Topic 2 - Cells Flashcards
Eukaryotic cells
Cells with membrane-bound organelles, including plants and animals.
Plasma membrane
Partially permeable barrier regulating molecule passage.
Nucleus
Contains DNA organized into chromosomes.
Nucleolus
Synthesizes ribosomal RNA and assembles ribosomes.
Rough endoplasmic reticulum
Site of protein synthesis, studded with ribosomes.
Smooth endoplasmic reticulum
Synthesizes and transports lipids and carbohydrates.
Mitochondria
Produces ATP through aerobic respiration.
Golgi apparatus
Modifies and packages proteins for transport.
Lysosomes
Digest worn-out organelles using hydrolytic enzymes.
Chloroplasts
Site of photosynthesis in plants and algae.
Cell wall
Rigid structure preventing cell bursting from osmosis.
Vacuole
Fluid-filled sac providing turgor pressure in plants.
Cell specialization
Eukaryotic cells adapt for specific functions.
Tissue
Group of identical cells performing a function.
Organ
Group of different tissues working together.
System
Collection of organs functioning together.
Prokaryotic cells
Cells without membrane-bound organelles, like bacteria.
70S ribosomes
Smaller ribosomes found in prokaryotic cells.
Circular genetic material
DNA structure in prokaryotes, free in cytoplasm.
Cell wall (prokaryotes)
Contains murein, preventing cell bursting.
Flagellum
Structure enabling movement in prokaryotic cells.
Plasmid
Small DNA circle carrying extra genes.
Capsule
Protective layer against antibiotics in bacteria.
Viruses
Non-living entities with genetic material and proteins.
Cell fractionation
Technique to isolate organelles by density.
Homogenization
Breaking cells open to release organelles.
Isotonic solution
Prevents osmotic damage to organelles.
Ice cold solution
Inactivates enzymes to protect organelles.
pH buffer
Maintains optimal pH for enzymatic activity.
Centrifugation
Separates organelles by density using centrifugal force.
Supernatant
Liquid above sediment after centrifugation process.
Optical Microscopy
Uses light to view thin specimens, limited resolution.
Eyepiece Graticule
Measuring tool calibrated with a stage micrometer.
Electron Microscopy
Uses electrons for high-resolution imaging of organelles.
Transmission Electron Microscope
Electrons pass through specimen, revealing internal structures.
Scanning Electron Microscope
Scans surface to create 3D images of specimens.
Resolution
Ability to distinguish two close objects clearly.
Magnification
Enlargement of an image, can cause blurriness.
Artefacts
False structures resulting from specimen preparation.
Interphase
Stage where DNA is unraveled for protein synthesis.
G1 Phase
Cell growth and function before DNA replication.
S Phase
DNA replication occurs, forming sister chromatids.
G2 Phase
Organelles replicate and ATP is generated for energy.
Mitosis
Cell division producing two genetically identical daughter cells.
Prophase
Chromosomes condense and become visible; spindle fibers form.
Metaphase
Chromosomes align at cell equator, spindle fibers attach.
Anaphase
Sister chromatids separate and move to opposite poles.
Telophase
Chromatids unravel, new nuclear membrane forms.
Cell Cycle
Sequence of stages a cell undergoes during division.
Actual Size Calculation
Actual size = image size / magnification.
Magnification Calculation
Magnification = image size / actual size.
Chromatin
Unraveled DNA during interphase, not visible as chromosomes.
Centromere
Region where sister chromatids are joined together.
Spindle Fibres
Protein fibers that facilitate chromosome movement during mitosis.
3D Imaging
Created by scanning electron microscopy of surfaces.
Living Tissue Observation
Not possible with electron microscopy due to vacuum requirement.
Nuclear Membrane
Membrane that surrounds the nucleus, breaks down in mitosis.
Cell Growth
Increase in cell size and function during G1 phase.
Cytokinesis
Division of cytoplasm producing two daughter cells.
Mitotic Index
Ratio of cells in mitosis to total cells.
Cell Cycle Length
Duration varies with cell division rate.
Interphase
Phase where rapidly dividing cells spend less time.
Cancer
Uncontrolled cell division due to gene damage.
Tumor
Mass formed by uncontrolled cell division.
Cancer Treatment
Involves blocking parts of the cell cycle.
DNA Replication Prevention
Stops cancer cells from duplicating DNA.
Spindle Formation Prevention
Inhibits chromosome separation during mitosis.
Binary Fission
Prokaryotic cell division method.
Circular DNA
Single DNA molecule in prokaryotes.
Plasmids
Small DNA molecules in prokaryotes.
Viruses
Non-living entities that infect host cells.
Virus Replication
Uses host cell machinery for reproduction.
Surface Antigens
Viral markers left on host cell membrane.
Phospholipid
Molecule with glycerol, fatty acids, and phosphate.
Hydrophobic
Water-repelling property of fatty acid tails.
Hydrophilic
Water-attracting property of phosphate heads.
Phospholipid Bilayer
Two layers of phospholipids in cell membranes.
Fluid Mosaic Model
Describes membrane structure with embedded proteins.
Cholesterol in Membranes
Regulates fluidity of the phospholipid bilayer.
Intrinsic Proteins
Proteins that span both membrane layers.
Extrinsic Proteins
Proteins located on one membrane layer.
Glycoproteins
Proteins associated with carbohydrates on membranes.
Membrane Function
Prevents water-soluble molecules from diffusing out.
Diffusion
Movement from high to low concentration.
Concentration Gradient
Difference in concentration across a membrane.
Factors Affecting Diffusion
Temperature, surface area, distance, and gradient.
Oxygen Diffusion
Small molecules pass through membranes easily.
Facilitated Diffusion
Movement of molecules via specific channel proteins.
