Chapter 3 Flashcards
Basic unit of structure and function in the body
Cell
Cells are measured in
Micrometers
Cells that have developed specialized characteristics are said to be
Differentiated
There is no typical cell, but a composite cells shows what
Components found in most cells
Name the three major parts of a cell
Nucleus
Cytoplasm
Cell membrane
Cell Membrane
- Outer boundary
- Maintains integrity
- Consists mainly of lipids and protein with some carbohydrates
- Selectively Permeable: Regulates entry and exit of substances
- Signal Transduction: Receive and respond to messages
Cell Membrane Structure
- Framework is a phospholipid bilayer: Hydrophilic (water soluble heads) and Hydrophobic (water insoluble tails)
- Cholesterol stabilizes and helps keep impermeable to water soluble substances
- Membrane proteins: Pores, channels, receptors, cell contact, and identification
- Carbohydrates: Cell recognition and interaction, self makers
Cellular Adhesion Molecules
- Guides cells
- Provides friction
- Makes connections with nerve cells
Cytoplasm
- Networks of membranes and organelles in cytosol
- Cytoplam=Cytosol (fluid) + Organelles (tiny solid structures with specific functions)
- Cytoskeleton: supporting framework of protein stuff
Cytoplasmic Organelle: Ribosome
- Composed of RNA and protein
- Enzyme activity to link amino acids in protein synthesis
- Provide structural support
Cytoplasmic Organelle: Endoplasmic Reticulum
- Membrane bound sacs, canals, and vesicles
- Tubular transport system
- Rough: Ribosomes, conducts protein synthesis
- Smooth: Conducts lipid synthesis, NO ribosomes
Cytoplasmic Organelle: Vesicles
- Membranous sacs
- Store or transport substances
Cytoplasmic Organelle: Golgi Apparatus
- Sacs own membranous sacs
- Refines, packages, and delivers proteins
Cytoplasmic Organelle: Mitochondria
- Fluid filled membrane sacs
- House chemical reactions that extract energy from nutrients
- “Powerhouse of the cell”
Cytoplasmic Organelle: Lysosomes
- Small membranous sacs
- Contain enzymes that digest proteins, carbohydrates, nucleic acids, bacteria, debris, worn out parts
- “Garbage disposals of cell” and “Suicide sac”
Cytoplasmic Organelle: Peroxisomes
- Membranous sacs similar to lysosomes
- Contain enzymes that digest lipids, alcohol, hydrogen peroxide
Cellular Structures: Centrosome
- Central body
- Consists of 2 centrioles
- Composed of microtubules
- Produces spindle fibers during cell division
Cellular Structures: Cilia
- Motile extensions
- Propel mucus in respiratory tract
- Propel egg towards uterus
Cellular Structures: Flagella
- Motile extensions
- Longer than cilia
- Tail of sperm is the only flagella
Cellular Structures: Filaments
Microfilaments: Tiny rods of actin; cellular movement
Microtubules: Tubes; help move organelles; cell shape; cilia, flagella, and centrioles
Intermediate Filaments: Several proteins; cytoskeleton structure; support nuclear envelope
Nucleus
- Contains genetic material
- Controls cell activities
- “Brain”
Cell Nucleus
- Nucleus Envelope: Allow passage of certain substances
- Nucleolus: RNA and protein; site of ribosome production’
- Chromatin: Cell’s chromosomes; stores information for protein synthesis
Physical (Passive) Processes
- Do not require ATP
- Diffusion
- Osmosis
- Facilitated Diffusion
- Filtration
Physiological (Active) Processes
- Require ATP
- Active Transport
- Endocytosis
- Exocytosis
- Transcytosis
Diffusion
- Movement of atoms, molecules, or ions, from region of higher concentration to lower concentration until evenly dispersed
- Move by bouncing off of each other
- Occurs due to constant motion of atoms, molecules, ions.
Facilitated Diffusion
- Diffusion across the cell membrane through ion channels or transporters
- Passive process- no ATP required
- Difference is the channels*
Osmosis
- Movement of water across the selectively permeable membrane from region of higher water concentration to lower.
- Water moves into region with the higher concentration
- Passive process- no ATP required
Ability of osmosis to generate enough pressure to life a volume of water
Osmotic Pressure
Same osmotic pressure; No net gain or water loss
Isotonic solution
Higher osmotic pressure; lose water
Hypertonic solution
Lower osmotic pressure; gain water
Hypnotic solution
Filtration
- Process that forces molecules through membranes by exerting pressure
- Separate solids from water, or small particles from large
- Passive process- no ATP required
Active Transport
- Lower concentration-Higher concentration
- Active process- ATP required
- Example: NA/K pump
Movement of a substance into the cell inside a vesicle
Endocytosis
Engulfs droplets of liquid
Pinocytosis
Engulfs soils particles
Phagocytosis
Engulfs specific substances which have bound to receptors proteins on the membrane
Receptor mediated endocytosis
Sac that stores
Vesicle
Release substances from cell
Example neurotransmitters from nerve cells
Exocytosis
Quickly transports substance from one end of cell not another(Example HIV)
Transcytosis
Series of changes a cell undergoes from the time it forms until the time it divides
The cell cycle: Interphase-Mitosis-Cytokinesis
Interphase
- Active period
- Cell grows
- Cell has normal functions
- Replicates genetic material to prepare for mitosis
- Synthesizes organelles, membranes, and chemicals
- Phases: Synthesis-DNA replicates, G1-G2-Other structures replicate and grow
Divison of nucleus
Mitosis
Division of the cytoplasm
Cytokinesis
Phases of Mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
- Begins during anaphase
- Continues through telophase
- Pinches cytoplasm in half
What can result form a loss of control over frequency of mitosis
Tumors
A tumor that remains in local area
Benign
A tumor that is invasive
Maligent
Abnormal forms of genes that control cell cycle
Oncogenes
Normally limit mitosis but if inactivated/removed, cannot regulate anymore
Tumor Suppressor Genes
