Chapter 2 Pro Flashcards
Define Solution.
Solution consists of particles called the solute mixed with a more abundant substance (usually water) called the solvent
Define Colloids
Colloids in the body are often mixtures of protein and water
Suspension are defined by certain physical properties. What are they and give an example.
- Particles exceed 100 nm
- Too large to penetrate selectively permeable membranes
- Cloudy or opaque in appearance
- Separates on standing
Example: blood cells in blood plasma
Define emulsion
Emulsion is the suspension of one liquid in another
Examples: oil-and-vinegar salad dressing; fat in breast milk
Define Acid
Proton donor (releases H+ ions in water)
Define Base
Proton acceptor (accepts H+ ions or releases OH− ions)
What is pH.
Measure of acidity derived from the molarity of H+
pH of 7.0 is:
neutral (H+ = OH−)
pH of less than 7 is:
acidic (H+ > OH−)
pH of greater than 7 is:
basic (OH− > H+)
Define buffers.
Buffers are chemical solutions that resist changes in pH
The negative logarithm of hydrogen ion molarity is:
pH = -log[H+]
Electrolyte concentration is measured in:
equivalents (Eq)
Define Energy
Capacity to do work
Define Potential Energy.
Energy stored in an object, but not currently doing work
Define Chemical energy.
Potential energy in molecular bonds
Define free energy
Potential energy available in a system to do useful work
Define Kinetic Energy
It is the energy of motion
Define Heat
It is Kinetic energy of molecular motion
Define Electromagnetic energy.
It is the Kinetic energy of moving packets of radiation called photons
Define Chemical reaction
Process in which a covalent or ionic bond is formed or broken
What are the 3 classes of chemical reactions.
*Decomposition reactions (Catabolism)
*Synthesis reactions (Anabolism)
*Exchange reactions
Describe Decomposition reactions.
*Large molecule breaks down into two or more smaller ones. AB → A + B
Describe Synthesis reactions.
- Two or more small molecules combine to form a larger one
A + B → AB
Describe Exchange Reactions
- Two molecules exchange atoms or group of atoms
AB + CD → ABCD → AC + BD
Describe Reversible reactions.
- Can go in either direction under different circumstances
Example: CO2 + H2O ↔ H2CO3 ↔ HCO3− + H+
Reaction rates increase when:
- Concentration of reactants increases
- Temperature rises
- A catalyst is present
* Enzyme catalysts bind to reactants and hold them in orientations that facilitate the reaction
* Catalysts are not changed by the reaction and can repeat the process frequently
Define Metabolism.
All chemical reactions of the body
Describe Catabolism
- Energy-releasing (exergonic) decomposition reactions
- Breaks covalent bonds
- Produces smaller molecules
Describe Anabolism
- Energy-storing (endergonic) synthesis reactions
- Requires energy input
Example: production of protein or fat
Molecule are oxidized when it:
it loses electrons (OIL RIG)
Molecule is reduced when it:
it accepts electrons (OIL RIG)
The oxidizing agent is the:
electron acceptor
The reducing agent is the molecule that:
donates electrons
In Oxidation-reduction (redox) reactions, Electrons are often transferred as:
hydrogen atoms
Describe organic chemistry.
The study of compounds containing carbon
What are the 4 categories of carbon compounds.
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
Name some functional groups of organic molecules.
- Hydroxyl (-OH)
- Methyl (-CH2)
- Carbonyl (-COOH)
- Amino (-NH2)
- Phosphate (-H2PO4)
Describe Macromolecules.
Very large organic molecules with high molecular weights
Describe Polymers
Macromolecules made of a repetitive series of identical or similar subunits (monomers). Example: starch is a polymer of about 3,000 glucose monomers
Describe Polymerization.
Joining monomers to form a polymer
Describe Dehydration synthesis (condensation)
- Monomers covalently bind together to form a polymer
- A hydroxyl (-OH) group is removed from one monomer, and a hydrogen (-H) from another
- Water produced as a by-product
Describe Hydrolysis.
- Splitting a polymer in monomers by the addition of water
- Enzyme helps break the covalent bond that links two monomers together
Describe Carbohydrates
- Carbohydrates are hydrophilic organic molecules
Examples: sugars and starches - General formula: (CH2O)n, n = number of carbon atoms
Glucose, n = 6, so formula is C6H12O6
Describe Monosaccharides
- Simplest carbohydrates
- Monomers
Three important monomers of carbohydrates are:
glucose, galactose, and fructose
Describe Disaccharides.
Sugars made of two covalently bonded monosaccharides
Name the 3 important Disaccharides.
- Sucrose (table sugar)
*Glucose + fructose - Lactose (milk sugar)
* Glucose + galactose - Maltose (sugar in grain products)
* Glucose + glucose
Describe Oligosaccharides.
They are Short chains of three or more monosaccharides (at least 10)
Describe Polysaccharides.
Long chains of monosaccharides (at least 50)
Name 3 important polysaccharides.