Channel Protein
Intrinsic protein allowing water-soluble molecule passage.
Carrier Protein
Protein that transports molecules across membranes.
Saturation
Maximum rate of transport when proteins are full.
Active Transport
Movement of molecules against concentration gradient using ATP.
ATP
Energy molecule used in active transport processes.
Shape Change
Alteration of protein structure to transport molecules.
Co-transport
Simultaneous transport of two substances across a membrane.
Sodium Ions
Charged particles actively transported into blood from cells.
Lumen
Interior space of a tubular structure, like intestines.
Osmosis
Water movement from high to low water potential.
Water Potential
Pressure potential of a solution, measured in kPa.
Isotonic Solution
Solution with equal water potential to another solution.
Turgor Pressure
Pressure from water inside plant cells against cell wall.
Plasmolysis
Loss of turgor pressure causing plant cell wilting.
Phagocytosis
Process of engulfing bacteria by phagocytes.
Phagocyte
Cell that engulfs and digests pathogens.
Phagosome
Vesicle formed around engulfed bacteria in phagocytes.
Lysozyme
Enzyme that digests bacteria within phagosomes.
Antigen
Foreign substance triggering immune response.
T Lymphocytes
White blood cells involved in cell-mediated immunity.
Stem Cells
Undifferentiated cells that produce T lymphocytes.
Thymus Gland
Organ where T lymphocytes mature and activate.
Non-self Antigens
Antigens from outside the body recognized by T cells.
Specific Immune Response
Targeted immune response to specific pathogens.
Microbe
Microorganism that can trigger an immune response.
Antigenic Variation
Different shapes of antigens on various microbes.
Antigen Presenting Cells
Cells that display antigens for T cell recognition.
Phagocytes
Engulf pathogens and present their antigens.
Helper T Lymphocyte
Activates immune cells upon binding specific antigens.
Clonal Selection
B cell division triggered by T helper cell binding.
Cytotoxic T Lymphocytes
Destroy virus-infected host cells using cytotoxins.
Memory Cells
Long-lived cells that remember past infections.
Humoral Immunity
B cell-mediated immune response involving antibodies.
B Lymphocyte Activation
Triggered by antigen binding to membrane antibodies.
Plasma Cells
B cell clones that produce specific antibodies.
Monoclonal Antibodies
Antibodies produced by identical B cell clones.
Antibody Structure
Proteins with specific shapes binding to antigens.
Antibody-Antigen Complex
Lattice structure formed by multiple antibody bindings.
Agglutination
Binding of antibodies causing clumping of pathogens.
Toxin Precipitation
Antibodies neutralize soluble toxins, rendering them harmless.
Pathogen Binding Prevention
Antibodies block pathogens from entering host cells.
Phagocyte Activation
Antibodies stimulate phagocytes to engulf complexes.
Primary Immune Response
Initial response to first pathogen exposure.
Latent Period
Time before antibodies are produced after infection.
Antibody Concentration Rise
Increase in antibodies after primary infection.
Secondary Immune Response
Faster and stronger response to re-infection.
Natural Active Immunity
Immunity from natural pathogen exposure.
Antigenic Variability
Pathogen mutations leading to different antigen forms.
Vaccine
Contains antigens to provoke immune response without disease.
Memory Cell Production
Generated after vaccination for future pathogen defense.
Immune System Activation
Triggered by pathogen detection and antigen presentation.
Cytotoxin Release
Mechanism used by cytotoxic T cells to kill infected cells.
Antibody Release
Plasma cells secrete antibodies into the bloodstream.
Infection Symptoms
Caused by pathogen reproduction during immune response.
Rapid Antibody Production
Occurs during secondary response for quick pathogen elimination.
Artificial Active Immunity
Immunity developed through vaccination.
Herd Immunity
Population immunity preventing disease spread.
Passive Immunity
Immunity from externally administered antibodies.
Human Immunodeficiency Virus (HIV)
Virus causing Acquired Immune Deficiency Syndrome (AIDS).
RNA Nucleic Acid
Genetic material in HIV, consists of two copies.
Reverse Transcriptase Enzyme
Enzyme converting viral RNA into DNA.
Protein Coat (Capsid)
Protective layer surrounding viral genetic material.
Lipid Envelope
Membrane surrounding HIV, contains glycoprotein spikes.
CD4 Protein
Receptor HIV attaches to on T lymphocytes.
HIV Positive
State indicating antibodies against HIV are present.
Opportunistic Diseases
Infections arising from weakened immune system.
AZT
Antiviral drug inhibiting HIV replication.
Monoclonal Antibodies
Identical antibodies from a single B lymphocyte clone.
ELISA Test
Test detecting proteins like anti-HIV antibodies.
Cytotoxic Drug
Drug targeting and killing cancer cells.
Antibiotics
Chemicals that kill bacteria without harming human cells.
Bacterial Cell Targeting
Antibiotics disrupt bacterial structures, causing cell death.
Viral Resistance to Antibiotics
Viruses lack structures targeted by antibiotics.
Animal Experimentation
Ethical concern in vaccine production.
MMR Vaccine
Vaccine linked to controversial autism claims.
Scientific Scrutiny
Process ensuring scientific theories are validated.
Sample Size Flaw
Small sample undermines reliability of study results.
Vested Interest
Personal gain influencing scientific research outcomes.
Long-term Side Effects
Potential risks from vaccine testing on volunteers.
Compulsory Vaccination Debate
Discussion on mandatory vaccination for public health.
Measles Resurgence
Increase in measles cases due to vaccination decline.
Tiredness
Common symptom of HIV infection.
Fever
Another symptom associated with HIV infection.
Weight Loss
Sign of advanced HIV infection.
Diarrhoea
Gastrointestinal symptom linked to HIV/AIDS.
