Biology Chapter 5: Evolution and Classification

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Questions and Answers

What role do mutations in genes play in a population?

They lead to diversity in the population. (correct)

They eliminate the need for horizontal gene transfer.

They cause all traits to be equally favorable.

They decrease genetic diversity.

Which type of bond involves the transfer of electrons between atoms?

Hydrogen bond

Covalent bond

Ionic bond (correct)

Metallic bond

What is a characteristic of polar molecules?

They have equal sharing of electrons.

They are hydrophobic.

They do not interact with water.

They possess partial charges. (correct)

Which functional group is represented by the formula -CHO?

Carbonyl (Aldehyde) group Signup and view all the answers

What is the primary function of the Golgi apparatus in a eukaryotic cell?

Modification, sorting, and secretion of proteins Signup and view all the answers

Which component of a prokaryotic cell is responsible for allowing bacteria to attach to surfaces?

Pili Signup and view all the answers

Which of the following correctly describes the pH scale?

Acids release H+ ions when dissolved in water. Signup and view all the answers

Which organelle is primarily involved in ATP synthesis?

Mitochondrion Signup and view all the answers

Which domain includes organisms with prokaryotic cells?

Both B and C Signup and view all the answers

What is the role of the cytoskeleton in eukaryotic cells?

Providing shape and aiding movement Signup and view all the answers

What does Mendel's Law of Segregation state about alleles during gamete formation?

Alleles separate randomly during gamete formation. Signup and view all the answers

In a monohybrid cross of Tt x Tt, what is the expected phenotypic ratio?

3:1 Signup and view all the answers

Which of the following best describes codominance?

Both phenotypes are simultaneously expressed. Signup and view all the answers

What does the dihybrid cross of AABB x aabb produce in the F1 generation?

AaBb only Signup and view all the answers

What is an example of polygenic inheritance?

Skin color related to multiple genes. Signup and view all the answers

Which process describes the effect where multiple genes influence a single trait?

Polygenic inheritance Signup and view all the answers

What is meant by linkage in genetics?

Genes that are close together on a chromosome are less likely to separate. Signup and view all the answers

What occurs during X chromosome inactivation?

One of the two X chromosomes is randomly condensed. Signup and view all the answers

What is the primary function of the plasma membrane?

To act as a selectively permeable barrier Signup and view all the answers

Which of the following best describes passive transport?

Occurs without the need for cellular energy Signup and view all the answers

In glycolysis, what is the net gain of ATP produced from one molecule of glucose?

2 ATP Signup and view all the answers

Which reaction occurs during the transition state in an enzyme-catalyzed reaction?

Substrates are converted to products Signup and view all the answers

What is the role of cyclic AMP (cAMP) in cellular signaling?

It regulates protein activity inside the cell Signup and view all the answers

What is produced during anaerobic respiration in yeast cells?

Ethanol Signup and view all the answers

What is the function of the porphyrin ring in chlorophyll?

To absorb light energy Signup and view all the answers

What is the consequence of the domino effect during anaerobic respiration?

Interruption of electron transport Signup and view all the answers

Which is NOT a characteristic of the G-protein-coupled receptors (GPCRs)?

They directly catalyze a chemical reaction Signup and view all the answers

In the Calvin Cycle, what compound is fixed in the carbon fixation process?

Ribulose bisphosphate (RuBP) Signup and view all the answers

How do enzymes specifically bind to their substrates?

Through complementary shapes at the active site Signup and view all the answers

Which of the following statements about DNA structure is correct?

Complete turn of the double helix consists of 10 base pairs Signup and view all the answers

What does the Meselson-Stahl experiment demonstrate about DNA replication?

DNA replication is semiconservative Signup and view all the answers

What is served by the structure of the promoter in DNA?

Facilitates RNA polymerase binding Signup and view all the answers

What is the role of the 5' cap in mRNA?

Protects mRNA from degradation Signup and view all the answers

Which phase of the cell cycle involves the replication of DNA?

S phase Signup and view all the answers

What primarily provides a signal for the transition from metaphase to anaphase?

