
configuration
types of sugars
- Maltose =
glucose+glucose
- Lactose= galactose + glucose
- Sucrose= fructose+ glucose
case 2 the most beautiful experiment in biology
What is DNA and how does it replicate?
DNA is the most important ‘building brick’ in life, it provides a blueprint for every single
protein and cell that needs to be synthesized or
repaired. Most of our DNA is located inside the
cell nucleus, but some also is inside our
mitochondria, mtDNA. mtDNA is a circular DNA
that only inherits from the maternal site. DNA has
4 nucleotide bases: Guanine, Thymine, Adenine
and Cytosine. A complements T and G
complements C. Whereas G and C are most
strongly connected to each other because there is
one more hydrogen bound.
6