- Glycogen: Energy storage in cells of liver, muscle, brain, uterus, vagina
- Starch: Energy storage in plants that is digestible by humans
- Cellulose: Structural molecule in plants that is important for human dietary fiber (but indigestible to us)
All digested carbohydrates converted to what and
Oxidized to make what?
All digested carbohydrates converted to glucose and
Oxidized to make ATP
Describe Lipids.
Lipids are hydrophobic organic molecules with a high ratio of hydrogen to oxygen
What are Five primary types of lipids in the human body.
- Fatty acids
- Triglycerides
- Phospholipids
- Eicosanoids
- Steroids
What are the two ends of a fatty acid molecule?
A carboxyl group (-COOH) on one end and a methyl group (-CH₃) on the other.
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids have all single covalent bonds between carbon atoms, while unsaturated fatty acids contain some double bonds between carbons.
Why are some fatty acids considered essential?
Essential fatty acids must be obtained from food because the body cannot synthesize them.
What defines a polyunsaturated fatty acid?
A polyunsaturated fatty acid contains multiple double bonds between carbon atoms.
What are triglycerides composed of?
Triglycerides are composed of three fatty acids linked to a glycerol molecule.
What is the primary function of triglycerides?
The primary function of triglycerides is energy storage, but they also help with insulation and shock absorption.
How do triglycerides form and break down?
Triglycerides are formed by dehydration synthesis and broken down by hydrolysis.
What is the difference between oils and fats?
Oils are usually liquid at room temperature (e.g., plant-derived polyunsaturated triglycerides like olive oil), while fats are usually solid (e.g., animal-derived saturated triglycerides like animal fat).
What is the structure of trans-fatty acids?
In trans-fatty acids, the two covalent single C–C bonds are angled in opposite directions across from each other on each side of the C=C double bond.
Why are trans-fatty acids considered harmful to health?
Trans-fatty acids resist enzymatic breakdown, remain in circulation longer, and can deposit in arteries, raising the risk of heart disease.
What is the structural difference between trans-fatty acids and cis-fatty acids?
The term “cis” and “trans” describe the positions of the two hydrogen atoms located next to the carbon atoms where the double bond exists. Cis fatty acid has both hydrogen atoms located on the same side. On the contrary, trans fatty acid has the two hydrogen atoms on opposite sides.
How do cis-fatty acids differ in terms of health impact compared to trans-fatty acids?
Cis-fatty acids are generally considered healthier as they do not resist enzymatic breakdown like trans-fatty acids, thus posing less risk to heart health.
How are phospholipids different from neutral fats?
In phospholipids, one fatty acid is replaced by a phosphate group.
What is the primary function of phospholipids in cells?
Phospholipids form the structural foundation of the cell membrane.
What does it mean that phospholipids are amphipathic?
Being amphipathic means phospholipids have both hydrophobic fatty acid “tails” and a hydrophilic phosphate “head.”
Which part of a phospholipid is hydrophobic and which part is hydrophilic?
The fatty acid “tails” are hydrophobic, while the phosphate “head” is hydrophilic.
Which of the following is a type of phospholipid?
A) Steroids
B) Lecithin
C) Eicosanoids
D) Triglycerides
B) Lecithin eg Soap
Eicosanoids are derived from which of the following?
A) Phosphate group
B) Arachidonic acid
C) Choline
D) Cholesterol
B) Arachidonic acid
Which of the following is NOT a function or characteristic of phospholipids?
A) Form the structural foundation of cell membranes
B) Act as signaling molecules in inflammation
C) Have hydrophobic tails and hydrophilic heads
D) Are amphipathic molecules
B) Act as signaling molecules in inflammation
Note: Eicosanoids play important role.
What is the characteristic structure of steroids?
A) Three fatty acid tails linked to glycerol
B) Four carbon rings
C) A phosphate group and fatty acid tails
D) A long chain of double bonds
B) Four carbon rings
Which of the following lipids plays a key role in forming cell membranes?
A) Eicosanoids
B) Steroids
C) Phospholipids
D) Triglycerides
C) Phospholipids
Cholesterol, testosterone, and estrogen are examples of which type of lipid?
A) Eicosanoids
B) Phospholipids
C) Steroids
D) Lecithin
C) Steroids
What do “good” and “bad” cholesterol refer to?
A) Different types of cholesterol molecules
B) Droplets of lipoproteins that are complexes of cholesterol, fat, phospholipid, and protein
C) Types of fat found in the blood
D) The amount of cholesterol produced by the liver
B) Droplets of lipoproteins that are complexes of cholesterol, fat, phospholipid, and protein
Which type of lipoprotein is known as “good cholesterol”?
A) LDL (low-density lipoprotein)
B) HDL (high-density lipoprotein)
C) Triglycerides
D) VLDL (very low-density lipoprotein)
B) HDL (high-density lipoprotein)
Why is HDL considered “good cholesterol”?
A) It has a high ratio of lipid to protein
B) It may help prevent cardiovascular disease
C) It contributes to artery blockage
D) It increases the amount of cholesterol in the body
B) It may help prevent cardiovascular disease
What is the characteristic of LDL, often called “bad cholesterol”?
