Biology Chapter 1: Unifying Themes

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Questions and Answers

What property of water is primarily responsible for its ability to regulate body temperature through processes like sweating?

Viscosity

High surface tension

Heat capacity (correct)

Low freezing point

Why does ice float on liquid water?

Ice contains more oxygen than liquid water.

Ice is less dense due to hydrogen bonding. (correct)

Ice is formed under higher pressure.

Ice has a higher temperature than water.

Which of the following statements about carbon is true?

Carbon can only bond with oxygen.

Carbon can form long chains and rings. (correct)

Carbon has three valence electrons.

Carbon can only form single bonds.

What is an example of a geometric isomer?

cis-2-butene Signup and view all the answers

How do acids and bases influence the hydrogen concentration of a solution?

Acids increase hydrogen ion concentration, while bases decrease it. Signup and view all the answers

Which of the following types of isomers differ in connectivity of their atoms?

Structural isomers Signup and view all the answers

Which of the following elements is NOT one of the four most abundant in living organisms?

Iron Signup and view all the answers

What defines a hydrophilic substance?

Attracts water and dissolves in it. Signup and view all the answers

What is the role of buffers in biological systems?

Buffers help maintain stable pH levels. Signup and view all the answers

What is the molecular formula for water?

H2O Signup and view all the answers

Which term best describes a substance made of two or more different elements chemically bonded together?

Compound Signup and view all the answers

How many protons are present in a Nitrogen atom?

7 Signup and view all the answers

What is the primary function of valence electrons in atoms?

Influence chemical bonding Signup and view all the answers

What defines an isotope of an element?

Different numbers of neutrons Signup and view all the answers

Which bond type is characterized by the transfer of electrons?

Ionic bond Signup and view all the answers

What is electronegativity primarily used for?

To predict the strength of chemical bonds Signup and view all the answers

Which functional group is considered acidic due to its ability to release H+ ions into solution?

Carboxyl Signup and view all the answers

What type of reaction involves the joining of monomers and the release of water?

Dehydration Reaction Signup and view all the answers

Which macromolecule has amino acids as its monomers?

Proteins Signup and view all the answers

Which of the following functional groups contains a sulfur atom?

Sulfhydryl Signup and view all the answers

What class of sugars includes glucose and fructose?

Monosaccharides Signup and view all the answers

What is a common characteristic of all carbohydrates?

They are energy sources and storage units for cells. Signup and view all the answers

Which type of lipid is formed by a combination of glycerol and fatty acids?

Triglycerides Signup and view all the answers

Which of the following statements is true about hydrolysis reactions?

They break down polymers and consume water. Signup and view all the answers

What is reductionism as it applies to biology?

A method that reduces complex systems to simpler components for analysis. Signup and view all the answers

Which level comes directly after 'molecules' in the biological organization hierarchy?

Organelles Signup and view all the answers

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells possess a nucleus and are generally more complex. Signup and view all the answers

What is genome sequencing primarily used for in genomics?

To determine the complete set of an organism's genetic material. Signup and view all the answers

Which of the following is an example of an emergent property in biology?

The ability of an entire flock of birds to maneuver together. Signup and view all the answers

Which of these human activities contributes to climate change primarily through the release of greenhouse gases?

Burning fossil fuels for energy. Signup and view all the answers

What purpose does bioinformatics serve in biological sciences?

To analyze and manage biological data using computational tools. Signup and view all the answers

What does gene expression describe in biological terms?

The synthesis of proteins from DNA segments. Signup and view all the answers

What is the primary function of monosaccharides?

Serving as a quick energy source Signup and view all the answers

Which of the following describes the structure of polysaccharides?

Long chains of monosaccharides Signup and view all the answers

What is a characteristic of saturated fats?

They are solid at room temperature Signup and view all the answers

How do phospholipids contribute to cell membranes?

By creating a lipid bilayer with hydrophilic heads and hydrophobic tails Signup and view all the answers

What is the significance of the R group in amino acids?

It defines the amino acid's identity and properties Signup and view all the answers

What type of bond joins two amino acids together?

Peptide bond Signup and view all the answers

Which level of protein structure is characterized by a unique 3D shape determined by interactions among R groups?

Tertiary structure Signup and view all the answers

What occurs when a protein is denatured?

