Chapter 15 Mostly Flashcards
What are glycosaminoglycans?
A type of unbranched polysaccharide consisting of repeating disaccharide units
Each disaccharide unit is composed of one amino sugar and either one uronic acid or one galactose.
What is the composition of each disaccharide unit in glycosaminoglycans?
One amino sugar and either one uronic acid or one galactose
This composition contributes to their structure and function.
What properties do glycosaminoglycans have?
Very polar and negatively charged
These properties allow them to attract water and provide cushioning or lubrication.
Where is keratan sulfate found in the body?
In the cornea of the eye, cartilage, bone, and the horns of animals
Keratan sulfate is a type of glycosaminoglycan.
What causes cloudiness in the cornea?
Unsulfonated keratin deposits
These deposits can affect vision.
What is a Fischer projection?
A two-dimensional representation of a molecule
It places the most oxidized group at the top and shows the arrangement of groups around chiral centers.
What are the most important monosaccharides?
- Glucose
- Galactose
- Fructose
These monosaccharides are crucial in various metabolic processes.
What is the normal blood glucose level?
A specific range that varies but is typically around 70-100 mg/dL
This level is important for metabolic health.
What occurs during hyperglycemia?
The pancreas is unable to produce sufficient quantities of insulin
This leads to elevated glucose levels in the body.
What are the symptoms of diabetes?
- Thirst
- Excessive urination
- Increased appetite
- Weight loss
These symptoms can indicate uncontrolled blood sugar levels.
What is d-fructose?
A ketohexose with the formula C6H12O6
It is the sweetest of carbohydrates, twice as sweet as sucrose.
What is the difference between aldoses and ketoses?
Aldoses contain an aldehyde group, while ketoses contain a ketone group
This classification is based on the functional groups present.
What is lactose?
A disaccharide composed of d-galactose and d-glucose
It is found in milk and milk products.
What type of bond is found in lactose?
Glycosidic bond
The bond forms between carbon 1 of d-galactose and carbon 4 of d-glucose.
What is the molecular formula for d-glucose?
C6H12O6
It is the most common hexose and a primary energy source.
What defines chiral carbon atoms?
Carbon atoms with four different atoms or groups
These atoms create stereoisomers that cannot be superimposed.
What distinguishes d and l isomers in Fischer projections?
The position of the hydroxyl group on the chiral carbon farthest from the carbonyl group
Left gives L and right gives D.
What is a common sweetener derived from sucrose?
High-fructose corn syrup (HFCS)
It is produced by enzymatically breaking down sucrose into glucose and fructose.
What are the three types of carbohydrates?
- Monosaccharides
- Disaccharides
- Polysaccharides
These classifications are based on the number of sugar units.
What is the structure of Haworth structures?
Five- or six-atom rings
They are the most stable forms of pentose and hexose sugars.
What is the significance of chirality in biological systems?
Molecules can have different biological effects based on their stereoisomers
For example, carvone has different smells depending on its chirality.
What is the formula for d-galactose?
C6H12O6
It is an aldohexose obtained from lactose.
Fill in the blank: A molecule is ______ if it has nonsuperimposable mirror images.
chiral
This property is crucial in determining the behavior of molecules in biological systems.
What type of bond is formed in lactose?
Glycosidic bond
The bond is formed between carbon 1 of D-galactose and carbon 4 of D-glucose.
What is lactose and where is it commonly found?
A disaccharide found in milk and milk products, making up 6–8% of human milk and about 4–5% of cow’s milk.
What is maltose also known as?
Malt sugar
What are the monosaccharide units that compose maltose?
Two D-glucose molecules
How is maltose obtained?
From the hydrolysis of starch.
What is melibiose and how sweet is it compared to sucrose?
A disaccharide that is 30 times sweeter than sucrose.
What type of glycosidic bond links the monosaccharides in melibiose?
Not specified in the content
What is cellulose primarily composed of?
