Exam One: Chapters 1-3

What elements do organic molecules primarily contain?

Carbon and hydrogen atoms bonded to other atoms.

What are the four types of organic molecules found in organisms?

Carbohydrates, lipids, proteins, and nucleic acids.

How many organic molecules can a simple bacterial cell contain?

Approximately 5,000 organic molecules.

What allows carbon atoms to form covalent bonds with multiple elements?

The chemistry of the carbon atom.

What are hydrocarbons?

Chains of carbon atoms bonded exclusively to hydrogen atoms.

What is the carbon skeleton of an organic molecule?

The carbon chain that serves as the backbone of the molecule.

What is a functional group?

A cluster of specific atoms bonded to the carbon skeleton that has characteristic structure and functions.

What effect does the hydroxyl group (-OH) have on a carbon skeleton?

It turns the molecule into an alcohol and makes it hydrophilic.

What are isomers?

Organic molecules with identical molecular formulas but different arrangements of their atoms.

What are polymers?

Large biomolecules constructed by linking many of the same type of small subunits called monomers.

What is a dehydration reaction?

A reaction that synthesizes biomolecules by removing a water molecule and forming a covalent bond between two monomers.

What is hydrolysis?

A reaction that breaks down polymers by adding water, attaching a hydroxyl group to one monomer and a hydrogen to the other.

What are monosaccharides?

Simple sugars with a backbone of three to seven carbon atoms.

What is the molecular formula for glucose, fructose, and galactose?

C6H12O6.

What is the primary source of biochemical energy in nearly all organisms?

Glucose.

What are disaccharides?

Carbohydrates composed of two monosaccharides joined by a dehydration reaction.

What is maltose composed of?

Two glucose molecules.

What is the storage form of glucose in animals?

Glycogen.

What is cellulose?

A polymer of glucose that forms microfibrils, the primary constituent of plant cell walls.

What is chitin?

A polymer of glucose with an amino group, found in the exoskeleton of crabs and insects.

What are lipids?

A diverse group of hydrophobic molecules that include fats, oils, phospholipids, and steroids.

What are triglycerides?

Fats and oils composed of glycerol and fatty acids.

What distinguishes saturated fatty acids from unsaturated fatty acids?

Saturated fatty acids lack double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

What are phospholipids?

Lipids that form the plasma membrane, consisting of a glycerol backbone, two fatty acids, and a phosphate group.

What is the role of enzymes in biochemical reactions?

They speed up chemical reactions by bringing reactants together and may participate in the reaction without being changed.

What is the primary function of waxes in organisms?

To provide protective functions.

What property allows phospholipids to form a plasma membrane?

Phospholipids can form an interface or separation between two solutions.

What is the structure of steroids?

Steroids have skeletons of four fused carbon rings.

What role does cholesterol play in animal cells?

Cholesterol is a component of the plasma membrane and a precursor for other steroids.

What health issues can arise from a diet high in saturated fats and cholesterol?

It can lead to cardiovascular disorders.

What are waxes composed of?

Waxes are long-chain fatty acids bonded to long-chain alcohols.

What are the properties of waxes?

Waxes have a high melting point, are waterproof, and resist degradation.

How do waxes function in plants?

They form a protective covering that prevents water loss in leaves and fruits.

What is the primary importance of proteins in cells?

Proteins are crucial for the structure and function of cells.

What is the function of enzymatic proteins?

They act as organic catalysts to accelerate chemical reactions within cells.

What is keratin and where is it found?

Keratin is a structural protein that makes up hair and nails.

What is the role of hemoglobin in the body?

Hemoglobin transports oxygen in red blood cells.

What are antibodies and their function?

Antibodies are proteins that prevent infection.

What is the significance of insulin in the body?

Insulin is a regulatory protein that influences glucose metabolism.

What are the components of amino acids?

Amino acids contain an acidic group (-COOH) and an amino group (-NH2).

What distinguishes one amino acid from another?

Amino acids differ according to their particular R group.

What is a peptide bond?

A peptide bond is a covalent bond between two amino acids.

What is the primary structure of a protein?

The primary structure is the specific sequence of amino acids in a protein.

What forms the secondary structure of proteins?

The secondary structure results from coiling or folding of a polypeptide.

What is the difference between α helix and β sheet in protein structure?

α helix is a spiral shape, while β sheet is a pleated structure.

What is the tertiary structure of a protein?

The tertiary structure is the final three-dimensional shape due to interactions among R groups.

What is quaternary structure in proteins?

Quaternary structure occurs when two or more polypeptides combine.

What role do chaperone proteins play in protein synthesis?

Chaperone proteins help proteins fold into their correct shapes.

