Biological Fundamentals and Cell Biology Practice Exam Flashcards

Practice flashcards for biology fundamentals, macromolecules, enzymes, and cell structure based on the lecture notes.

How is electronegativity defined in the transcript?

An atom's ability to attract shared electrons toward itself.

What is the relationship between electronegativity difference and electron sharing?

The greater the electronegativity difference between atoms, the more unequal the electron sharing.

What type of bond is formed when electrons are completely transferred from one atom to another?

Ionic bond.

What specific type of bond forms when electrons are shared between atoms?

Covalent bond.

DAT Application: If sodium loses an electron and chlorine gains it, what bond results?

Ionic bond.

What defines a nonpolar covalent bond?

A covalent bond with equal sharing of electrons.

What characterizes a polar covalent bond?

A covalent bond with unequal sharing of electrons.

DAT Application: Why is water ($H_2O$) considered a polar molecule?

Oxygen is more electronegative than hydrogen, causing unequal electron sharing.

In molecular terms, what is a dipole?

A separation of charge within a molecule.

What is the first mandatory condition for a hydrogen bond to occur?

Hydrogen must be covalently bonded to $F$, $O$, or $N$.

What is the second mandatory condition for hydrogen bonding?

That hydrogen must be attracted to another $F$, $O$, or $N$.

DAT Application: What type of bonds keep DNA strands together?

Hydrogen bonds between complementary nitrogen bases.

DAT Trap: Are hydrogen bonds more powerful than covalent bonds?

No. Covalent bonds are much stronger.

What causes the interactions known as Van der Waals forces?

Temporary uneven electron distributions.

DAT Application: What allows geckos to stick to walls?

Large numbers of Van der Waals interactions.

Why is water regarded as an excellent solvent?

Its polarity allows it to surround and dissolve ionic and polar substances.

DAT Application: Why does table salt ($NaCl$) dissolve when placed in water?

Water molecules surround and stabilize $Na^+$ and $Cl^-$ ions.

What is the meaning of the phrase 'like dissolves like'?

Polar substances dissolve in polar solvents; nonpolar substances dissolve in nonpolar solvents.

DAT Application: Why is oil unable to dissolve in water?

Oil is nonpolar and lacks charges for water to interact with.

What is cohesion?

Attraction between molecules of the same substance.

DAT Application: What property of water allows insects to walk on its surface?

Water's strong cohesion creates high surface tension.

What is adhesion?

Attraction between different substances.

DAT Application: What mechanism allows water to climb up plant stems?

Adhesion and cohesion produce capillary action.

Why does ice float on liquid water?

Ice is less dense than liquid water.

DAT Trap: Which state of water is denser: ice or liquid water?

Liquid water.

Why does water exhibit a high heat capacity?

Hydrogen bonds absorb large amounts of heat before breaking.

DAT Application: How do oceans contribute to climate stabilization?

Water resists rapid temperature changes.

Which four vitamins are categorized as fat-soluble?

Vitamins $A$, $D$, $E$, and $K$.

DAT Application: A deficiency in which vitamin leads to vision problems?

Vitamin $A$ deficiency.

Which vitamin is responsible for regulating the absorption of calcium?

Vitamin $D$.

DAT Application: Which vitamin can be produced in the skin via sunlight?

Vitamin $D$.

Which vitamin acts as an antioxidant?

Vitamin $E$.

Which vitamin is fundamentally essential for the process of blood clotting?

Vitamin $K$.

DAT Application: Excessive bleeding after a cut might indicate a deficiency in what?

Vitamin $K$ deficiency.

What is the primary biological function of Vitamin $C$?

Collagen synthesis.

DAT Application: Which vitamin deficiency is the cause of scurvy?

Vitamin $C$ deficiency.

What major role do B vitamins play in the body?

They act as coenzymes or coenzyme precursors.

Which four biological macromolecules are present in living organisms?

Carbohydrates, lipids, proteins, and nucleic acids.

What is the definition of a monomer?

A single molecular subunit.

What is a polymer?

A chain of repeating monomers.

DAT Application: What chemical process joins monomers together?

Dehydration synthesis.

DAT Application: What chemical process is used to break polymers apart?

Hydrolysis.

DAT Trap: Does the process of dehydration synthesis produce or consume water?

Produces water.

DAT Trap: Does the process of hydrolysis produce or consume water?

Consumes water.

What are the two primary functions of carbohydrates?

Energy storage and structural support.

What is the specific monomer of carbohydrates?

Monosaccharide.

What is the specific polymer name for carbohydrates?

Polysaccharide.

What type of chemical bond connects carbohydrate subunits?

