Effective Communication Skills Quiz

The Cell

• Cell: the basic morphological, functional, and reproductive unit of all unicellular and multicellular organisms.
• Cell Theory: cells are the basic unit of life and all organisms; all life is composed of cells each containing a nucleus and cytoplasm; cells arise from already existing cells.
• Cell History: the cell was first observed by Robert Hooke in 1665 and named according to monk prayer cells; he observed the structure of cork using a simple microscope.

Prokaryotic Cells

• General Information: small (about 1µm) and considered the simplest cells; they form only single-celled organisms such as bacteria and archaebacteria; bacteria are usually reproduced by binary fission or conjugation; their shapes can be spherical (cocci) or rod-shaped (bacilli); bacteria can be aerobic and anaerobic with some forming endospores.
• Components: nucleoid (single circular DNA connected to cytoplasm), cytoplasm, small ribosomes, cytoplasmic membrane, cell wall, and locomotive organelles (e.g., flagellum, cilia) and pili.

Eukaryotic Cells

• General Information: they form unicellular and multicellular organisms such as plants, animals, fungi, and algae; they undergo differentiation and specialization; divided and reproduced by mitosis; generally considered big cells (10-100 µm); small (less than 10 µm) such as erythrocytes and lymphocytes; medium (10-30 µm) such as macrophages; and large (greater than 30 µm) such as oocytes and neurons; cell shape determined by genetic and epigenetic factors, differentiation, and environmental factors; primary shape is spherical, oval, rod, and bizarre.
• Components: nucleus, cytoplasm, cytoplasmic membrane, cytoskeleton, organelles (e.g., mitochondria, ribosomes, lysosomes, centrioles, endoplasmic reticulum, Golgi apparatus; organelles have their own membrane (biomembrane)), plant cells have cell walls and chloroplasts, animal cells have centrioles, cilia, and flagella.

Cell Membrane - Plasma Membrane - Cytoplasmic Membrane

• General Information: separates intracellular and extracellular space of the cell; plays a dynamic role in cellular activity; contains enzymes, receptors, transport proteins, signaling system, and antigens.
• Structure: lipid bilayer of phospholipids and proteins;
  • Phospholipids: modified triglycerides with two fatty acid groups and one phosphate group; considered the main component of cell membranes; polar heads (hydrophilic) oriented towards water and nonpolar tails (hydrophobic) oriented towards each other.
  • Proteins: integral (70%) affect the hydrophobic parts of the phospholipid bilayer, peripheral outside the lipid bilayer and easily separated from the biomembrane, and have electrostatic bonds.
• Function of membrane proteins
  • Transport: protein may provide a hydrophilic channel across the membrane; some transport proteins hydrolyze ATP to actively pump substances across the membrane.
  • Enzymatic activity: a protein might be an enzyme with its active site exposed to substances in the adjacent solution; sometimes several enzymes act as a team.
  • Signal transduction: a protein outside of the cell may have a site that binds with the shape of a chemical messenger (e.g., hormone); the external signal may cause conformational change in the protein (receptor), starting a chain of chemical reactions in the cell.
• Cell-to-cell recognition (glycocalyx): some glycoproteins serve as identification tags recognized by other cells.
• Intercellular adhesion (CAMs)/Intercellular joining: membrane proteins of adjacent cells may be hooked together in various kinds of junctions; CAMS proteins provide temporary binding sites that guide cell migration.
• Attachment to the cytoskeleton and extracellular matrix (ECM): elements of cytoskeleton and ECM may be secured to membrane proteins helping maintain cell shape and stabilize location of certain membrane proteins.
• Characteristics: selectively permeable membrane allows only "selected" substances to pass through; flow of information, creates and maintains electrical potential, intracellular communication, and other functions.
• Cell membrane transport:
  • Passive: diffusion (simple-facilitated), osmosis, and filtration
  • Active: primary, secondary
  • Vesicular: exocytosis, endocytosis (pinocytosis, phagocytosis).
• Diffusion: tendency of molecules to scatter evenly throughout the environment; molecules move from areas of high concentration to areas of low concentration; the speed is influenced by molecular size and temperature; the driving force is kinetic energy; at equilibrium there's a uniform distribution of particles with no net movement.
• Simple diffusion: nonpolar and lipid-soluble substances diffuse directly through the lipid bilayer (e.g., oxygen, CO2, fat-soluble vitamins).
• Facilitated diffusion: molecules combine with protein carriers, changing their conformation, opening the way; no energy consumed; typical for amino acid transportation inside the cell.
• Osmosis: spontaneous and passive net movement of water across a semi-permeable membrane; water passes from low concentration to high concentration until equalisation; hypotonic environment (hemolysis of red blood cells), hypertonic environment (plasmolysis of plant cells), and isotonic environment.
• Filtration: movement of molecules across the membrane by hydrostatic pressure and according to the size of pores; occurs in Bowman's capsule in kidneys and liver cells.
• Active Transport: transfer of substances against the concentration or electrochemical gradient; energy is consumed;
  • Primary: energy from ATP hydrolysis
  • Secondary: energy from ionic gradients (symport and antiport).
• Vesicular: transport of large molecules and fluid across plasma and intracellular membranes;
  • Endocytosis: substances get transferred into the cell through vesicles (pinocytosis, phagocytosis).
  • Exocytosis: substances transported from the cell to the extracellular environment through vesicles; vesicles arise from the ER and Golgi apparatus.

