Organic chemistry screencast segment 3 - Carbohydrates.mp4
Summary
TLDRIn this engaging screencast, Mr. Workman delves into the world of organic chemistry, focusing on carbohydrates. He explains their chemical composition, highlighting the 1:2:1 ratio of carbon, hydrogen, and oxygen atoms. Monosaccharides, disaccharides, and polysaccharides are discussed, with examples like glucose, fructose, and sucrose. The video also touches on the hydrophilic nature of sugars due to their polar bonds and their role in energy transfer and storage. Mr. Workman emphasizes the difference between structural and energy storage polysaccharides, like cellulose and starch, and their importance in nutrition and biology.
Takeaways
- đ Carbohydrates are composed of carbon, hydrogen, and oxygen, with a ratio of 1:2:1 respectively.
- đ The term 'carbohydrate' should not be confused with 'hydrocarbons'; the former contains oxygen, while the latter does not.
- đŹ Monosaccharides, or simple sugars, are the basic building blocks of carbohydrates.
- đ Disaccharides are formed by the linkage of two monosaccharides through a dehydration synthesis reaction.
- đ Polysaccharides are complex carbohydrates formed by the repeated linkage of many monosaccharides.
- đ§Ș The general empirical formula for monosaccharides is CH2O, indicating twice as many hydrogens as carbons.
- đ Glucose and fructose are examples of monosaccharides that are isomers, having the same molecular formula but different structural arrangements.
- đ° Sucrose, commonly known as table sugar, is a disaccharide composed of glucose and fructose linked by a glycosidic linkage.
- đ„ Starch is the energy storage polysaccharide in plants, while glycogen serves the same purpose in animals.
- đŸ Cellulose is the structural polysaccharide in plants, and chitin serves a similar role in arthropods and some fungi.
Q & A
What is the defining ratio of atoms in a carbohydrate?
-Carbohydrates have a defining ratio of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio.
How do carbohydrates differ from hydrocarbons?
-Carbohydrates contain carbon, hydrogen, and oxygen, whereas hydrocarbons contain only carbon and hydrogen.
What is the basic building block of carbohydrates known as?
-The basic building block of carbohydrates is known as monosaccharides.
How are disaccharides formed?
-Disaccharides are formed by linking two monosaccharides together through a dehydration synthesis or condensation synthesis reaction.
What is the general empirical formula for monosaccharides?
-The general empirical formula for monosaccharides is CH2O, indicating twice as many hydrogens as carbons.
What is the difference between aldose and keto sugars?
-Aldose sugars have their carbonyl group (C=O) at the end of the carbon chain, forming an aldehyde, while keto sugars have their carbonyl group somewhere in the middle of the chain.
Why are monosaccharides hydrophilic?
-Monosaccharides are hydrophilic due to their polar covalent bonds, particularly the O-H and C=O bonds, which allow them to interact with water.
What is the role of glycosidic linkage in carbohydrates?
-Glycosidic linkage is the strong covalent bond that links monosaccharides together in disaccharides and polysaccharides.
How does the human body utilize complex carbohydrates?
-The human body utilizes complex carbohydrates for energy storage and to provide sustained energy over a longer period, which can help prevent energy crashes.
What are the structural polysaccharides in plants and animals?
-The structural polysaccharides in plants are cellulose molecules, while in animals, it is chitin found in exoskeletons.
Why can't humans digest cellulose?
-Humans can't digest cellulose because they lack the enzyme necessary to break down the strong glycosidic linkages and cross-bridging found in cellulose.
Outlines
đŹ Introduction to Carbohydrates
This segment introduces the topic of carbohydrates in organic chemistry. Mr. Workman emphasizes the importance of taking detailed notes, including definitions, explanations, and diagrams. Carbohydrates are distinguished from hydrocarbons by their composition of carbon, hydrogen, and oxygen in a 1:2:1 ratio. The building blocks of carbohydrates are monosaccharides, which can be linked together to form disaccharides and polysaccharides through dehydration synthesis. Monosaccharides are commonly referred to as sugars, while polysaccharides are known as complex carbohydrates. The general empirical formula for sugars is Cn(H2O)n, indicating twice as many hydrogens as carbons. The segment also highlights the difference between aldose sugars like glucose and ketose sugars like fructose, despite their similar molecular composition.
đż Properties and Formation of Sugars
This paragraph delves into the characteristics of monosaccharides, highlighting their polar covalent bonds which make them hydrophilic. The discussion includes the various forms of monosaccharides, such as straight chains or ring structures. It explains that monosaccharides like glucose, fructose, galactose, and mannose are all isomers, having the same chemical formula but different structural arrangements. The paragraph also covers the formation of disaccharides like sucrose through glycosidic linkages, which are strong covalent bonds. The difference in the molecular formula of sucrose compared to the sum of its constituent monosaccharides is explained, accounting for the removal of water molecules during the linkage process.
