Organic chemQuick Reference Flashcards

A comprehensive set of 200 question-and-answer flashcards covering carbohydrates, lipids, amino acids, and acid–base chemistry concepts from the lecture notes.

What is the general chemical formula for carbohydrates?

CnH2nOn

Which three elements compose carbohydrates?

Carbon, hydrogen, and oxygen

List three primary functions of carbohydrates in the body.

Energy source, structural support, and cell signaling

What class of carbohydrate consists of single sugar units?

Monosaccharides

Give two examples of monosaccharides.

Glucose and fructose

What class of carbohydrate is formed by two monosaccharides linked together?

Disaccharides

Name two examples of disaccharides.

Sucrose and lactose

How many sugar units make up an oligosaccharide?

Three to ten

Where are oligosaccharides commonly found and what is their role?

On glycoproteins where they participate in cell signaling

Starch, glycogen, and cellulose belong to which carbohydrate class?

Polysaccharides

What is the primary function of starch in plants?

Glucose storage

What is the primary function of glycogen in animals?

Glucose storage

What role does cellulose serve in plants?

Structural component of the cell wall

How many carbon atoms are in a triose?

Three

How many carbon atoms are in a pentose?

Five

How many carbon atoms are in a hexose?

Six

If the carbonyl group is at the end of a monosaccharide, what type is it?

An aldose

If the carbonyl group is within the carbon chain of a monosaccharide, what type is it?

A ketose

What term describes molecules with the same formula but different structures?

Isomers

What term describes molecules that are non-superimposable mirror images?

Enantiomers

D-glucose and L-glucose are examples of what stereochemical relationship?

Enantiomers

What are epimers?

Isomers that differ at only one chiral carbon

At which carbon do glucose and galactose differ to be epimers?

Carbon 4

What term describes the formation of ring structures by monosaccharides in water?

Cyclization

The six-membered ring form of glucose is called what?

A pyranose

What type of glycosidic bond joins the glucose units in maltose?

α(1→4)

Which enzyme hydrolyzes maltose?

Maltase

What monosaccharides compose lactose?

Glucose and galactose

What glycosidic linkage is found in lactose?

β(1→4)

Which enzyme breaks down lactose?

Lactase

What two monosaccharides make up sucrose?

Glucose and fructose

What linkage joins glucose and fructose in sucrose?

α(1→2)

Which enzyme hydrolyzes sucrose?

Sucrase

What linkage types are found in glycogen?

α(1→4) linear and α(1→6) branch points

Is glycogen digestible by humans?

Yes

Which linkage type makes cellulose indigestible to humans?

β(1→4)

Which enzyme lacking in humans prevents cellulose digestion?

Cellulase

Where does salivary amylase begin carbohydrate digestion?

In the mouth

What is the function of pancreatic amylase?

Breaks starch into smaller polysaccharides in the small intestine

Which brush-border enzymes convert disaccharides into monosaccharides?

Maltase, sucrase, and lactase

During carbohydrate digestion, where are monosaccharides absorbed?

In the small intestine

Which property makes carbohydrates the body’s primary energy source?

Rapid conversion of glucose to ATP

To which biomolecules are carbohydrates often attached for cell signaling?

Proteins and lipids (forming glycoproteins and glycolipids)

In Fischer projections, if the OH on the penultimate carbon points right, what configuration is it?

D-configuration

What reaction forms a hemiacetal during monosaccharide cyclization?

An intramolecular reaction between the carbonyl carbon and a hydroxyl group

Which storage polysaccharide in plants is composed only of α(1→4) linkages?

Amylose

Which starch component contains both α(1→4) and α(1→6) linkages?

Amylopectin

What property of cellulose contributes to plant rigidity?

Extensive hydrogen bonding between β(1→4) chains

How does branching in glycogen affect glucose mobilization?

Increases surface area for rapid glucose release

What makes lipids insoluble in water?

Their hydrophobic non-polar hydrocarbon chains

List four major biological functions of lipids.

Energy storage, membrane structure, cell signaling, and hormone synthesis

What lipid is composed of a glycerol backbone and three fatty acids?

