Biology Chapter: Cell Structure and Function
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Questions and Answers

Which characteristic of living organisms involves sensitivity to environmental changes?

  • Sensitivity (correct)
  • Cellular organization
  • Energy utilization
  • Ordered complexity

    • What type of organisms are classified under the domain Prokarya?

  • Unicellular organisms without a nucleus (correct)
  • Organisms with membrane-bound organelles
  • Complex multicellular organisms
  • Organisms possessing a nucleus

    • According to the Cell Theory, what is the smallest living unit?

  • Organisms
  • Tissues
  • Cells (correct)
  • Viruses

    • Which component is NOT typically found in prokaryotic cells?

    <p>Nucleus</p> Signup and view all the answers

    What is the primary composition of the bacterial cell wall?

    <p>Peptidoglycan</p> Signup and view all the answers

    What is the main function of the nucleolus in a cell?

    <p>Ribosome and RNA synthesis</p> Signup and view all the answers

    Which part of the Golgi apparatus is responsible for the exit of materials?

    <p>Trans face</p> Signup and view all the answers

    What is the primary role of lysosomes in a cell?

    <p>Digestion of macromolecules</p> Signup and view all the answers

    Which type of endoplasmic reticulum is involved in lipid synthesis?

    <p>Smooth ER</p> Signup and view all the answers

    What process involves the engulfing of another particle by a cell?

    <p>Phagocytosis</p> Signup and view all the answers

    What is the primary structure responsible for protein synthesis within a cell?

    <p>Ribosome</p> Signup and view all the answers

    Mitochondria are known to be involved in which process?

    <p>Oxidative metabolism</p> Signup and view all the answers

    What structural element is primarily involved in maintaining cell shape and facilitating movement?

    <p>Microfilaments</p> Signup and view all the answers

    Which component of the endomembrane system is primarily responsible for packaging and distributing synthesized molecules?

    <p>Golgi apparatus</p> Signup and view all the answers

    According to the endosymbiosis theory, what was engulfed by a cell to form eukaryotes?

    <p>A prokaryote</p> Signup and view all the answers

    What process describes the net diffusion of water across a membrane toward a higher solute concentration?

    <p>Osmosis</p> Signup and view all the answers

    Which type of junction directly connects the cytoskeletons of neighboring cells or to the extracellular matrix (ECM)?

    <p>Adhesive junctions</p> Signup and view all the answers

    What is a characteristic of homologous structures?

    <p>Same evolutionary origin, different structures</p> Signup and view all the answers

    In protein structure, what term describes the final folded shape of a globular protein?

    <p>Tertiary structure</p> Signup and view all the answers

    What type of bond is formed when atoms share two or more valence electrons?

    <p>Covalent bond</p> Signup and view all the answers

    Which substance is formed by linking two monosaccharides together?

    <p>Disaccharide</p> Signup and view all the answers

    What is the role of chaperones in protein biology?

    <p>To assist in protein folding</p> Signup and view all the answers

    How does a buffer function in biological systems?

    <p>Resists changes in pH</p> Signup and view all the answers

    Which of the following best describes triglycerides?

    <p>Made of one glycerol and three fatty acids</p> Signup and view all the answers

    What is the primary energy currency of the cell?

    <p>Adenosine triphosphate (ATP)</p> Signup and view all the answers

    What structure in plant cells allows for communication and connection between adjacent cells?

    <p>Plasmodesmata</p> Signup and view all the answers

    What proteins are responsible for the recognition of self and non-self cells by the immune system?

    <p>MHC proteins</p> Signup and view all the answers

    Which type of transport requires energy and moves substances from low to high concentration?

    <p>Active transport</p> Signup and view all the answers

    Which term describes small changes in influenza virus proteins that can evade vaccine-induced immunity?

    <p>Antigenic drift</p> Signup and view all the answers

    What is the primary reason why ATP is not suitable for long-term energy storage?

    <p>ATP is too reactive and unstable.</p> Signup and view all the answers

    What distinguishes exergonic reactions from endergonic reactions?

    <p>Exergonic reactions release free energy while endergonic store free energy.</p> Signup and view all the answers

    Which of the following accurately describes the role of retroviruses?