đ Functions of Polysaccharides
The third paragraph focuses on polysaccharides, which are large and complex carbohydrates. It discusses the primary functions of monosaccharides and disaccharides as energy transfer and storage, contrasting the quick energy boost from simple sugars with the potential for a subsequent energy crash. The concept of carbo-loading is introduced, explaining how consuming complex carbohydrates like starch can provide sustained energy. The paragraph also distinguishes between energy storage polysaccharides like starch in plants and glycogen in animals, and structural polysaccharides like cellulose in plants and chitin in animals and arthropods. The importance of these molecules in building cells and tissues is emphasized.
đ„ Digestibility and Nutritional Aspects of Polysaccharides
The final paragraph discusses the digestibility of polysaccharides, noting that humans lack the enzymes to break down cellulose, which is why it provides dietary fiber. It contrasts this with the ability of cows and termites to digest cellulose due to the presence of necessary enzymes. The structural differences between cellulose and chitin are highlighted, with chitin containing nitrogen cross-linkages that make it tougher. The paragraph concludes by mentioning that while some forms of chitin, like that in soft-shell crabs, can be digested by humans, tougher exoskeletons like those of lobsters and shrimp are inedible. The segment ends with an invitation for questions and aéąć of the next screencast segment.
Mindmap
Keywords
đĄCarbohydrates
đĄMonosaccharides
đĄDisaccharides
đĄPolysaccharides
đĄAldose and Ketose
đĄHydrophilic
đĄIsomers
đĄGlycosidic Linkage
đĄStarch
đĄGlycogen
đĄCellulose
Highlights
Introduction to carbohydrates and their components: carbon, hydrogen, and oxygen.
Difference between carbohydrates and hydrocarbons: carbohydrates contain oxygen.
Carbohydrate ratio: 1:2:1 for carbon, hydrogen, and oxygen.
Monosaccharides are the building blocks of carbohydrates.
Dehydration synthesis links monosaccharides to form disaccharides.
Polysaccharides are complex carbohydrates formed by linking multiple monosaccharides.
Glucose is an aldose sugar with a C=O group at the end of the chain.
Fructose is a ketose sugar with the C=O group in the middle of the carbon chain.
Sugars are hydrophilic due to polar bonds and their interaction with water.
Isomers: molecules with the same chemical formula but different arrangements.
Glucose and fructose are isomers and combine to form sucrose.
Sucrose formation involves a glycosidic linkage between glucose and fructose.
Polysaccharides are used for energy storage (starch in plants, glycogen in animals).
Cellulose and chitin are structural polysaccharides in plants and animals, respectively.
Humans cannot digest cellulose, but it acts as dietary fiber in nutrition.
Transcripts
hello biology 400 this is mr. workman
and this will be your organic chemistry
screencast segment three on
carbohydrates as you view this
screencast please make sure that you
have some paper with you so that you can
take good two-column notes and write
down of course any definitions any
explanations even diagram oh and draw
some of the figures that you see that
you think are going to be important to
your understanding of carbohydrates
let's get to it so let's talk about how
you can recognize what a carbohydrate is
first of all if you look at this word
carb oh that is like carbon and if you
look at hydrate here and that looks like
hydrogen don't confuse these
carbohydrates with hydrocarbons
carbohydrates contain carbon oxygen and
hydrogen hydrocarbons on the other hand
contain just carbon and hydrogen they do
not contain any oxygen so pardon me if
you see a molecule that contains the
atoms carbon hydrogen and oxygen in a
one to two to one ratio you're most
likely looking at a carbohydrate so this
1 to 2 to 1 ratio this one to one refers
to carbon hydrogen and oxygen in other
words there are twice as many hydrogen's
as there are carbons there are also
twice as many hydrogen's as there are
oxygens and the number of carbons and
the number of oxygens will be just about
equal the building blocks of
carbohydrates the monomers the single
units that is are referred to as
monosaccharides and if you like two
monosaccharides together by way of
dehydration synthesis or the formation
of water condensation synthesis you get
what we call a dasa disaccharide and if
that process happens over and over again
we get what we call polysaccharides
monosaccharides are simply referred to
as sugars in everyday language sometimes
called simple sugars disaccharides can
be fairly classified as simple sugars as
well whereas polysaccharides are
referred to in the nutritional world as
complex carbohydrates or complex sugars
when you look at the formula of any
sugar the general empirical formula is
going to be C h2o and how often that
repeats depends on how big of a
carbohydrate we're talking about this is
just another way to show that there's
going to be twice as many hydrogen's as
there are carbons so let let's look at
this hydrocarbon hexane this word this
prefix on this word hex means six can
you see here that there are six carbons
lined up in a chain and they're
surrounded by enough hydrogen it's fully
saturated with hydrogen so that each
carbon is making four bonds as required
by its tetra valency in contrast if you
look over here these chains of six
carbons are a little bit more
interesting do you see why there are
