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Questions and Answers
What is the principal fluid medium of the cell?
What is the principal fluid medium of the cell?
Water
What is the concentration of water in most cells, except for fat cells?
What is the concentration of water in most cells, except for fat cells?
70% to 85%
What are the most important ions in the cell?
What are the most important ions in the cell?
K+, Mg2+, PO43-, SO42-, HCO3-
What two types of proteins are found in cells?
What two types of proteins are found in cells?
What are two examples of structural proteins?
What are two examples of structural proteins?
What are three examples of functional proteins?
What are three examples of functional proteins?
What two lipids are particularly important for cell function?
What two lipids are particularly important for cell function?
What is another name for triglycerides?
What is another name for triglycerides?
What is the primary function of triglycerides in fat cells?
What is the primary function of triglycerides in fat cells?
In human cells, what is the approximate percentage of carbohydrates?
In human cells, what is the approximate percentage of carbohydrates?
What is the form of carbohydrate that is stored in cells?
What is the form of carbohydrate that is stored in cells?
What determines the different types of chemical bonding?
What determines the different types of chemical bonding?
What are the two primary types of chemical bonding?
What are the two primary types of chemical bonding?
When does pure covalent bonding occur?
When does pure covalent bonding occur?
What type of bonding occurs when two different nonmetal atoms are bonded or a nonmetal and a metal are bonded?
What type of bonding occurs when two different nonmetal atoms are bonded or a nonmetal and a metal are bonded?
What is the quantitative measure of a molecule's polarity called?
What is the quantitative measure of a molecule's polarity called?
What happens to the valence electrons in ionic bonding?
What happens to the valence electrons in ionic bonding?
When do ionic bonds occur?
When do ionic bonds occur?
What is a hydrogen bond?
What is a hydrogen bond?
What are the most common electronegative atoms involved in hydrogen bonding?
What are the most common electronegative atoms involved in hydrogen bonding?
According to the Bronsted-Lowry theory, what is an acid?
According to the Bronsted-Lowry theory, what is an acid?
According to the Arrhenius theory, what do acids produce in solution?
According to the Arrhenius theory, what do acids produce in solution?
What is the common way pH is expressed?
What is the common way pH is expressed?
What is the pH of pure water?
What is the pH of pure water?
What is the range of pH for acids?
What is the range of pH for acids?
How is pH measured using a pH meter?
How is pH measured using a pH meter?
What is the purpose of standardizing a pH meter?
What is the purpose of standardizing a pH meter?
What is the limitation of indicator dyes and test strips for pH measurement?
What is the limitation of indicator dyes and test strips for pH measurement?
Why are indicator dyes and test strips sometimes preferable for pH measurements?
Why are indicator dyes and test strips sometimes preferable for pH measurements?
How does pH affect solubility of substances?
How does pH affect solubility of substances?
How does pH affect the structure and function of proteins?
How does pH affect the structure and function of proteins?
What is the pH range of blood plasma in healthy individuals?
What is the pH range of blood plasma in healthy individuals?
What is the typical pH of gastric fluid?
What is the typical pH of gastric fluid?
What is the typical pH of pancreatic secretions?
What is the typical pH of pancreatic secretions?
What is the term for the amount of acid or base that can be added to a buffer without significantly changing its pH?
What is the term for the amount of acid or base that can be added to a buffer without significantly changing its pH?
What is the term for the range of pH values for which a buffer system is most effective?
What is the term for the range of pH values for which a buffer system is most effective?
What are the three important buffer systems in the human body?
What are the three important buffer systems in the human body?
Why is histidine an important amino acid in the protein buffer system?
Why is histidine an important amino acid in the protein buffer system?
What is the approximate pKa of the conjugate acid of histidine?
What is the approximate pKa of the conjugate acid of histidine?
Where do protein buffers occur in the body?
Where do protein buffers occur in the body?
Why is the phosphate buffer system less effective at maintaining a pH of 7?
Why is the phosphate buffer system less effective at maintaining a pH of 7?
What two forms of phosphate ions are involved in the phosphate buffer system?
What two forms of phosphate ions are involved in the phosphate buffer system?
What is the most important extracellular buffer?
What is the most important extracellular buffer?
What are the primary buffering agents in blood plasma?
What are the primary buffering agents in blood plasma?