    <p>Reverse transcribe RNA into DNA</p> Signup and view all the answers

    Which statement about the 2nd Law of Thermodynamics is true?

    <p>Entropy is a measure of the disorder of a system.</p> Signup and view all the answers

    What type of junction allows for direct communication between animal cells?

    <p>Communicating junctions</p> Signup and view all the answers

    Which of the following correctly describes the role of enzymes in a chemical reaction?

    <p>Enzymes lower the activation energy required for reactions.</p> Signup and view all the answers

    Which component of the cell membrane contributes to its fluidity?

    <p>Cholesterol</p> Signup and view all the answers

    What happens during glycolysis?

    <p>A six-carbon glucose molecule is split into two three-carbon pyruvate molecules.</p> Signup and view all the answers

    What is the primary component of the viral capsid?

    <p>Proteins</p> Signup and view all the answers

    Which characteristic of the Electron Transport Chain is accurate?

    <p>It transfers electrons through a series of linked protein reactions.</p> Signup and view all the answers

    In which condition do cells typically swell due to excess water intake?

    <p>Hypotonic</p> Signup and view all the answers

    What is the main role of NAD+ in cellular respiration?

    <p>To recycle high-energy electrons for continued glycolysis.</p> Signup and view all the answers

    Which of the following accurately describes facilitated diffusion?

    <p>Involves specific carrier proteins</p> Signup and view all the answers

    What describes the process by which a virus hijacks a host cell to reproduce?

    <p>Viral replication</p> Signup and view all the answers

    Which process involves the transfer of a phosphate group directly to ADP to produce ATP?

    <p>Substrate-level phosphorylation.</p> Signup and view all the answers

    What type of solvent typically allows the passage of small polar molecules through the membrane?

    <p>Water</p> Signup and view all the answers

    Which of the following organisms captures energy through photosynthesis?

    <p>Autotrophs.</p> Signup and view all the answers

    What is a primary function of the sodium-potassium pump?

    <p>Maintains sodium and potassium gradients across the membrane</p> Signup and view all the answers

    What is the definition of free energy (G)?

    <p>The energy available to do work in a system.</p> Signup and view all the answers

    Which type of transport protein moves two molecules in opposite directions?

    <p>Antiporter</p> Signup and view all the answers

    What occurs to pyruvate when oxygen is not available?

    <p>It is reduced to ethanol or lactic acid.</p> Signup and view all the answers

    What total yield of ATP is produced per glucose molecule during cellular respiration in eukaryotes?

    <p>30 ATP</p> Signup and view all the answers

    Which enzyme catalyzes the conversion of pyruvate to acetyl-CoA?

    <p>Pyruvate dehydrogenase</p> Signup and view all the answers

    What is produced from each 3-carbon pyruvate molecule during its oxidation?

    <p>1 CO2, 1 Acetyl-CoA, and 1 NADH</p> Signup and view all the answers

    What is the primary function of DNA polymerase during DNA replication?

    <p>To match existing DNA bases with complementary nucleotides</p> Signup and view all the answers

    Which feature distinguishes the leading strand from the lagging strand during DNA replication?

    <p>The leading strand is synthesized continuously, the lagging strand in fragments</p> Signup and view all the answers

    Where does the citric acid cycle occur in eukaryotic cells?

    <p>Mitochondrial matrix</p> Signup and view all the answers

    What is a primary function of the electron transport chain (ETC)?

    <p>Transport electrons and pump protons</p> Signup and view all the answers

    What role does helicase play in DNA replication?

    <p>Unwinds the DNA double helix</p> Signup and view all the answers

    Which product is associated with lactic acid fermentation?

    <p>Lactic acid</p> Signup and view all the answers

    What is the significance of telomerase in eukaryotic cells?

    <p>It maintains the integrity of chromosome ends</p> Signup and view all the answers

    In anaerobic respiration, which molecules can serve as final electron acceptors?

    <p>Inorganic substances like nitrate or sulfate</p> Signup and view all the answers

    Which statement correctly describes the antiparallel nature of DNA strands?

    <p>One strand extends from 3' to 5' and the other from 5' to 3'</p> Signup and view all the answers

    What distinguishes the semiconservative model of DNA replication from other models?