It loses its functional shape Signup and view all the answers

Study Notes

Five Unifying Themes of Biology

Cell Theory: All living things are made of cells, and cells are the basic units of life.
Gene Theory: Information to build and maintain organisms is carried in genes, which are units of heredity.
Evolution: Organisms have evolved over time through natural selection, giving rise to diversity among life forms.
Interdependence: Living organisms interact with each other and with the environment, shaping ecosystems.
Regulation: Living organisms maintain a stable internal environment through a series of regulatory mechanisms.

Levels of Biological Organization

Atoms are the basic unit of matter
Atoms combine to form molecules
Molecules associate to form organelles
Organelles are organized into cells
Cells form tissues,
Tissues combine to create organs
Organs work together to form organisms
Organisms of the same species form populations
Populations of different species interact within communities
Communities interacting with their environment make up an ecosystem
All ecosystems together encompass the biosphere

Eukaryotic vs. Prokaryotic Cells

Eukaryotic cells are complex, with a nucleus and other membrane-bound organelles (plants and animals).
Prokaryotic cells are simpler, lacking a nucleus and membrane-bound organelles (bacteria).

Human activities contributing to climate change

Burning Fossil Fuels releases large amounts of carbon dioxide and other greenhouse gases into the atmosphere.
Deforestation reduces the amount of carbon dioxide absorbed from the atmosphere.
Agriculture, particularly livestock and rice production, releases methane. Fertilizers also release nitrous oxide.
Industrial Processes contribute to greenhouse gas emissions.
Waste Management produces methane from decomposing waste.
Urbanization leads to an increase in energy usage and emissions.

Elements Abundant in Living Organisms

The most abundant elements in living organisms are carbon (C), hydrogen (H), oxygen (O), and nitrogen (N).

Important Elements

Potassium (K)
Sodium (Na)
Oxygen (O)
Hydrogen (H)
Calcium (Ca)
Nitrogen (N)
Sulfur (S)
Phosphorus (P)
Chlorine (Cl)

Elements, Compounds, and Atoms

Atoms are the smallest unit of matter, containing protons, neutrons, and electrons.
Elements are pure substances comprised of a single type of atom.
Compounds are formed when two or more different elements chemically combine in a fixed ratio.

Electrons, Neutrons, Protons, Atomic Number, and Mass Number

Electrons are negatively charged particles; found in the electron shells surrounding the nucleus.
Protons are positively charged particles; located in the nucleus of an atom.
Neutrons are neutral particles; found in the nucleus of an atom.
Atomic number represents the number of protons in an atom's nucleus.
Mass number represents the total number of protons and neutrons in an atom's nucleus.
Isotopes are atoms of the same element that have the same atomic number but different mass numbers (different number of neutrons).
Electron shell depicts the energy level of an electron. The further away from the nucleus an electron is, the more potential energy it has.

Valence Electrons and Bonding Behavior

Valence electrons are electrons in the outermost electron shell, and determine the bonding behavior of an atom.
Electronegativity is an atom's ability to attract electrons in a covalent bond; electronegativity differences influence bond polarity (ionic, nonpolar covalent, polar covalent).

Main Types of Chemical Bonds

Ionic bonds form when one atom donates an electron to another atom, resulting in oppositely charged ions that attract each other.
Nonpolar covalent bonds form when two atoms of similar electronegativity share electrons equally.
Polar covalent bonds form when two atoms of different electronegativity share electrons unequally.
Hydrogen bonds weak attractions between a hydrogen atom covalently linked to a highly electronegative atom (e.g., oxygen, nitrogen) and an electronegative atom in another molecule.

Water - a Unique Molecule

Water is polar, meaning it has partially positive and partially negative charges in different regions, making it a good solvent.
Cohesion results from hydrogen bonding, allowing water molecules to stick together, contributing to its high surface tension.
Adhesion is water's ability to stick to other molecules like glass, which explains capillary action in plants.
High Specific heat indicates the amount of heat required to raise the temperature of a given amount of water. This property helps moderate temperature fluctuations, especially in bodies of water.
High heat of vaporization is the amount of energy needed to change water from a liquid to a gas, contributing to cooling through evaporation.
Density: Water is most dense at 4°C; ice floats because the hydrogen bonds form a lattice structure making it less dense than liquid water.