Why is the carbonic acid buffer system less effective at maintaining blood pH than expected based on its pKa?
Why is the carbonic acid buffer system less effective at maintaining blood pH than expected based on its pKa?
What is the consequence of very high concentrations of bicarbonate in blood plasma?
What is the consequence of very high concentrations of bicarbonate in blood plasma?
Why is the concentration of carbonic acid maintained at a very low level in blood plasma?
Why is the concentration of carbonic acid maintained at a very low level in blood plasma?
What happens to blood pH when you breathe too fast?
What happens to blood pH when you breathe too fast?
How do proteins containing histidine can help maintain the pH of body fluids around 7?
How do proteins containing histidine can help maintain the pH of body fluids around 7?
Flashcards
What is the main fluid within a cell?
What is the main fluid within a cell?
Water is the primary fluid medium in most cells, constituting 70-85% of the cell's volume.
What are the key mineral components inside a cell?
What are the key mineral components inside a cell?
Ions, like K+, Mg2+, PO43-, SO42-, HCO3-, Na+, Cl-, and Ca2+, are essential for a variety of cellular processes.
What's the second most common molecule in a cell?
What's the second most common molecule in a cell?
Proteins are the most abundant substances in cells after water, accounting for 10-20% of the cell's mass.
How are proteins classified based on their roles?
How are proteins classified based on their roles?
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What molecules are crucial for creating the cell's boundaries?
What molecules are crucial for creating the cell's boundaries?
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What's the main energy source for cells when carbohydrates are low?
What's the main energy source for cells when carbohydrates are low?
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What molecule gives the cell quick energy?
What molecule gives the cell quick energy?
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What's the storage form of glucose inside the cell?
What's the storage form of glucose inside the cell?
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What type of bonding involves sharing electrons?
What type of bonding involves sharing electrons?
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What kind of bonding creates a molecule with a partial positive and negative end?
What kind of bonding creates a molecule with a partial positive and negative end?
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What type of bonding involves complete electron transfer?
What type of bonding involves complete electron transfer?
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What type of weak bond involves a hydrogen atom?
What type of weak bond involves a hydrogen atom?
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According to Bronsted-Lowry, what defines an acid and a base?
According to Bronsted-Lowry, what defines an acid and a base?
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According to Arrhenius, what defines an acid and a base?
According to Arrhenius, what defines an acid and a base?
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What happens when an acid and a base react?
What happens when an acid and a base react?
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What does pH measure, and how is it defined?
What does pH measure, and how is it defined?
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What are the pH ranges for acidic, neutral, and basic solutions?
What are the pH ranges for acidic, neutral, and basic solutions?
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What instrument is used for precise pH measurement?
What instrument is used for precise pH measurement?
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What are less precise methods for measuring pH?
What are less precise methods for measuring pH?
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Why is pH important in biological systems?
Why is pH important in biological systems?
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What's the normal pH range of blood plasma?
What's the normal pH range of blood plasma?
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What is a buffer solution, and what does it do?
What is a buffer solution, and what does it do?
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What are the components of a buffer solution?
What are the components of a buffer solution?
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What equation helps calculate the pH of a buffer solution?
What equation helps calculate the pH of a buffer solution?
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What is the phosphate buffer system, and where is it found?
What is the phosphate buffer system, and where is it found?
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What is the carbonic acid buffer system, and where is it found?
What is the carbonic acid buffer system, and where is it found?
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What is the protein buffer system, and what is its special characteristic?
What is the protein buffer system, and what is its special characteristic?
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Why does breathing too fast cause blood pH to increase?
Why does breathing too fast cause blood pH to increase?