    <p>Each daughter DNA strand contains one parental and one new strand</p> Signup and view all the answers

    During the citric acid cycle, what is regenerated to allow the cycle to continue?

    <p>Oxaloacetate</p> Signup and view all the answers

    Which type of DNA polymerase in E. coli is primarily responsible for DNA replication?

    <p>DNA polymerase III</p> Signup and view all the answers

    Which of the following describes the role of ATP synthase in cellular respiration?

    <p>Generates ATP by utilizing a proton gradient</p> Signup and view all the answers

    What is the function of the sliding clamp during DNA replication?

    <p>To enhance the processivity of DNA polymerase</p> Signup and view all the answers

    What molecule serves as the final electron acceptor in fermentation?

    <p>An organic molecule</p> Signup and view all the answers

    What type of activity do all three DNA polymerases possess, which is essential for proofreading?

    <p>3' to 5' exonuclease activity</p> Signup and view all the answers

    Which reaction occurs in the presence of oxygen during cellular respiration?

    <p>Pyruvate is oxidized to acetyl-CoA.</p> Signup and view all the answers

    What is the main pigment responsible for photosynthesis in plants?

    <p>Chlorophyll a</p> Signup and view all the answers

    Which of the following best describes the primary role of carotenoids in photosynthesis?

    <p>Aid in the absorption of light energy</p> Signup and view all the answers

    What critical process occurs during anaphase I of meiosis that distinguishes it from mitosis?

    <p>Cohesion is lost from the chromosome arms.</p> Signup and view all the answers

    What major feature of meiosis contributes to genetic variation in sexually reproducing populations?

    <p>Independent assortment of chromosomes.</p> Signup and view all the answers

    How does sister chromatid attachment differ between meiosis I and mitosis?

    <p>Sister kinetochores attach to the same pole in meiosis I.</p> Signup and view all the answers

    What suppresses DNA replication between meiosis I and meiosis II?

    <p>The complete loss of Cyclin B.</p> Signup and view all the answers

    What event occurs during prophase I that significantly alters genetic material?

    <p>Crossing over between homologous chromosomes.</p> Signup and view all the answers

    What is the primary function of the antenna complex in photosynthesis?

    <p>Capture photons and channel light energy</p> Signup and view all the answers

    Which photosystem is primarily responsible for generating NADPH?

    <p>Photosystem 1</p> Signup and view all the answers

    What molecule replenishes the electron 'hole' in chlorophyll after it is excited by light?

    <p>Water</p> Signup and view all the answers

    Which statement describes cyclic photophosphorylation?

    <p>It generates a proton gradient for ATP synthesis</p> Signup and view all the answers

    What is the end product of the Calvin cycle?

    <p>G3P</p> Signup and view all the answers

    What is the role of RuBisCO in the Calvin cycle?

    <p>Catalyze the fixation of CO2</p> Signup and view all the answers

    During photorespiration, what causes the enzyme RuBisCO to favor the oxidation of RuBP?

    <p>Closed stomata in hot conditions</p> Signup and view all the answers

    In which type of plants does C4 photosynthesis occur?

    <p>Corn and sugarcane</p> Signup and view all the answers

    What unique feature distinguishes CAM plants from C4 plants?

    <p>C4 pathway occurs during the night</p> Signup and view all the answers

    Which product is created from the reduction phase of the Calvin Cycle?

    <p>G3P</p> Signup and view all the answers

    What characterizes the direction of a nucleotide chain in DNA?

    <p>5'-to-3' orientation</p> Signup and view all the answers

    What type of bond connects nucleotides in a DNA strand?

    <p>Phosphodiester bond</p> Signup and view all the answers

    What was Rosalind Franklin known for in the study of DNA?

    <p>Discovering the helical structure via X-ray diffraction</p> Signup and view all the answers

    Which of the following best represents Chargaff's rules in DNA composition?

    <p>A = T and C = G</p> Signup and view all the answers

    What is the primary role of meiosis in sexual reproduction?

    <p>To halve the chromosome number and produce gametes</p> Signup and view all the answers

    During which stage of meiosis does crossing over occur?

    <p>Prophase I</p> Signup and view all the answers

    What term describes the failure of chromosomes to separate properly during meiosis?

