Microscope and Cell Structure Quiz

DNA Replication

• Replication continues until the entire DNA molecule is copied, ending when replication forks meet or the process reaches the end of the DNA strand

Protein Synthesis

• Process by which cells build proteins, essential molecules for various biological functions
• Takes place in the nucleus of eukaryotic cells and the cytoplasm of prokaryotic cells
• RNA polymerase binds to the DNA and synthesizes a complementary mRNA (messenger RNA)

RNA Structure

• Single-stranded structure, no helix formed
• Composed of nucleotides, with ribose instead of deoxyribose
• Four bases: guanine, cytosine, adenine, and uracil

Transcription

• First stage of protein synthesis
• RNA polymerase binds to the DNA and synthesizes a complementary mRNA (messenger RNA)

Translation

• Second stage of protein synthesis
• mRNA exits the nucleus into the cytoplasm and binds to a ribosome
• Transfer RNA (tRNA) molecules, each carrying a specific amino acid, recognize and bind to the mRNA codons
• Ribosome catalyzes the formation of peptide bonds between adjacent amino acids, forming a polypeptide chain

Codon

• Makes up mRNA

Genetic Engineering

• Process by which genes are altered and DNA is transferred to another organism
• Results in a phenotype that shows the distinct expression of both alleles without any blending or intermediate phenotype

Incomplete Dominance

• Dominant allele fails to mask the recessive allele completely
• Offspring does not resemble either parent

Codominance

• Both alleles for a trait are fully expressed in the heterozygous phenotype
• Neither allele is dominant or recessive to the other

Multiple Alleles

• Presence of more than two different forms of a gene (alleles) at a particular locus (position) on a chromosome within a population

Application of Mendelian Genetics

• Selective Breeding: Mendelian genetics principles applied in agriculture and animal husbandry to selectively breed organisms with desired traits
• Medical Genetics: Mendelian genetics applied to understand the inheritance of genetic disorders

Application of Non-Mendelian Genetics

• Complex Traits: Non-Mendelian genetics plays a crucial role in understanding complex traits and diseases that involve multiple genes and environmental factors
• Population Genetics: Non-Mendelian genetics principles applied to study genetic variation within and between populations

Microscopy

• Base: Support for microscope
• Magnification: Multiply the eyepiece magnification (10X) by the objective magnification (4X, 10X, 40X)
• How to use a microscope:
  • Place the slide on the stage
  • Use stage clips to secure slide
  • Adjust nosepiece to lowest setting (Lowest = shortest objective)
  • Look into eyepiece
  • Use coarse focus knob

Prokaryotes and Eukaryotes

• Prokaryotes:
  • “Pro” means before nucleus
  • Nucleoid: central open part of the cell where the DNA is found
  • 1-10 microns
  • Unicellular, include kingdom Eubacteria and Archaebacteria
  • Single loop if stable chromosomes
  • Semi-rigid cell wall is present, but membrane-bound organelles with specialized functions are absent
• Eukaryotes:
  • Unicellular/multicellular, have nucleus
  • Composed of membrane-bound organelles (Cytoskeleton, Mitochondria, Cell membrane, nucleus, Golgi apparatus, lysosomes, vacuoles, vesicles, and etc.)
  • Include kingdoms Protista, Fungi, Plantae, and Animalia
  • Larger in size compared to prokaryotes (but still microscopic)
  • Reproduce sexually or asexually
  • Nucleus contains the cell’s DNA

Cell Organelles and Organization

• Protoplasm: Mixture of compounds forming a jellylike substance where the nucleus, cytoplasm, and cell membrane are located
• Suspended in the protoplasm are the organelles acting like little organs that carry out specific functions
• Organelles:
  • Cell Membrane: composed of phospholipids and proteins, provides a barrier between the internal and external environment of the cell
  • Cytoplasm: Eukaryotes - everything within the cell outside the nucleus; Prokaryotes - everything contained inside the cell membrane
  • Cytosol: Major part of the cytoplasm; site of the cell’s metabolic processes, including protein synthesis; Gel-like

Organelles for Protection

• Cell Membrane: helps the cell communicate with other cells (cell-to-cell interaction)
• Cell Wall: surrounds the cells of plants, fungi, bacteria, and some protozoans, making them rigid; made up of cellulose and chitin and other proteins

Organelles for Energy Processing

• Mitochondria: Small double-membraned and spherical or sausage-shaped organelles; produces adenosine triphosphate (ATP); powerhouse of the cell
• Plastids:
  • Chloroplasts: most common plastids found in green plants; trap energy from the sun during photosynthesis
  • Chromoplasts: give yellow and orange colors to flowers and fruits
  • Leucoplasts: Colorless plastids; store carbohydrates, proteins, and fats

Organelles for Manufacturing Products

• Ribosomes: small granular structures that are made up of ribonucleic acid (RNA) and proteins; produce proteins from RNA
• Endoplasmic Reticulum: a membranous structure that forms a network of canals through which proteins and other molecules are transported

Transport Mechanism

• Concentration Gradient: stored energy that drives movement of particles from high to low concentrations in diffusion

Type of Transport Mechanism

• Passive Transport (Diffusion, Osmosis, Facilitated Diffusion)
• Active Transport (Sodium-Potassium, Bulk Transport)

Passive Transport

• Diffusion: occurs when solutes or solvents move from an area of higher concentration to an area of lower concentration without energy
• Factors that affect Diffusion:
  • Temperature: Rate of the diffusion increases
  • Pressure: Rate of diffusion decreases
  • Size: Rate of diffusion decreases
  • Viscosity: Rate of diffusion decreases
• Osmosis: diffusion of water through a semipermeable membrane; moves from high concentration to low concentration
• Facilitated Diffusion: amino acids and glucose cannot pass through the lipid bilayer; integral proteins serve as gateways for facilitating their transport
• Channel Proteins: allows the passage of molecules of appropriate size and shape
• Carrier Proteins: changes shape to accommodate sugars, amino acids, and nucleosides

Application of Osmosis and Diffusion

• Dialysis and Dialyser: ensures that the regions inside and outside of the body have a balanced amount of fluids

Test your knowledge on using a microscope and understanding cell structures such as prokaryotes and eukaryotes. Learn about magnification, adjusting the microscope, and the basic components of cells.