Biology Chapter 4: pH and Buffers

Questions and Answers

What are the three types of lipids mentioned?

Phospholipids, steroids, carbohydrates

Triglycerides, phospholipids, proteins

Fats, waxes, oils

Phospholipids, steroids, fats (correct)

What are the subunits that compose a triglyceride?

Fatty acids and phosphates

Glycerol and two fatty acids

Carbon and nitrogen

Glycerol and three fatty acids (correct)

What does the pH scale primarily measure?

Hydrogen ion concentration (correct)

Alkalinity of carbon compounds

Concentration of minerals in solution

Oxygen ion concentration

How does the energy efficiency of fat compare to carbohydrates?

Fat supplies more energy than carbohydrates Signup and view all the answers

Which statement about acids is true?

Acids have a pH less than 7. Signup and view all the answers

What bonds hold two amino acids together?

Peptide bonds Signup and view all the answers

What does the term denaturation refer to in proteins?

Loss of function due to structural change Signup and view all the answers

What is the main role of buffers in biological systems?

They resist changes in pH. Signup and view all the answers

Which of the following is a function of proteins?

Aid in structure and function of the body Signup and view all the answers

What are the two overall structures of proteins?

Primary and secondary structures Signup and view all the answers

In the dehydration reaction process, what happens?

Water is removed to form new bonds. Signup and view all the answers

Why are enzymes essential for biological processes?

They speed up chemical reactions Signup and view all the answers

Which of these substances is classified as a polysaccharide?

Starch Signup and view all the answers

What happens to an enzyme at its optimal temperature and pH?

It works most efficiently Signup and view all the answers

What is a characteristic feature of lipids?

They are hydrophobic and do not dissolve in water. Signup and view all the answers

Which process is used to break down complex molecules into simpler ones?

Hydrolysis Signup and view all the answers

What primary role does the nucleolus play in the cell?

Site of ribosomal production Signup and view all the answers

Which of the following substances can readily pass through the cell membrane?

Oxygen Signup and view all the answers

What characterization best describes hypertonic solutions in relation to cells?

Higher concentration outside the cell causing water loss Signup and view all the answers

How does facilitated diffusion differ from simple diffusion?

It utilizes protein transport to move substances Signup and view all the answers

What is the role of microvilli in cells?

Increase surface area Signup and view all the answers

Which process involves the movement of liquid through a semi-permeable membrane due to pressure?

Filtration Signup and view all the answers

What is required for active transport to occur in cells?

Energy input to move against the concentration gradient Signup and view all the answers

What defining feature does the phospholipid bilayer possess?

It has hydrophilic heads and hydrophobic tails Signup and view all the answers

What effect do extreme pH values have on enzymes?

They alter the enzyme's charge distribution and may cause denaturation. Signup and view all the answers

Which two bases pair together in DNA?

Adenine and Thymine Signup and view all the answers

What are the components of a nucleotide which carries genetic information?

5 carbon sugar, phosphate group, and nitrogenous base Signup and view all the answers

How do enzyme inhibitors function?

By binding to the active site or another site on the enzyme. Signup and view all the answers

What is the primary function of mitochondria in a cell?

Sites of aerobic respiration that form ATP Signup and view all the answers

Which part of DNA's structure differentiates it from RNA?

The double-stranded structure of DNA Signup and view all the answers

What type of bond holds the two strands of DNA together?

Hydrogen bond Signup and view all the answers

Which function is NOT performed by the Golgi apparatus?

Digestion of foreign substances Signup and view all the answers

Study Notes

pH Scale and Acids

The pH scale measures hydrogen ion concentration in a solution, indicating acidity (pH < 7) or alkalinity (pH > 7).
Acids have more H+ ions than OH- ions with a pH less than 7.
A neutral solution has equal amounts of H+ and OH- ions, specifically at pH 7.
Pure water has a pH of 7.

Buffers

Buffers resist changes in pH by combining or releasing hydrogen ions.
Example: The bicarbonate/carbonic acid system regulates blood pH around 7.4.

Molecules of Life

Four classes: Carbohydrates, Lipids, Proteins, Nucleic Acids.
Carbohydrates provide energy and consist of carbon, hydrogen, and oxygen.
Lipids also provide energy, serve in storage, and form structures; subunits include carbon, hydrogen, and oxygen.
Proteins support body structure and function, consisting of carbon, hydrogen, oxygen, and nitrogen.
Types of proteins include structural, storage, contractile, transport, and enzymes.
Nucleic acids (DNA and RNA) carry genetic information and direct cell functions.