    <p>Nondisjunction</p> Signup and view all the answers

    What occurs during anaphase I of meiosis?

    <p>Homologous chromosomes are pulled apart</p> Signup and view all the answers

    How many genetically distinct gametes are produced at the end of meiosis?

    <p>Four</p> Signup and view all the answers

    How do homologous chromosomes differ from each other?

    <p>They may carry different alleles for the same genes.</p> Signup and view all the answers

    What is the result of the second meiotic division?

    <p>Four haploid cells</p> Signup and view all the answers

    What is the significance of independent assortment during meiosis?

    <p>It increases genetic diversity among gametes.</p> Signup and view all the answers

    What is a characteristic of sister chromatids after meiosis I?

    <p>They carry different genetic information.</p> Signup and view all the answers

    What role does synapsis play in meiosis?

    <p>It allows homologous chromosomes to closely associate.</p> Signup and view all the answers

    Which statement best describes the end result of meiosis in animals?

    <p>Four haploid cells that develop into gametes are formed.</p> Signup and view all the answers

    What happens during telophase II of meiosis?

    <p>Four haploid cells are formed.</p> Signup and view all the answers

    What primarily distinguishes leading strand synthesis from lagging strand synthesis?

    <p>Leading strand synthesis occurs continuously, while lagging strand synthesis is discontinuous.</p> Signup and view all the answers

    Which enzyme is responsible for removing RNA primers during DNA replication?

    <p>DNA Pol I</p> Signup and view all the answers

    What is the role of the FtsZ protein in bacterial cell division?

    <p>To assist in the formation of the septum.</p> Signup and view all the answers

    What characterizes heterochromatin in a chromosome?

    <p>It is highly condensed, gene-poor, and transcriptionally silent.</p> Signup and view all the answers

    Which statement best describes the process of chromatin condensation during the cell cycle?

    <p>Condensed chromosomes are typically visible during prophase.</p> Signup and view all the answers

    What occurs during prophase of mitosis?

    <p>The nuclear envelope begins to break down.</p> Signup and view all the answers

    What is the purpose of ligase in DNA replication?

    <p>To join Okazaki fragments together.</p> Signup and view all the answers

    What marks the beginning of telophase in cell division?

    <p>Nuclear envelope forms</p> Signup and view all the answers

    Which feature distinguishes eukaryotic chromosomes from prokaryotic chromosomes?

    <p>Eukaryotic chromosomes contain histones.</p> Signup and view all the answers

    What is the function of the cohesin protein during cell division?

    <p>To hold sister chromatids together until anaphase.</p> Signup and view all the answers

    Which process is responsible for the physical division of the cytoplasm in animal cells?

    <p>Cleavage furrow formation</p> Signup and view all the answers

    How does the structure of chromatin influence gene expression?

    <p>Less condensed chromatin is generally more transcriptionally active.</p> Signup and view all the answers

    What is the primary role of cyclin-dependent kinases (Cdks) in the cell cycle?

    <p>To phosphorylate proteins</p> Signup and view all the answers

    What is primarily responsible for the compaction of DNA within a chromosome?

    <p>Interactions with positively charged histone proteins.</p> Signup and view all the answers

    Which checkpoint assesses the success of DNA replication in the cell cycle?

    <p>G2/M checkpoint</p> Signup and view all the answers

    Which phase of the eukaryotic cell cycle involves DNA replication?

    <p>S phase</p> Signup and view all the answers

    What is the function of the Anaphase-Promoting Complex (APC)?

    <p>To trigger anaphase</p> Signup and view all the answers

    What characterizes proto-oncogenes when they become mutated?

    <p>They become oncogenes</p> Signup and view all the answers

    What is the primary characteristic of a chromosome when it is composed of sister chromatids?

    <p>It is compacted and visible during mitosis.</p> Signup and view all the answers

    Which of the following best describes the kinetochores?

    <p>They are attachment sites for microtubules.</p> Signup and view all the answers

    Which gene is notably involved in the G1 checkpoint and plays a role in determining cell fate after DNA damage?

    <p>p53 gene</p> Signup and view all the answers

    What defines a diploid organism?

    <p>Having two complete sets of chromosomes.</p> Signup and view all the answers

    What is the role of growth factors in cell division?