Alignment of chromosomes Signup and view all the answers

Which type of RNA directly carries amino acids during translation?

tRNA Signup and view all the answers

What happens during the process of transcription termination?

RNA polymerase dissociates from the DNA Signup and view all the answers

What is the significance of crossing over during meiosis?

It increases genetic variation among gametes Signup and view all the answers

What is the function of the ribosomal-binding site in mRNA?

To provide a binding site for ribosomes Signup and view all the answers

Which cellular structure is responsible for the removal of introns from pre-mRNA?

Spliceosome Signup and view all the answers

What is the primary error-checking mechanism in the cell cycle?

P53 protein Signup and view all the answers

In which phase of mitosis do sister chromatids align at the metaphase plate?

Metaphase Signup and view all the answers

What cellular event occurs during telophase in mitosis?

Nuclear envelope reforms Signup and view all the answers

During which phase of the cell cycle do cyclin D and E synthesis occur?

G1 phase Signup and view all the answers

What is the role of amino acid transferase in protein synthesis?

Attaches amino acids to tRNA Signup and view all the answers

Study Notes

Mechanisms of Evolution

Vertical descent with mutations: Mutations in genes create diversity within a population. Genes for advantageous traits become more common in subsequent generations.
Horizontal gene transfer: Genetic material is exchanged between different organisms (e.g., plants to animals).

Phylogenetic Trees and Classification

Phylogenetic trees illustrate evolutionary relationships among groups.
Taxonomy uses evolutionary relationships to categorize organisms.
Principle categories: Domain (bacteria, archaea, eukarya), Kingdoms (plants, protists, fungi, animals), Phylum, Class, Order, Family, Genus (capitalized), Species (underlined).

Chemical Bonding and Water Properties

Covalent Bonds: Atoms share electrons to form stable electron pairs.
Ionic Bonds: Atoms transfer electrons.
Polarity: Unequal electron sharing creates partial charges (mainly in nitrogen and oxygen).
Hydrophilic: Substances attracted to water (polar).
Hydrophobic: Substances repelled by water (nonpolar).
Water as a Solvent: Water dissolves solutes with similar properties ("like dissolves like"). Hydrophilic compounds (polar) dissolve in water; hydrophobic compounds (nonpolar) do not.
pH: Measures acidity or basicity. Water dissociates into H+ and OH-. pH 7 is neutral. Higher numbers indicate basicity; lower numbers indicate acidity. Acids release H+ in water; bases accept H+.

Functional Groups

Amino (-NH2)
Carbonyl (Ketone -CO, Aldehyde -CHO)
Carboxyl (-COOH)
Hydroxyl (-OH)
Methyl (-CH3)
Phosphate (-PO4 2-)

Prokaryotic and Eukaryotic Cell Structures

Prokaryotic:*
Pili: Attachment to surfaces/each other.
Cytoplasm: Metabolic site.
Ribosomes: Synthesize polypeptides.
Nucleoid: DNA location.
Plasma membrane: Encloses cytoplasm.
Cell wall: Support and protection.
Glycocalyx: Gelatinous outer covering.
Flagella: Movement.
Eukaryotic:*
Centrosome: Microtubule growth and centriole location.
Rough ER: Protein sorting/secretion.
Smooth ER: Detoxification/lipid synthesis.
Mitochondria: ATP synthesis.
Cytoskeleton: Protein filaments for shape and movement.
Peroxisome: Breakdown of harmful molecules.
Golgi apparatus: Modification, sorting, and secretion of lipids/proteins.
Cytosol: Site of many metabolic pathways.
Plasma membrane: Controls substance movement, cell signaling.
Ribosomes: Polypeptide synthesis.
Lysosomes: Macromolecules degradation.
Nuclear envelope: Double membrane surrounding the nucleus.
Nucleus: Passageway for molecules
Nuclear pore: Passageway for molecules into/out of nucleus.
Endosymbiotic theory: Mitochondria and chloroplasts originated from engulfed prokaryotes.

Plasma Membrane and Transport

Plasma membrane: Selectively permeable phospholipid bilayer. Controls movement of molecules.
Passive transport: Movement down a concentration gradient (no energy required).
Active transport: Movement against a concentration gradient (requires energy).