Glucose units connected by glycosidic bonds.
What structural role does cellulose serve in plants?
Provides a rigid structure to the cell walls in wood and fiber.
Why can’t humans digest cellulose?
Humans cannot break down the glycosidic bonds in cellulose.
What is glycogen and where is it stored in the body?
A polymer of glucose stored in the liver and muscle.
How often do branches occur in glycogen?
Every 10–15 glucose units.
What are the two components of starch?
- Amylose
- Amylopectin
What percentage of starch does amylopectin constitute?
Up to 80%
What is the main feature of amylose?
Consists of 250 to 4000 glucose molecules connected in a continuous chain.
What are polysaccharides formed from?
Many monosaccharides joined together.
List the most common disaccharides.
- Maltose
- Lactose
- Sucrose
What is a disaccharide?
Consists of two monosaccharides linked together.
What is the process of forming a disaccharide called?
Dehydration reaction.
What is fructose classified as?
A ketohexose.
What happens to fructose in a basic Benedict’s solution?
Rearranges to form glucose and can then be oxidized.
What are sugar alcohols and give examples.
- D-sorbitol
- D-xylitol
- D-mannitol
What is a reducing sugar?
A carbohydrate that reduces another substance.
What characterizes the oxidation of monosaccharides?
Oxidation converts an aldehyde group to a carboxylic acid.
What are the elements that make up carbohydrates?
- Carbon
- Hydrogen
- Oxygen
What is the significance of the endocrine system in diabetes management?
Involvement with obesity and other diseases.
Polysaccharides: Many are polymers of…
Glucose!
Polysaccharides: many are polymers of glucose. Found in animals as glycogen, found in plants as:
Amylose, amylopectin, and cellulose.
Carbohydrates are classified as Disaccharides: they include…
Maltose, Lactose, and Sucrose.
TRUE OR FALSE: Maltose and Lactose are not carbohydrates.
FALSE: Both Maltose and Lactose are carbohydrates.
There are 5 reducing sugars:
Glucose, Galactose, Fructose, Maltose, and Lactose.
Oils from olive and peanut are monounsaturated because they contain large amounts of:
Oleic Acid
Palm and Coconut are solids at room temperature because they consist of mostly:
SATURATED Fatty acids
The trans isomer of oleic acid is called ___ and has a straight chain without a kink.
ELAIDIC ACID
You can NOT hydrolize ____.
STEROIDS! Steroids can NOT be hydrolized.
Lipids are biomolecules that contain: (2 items)
Fatty Acids
Steroid Nucleus
Cellulose’s Glycosidic Bond is:
Beta: 1->4 Glycosidic Bonds
Amylose’s Gylocsidic Bond is:
Alpha 1->4 Glycosidic Bond
Amylopectin’s glycosidic bonds are:
Alpha 1->4 and Alpha 1->6 Glycosidic bonds
When two monosaccharides combine in a ___- reaction, the product is a disaccharide.
Dehydration.
The most common disaccharides are: (3 items)
Maltose, lactose, and sucrose.
Glycosamingoglycans are polar and negatively charged. What is their role in the human body?
Glycosaminoglycans can attract water. They also cushion and lubricate structures in the body, such as the eyes, cartilage, bones, and animal horns.
What are glycosaminoglycans made out of?
An unbranched polysaccharide of repeating disaccharide units.
The disaccharide units are composed of one amino sugar molecule and either: a) one urinoc acid or b) galactose molecule.
TRUE OR FALSE: Cellulose is soluble with water.
FALSE.
Which of the following statements are true?
Cellulose….
A) gives a rigid structure to cell walls.
B) is found in sediment.
C) Cannot be digested in humans.
D) A and C.
D) A and C.
Humans CANNOT digest or break down which bonds?
A) Alpha 1->6 Glycosidic
B) Beta 1->3 Glycosidic
C) Beta 1->4 Glycosidic
D) A and C
C) Beta 1->4 Glycosidic