    <p>To trigger intracellular signaling systems</p> Signup and view all the answers

    How does the control of the cell cycle differ in multicellular eukaryotes compared to yeast?

    <p>Eukaryotes have a more complex control system</p> Signup and view all the answers

    What occurs during cytokinesis in plant cells?

    <p>A cell plate forms</p> Signup and view all the answers

    What critical role does the cdc2 gene serve in cell cycle progression?

    <p>Pushing boundaries for mitosis</p> Signup and view all the answers

    What happens to tumor-suppressor genes in the development of cancer?

    <p>Both copies must be mutated to develop cancer</p> Signup and view all the answers

    What is a characteristic of asexual reproduction?

    <p>Generates genetically identical offspring</p> Signup and view all the answers

    What is the significance of whole-genome sequencing in cancer research?

    <p>It provides insights into tumor heterogeneity</p> Signup and view all the answers

    Study Notes

    Living Organisms

    • Characteristics of living organisms include cellular organization, ordered complexity, sensitivity to the environment, growth, development, reproduction, energy utilization, and homeostasis.

    Taxonomy

    • Taxonomy is a system used to name and classify organisms.
    • The highest level of biological classification is the domain.

    Prokaryotes

    • Prokaryotes are organisms with small, single-celled cells lacking a nucleus.
    • Examples include bacteria and archaea.
      • Prokaryotic cells are the simplest organisms.
      • They lack a membrane-bound nucleus.
      • DNA is present in the nucleoid.
      • A cell wall is outside the plasma membrane.
      • Ribosomes are present.
      • They lack common organelles.
      • Bacterial cell walls are composed of peptidoglycan.
      • Archaea cell walls lack peptidoglycan.

    Eukaryotes

    • Eukaryotes are organisms with larger, complex cells that have nuclei.
      • They contain a membrane-bound nucleus.
      • Their cells are more complex than prokaryotic cells.

    Cell Theory

    • All organisms are composed of cells.
    • Cells are the smallest living units.
    • Cells arise only from pre-existing cells.

    Basic Structural Similarities

    • Genetic material
    • Cytoplasm
    • Ribosomes
    • Plasma membrane are found in all living organisms

    Cytoskeleton

    • Molecules related to actin and tublin are found in prokaryotes and influence cell wall shape, strength, and shape.
    • Keeps organelles in fixed location

    Nucleus

    • Nucleus is the repository of genetic information.
    • Nucleolus is the region where ribosomes/RNA synthesis takes place.
    • The nucleus envelope is composed of two phospholipid bilayers.
    • Nuclear pores control the movement of materials in and out of the nucleus.

    Ribosomes

    • Ribosomes are the cell's protein synthesis machinery.
    • Found in all three domains (bacteria, archaea, and eukaryotes).
    • A complex of ribosomal RNA (rRNA) and protein.

    Endomembrane System

    • A series of membranes throughout the cytoplasm in eukaryotic cells.
    • Divides the cell into compartments for different functions.
    • This system is a fundamental distinction between eukaryotes & prokaryotes.
    • Proteins are transported through the endomembrane system.

    Endoplasmic Reticulum (ER)

    • Rough ER: site of protein synthesis, ribosomes attached
    • Smooth ER: lipid synthesis (phospholipids, store calcium), detoxification
    • The longest internal membrane system

    Golgi Apparatus

    • Flattened stacks of interconnected membranes (Golgi bodies).
    • Function in packaging & distribution of molecules.
    • Has a cis (receiving) face near the ER and a trans (shipping) face.

    Lysosomes

    • Membrane-bounded digestive vesicles.
    • Arise from the Golgi apparatus.
    • Contain enzymes that break down macromolecules (garbage disposal).
    • Break down old organelles.
    • Activated by fusing with a vesicle produced by phagocytosis.

    Microbodies

    • Variety of vesicles in eukaryotes that contain enzymes.

    Peroxisomes

    • Microbodies containing enzymes for oxidizing fatty acids.
    • Produce hydrogen peroxide as a byproduct.

