Cellular Organisation - WK 2 Flashcards
(31 cards)
What are the two types of cells?
Eukaryotic: contains nucleus and organelles, bound by plasma membrane.
Prokaryotic: no nucleus or organelles bound by plasma membrane.
Describe the plasma membrane and its layers.
Phospholipid bilayer that covers the surface of the cell.
Hydrophilic heads - water loving. Interior and exterior surface.
Hydrophobic tails - water hating. Centre of membrane.
Name the integral and peripheral membrane proteins of the plasma membrane.
Integral: ion channel, carrier, receptor.
Peripheral and integral: enzymes, linker.
Name the non-membranous and membranous organelles within the cell.
Non-membranous: cytoskeleton, cilia, microvilli, centrioles, ribosomes.
Membranous: mitochondria, endoplasmic reticulum, Golgi complex, lysosomes.
What are the functions and components of the cytoskeleton?
Functions: structural support, movement.
Components: Microfilaments: process contractile ability.
Intermediate filaments: stabilize cell.
Microtubules: determine cell shape.
What do microfilaments contain?
Actin and Myosin.
What are microtubules involved in?
Movement - by cilia and flagella.
Describe microvilli and cilia. Where are they found in the body?
Microvilli: increase surface area. Finger-like projections. Found in digestive tract.
Cilia: move mucus to throat for swallowing. Finger-like extensions. Line respiratory tract.
Describe the endoplasmic reticulum.
Rough: studded with ribosomes, makes and stores proteins.
Smooth: no ribosomes, makes and stores lipids and steroids.
Both continuous with nuclear membrane.
What is the function of the Golgi apparatus? What are its two faces?
Receives vesicles from ER. Modifies and packages proteins and lipids for destination.
Cis face - where vesicles enter, trans - where vesicles exit.
What is the function and features of lysosomes?
Garbage disposal and recycling. Small vesicles with extremely acidic enzymes. Breaks down contents and ejects unwanted components.
Name the types of membrane transport.
Passive - no energy: Simple diffusion, Osmosis, Facilitated diffusion.
Active - energy required: Pumps, Vesicle: exocytosis and endocytosis.
Describe diffusion and its two types.
Molecules constantly in motion, over time evenly distributed.
Movement: higher concentration to lower concentration.
Simple: diffusion of nonpolar molecules through phospholipid bilayer.
Facilitated: diffusion of ions through channel and diffusion of polar and ionic molecules using a carrier.
What is a concentration gradient?
Difference between areas of high and lower concentrations.
What can influence the rate of diffusion?
Distance, molecule size, temperature, steepness, electrical forces.
Describe osmosis.
Water movement across cell membrane by diffusion.
Occurs across a selectively permeable membrane.
Water flows toward solution with higher concentration of solutes, where lower concentration of water is.
What is tonicity? Name the three types of solutions.
Amount of solute in extracellular fluid.
Isotonic solution: concentration EQUAL inside and outside.
Hypotonic solution: higher solute inside. Cell swells (bursts).
Hypertonic solution: higher solute outside. Crenation (shrivels).
Describe the sodium-potassium pump and its process.
3 sodium ions bind to pump. Triggers ATP to bind, splitting ATP into ADP and P (P is attached to pump). Trigger changes shape of pump, moving the sodium to outside. 2 potassium ions bind to pump outside cell, causes P to be released. Release of P causes pump to return to original shape, causing potassium to move into the cell.
Describe vesicular transport.
Movement into and out of cell via vesicles. Vesicles and cell membrane fuse and contents dispersed. Requires ATP.
Endocytosis: entry into cell.
Exocytosis: exit from cell.
Describe the sequence of the cell cycle.
Interphase: 3 phases:
1. G1 phase = duplication of organelles, centrosome replication begins (8-10 hours).
2. S phase = DNA replication (8 hours).
3. G2 phase = synthesize proteins and enzymes, centrosome replication completed.
Mitotic phase: 4 phases:
- Division of the nucleus:
1. Prophase = Preparation.
2. Metaphase = Move to Middle, chromatids align on metaphase plate.
3. Anaphase = Apart. Chromosomes pulled to opposite poles.
4. Telophase = Termination phase. Cleavage furrow forms.
Why is a karyotype taken at metaphase?
Chromosomes are most condensed and visible.
Explain cytokinesis and how it occurs.
Cytoplasmic division of daughter cells, begins in late anaphase.
Cytoplasm constricted by ring of actin filaments.
What are the three main components of a nucleotide of RNA?
A phosphate group, ribose, and a nitrogenous base.
Describe the structure of a gene.
Promoter, acts as a switch. Coding sequence, encodes amino acid sequence. Terminator, defines end of gene. Sections of DNA.