Enzyme Mechanisms

Enzymes reduce activation energy for reactions.
Substrates bind to active sites (specific).
Enzymes catalyze reactions by pushing substrates toward products.
Steps of enzyme-catalyzed reactions: substrate binding, conformational change, product formation, product release.

Aerobic Respiration

Glycolysis: Glucose (6C) → 2 pyruvates (3C), producing 2 ATP and 2 NADH in the cytoplasm.
Pyruvate oxidation: Pyruvate → Acetyl CoA (2C), producing CO2 and NADH.
Citric acid cycle: Acetyl CoA → 2 ATP, 6 NADH, 2 FADH2.
Oxidative phosphorylation (ETC): Electron transport chain and ATP synthesis; ATP production from electron transport.

Anaerobic Respiration and Fermentation

Anaerobic respiration: Alternatives to oxygen as final electron acceptors (e.g., nitrate).
Fermentation: Only glycolysis occurs; pyruvate is reduced to lactic acid (humans) or ethanol (yeast/bacteria).

Photosynthesis: Light-Dependent and Calvin Cycle

Light-dependent reactions: Light absorption by pigments (chlorophyll a absorbs red, violet, and blue light; reflects green). Electrons are ejected.
Calvin Cycle: Carbon fixation (CO2 + RuBP → 3PGA), reduction (ATP + NADPH used to convert 3PGA to sugars), regeneration of RuBP.

Cellular Receptors

Enzyme-linked receptors: Often kinases; often involve phosphorylation cascades (e.g., receptor tyrosine kinases).
G protein-coupled receptors (GPCRs): 7 transmembrane domains; G protein activation; second messenger signaling (e.g., cAMP).
Ligand-gated ion channels: Channels open/close in response to ligands.

DNA Structure and Replication

DNA structure: Double helix; nucleotides (A, T, G, C).
Chargaff's rule: %A = %T, %G = %C.
Watson and Crick's model: Used Franklin's X-ray data.
DNA replication: Semiconservative (each original strand serves as a template for a new strand).
PCR (Polymerase Chain Reaction): Amplifies DNA segments; steps: denaturation, annealing, extension.
Sanger sequencing: Determines DNA sequence.

Transcription

Gene structure: Promoter, transcribed region, terminator, regulatory sequences.
Transcription process: RNA polymerase binds promoter, elongation (complementary RNA strand built), termination.
RNA modifications: 5' cap and 3' poly-A tail for stability and translation signals. Removal of introns via spliceosomes.

Translation

mRNA structure: Ribosomal binding site (prokaryotes only), start codon (AUG), coding sequence, stop codon. Codons code for amino acids (degenerate code).
tRNA structure: Cloverleaf model; anticodon; amino acid attachment site.
Ribosome structure and composition: Composed of RNA and proteins; have A, P, and E sites. Bacterial (70S) and eukaryotic (80S) ribosomes.

Lac Operon Regulation

Lac operon: Bacterial gene regulation of lactose metabolism. Regulated by a repressor protein.

Eukaryotic Cell Cycle

Cell cycle phases: G1, S, G2, M (mitosis).
G0 phase: Non-dividing cells.
Cyclins and CDKs: Regulate the cell cycle.
Checkpoints: Control points in the cell cycle (G1, G2, M). p53 regulates these checks.
Proto-oncogenes and tumor suppressor genes: Control cell division.
Mitosis and cytokinesis: Process of cell division.
Meiosis: Cell division for gamete formation.

Mendelian Genetics

Mendel's laws of segregation and independent assortment.
Monohybrid and dihybrid crosses.
Extensions of Mendel's laws: incomplete dominance, codominance, environmental influence, pleiotropy, epistasis, polygenic inheritance.
Linkage and extranuclear inheritance (mitochondria, chloroplasts).
Epigenetic inheritance (X chromosome inactivation).

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Description

This quiz covers mechanisms of evolution, including vertical descent with mutations and horizontal gene transfer. Additionally, it explores phylogenetic trees, taxonomy, and the basic principles of chemical bonding and properties of water. Test your knowledge on how these concepts are interrelated in biology.