    Vacuoles

    • Membrane-bound structures, typically found in plants, fungi, and protists.
    • Central vacuole: involved in cell growth (plants)
    • Contractile vacuole: in some protists for maintaining water balance
    • Storage vacuole: in plants for storage

    Mitochondria

    • Found in all types of eukaryotic cells.
    • Has two membranes (smooth outer and inner folded membrane).
    • Has its own DNA.
    • Has matrix and intermembrane compartments.
    • Embedded proteins carry out oxidative metabolism.

    Chloroplast

    • Present in plants and some other eukaryotic cells.
    • Surrounded by two membranes.
    • Contains chlorophyll (green pigment).
    • Has thylakoids (membrane sacs) and grana (stacked thylakoids).
    • Has its own DNA.

    Microfilaments (Actin)

    • Two protein chains loosely twined together.
    • Involved in contraction, crawling, and pinching movements.

    Microtubules

    • Largest cytoskeletal elements.
    • Dimers of α- and β-tubulin subunits.
    • Facilitate movement of cell and materials.

    Intermediate Filaments

    • Very stable, not usually broken down.
    • Medium size.

    Endosymbiosis Theory

    • Prokaryote engulfed by another cell = eukaryote.

    Eukaryotic Cell Walls

    • Different composition depending on the organism.
    • Plants and protists: cellulose. Fungi: chitin.
    • Animals lack cell walls but have glycoproteins and collagen

    Cell Connections

    • Three main types:
      1. Adhesive junctions
      2. Tight junctions
      3. Communicating junctions

    Cell-to-Cell Interactions

    • Cells make contact, read signals, and respond.

    Glycoproteins/Glycolipids

    • cell-surface markers

    Plasmodesmata

    • Specialized openings in plant cell walls.
    • Connect the cytoplasm of adjoining cells, similar to gap junctions in animal cells.

    Viruses

    • Nucleic acid core surrounded by a protein coat (capsid).
    • No cytoplasm (not a cell).
    • Nucleic acid: DNA or RNA, single or double-stranded, linear or circular, segmented or not.
    • Host range: types of organisms infected.
    • Tissue tropism: viruses may only infect certain tissues in a host.

    Viral Replication

    • Viruses hijack host cellular machinery for replication, transcription and translation
    • End result assembly and release of virus.

    Virus Structure

    • Viral structure types:
      1. Helical: spiral
      2. Icosahedral: almost spherical

    Viral Genomes

    • Can vary greatly in both type of nucleic acid (DNA or RNA) and number of strands (single or double).
    • Most RNA viruses are single-stranded.

    Retroviruses

    • Have a single-stranded RNA genome reverse-transcribed into double-stranded DNA.
    • Employ reverse transcriptase.

    Virus Classification

    • Methods include taxonomy, disease caused, or host infected.
    • Baltimore system sorts viruses based on genome structure & expression.

    Viral Diseases in Humans

    • Categorized as persistent (chronic or latent), or acute
    • Influenzavirus as an example.

    Influenza

    • Examples: 1918-1919 pandemic
    • Subtypes differ in protein spikes (hemagglutinin & neuraminidase).
    • Antigenic drift & shift can cause pandemics.

    Prions

    • Infectious proteins.

    Viroids

    • Tiny naked molecules of circular RNA; use host proteins to replicate.

    Cell Membranes

    • Form a barrier; regulate passage; receive stimuli; composed of a phospholipid bilayer; with proteins embedded.

    Fluid Mosaic Model

    • Proteins float in a fluid bilayer.

    Membrane Components

    • Phospholipid bilayer
    • Transmembrane proteins
    • Interior protein network
    • Cell-surface markers

    Types of Lipids

    • Phospholipids
      • Amphipathic, spontaneously form bilayers.
    • Sphingolipids
    • Cholesterol

    Protein Functions

    • Transport
    • Enzymes
    • Cell-surface receptors
    • Cell-surface identity markers
    • Cell-cell adhesion
    • Attachment to cytoskeleton
    • Affect membrane structure

    Anchoring Molecules

    • Link membrane proteins to the membrane surface: modified lipids (non-polar regions insert into the bilayer, chemical bonds link to proteins).

    Transmembrane Proteins

    • Spanning the lipid bilayer: non-polar regions embedded, polar regions protrude.

