Lecture 4: Carbohydrates Flashcards
What are the most abundant class of biomolecules on earth?
carbohydrates
What is “the mass” that we find in nature?
biomass
By which process is most of biomass produced?
photosythesis
cellulose in plants
What are the five functions of carbohydrates in cells?
Give 6 examples of the most common carbohydrates.
For each describe its function and the organisms that use this carbohydrate.
Sucrose: source of energy (animals and plants); transport of sugars through pholem (plants)
Starch: long term energy storage (plants)
Glycogen: short term energy storage (animals)
Cellulose: Structural component of cell wall (plants, algea and some bacterias)
Chitin: component of exoskeleton (insects and crustaceans); cell wall (fungi, protists)
Peptidoglycan: cell wall of bacteria
What four forms of structure can carbohydrates be in?
Which elements do sugars contain?
carbon, hydrogen, oxygen
What is the general structure of monosaccharides?
repeating units of CH2O (but just one is too small to be a sugar)
How many CH2O units does the smallest sugars have?
3
ex: 3x( CH2O ) = C3H6O3
What are formulas of ribose and deoxyribose?
In what four ways can carbohydrates vary?
How many type of “carbonyl location” is there and how are they called?
2
How are carbohydrates called depending on the number of carbon there is in their formula?
greek prefix + -ose
Which type of isomers are these?
stereoisomers
Stereoisomers have different ________ of the atoms and ________.
spatial arrangement; different biological properties
How many isomers does glucose have and how do you calculate it?
2^n
n= # of chiral carbon (4 diff bonds)
glucose has 2 chiral carbons: 4 isomers
In what conditions do large monosaccharides form ring structures?
in aqueous solutions
What is the other structure than ring structure?
linear
What are the functions of monosccharides?
Why does this molecule have high chemical energy?
The electrons from non-polar bonds , brought to lower energy levels are the ones to carry reactions
What is a dissacharide?
Comprised of two monosaccharide monomers (same or different).
How is the covalent bond between two monosaccharides called?
glycosidic linkage
How can the type of bond vary in disaccharides?
based on carbons involved and spatial arrangement of the bond
What kind of reaction are these?
Dehydration Synthesis
(one loses an OH and the other an H and produces water)
Synthesis of a new sugar
What is the difference between sucrose, lactose and maltose?
What are general functions of disaccharides?
How is sucrose produced and stored?
Stored as starch
Sucrose is produced in the photosynthetic tissues of plants and transported into non- photosynthetic tissues.
How is lactose produced and its function?
What is lactose intolerance?
- Individuals do not make sufficient amounts of the hydrolytic enzyme lactase.
- Lactose passes through the small intestine and is undigested.
- Lactose gets digested by microorganisms in the large intestine and leads to bloating and cramps.
What are polysaccharides?
polymers of monosaccharide monomers.
What are structural types of polysaccharides?
Are monomers in a polysaccharides necessarily the same?
no, they can be the same or different
Are all bonds in polysaccharides the same type?
no, they can vary
What are the two functional classes of polysaccharides? Give an example of each
Storage carbohydrates: Store energy (starch)
Structural carbohydrates: provide support and protection (cellulose)
Why are starch and glycogen efficient energy storage molecules?
A. They are compact: a- linkages produce helical chains and the chains can branch.
B. They are easily hydrolyzed: a-linkages can be easily broken by hydrolysis when the appropriate enzymes are present. Enzymes are abundant in life.
What is similar and different about starch and glycogen’s structures?
same: both alpha glucose with alpha-1,4-glycosidic linkage
branching linkage also the same: alpha-1,6-glycosidic linkages
different: branching structure
What are structural characteristics of glucose polymers with alpha-1,4-glycosidic linkages?
they are highly helical and can branch
Why are cellulose, chitin and peptidoglycan efficient structural molecules?
A. They are linear and can interact to form higher-order structures.
B. They are resistant to hydrolysis: b-linkages are not easily broken down by hydrolysis since the higher order structures produced exclude water. Few organisms possess the necessary enzymes.
What are structural-function relations for beta-linkages?
function= structure of plants (need to be solid)
Structure= long high-order structures harder to break by hydrolysis
What are structural features of products from beta-linkages?
b-linkages produce straight chains and with no branching
What are characteristics of glucose polymers with beta-1,4-glycosidic linkages?
they are linear and can interact with each other to form bigger structures
Where do dietary fibers come from?
Cellulose and other indigestible fibrous material from plants provide us with dietary fiber.
Is fiber soluble?
Some fiber is soluble while other forms are insoluble.
What are the benefices of a high-fiber diet?
A. Keep your digestive system working well.
B. Maintain a healthy weight.
C. Prevent disease such as diabetes mellitus, heart disease, and cancer.
What is glycosylation?
adding sugar to proteins
What are oligosaccharides?
small chains of monosaccharides
What is it called when proteins or lipids are joined with oligosaccharides by covalent bonds?
glycoproteins and glycolipids
Where does glycosylation happen?
In the endomembrane system
What are the functions of the endomembrane system
transportation (proteins to outside)
building of membrane (proteins into membrane)
What type of proteins are most membrane proteins and secreted proteins?
glycoproteins
Compare membrane glycoproteins and secreted glycoproteins.
What determines blood groups?
specific glycoproteins expressed at the surface of red blood cells.
What is hypoglycemia?
it is the technical term for low blood sugar
What is a result of low blood glucose?
Low blood glucose can starve brain cells and impair brain function. Can lead to unconsciousness, seizures, and permanent brain damage.
What is hyperglycemia?
technical term for high blood sugar
What is a result of high blood glucose?
High blood glucose levels can damage your blood vessels, nerves,
heart, eyes, and kidneys. Can lead to dehydration.
What are the components of blood glucose homeostasis?
What is diabetes mellitus?
- Condition caused by abnormal homeostatic mechanism.
- Unable to bring glucose levels down into the normal (set-point) range because of abnormal insulin activity.
What is the difference between the two types of diabetes?