Hydrophilic & Hydrophobic Interactions

Hydrophilic (water-loving) substances interact with and dissolve in water due to their polar nature.
Hydrophobic (water-fearing) substances do not dissolve in water because of their nonpolar nature; they tend to cluster together.

pH

pH measures the hydrogen ion (H+) concentration in a solution.
Acids are substances that donate H+ ions to a solution.
Bases are substances that accept H+ ions from a solution.
Buffers are substances that resist changes in pH by absorbing or releasing H+ ions.

Bicarbonate Buffer System

Carbonic acid (H2CO3) in the blood acts as a weak acid.
Bicarbonate (HCO3-) acts as a weak base.
The bicarbonate buffer system maintains a stable blood pH by reacting with acids and bases.

Organic Compounds

Organic compounds are molecules containing carbon (C), excluding carbon dioxide (CO2), carbonates, and carbides.

Significance and Properties of Carbon

Tetravalence allows carbon to form four covalent bonds with other elements.
Bonding Diversity enables carbon to form stable bonds with various elements like H, O, N, and S, creating the great diversity of organic compounds.
Chain and ring structures formed by carbon allow the formation of long chains of molecules and rings.
Stability of carbon-carbon (C-C) and carbon-hydrogen (C-H) bonds contributes to the structure and integrity of molecules.
Isomerism occurs when different molecules have the same molecular formula but different structures.

Types of Isomers

Structural Isomers differ in the connectivity of their atoms.
Geometric Isomers differ in the spatial arrangement of atoms around a double bond or a ring structure.
Stereoisomers: Have the same connectivity of atoms but different spatial arrangement.

Monomers & Polymers

Monomers are small building blocks, the basic units that make up polymers.
Polymers are large molecules formed through the joining together of monomers.

The Four Major Biological Macromolecules

Carbohydrates are polymers composed of monosaccharides and provide energy and structural support.
Proteins are polymers of amino acids, fulfilling a vast array of roles, including catalysis and transport.
Nucleic Acids are polymers of nucleotides, playing a vital role in storing and transmitting genetic information.
Lipids are a diverse group of hydrophobic molecules consisting of fatty acids and glycerol, providing energy storage, insulation, and structural components.

Dehydration and Hydrolysis Reactions

Dehydration reactions remove a water molecule, joining monomers to form polymers.
Hydrolysis reactions add a water molecule, breaking down polymers into monomers.

Carbohydrates Structure and Function

General formula: (CH2O)n, where n is the number of carbon atoms.
Monosaccharides are simple sugars, like glucose and fructose.
Disaccharides are formed when two monosaccharides join together.
Polysaccharides are long chains of monosaccharides.

Polysaccharides Differences

Starch: Energy storage in plants; alpha-glucose monomers linked in a helical structure.
Glycogen: Energy storage in animals; alpha-glucose monomers linked in a branched structure.
Cellulose: Structural component of plant cell walls; beta-glucose monomers in a straight chain with hydrogen bonding.

Lipids - Diverse Hydrophobic Molecules

Fats: Energy storage; composed of glycerol and fatty acids.
Phospholipids: Form cell membranes; have a hydrophilic head and two hydrophobic tails.
Steroids: Act as hormones and help stabilize cell membranes.

Saturated vs. Unsaturated Fats

Saturated fats contain only single bonds between carbon atoms, making them solid at room temperature.
Unsaturated fats have at least one double bond between carbon atoms, making them liquid at room temperature (oils).

Amino Acids - The Building Blocks of Proteins

Amino Acids have a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a variable R group.
The R group determines the amino acid's identity, affecting its properties and interactions.

Peptide Bond and Levels of Protein Structure

Peptide bonds link amino acids to form proteins.
Primary Structure: The sequence of amino acids in a polypeptide chain.
Secondary Structure: Alpha-helices and beta-sheets formed through hydrogen bonding between backbone atoms.
Tertiary Structure: Three-dimensional folding of a polypeptide chain, influenced by interactions between R groups.
Quaternary Structure : The arrangement of multiple polypeptide chains in a protein complex.

Protein Structure Importance

Shape determines function.
Chaperone proteins assist with protein folding.

Protein Denaturation

Denaturation involves the unraveling and loss of a protein's structure, disrupting its function.
This can occur due to changes in temperature, pH, or salt concentration.

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Description

Explore the five unifying themes of biology that shape our understanding of life. From cell theory to evolution, this quiz covers the foundational ideas and levels of biological organization. Test your knowledge on how these concepts interconnect and contribute to the diversity of living organisms.