    Transmembrane Domains

    • Hydrophobic amino acids arranged in helices.
    • Single transmembrane domain anchors proteins.

    Membrane Pores

    • Non-polar regions create pores in transmembrane proteins for water and small polar molecules to pass

    Membrane Transport

    • Active transport (requires energy, substances move against concentration gradient.
    • Passive transport (no energy needed, substances move down concentration gradient).

    Active Transport Mechanisms

    1. Uniporters (one molecule at a time).
    2. Symporters (two molecules in the same direction).
    3. Antiporters (two molecules in opposite directions).
    4. Coupled transport

    Vesicular Transport (Endocytosis & Exocytosis)

    • Endocytosis: movement INTO cell (requires energy, phagocytosis, pinocytosis, receptor-mediated).
    • Exocytosis: movement OUT of cell (requires energy)

    ATP

    • Energy currency of cells

    Cellular Respiration

    • Series of chemical reactions releasing energy from sugar, producing ATP.

    Sodium-Potassium Pump

    • Direct use of ATP, antiporter action.

    Facilitated Diffusion

    • Uses proteins (channels or carriers) to aid movement across membrane.

    Channel Proteins

    • Hydrophobic interior; "open or close". (aqueous channels) - polar molecules

    Carrier Proteins

    • Bind molecules for assisted passage
    • Movement through diffusion Requires a concentration difference.

    Osmosis

    • Net diffusion of water across membrane towards higher solute concentration.

    Osmolarity

    • Hypertonic (higher solute concentration). Hypotonic (lower solute concentration). Isotonic (equal concentrations).

    Factors Affecting Diffusion

    • Concentration, molecular size, temperature

    Scientific Method

    • Hypothesis: possible explanation tested.
    • Experiment: designed test to validate hypothesis.
    • Control group: baseline for comparison.
    • Experimental groups: different from control group.

    Homologous & Analogous Structures

    • Homologous: same origin, different structure/function.
    • Analogous: different origin, similar function.

    Genes, Genomes, and Atomic Components

    • Gene: discrete info unit. Genome: entire DNA instructions.
    • Ions: unbalanced charged particles. Isotopes: atoms with same element differing neutrons.
    • Half-life: decay time. Valance electrons: outermost energy level electrons.

    Chemical Bonds and Compounds

    • Molecules: groups of atoms; compounds: more than one type of element.
    • Ionic bonds: electron donation; covalent bonds: electron sharing.
    • pH: potential of hydrogen, acids increase H+, bases decrease H+.

    Macromolecules

    • Carbohydrates (1:2:1 ratio C, H, O).
    • Monosaccharides: simple sugars. Disaccharides: two simple sugars linked. Polysaccharides: long chains.
    • Nucleic acids: nucleotides (sugar, phosphate, base). DNA (amino acid codes), RNA (similar to DNA but with ribose).
    • Proteins: amino acids linked by peptide bonds.

    Protein Structure

    - Primary structure: amino acid sequence
- Secondary structure: peptide backbone interactions
- Tertiary structure: final folded shape
- Quaternary structure: multiple polypeptide chain arrangement

    Chaperones

    • Proteins that assist in protein folding.
    • Denaturation: protein loses structure and function.

    Lipids

    • Triglycerides: glycerol + 3 fatty acids.
    • Phospholipids: glycerol + 2 fatty acids + phosphate.
    • Micelles & Phospholipid bilayers
    • Waxes: fatty acids + alcohols.
    • Steroids: important lipid molecules (cholesterol, sex hormones).

    Energy and Thermodynamics

    • Energy: capacity to do work.
    • Kinetic energy: energy of motion; potential energy: stored energy.
    • Heat: convenient energy measure.
    • Energy flow: passage of energy through ecosystem (photosynthesis, potential energy, breaking bonds); oxidation (atom/molecule loses electron); reduction (gains electron); Electron transport chain.
    • 1st & 2nd laws of thermodynamics; free energy (G = H - TS), enthalpy (H), entropy (S), exergonic, endergonic reactions; activation energy (raising energy of reacting molecules & lowering activation energy).

    Catalysts and Enzymes

    • Catalysts: lower activation energy of chemical reactions.
    • Enzymes: most are proteins; speed up reactions by binding substrates in active sites.