some oxygens there's a C double bond o
here this one is another chain of six
carbons here's a C double bond o and I
want to let you know that this diagram
is actually inaccurate this hydrogen
should not be here that hydrogen would
indicate that this carbon is making five
bonds so this hydrogen is actually an
error in this diagram take a look at the
difference between these two molecules
glucose and fructose you can see here
that this is called an aldose sugar and
this is called a keto sugar but if you
count up the total number of carbons and
hydrogen's and oxygens they have the
same number of carbons they have the
same number of hydrogen's in the same
number of oxygens the way that they
differ is in how those carbons and
hydrogen's and ox
Asians are put together the way that
they're arranged and you can see here
that the C double bond o and glucose is
at the end of the chain of carbons so
it's on the last carbon and as a result
that's an aldehyde so we call glucose
and aldose sugar you might start to note
that many sugars are named with the
ending OS e okay so glucose OSE fructose
OSE fructose is a ketose sugar because
it's carbonyl it's C double bond o is
not at the end of the chain of carbons
it's somewhere in the middle of the
chain of carbons monosaccharides some
characteristics of sugar you know the
fact that they have polar bonds in them
polar covalent bonds if you remember
your electronegativity bonding rules
oxygen bonded to hydrogen is a moderate
difference in electronegativity see
carbon bonded to oxygen especially a
double bond that's gonna be a polar bond
because there's a moderate difference in
electronegativity there there's o H
bonds and they're Co bonds all over this
molecule which means because there are
lots of polar bonds in this molecule
it'll interact with water which is also
a polar molecule so because sugars will
interact with water they are literally
water loving they're called hydrophilic
because of their polar bonds that they
contain monosaccharides can be found in
six carbon chains straight chains or
sometimes they can fold back on
themselves as you see here in the form
of rings sorry about that
so look at this do you notice that this
is a roughly a hexagon shape I want you
to make note of that because we're gonna
see some diagrams you've already seen
some diagrams and you're gonna see some
more diagrams where not all these
carbons are necessarily noted glucose
and fructose as mentioned on the earlier
slide as well as galactose and mannose
are all I know saccharides and they all
have six carbons they all have 12
hydrogen's and they all have six oxygens
so let's think about why would there be
four different names for molecules that
all have this same formula with six
carbons 12 hydrogen's and six oxygens
well the answer is that these molecules
are all isomers of one another an isomer
is a molecule or isomers our molecules
that have the same chemical formula all
right so that means that have the same
types of atoms the same number of atoms
but that those atoms are arranged in a
different pattern so same pieces just
built differently so picture me giving
you 24 Legos and me giving somebody else
24 Legos and all those same Legos were
used but built up and connected
differently you know that's a fair way
to think about what an isomer is here's
glucose and here's fructose and I do
want to let you know that fructose is
named for fruit sugars we find fructose
a lot in fruit sugars and fructose can
be commonly linked to glucose to form
what we call common table sugar which is
sucrose right the stuff that you
actually sprinkle out onto your Wheaties
to make them taste better the stuff that
you know donuts and really high sugar
content
he has a ton of is sucrose sucrose of
course is what we would refer to as a
disaccharide
as stated before monosaccharides and
disaccharides are fairly classified as
simple sugars do you recall what the
formula is for a monosaccharide that's
right
it's c6 h-12 o-6 so when you link two
monosaccharides together you'd think
that there would be two times six
carbons which is 12 2 times 12
hydrogen's which is 24 and 2 times 6
oxygens which is 12 so let's think about
why this formulas for sucrose is c12 h22
o11 well you got to take out two
hydrogen's and you got to take out one
oxygen because when these are linked
together water is made so if you add up
the c6 h-12 o-6
and the c6 h-12 o-6 and you take away
two H's and 100 you get c12 h22 o11 this
bond right here between the first carbon
of this glucose and the second carbon of
this fructose is referred to as a
glycosidic linkage alright there's that
term glycosidic linkage it's a really
strong covalent bond that keeps this
monosaccharides linked to this
monosaccharide
taking that same concept further than we
have what we call polysaccharides these
of course are gonna be the large more
complex carbohydrates so if you think of
complex carbohydrates or complex sugars
as I stated nutrition in the nutritional
language those are they're gonna be the
big big big sugar molecules lots and
lots and lots and lots of
monosaccharides maybe thousands of
monosaccharides the primary purpose of
course of the monosaccharides and the
disaccharides are going to be energy
transfer and energy storage you eat
sugar you get lots of energy very
rapidly but you might crash I don't know
if you've ever heard of the sugar crash
so if you eat or drink a high sugar
content a simple sugar content food or