A) It has a lower ratio of lipid to protein
B) It helps remove cholesterol from the bloodstream
C) It has a higher ratio of lipid to protein and contributes to cardiovascular disease
D) It is not related to cardiovascular health
C) It has a higher ratio of lipid to protein and contributes to cardiovascular disease
What are cofactors and what role do they play in enzyme function?
Cofactors are non-protein helper molecules required for many enzymes to function. They can be inorganic ions (e.g., iron, copper, zinc) and help activate the enzyme’s active site.
What are coenzymes, and how are they different from cofactors?
Coenzymes are organic cofactors, often derived from vitamins. They assist in enzyme activity. Example: NAD+ (derived from niacin) helps in metabolism and ATP production by shuttling electrons between enzymes.
What is a metabolic pathway?
A metabolic pathway is a chain of reactions, each catalyzed by a different enzyme, where a series of substrates are converted into intermediates and eventually into an end product.
In a metabolic pathway, what role do intermediates play?
A) They are the final products of the pathway
B) They are substrates in between the initial reactant and the end product
C) They are enzymes that speed up reactions
D) They prevent feedback inhibition
B) They are substrates in between the initial reactant and the end product
How can a metabolic pathway be turned on or off?
Metabolic pathways can be regulated by altering enzyme activity, through mechanisms such as binding or dissociation of cofactors and feedback inhibition
What is feedback inhibition in a metabolic pathway?
A) The pathway is sped up when the end product is formed
B) The end product inhibits an earlier enzyme, shutting down the pathway
C) The pathway is slowed down by intermediates
D) The enzyme at the last step stops working
B) The end product inhibits an earlier enzyme, shutting down the pathway
What happens to a metabolic pathway when the end product concentration is low?
The pathway is turned on, and enzyme activity resumes to produce more of the end product.
What are the three parts of a nucleotide?
A nucleotide consists of a five-carbon sugar (ribose in RNA, deoxyribose in DNA), a phosphate group, and a nitrogenous base
Which nitrogenous base is found in RNA but not in DNA?
A) Adenine
B) Guanine
C) Thymine
D) Uracil
D) Uracil
How do nucleotides bond to form a polynucleotide chain?
Nucleotides bond through dehydration reactions where the phosphate of one nucleotide binds to the sugar of the next, creating a sugar-phosphate backbone with protruding nitrogenous bases.
What is the structure of RNA compared to DNA?
RNA is usually a single polynucleotide strand, while DNA is a double helix with two polynucleotide strands that wrap around each other.
In DNA, which nitrogenous base pairs with adenine (A)?
A) Guanine (G)
B) Thymine (T)
C) Cytosine (C)
D) Uracil (U)
B) Thymine (T)
How are the two strands of DNA held together?
The two strands of DNA are held together by hydrogen bonds between complementary base pairs: adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
What are the three principal components of a nucleotide?
A nucleotide consists of a nitrogenous base, a sugar (monosaccharide), and one or more phosphate groups.
Which of the following is an example of a nucleotide?
A) Glucose
B) ATP (Adenosine triphosphate)
C) Protein
D) Lipid
B) ATP (Adenosine triphosphate)
What is the primary function of ATP in the body?
ATP is the body’s most important energy-transfer molecule, storing energy from exergonic reactions and releasing it for physiological work.
How is energy stored and released in ATP?
ATP stores energy in covalent bonds, particularly in the high-energy bonds between the second and third phosphate groups. Energy is released when the third phosphate group is removed
What enzyme catalyzes the hydrolysis of ATP to release energy?
A) Kinases
B) ATPases
C) Proteases
D) Lipases
B) ATPases
What is phosphorylation, and which enzyme carries it out?
Phosphorylation is the addition of a free phosphate group to a molecule, and it is carried out by enzymes called kinases.
What are the products of ATP hydrolysis?
The products of ATP hydrolysis are ADP (adenosine diphosphate), inorganic phosphate (Pi), and energy.
What is glycolysis?
Glycolysis is the process of splitting glucose into two pyruvates, which occurs in the cytoplasm of cells.
What happens if ATP demand outpaces oxygen supply during glycolysis?
A) Pyruvate ferments to lactate
B) Pyruvate undergoes aerobic respiration
C) Glucose is not broken down
D) Oxygen is produced as a by-product
A) Pyruvate ferments to lactate
What occurs if there is sufficient oxygen during glucose oxidation?
If there is enough oxygen, aerobic respiration occurs in the mitochondria, allowing more ATP to be produced.
What is guanosine triphosphate (GTP)?
GTP is another nucleotide involved in energy transfer, similar to ATP.
How is cyclic adenosine monophosphate (cAMP) formed?
A) By adding phosphate groups to GTP
B) By removing the second and third phosphate groups from ATP
C) Through the breakdown of glucose
D) By splitting pyruvate
B) By removing the second and third phosphate groups from ATP
What role does cAMP play in cellular processes?
cAMP acts as a “second messenger” within the cell, often in response to hormone signaling.