    Cellular Respiration

    • 4 stages of aerobic respiration: glycolysis, pyruvate oxidation, citric acid cycle, electron transport chain & chemiosmosis
    • Glycolysis: splitting of glucose, produces 2 ATP, 2 NADPH.
    • Pyruvate oxidation: produces Acetyl-CoA, 2 CO2, 2 NADH
    • Krebs Cycle: Oxidizes acetyl group, 6 CO2, 4 ATP, 10 NADH, 2 FADH2
    • ETC/Chemiosmosis: electron carriers generate a proton gradient which in turn used by ATP synthase to make ATP (32 or 30 ATP).

    Oxidation Without O2

    • Anaerobic respiration (inorganic molecules as final electron acceptor)
    • Fermentation (organic molecules as final electron acceptor).

    Photosynthesis

    • Overview: captures energy from the sun (6CO2 + 12H2O + Light = C6H12O6 + 6H2O + 6O2).
    • Stages: light-dependent reactions (capture energy, make ATP & NADPH), light-independent reactions (Calvin Cycle: carbon fixation, reduction, RuBP regeneration).
    • Pigments (Chlorophyll, carotenoids).
    • Photosystems: antenna complex & reaction center.

    Calvin Cycle

    • 3 phases: carbon fixation, reduction, regeneration.
    • Output: G3P (3-carbon sugar formed); used to make glucose, sucrose and starch; cycle runs in reverse during glucose formation.

    Photorespiration

    • Rubisco: enzyme with carboxylation and photorespiration activities; issues with maximizing CO2 uptake in C3 and environmental conditions.

    C4 and CAM Photosynthesis

    • Adaptations for carbon fixation in hot, dry environments
      • C4 plants: spatial separation of CO2 fixation pathways in different cell types.
      • CAM plants: temporal separation of CO2 fixation, with carbon fixation in different conditions.

    DNA Replication

    • Replication requires a template, enzymes, and building blocks of nucleotides.
    • Stages: initiation, elongation, termination.
    • DNA polymerases: main enzyme for building new strands; proofreading functions.
    • Replication fork: point of opening.
    • Leading strand. Lagging strand. Okazaki fragments

    Eukaryotic DNA Replication

    • Multiple origins.
    • Complexity of replication enzymes.

    Telomeres and Telomerase

    • Protective structures at chromosome ends.
    • Enzyme that maintains telomere length.
    • Telomerase activity during development

    DNA Repair Mechanisms

    • Mismatch repair
    • Photorepair (thymine dimers)
    • Excision repair

    Bacterial Cell Division

    • Binary fission

    Prokaryotic & Eukaryotic Chromosomes

    • Chromatin: DNA & protein complex.
    • Eukaryotes: multiple linear chromosomes.
    • Prokaryotes: single circular chromosome.

    Eukaryotic Cell Cycle

    • G1 (gap 1). S (synthesis). G2 (gap 2). M (mitosis). C (cytokinesis).
    • checkpoints: regulate progression.

    Mitosis

    • Stages: prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.
      • Spindle apparatus. Centromeres. Kinetochores.

    Meiosis

    • Stages: 2 rounds of nuclear division (I, II),
    • Synapsis Recombination (crossing over)
    • Independent assortment
    • Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II.
    • Final result: 4 haploid cells (gametes).

    Meiosis vs Mitosis

    • Differences in chromosomal behavior and outcomes.

    Errors in Meiosis

    • Non-disjunction: failure of chromosome separation,
    • Aneuploidy: abnormal chromosome number.

    Sex Chromosomes

    • X and Y chromosomes.

    Sexual Reproduction

    • Meiosis and fertilization.
    • Variation increased.

    Cell Cycle Control

    • Checkpoints ensure accuracy.
    • MPF (cyclin-dependent kinase), Cyclins, CDKs.

    Cancer

    • Uncontrolled cell growth due to mutations in tumor suppressor genes and proto-oncogenes.

    Asexual Reproduction

    • Clonal reproduction; in organisms like bacteria

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    Description

    Test your knowledge on cell structure, function, and characteristics of living organisms. This quiz covers topics such as prokaryotic cells, various organelles, and the cell theory. Perfect for students studying biology and cell biology concepts.

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