Glycosidic bond.

DAT Application: If two glucose molecules join, what specific bond is formed?

Glycosidic bond.

What is a monosaccharide?

A single sugar molecule.

What are three examples of monosaccharides?

Glucose, Fructose, and Galactose.

What is a disaccharide?

Two monosaccharides joined by a glycosidic bond.

What is a polysaccharide?

Many monosaccharides linked together.

DAT Application: In which carbohydrate class is glycogen categorized?

Polysaccharide.

Which disaccharide is formed by combining glucose and fructose?

Sucrose.

Which disaccharide is formed by combining glucose and galactose?

Lactose.

Which disaccharide is formed by combining two glucose molecules?

Maltose.

DAT Application: Which disaccharide is commonly referred to as table sugar?

Sucrose.

What is starch?

The major energy-storage polysaccharide in plants.

DAT Application: What molecule is primarily used by plants to store excess glucose?

Starch.

What is glycogen?

The major energy-storage polysaccharide in animals.

DAT Application: Where in the human body is glycogen stored?

The liver and skeletal muscle.

DAT Compare: Contrast starch and glycogen.

Starch is for plants; glycogen is for animals. Both are for energy storage.

What is cellulose?

A structural polysaccharide found in plant cell walls.

DAT Application: Which carbohydrate is responsible for providing plants with rigidity?

Cellulose.

DAT Trap: Are humans capable of digesting cellulose?

No. Humans cannot break $\beta$-glycosidic linkages.

DAT Application: Why is dietary fiber largely indigestible by humans?

It contains cellulose with $\beta$-glycosidic bonds.

What is chitin?

A structural polysaccharide found in fungal cell walls and arthropod exoskeletons.

DAT Application: What molecule constitutes the exoskeleton of insects?

Chitin.

DAT Application: What molecule constitutes the cell walls of fungi?

Chitin.

DAT Compare: How do cellulose and chitin differ?

Cellulose is in plant walls; chitin is in fungal walls/arthropod exoskeletons and contains nitrogen.

DAT Rapid Fire: What is the energy storage molecule for plants?

Starch.

DAT Rapid Fire: What is the energy storage molecule for animals?

Glycogen.

DAT Rapid Fire: What is the structural polysaccharide for plants?

Cellulose.

DAT Rapid Fire: What is the structural polysaccharide for fungi?

Chitin.

DAT Rapid Fire: Is cellulose digestible by humans?

No.

DAT Rapid Fire: Name the bond type in carbohydrates.

Glycosidic bond.

What are lipids?

Nonpolar, hydrophobic molecules.

DAT Application: Why are lipids unable to dissolve in water?

They are nonpolar and hydrophobic.

Name five major functions of lipids.

Energy storage, insulation, membrane structure, hormone production, and cell protection.

DAT Application: Which macromolecule stores the highest amount of energy per gram?

Lipids.

What is the structure of a triglyceride?

Three fatty acids attached to a glycerol backbone.

What is glycerol?

A three-carbon molecule that forms the backbone of triglycerides.

DAT Application: What is the primary storage form of fat in the human body?

Triglycerides.

What defines a saturated fatty acid?

A fatty acid containing no carbon-carbon double bonds.

Why are saturated fats typically solid at room temperature?

Their straight chains pack tightly together.

DAT Application: Which type of fat is most associated with plaque formation?

Saturated fats.

What defines an unsaturated fatty acid?

A fatty acid containing one or more double bonds.

DAT Application: Why are unsaturated fats generally liquid at room temperature?

Double bonds create bends that prevent tight packing.

DAT Compare: Saturated vs unsaturated fatty acids.

Saturated: No double bonds, straight, tight packing, solid. Unsaturated: Double bonds, bent, loose packing, liquid.

What is the structure of a phospholipid?

Two fatty acids and one phosphate group attached to glycerol.

Why are phospholipids described as amphipathic?

They contain both hydrophobic and hydrophilic regions.

Which portion of a phospholipid molecule is hydrophilic?

The phosphate head.

Which portion of a phospholipid molecule is hydrophobic?

The fatty acid tails.

DAT Application: Why do phospholipids form bilayers automatically in water?

Hydrophilic heads face the water while hydrophobic tails avoid it.

What is the primary structural component of biological cell membranes?

Phospholipids.

What is the defining chemical structure of steroids?

Four fused hydrocarbon rings.

DAT Application: Which lipid class serves as the precursor for various hormones?

Steroids.

Provide four examples of molecules derived from steroids.

Cholesterol, steroid hormones, Vitamin $D$, and bile acids.

What is the major role of cholesterol within cell membranes?

It regulates membrane fluidity.