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Study Notes
Basic Cell Chemicals
- Cell chemistry is crucial for cellular functions
- Water is the principal fluid medium in most cells (70% to 85%), except fat cells
- Many cellular chemicals are dissolved in water; others are suspended
- Chemical reactions occur between dissolved chemicals, or on suspended particles/membranes
Ions
- Important cellular ions include K+, Mg2+, PO43-, SO42-, HCO3- and smaller quantities of Na+, Cl-, Ca2+
- Extracellular and intracellular fluid ion concentrations differ
- Ions are essential for cellular reactions and controlling mechanisms
- Ions at cell membranes facilitate electrochemical impulse transmission in nerves and muscles
Proteins
- Proteins are the most abundant substances after water, composing 10-20% cell mass
- Two types:
- Structural proteins: intracellular filaments, extracellular proteins (collagen, elastin)
- Functional proteins: enzymes, hormones, antibodies
Lipids
- Phospholipids and cholesterol (2% of total cell mass) are mainly insoluble in water
- Form cell membranes and intracellular barriers
- Some cells contain significant amounts of triglycerides (neutral fat)
- Triglycerides, in fat cells, can comprise up to 95% of cell mass and serve as energy storage
Carbohydrates
- Most human cells contain about 1% carbohydrates (up to 3% in muscle, occasionally 6% in liver)
- Dissolved glucose is always present in the surrounding extracellular fluid
- A small amount of carbohydrate is stored as glycogen (an insoluble glucose polymer)
Types of Bonding
- Chemical bonding types are determined by how valence electrons are shared between atoms
- Types of bonding: covalent and ionic
Covalent Bonds
- Valence electrons are shared as pairs between bonded atoms
- Pure covalent bonds occur between nonmetal atoms of the same kind
- Polar covalent bonds involve nonmetal atoms of different kinds, or nonmetals and metals, exhibiting a mixture of covalent and ionic bonding
Polar Covalent Bonding
- Involved in different nonmetal atoms or nonmetals and metals
- A mixture of covalent and ionic bonding
Polar Molecules
- Polar molecules have an overall dipole (can be represented by a dipole arrow pointing to the more electronegative end)
- A molecule's polarity is quantified by its dipole moment
Ionic Bonding
- Valence electrons are completely transferred from one atom to the other
- Occurs between metals and nonmetals when there's a large difference in electronegativity
Hydrogen Bonds
- Attractive force between a hydrogen atom attached to an electronegative atom in one molecule, and an electronegative atom of a different molecule
- Usually, the electronegative atom is oxygen, nitrogen, or fluorine, carrying a partial negative charge
Acids and Bases
- Brønsted-Lowry theory:
- Acid: proton (hydrogen ion) donor
- Base: proton (hydrogen ion) acceptor
- Arrhenius theory:
- Acid: a substance producing hydrogen ions in solution
- Base: a substance producing hydroxide ions in solution
- Neutralization occurs when hydrogen and hydroxide ions react to form water
pH
- pH is the negative logarithm of hydrogen (actually hydronium) ion molar concentration
- Pure water has pH 7
- Acids have high [H+] and low pH
- Bases have low [H+] and high pH
pH Measurement
- pH meter: measures H+ concentration; must be standardized before use
- Indicator dyes/test strips: Less precise, suitable for field usage, small volume, or noxious samples
pH in Biology
- pH influences many substances' solubility
- Affects protein structure and function
- Many cells/organisms survive within a specific pH range; blood pH 7.35–7.45 is crucial for optimal functioning
Buffer Solutions
- Buffer solutions resist pH changes when strong acid or base is added
- Consist of a weak acid and its conjugate base
- Example: acetic acid and sodium acetate, ammonium chloride and ammonia
- pH of a buffer solution is approximately equal to the pKa of the weak acid
Buffering Action
- Le Chatelier's Principle: shift in equilibrium in response to changes
- If acid is added, the reaction shifts to the left, increasing [HA] and decreasing [A-]
- If base is added, the reaction shifts to the right, decreasing [HA] and increasing [A-]
- Buffer capacity: amount of acid/base a buffer can absorb without significant pH change
- Buffer range: pH values where the buffer solution is most effective (usually ±1 pH unit of pKa)
Important Buffers in the Human Body
- Protein buffer system:
- Proteins are constructed from amino acids
- Histidine, a weak base, readily transitions to its conjugate acid
- Protein with histidine can be effective buffers around pH 7
- Phosphate buffer system:
- Phosphate ions (H2PO4⁻ and HPO4²⁻) form effective buffers near pH 7.2
- Carbonic acid buffer system:
- H₂CO₃ and bicarbonate ions act as primary buffers in blood plasma, maintaining a pH of 7.4
Tutorial Questions (provided)
- These questions are about the phosphate buffer system.
- The questions are focused on the contents of the slides. Understanding the material is important!
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Description
Explore the fundamental chemicals that compose cells, including the roles of water, ions, proteins, and lipids. This quiz will test your understanding of the chemical components vital for cellular functions and reactions. Get ready to delve into the intricacies of cell chemistry!