Triglyceride

Which lipid type forms the basic structure of cell membranes?

Phospholipids

Which class of lipids contains four fused carbon rings?

Steroids

What complexes transport lipids through the bloodstream?

Lipoproteins

What distinguishes a saturated fatty acid from an unsaturated one?

Absence versus presence of double bonds

Give an example of a saturated fatty acid.

Stearic acid

Give an example of a monounsaturated fatty acid.

Oleic acid

Why are unsaturated fatty acids often liquid at room temperature?

Double bond kinks prevent tight packing

Which fatty acids must be obtained from the diet?

Essential fatty acids

Name two essential fatty acids.

Linoleic acid and α-linolenic acid

What process breaks down fatty acids to generate ATP?

β-oxidation

During rest, which tissue preferentially uses fatty acids for energy?

Cardiac muscle

How does the energy yield of triglycerides compare to carbohydrates per gram?

About twice as much ATP per gram

Which parts of a phospholipid are hydrophilic and hydrophobic, respectively?

Phosphate head is hydrophilic; fatty acid tails are hydrophobic

What term describes molecules with both hydrophobic and hydrophilic regions?

Amphipathic

What self-assembling structure do phospholipids form in water?

A lipid bilayer

Which steroid is a key component of animal cell membranes?

Cholesterol

How does cholesterol affect membrane fluidity?

It modulates fluidity by preventing extremes of rigidity or looseness

Which steroid hormone is released in response to stress?

Cortisol

What is the primary function of aldosterone?

Regulation of sodium and potassium balance

Name two primary sex hormones derived from cholesterol.

Estrogen and testosterone

Which steroid is critical for calcium absorption and bone health?

Vitamin D

Which lipoprotein transports dietary triglycerides from the intestine to tissues?

Chylomicrons

Where are chylomicrons produced?

In the small intestine

Which lipoprotein delivers endogenous triglycerides from the liver to tissues?

VLDL

LDL is derived from which lipoprotein?

VLDL

What is the primary role of LDL?

Deliver cholesterol to cells

Why is LDL often called “bad cholesterol”?

It can deposit cholesterol in vessel walls

Which lipoprotein removes excess cholesterol and returns it to the liver?

HDL

Why is HDL nicknamed “good cholesterol”?

It helps clear cholesterol from circulation

What structural feature allows fatty acids to serve as efficient energy stores?

They are highly reduced and stored anhydrously

What differentiates phospholipids from triglycerides?

One fatty acid is replaced by a phosphate group

How many fatty acid chains are in a triglyceride molecule?

Three

What is the glycerol backbone composed of?

A three-carbon alcohol with hydroxyl groups

Why are essential fatty acids precursors to eicosanoids?

They contain specific unsaturated double bonds

Which fatty acid is the parent compound for omega-3 eicosanoids?

α-Linolenic acid

What biomolecule class includes bile acids derived from cholesterol?

Steroids

Which tissue stores large amounts of triglycerides?

Adipose tissue

In phospholipids, which type of molecule is attached to the phosphate to create head groups?

An alcohol such as choline

What determines whether a fatty acid is omega-3 or omega-6?

Position of the first double bond from the methyl end

Trans fats are produced primarily by what industrial process?

Partial hydrogenation

Why are trans fats considered harmful?

They raise LDL and lower HDL, increasing cardiovascular risk

What enzyme catalyzes the first step of β-oxidation?

Acyl-CoA dehydrogenase

What molecule transports fatty acids into mitochondria for β-oxidation?

Carnitine

Which pancreatic enzyme hydrolyzes dietary triglycerides?

Pancreatic lipase

What is the storage form of cholesterol in lipoproteins?

Cholesteryl ester

Name the process that releases fatty acids from adipose tissue under hormonal control.

Lipolysis

Which hormone activates hormone-sensitive lipase to initiate lipolysis?

Epinephrine

What four substituents are attached to the α-carbon of an amino acid?

Amino group, carboxyl group, hydrogen atom, and R-group