What are nucleic acids and their primary function?

Nucleic acids are polymers of nucleotides that store information in cells.

What is the difference between DNA and RNA?

DNA contains deoxyribose sugar and is double-stranded; RNA contains ribose and is single-stranded.

What is ATP and its significance in cells?

ATP is a high-energy nucleotide that supplies energy for cellular processes.

What happens when the terminal phosphate bond of ATP is hydrolyzed?

Energy is released, and ADP is formed.

What is the role of coenzymes in cells?

Coenzymes facilitate enzymatic reactions.

What is biology?

The study of life.

What is the basic unit of structure and function in living things?

The cell.

What is an ecosystem?

A community plus its physical environment.

What is homeostasis?

The maintenance of internal conditions within certain boundaries.

What is metabolism?

All the chemical reactions that occur in a cell.

What is photosynthesis?

The process that converts solar energy into the chemical energy of carbohydrates.

What is an adaptation?

Any modification that makes an organism better able to function in a particular environment.

What is taxonomy?

The discipline of biology that identifies, names, and classifies organisms.

What are the three domains of life?

Domain Archaea, Domain Bacteria, and Domain Eukarya.

What is the significance of mutations in evolution?

They introduce variations among members of a population, fueling natural selection.

What is the biosphere?

The zone of air, land, and water where organisms exist.

What is a species?

A group of similar, interbreeding organisms.

What is the role of energy in living organisms?

Energy is required to maintain organization and conduct life-sustaining processes.

What is the process of reproduction in living organisms?

All living organisms must reproduce to maintain a population and pass on genetic information.

What is the significance of feedback systems in living organisms?

They monitor internal conditions and make adjustments to maintain homeostasis.

What does the term 'emergent properties' refer to?

New characteristics that arise at each level of biological organization.

What is the difference between prokaryotes and eukaryotes?

Prokaryotes lack a membrane-bound nucleus, while eukaryotes have one.

What is the importance of chemical cycling in ecosystems?

Chemicals are recycled through food chains and returned to living plants after decomposition.

What is the evolutionary tree?

A diagram that traces the ancestry of life on Earth to a common ancestor.

What is the role of solar energy in ecosystems?

It is the ultimate source of energy for nearly all life on Earth.

What is the classification hierarchy from species to domain?

Species, genus, family, order, class, phylum, kingdom, supergroup, domain.

What is the significance of the common ancestor in evolution?

It suggests that all living organisms share a lineage that has evolved over time.

What type of cells do Archaea consist of?

Prokaryotic cells of various shapes.

How do Archaea obtain food?

They absorb or chemosynthesize food.

What is a characteristic feature of Bacteria?

Bacteria can adapt to all environments.

What is the main difference between Archaea and Bacteria?

They have unique chemical characteristics.

What are the four kingdoms under Domain Eukarya?

Kingdom Protista, Kingdom Fungi, Kingdom Plantae, Kingdom Animalia.

What is binomial nomenclature?

A two-part naming system for organisms, consisting of genus and species.

What is the first word in binomial nomenclature?

The genus, which is always capitalized.

What is the second word in binomial nomenclature?

The species designation, written in lowercase.

What is a hypothesis?

A tentative explanation for an observation.

What is the purpose of a control group in an experiment?

To compare results with a test group that is exposed to the experimental variable.

What does statistical significance indicate?

The probability that results are not due to chance, typically p < 0.05.

What happens if a hypothesis is supported by experimental results?

The hypothesis is accepted; if not, it is rejected.

What is the role of peer review in scientific research?

To evaluate findings and ensure reproducibility by other scientists.

What distinguishes a scientific theory from a scientific law?

A theory connects multiple hypotheses, while a law is a widely accepted principle with no serious challenges.

What is biodiversity?

The total number and relative abundance of species, genetic variability, and different ecosystems.

What is extinction?

The death of the last member of a species or larger classification category.

What is the estimated number of species on Earth?

As high as 8.7 million species.

What is the significance of statistical data in experiments?

To analyze results and determine the effectiveness of treatments.

What is the purpose of an experimental design?

To ensure that a specific variable is tested in an experiment.

What is the role of observations in the scientific method?

To gather information about a phenomenon or natural event.

What is the expected outcome of a good experimental design?

To isolate the effects of the experimental variable.

What is the function of statistical analysis in scientific research?

To interpret data and assess the validity of the hypothesis.

What is the significance of the p-value in statistical analysis?

A p-value less than 0.05 indicates strong evidence against the null hypothesis.

What is the relationship between science and technology?

Science provides knowledge; technology applies that knowledge for human benefit.

What ecosystems are threatened by human activities?

Tropical rain forests and coral reefs.