drink you might feel energetic for a few
minutes or maybe an hour so and then all
of a sudden a couple hours later you
feel really tired and maybe even lousy
again so sometimes athletes will
carbo-load maybe you've heard of carbo
loading you eat pasta or bread and what
you're doing when you're carbo loading
you're eating lots of complex
carbohydrates namely you're eating lots
of starch all right so you're getting
lots of sugar complex polysaccharides
sugars from plant materials and your
body has to work a little bit and it
takes a little bit of time to actually
break down this sugar because it's such
a big molecule so in a way if you carbo
load with large complex sugars it
provides you with energy for a
significant period of time and you won't
necessarily experience the crash that
you would if you are eating or drinking
a lot of simple sugars the other primary
function or purpose of large
polysaccharide molecules of course is
structural in nature so these are
materials that are used to build cells
or build tissues that cells will build
up themselves
the energy storage polysaccharides let's
make sure we write this down now the
energy storage polysaccharides the one
for plants is called starch this is a
photo graph using a microscope right so
we call it a photo micrograph is showing
you a mill applies which are starch
grains found within the cell of a plant
this is a photo micrograph or a
microscope a microscope photograph a
micrograph of animal cells and there's
been a stain used here to highlight the
glycogen material in red so starch is
the energy storage polysaccharide in
plants glycogen is the energy storage
polysaccharide in animals lactose is
another disaccharide that you might have
heard of and if you think of the word
lactate that's the process of making
milk and it's sort of an odd thing to
think about that humans are the only
mammals that drink other mammals milks
and you know we drink a lot of cow's
milk because the dairy industry tells us
it's good for us but actually for some
of us it's really not because we don't
have the enzyme that breaks down this
disaccharide not all of us do anyway and
not all of us have the enzyme that
breaks down this disaccharide that's
found in dairy material like milk or
cheese starch of course is a
polysaccharide if you eat potatoes
french fries chips pasta bread those
foods are loaded with starch if you're a
meat-eater if you're a carnivore
sometimes you might be at steak or
hamburger or chicken or pork chops or
something like that depending on what
you like to eat understand that when you
eat meat of course you're getting a
source of protein there but within those
muscle cells glycogen will also likely
be stored
these are polysaccharides
the structural polysaccharides for
plants are cellulose molecules cellulose
is a huge vast many many many many many
monosaccharides linked together in long
chains as well as cross bridges the
structural polysaccharide in animals we
call chitin and chitin is found in the
cuticle or the exoskeleton of insects
arthropods that is which are insects are
either pods or pods and so to our
crustaceans if you look at this diagram
here this is showing you a cellulose
molecule and notice that each individual
little hexagon here represents a
monosaccharide they're linked together
with glycosidic linkages but there's
also cross bridging here and the greater
the amount of cross bridging the tougher
this cellulose material is and this
cross bridging and these glycosidic
linkages are really really really
difficult to break down unless you have
the right enzyme in your digestive tract
to break it up humans don't have that
enzyme and so when we eat salad or other
cellulose material we're getting what
the nutritionists call fiber fiber helps
keep us regular and digestive ly healthy
although if you eat too much of it you
can feel kind of bloated and stopped-up
cows on the other hand can digest
cellulose which is why they chew on
grass and that's a good type of
nutrition for them and termites they can
chew on wood because they have the
enzyme that can break up the strong
cellulose fibres that make the woody
tissue the tough parts of wood tree
trunks and what have you chitin if you
look at this diagram is a little bit
different than cellulose
we've got chains of monosaccharides here
but the other key thing to look for is
that there are these nitrogen's now I
don't know if you can see this so I'm
going to zoom in here and I know it gets
fuzzy but that right there is an N
alright there's another end right there
if you zoom in there see and tighten
again that's the structural
polysaccharides in the exoskeletons of
insects and crustaceans and even in the
cell walls of some fungus like you know
mushrooms that is so for the most part
we also can't eat chitin but some
materials like soft-shell crab chitin
exoskeleton there aren't so many cross
linkages with the proteins and built in
between those nitrogen cross linkages so
the tightness material in the
exoskeleton of softshell crabs is not as
tough so we can chew it up and and
digest that but if you like eating
lobster or shrimp you know you can't eat
the shell that's just too tough for you
to eat so that'll be the end of our
screencast segment 3 here for
carbohydrates you can look forward to
screencast segment for next time
as always if you have any questions or
concern please talk to mr. gales or me
mr. workman if you have any questions
thanks everybody
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