Function of Organelles of Eukaryotic Cells

• Organelles: morphological and functional parts of the cell that operate in specialized activities.
  • Cytoplasm: inner environment of the cell containing mainly water (70-80%) and dissolved chemicals (ions, organic and organic compounds); gel-like and liquid form, and contains organelles.
  • Nucleus: central organelle that controls cellular activities including protein synthesis; contains DNA.
  • Mitochondria: generate energy for the cell (cellular respiration); have their own DNA (mtDNA) that replicates independently; reproduce by fission; contain transport proteins and enzymes involved in lipid metabolism; contain enzymes of the respiratory cascade and ATP synthases.
  • Endoplasmic reticulum: network of flat cisterns and vesicles composed of membranes; considered the center of synthesis in the cell; rough ER has ribosomes, mainly responsible for protein synthesis and smooth ER involved in lipid synthesis; plays a role in detoxification processes.
  • Golgi complex: stack of membranes that modify proteins and lipids; produces vesicles for material transport from or between cellular components; and involved in processes like protein modification and packaging.
  • Lysosomes: contain digestive enzymes for breaking down cellular components or ingested molecules; inactive enzyme production in the ER; activated in the Golgi forming primary lysosomes; fuse with target membrane forming secondary lysosomes.
  • Chloroplasts: found in plants, algae, and some bacteria; contain two membranes and their own DNA (cpDNA); capable of replication independently; function in capturing sunlight for photosynthesis.
  • Nucleolus: found in nuclei of eukaryotic cells; involved in rRNA synthesis and ribosomal subunit assembly.
  • Ribosomes: composed of two subunits (small and large); carry out protein synthesis by translating RNA into proteins; can be freely in cytoplasm or attached to the ER.
  • Cytoskeleton: network of fibers for cell shape, movement, and organelle movement (microtubules, microfilaments, intermediate filaments).

Endosymbiosis

• Possible origins of eukaryotic cells: infolding of outer membrane of prokaryotic cells; uptake of prokaryotes.
• Definition: theory that eukaryotic cells arose from an early prokaryote swallowing a second smaller prokaryote which became a symbiotic relationship with the host and now is part of the cell.
• Mitochondria and chloroplasts may have originated this way.

Molecular Genetics

• Definition: interaction of DNA, RNA, and proteins.
• Genome: set of DNA/RNA molecules in an organism or virus; can be DNA or RNA.
• Genes: segment of hereditary DNA/RNA that produces polypeptides or functional RNA.
• DNA in bacteria and eukaryotes.
• DNA types: Coding RNA (mRNA) carries genetic information for protein synthesis; Non-coding RNA regulate gene expression.
• Central dogma: DNA → RNA → protein.
• Retroviruses: RNA → reverse transcription → DNA.
• Nucleic acids:
  • Composition: DNA_RNA: linear sequences of repeating units forming long polymers; similar structures; backbone consists of repeating sugar-phosphate structure.
  • Ribonucleic acid (RNA): 5-carbon sugar ribose.
  • Deoxyribonucleic acid (DNA): 5-carbon sugar deoxyribose.
  • Nitrogenous bases: heterocyclic rings of carbon and nitrogen atoms (adenine, guanine, cytosine, thymine, uracil).
  • Nucleotide: base + sugar residue + phosphate group.
  • Primary structure: linear sequence of nucleotides linked by phosphodiester bonds (5’ → 3’).
• Genetic code: set of rules that encode amino acids in proteins; 3 nucleotides are called a codon; some codons represent specific amino acids while others are stop signals; a single codon specifying amino acid might not be exclusive to it, some codons can specify different amino acids.
• Secondary structure: 2 DNA strands held together by hydrogen bonds (antiparallel); discovered in 1953 by Watson and Crick.
• Tertiary structure: supercoiling.

DNA Replication in Prokaryotes and Eukaryotes

• Prokaryotes: replication begins at a single origin (Ori); proceeds in both directions.
• Semiconservative replication: one original strand of DNA and one newly synthesized strand.
• Enzymes: origin recognition complex (ORC) binds to Ori to start replication; DNA helicases separate the double helix; single-strand binding proteins prevent re-annealing. DNA polymerase III adds nucleotides to the 3’ end; Leading strand continuous, lagging strand discontinuous;
• DNA polymerase I removes RNA primers and replaces them with DNA; DNA ligase joins Okazaki fragments.

Cell Culture

• Cell culture: population of cells that proliferate in vitro (in a lab); these cells can be obtained from all cell types.
  • Primary culture: cells taken from tissues that have not yet been passed through a series of culturing and passaging phases.
  • Cell lines: population of diploid cells arising from primary cell cultures by repeated passages in a lab (immortalized).
• Types
  • short term: cells grown for a short period either by spontaneous division or stimulated cell division (mitogens).
  • long term: cells can live and reproduce continuously or for more than 10 days.

Cell Culture Laboratory & Tests

Cell Culture Methods & Applications:

• Cell culture laboratory
  • Aseptic Work Area: a sterile environment
  • Incubators: maintain pH, temperature, CO2 concentration, and humidity.
  • Culture Medium: maintain essential nutrients for cells.

Cell Viability Tests

• Cell viability tests: measure cell viability based on properties such as enzyme activity, cell membrane permeability, and cell adherence.
• Cytotoxicity tests: assess the effect of a compound on cell cultures; methods include dye tests (trypan blue, fluorescence dye, e.g.) and metabolic tests (MTT).

Gel Electrophoresis

• Gel electrophoresis: method for separating DNA and protein molecule and analyzing fragments using an electric field.
  • Agarose gel: used for DNA separation
  • Polyacrylamide gel: used for protein separation.
  • Capillary electrophoresis: used for genetic analysis.

Polyeme (sequence 4-8 nucleotides)

Test your understanding of effective communication and its components. This quiz covers key elements such as trust building, non-verbal cues, listening strategies, and conflict handling. Improve your communication skills with these essential concepts.