Monomers and Polymers

Monomers are small units, whereas polymers consist of many monomers.
Dehydration reactions involve the removal of water to bond molecules, while hydrolysis reactions use water to break bonds and split molecules.

Carbohydrate Classification

Monosaccharides: glucose, fructose, ribose, deoxyribose.
Disaccharides: sucrose, lactose, maltose.
Polysaccharides: starch, glycogen.

Energy from Food

Carbohydrate digestion (e.g., starch from spaghetti) leads to glucose, which is used in cellular respiration in the presence of oxygen, producing ATP for cellular work.

Characteristics of Lipids

Lipids are hydrophobic, meaning fats do not mix with water.
Types include phospholipids (membranes), steroids (hormones), and triglycerides (energy storage), which consist of glycerol and three fatty acids.

Amino Acids and Proteins

Amino acids consist of an amine group, acid group, hydrogen, and a variable R group.
Peptide bonds link amino acids.
Protein shape directly correlates to function; denaturation occurs with structural loss due to external factors (temperature, pH).
Primary structure is the amino acid sequence, secondary structure involves hydrogen bonding leading to helices or pleated sheets.

Enzymes

Enzymes are globular proteins that catalyze reactions, increasing reaction speed and specificity in metabolic pathways.
Enzyme activity is influenced by pH and temperature; optimal conditions enhance function, while extreme changes can lead to denaturation.
Inhibitors can bind to enzymes and block catalytic activity.

Nucleic Acids

DNA and RNA are the primary nucleic acids; DNA stores genetic information while RNA transmits instructions for protein synthesis.
Nucleotides comprise a 5-carbon sugar, phosphate group, and nitrogenous base (carries genetic info).
DNA consists of four bases: adenine (A), thymine (T), cytosine (C), guanine (G), with A pairing with T and C with G.

Chromosomes and Genes

Chromosomes are coiled structures of DNA and proteins, consisting of many genes.
Genes are DNA sections that code for proteins.

Differences Between DNA and RNA

DNA is double-stranded and uses thymine; RNA is single-stranded with uracil replacing thymine.

Cell Structures and Functions

Nucleus: control center.
Mitochondria: sites of aerobic respiration forming ATP.
Endoplasmic Reticulum (smooth & rough): transport materials; synthesize proteins/lipids.
Golgi apparatus: packages substances for export.
Lysosomes: digest foreign substances.
Ribosomes: protein synthesis sites.
Vesicles: transport/store substances.
Peroxisomes: break down fatty acids/amino acids.
Cytoskeleton: provides support/movement; microvilli increase surface area.
Flagella: enable sperm movement; cilia move materials along cell surfaces.

Cell Membrane Composition

Composed of a phospholipid bilayer, proteins, and cholesterol.
Phospholipids have a hydrophilic head and hydrophobic tails from two fatty acids.

Membrane Permeability

Allows small nonpolar molecules (O2, CO2, N2) to pass through.
Blocks ions (Na+, K+, Cl-), large uncharged polar molecules (glucose, sucrose), and small uncharged polar molecules (H2O, NH3, glycerol).

Transport Mechanisms

Passive transport occurs from high to low concentration without energy; active transport requires energy to move substances against the concentration gradient.

Diffusion and Osmosis

Simple diffusion moves molecules from high to low concentration.
Facilitated diffusion uses proteins to assist movement through membranes.
Osmosis refers to water diffusion across a semipermeable membrane.
Filtration moves small substances across membranes due to physical forces, such as blood pressure.

Tonicity Definitions

Hypertonic: higher solute concentration outside the cell causes water loss (cell shrinks).
Hypotonic: higher solute concentration inside the cell leads to water influx (cell may burst).
Isotonic: neutral balances osmosis of water in and out of the cell.

Sodium/Potassium Pump

The Na+/K+ pump actively transports sodium out of and potassium into cells, requiring energy for maintaining cellular ion balance.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers important concepts related to the pH scale, acids, neutral solutions, and buffers. It also discusses the four classes of molecules essential for life, providing a comprehensive overview for understanding biological chemistry. Test your knowledge on these pivotal topics.