Lecture 3 Cell Cycle Flashcards
Interphase 5 steps
G1
G1 Checkpoint
S Phase
G2
G2 Checkpoint
Phragmoplast
Are the cytoplasmic strands that bisect the wall, during interphase creates new wall & new cells
4 Steps of Mitosis
- Prophase
- Metaphase
- Anaphase
- Telophase
Known as nuclear division
Mitosis
Known as cell division
Cytokinesis
What type of division includes a complete set of previously duplicated chromosomes are allocated to the nuclei of each daughter cell?
Mitosis
What type of division includes an entire cell divided into daughter cells?
Cytokinesis
What type of cells are similar in structure to the parent cell?
Daughter cells
G1 Phase (2 total)
- Cell doubles in size
- Organelles, enzymes and other molecules increase in number
Gap 1 - G1 Checkpoint
Arrests the cycle OR initiates S phase
- Commits the cell to another round of cell division (Synthesis)
Synthesis - S Phase (2 total)
- DNA is replicated
- DNA associated proteins (histones) are synthesized
Gap 2 - G2 Phase (2 total)
- Cell division structures assemble
- Chromosomes begin to condense
G2 Checkpoint
Checks chromosome replication & any DNA damage repaired
2 unique interphase events in plant cells
- Nucleus migrates to the center of cell (appears as halfway thru)
- Appearance of a preprophase band during G2 just before the 1st phase of mitosis (appears as fully thru)
3 Parts of Prophase known as
Early, Mid & Late Prophase
Step 1 Prophase
Early: Chromosomes are visible are long threads
Mid: Chromosomes shorten & thicken, forms chromatids attached by centromere
Late: Kinetochores develop on both sides at centromere, nuclear envelope disappears
Step 2 Metaphase
Mitotic spindles arise and attach to Kinetochores
Kinetochore microtubules align the chromosomes at the metaphase plate
Step 3 Anaphase
Separation of sister chromatids at centromere, daughter chromosomes moves to opposite spindle poles
Motor proteins use ATP to pull chromosomes
Step 4 Telophase
ER creates nuclear envelopes
Spindle disassembles & chromosomes become long threads again
Plant cells cell division begin with the formation of ___
Phragmoplast
Osmosis
Diffusion, cells moving randomly to occupy space
Cytokinesis
Physical process of cell division, which divides the cytoplasm of parent cell into 2 daughter cells
Osmotic potential (solute potential)
Tendency of water to move across membrane due to differences of solute concentration
Pressure due to movement of high to low water conc. till equillibrium
What is the primary function of membranes
Movement of water through a selectively permeable membrane
Turgor Pressure
Water pressure is equal & opposite the pressure exerted by cell wall
Water moves in
Causes the cell to be Turgid (stiff)
Plasmolysis
When cell contacts higher # of solute, Water moves out and the plasma membrane shrinks away
Causes plant to collapse
Cell Membrane Structure (3 total)
- Lipid bi-layer
- Made up of transmembrane proteins, globular proteins crossing thru membrane
- 3 Classes of transport (pumps, carriers, channels)
2 Types of Transmembrane Proteins
Single alpha helix
Multi-pass proteins
3 Basic Classes of transport proteins
- Pumps
- Carriers
- Channels
Pumps
- Active Transport (slow)
- H+ pumps driven by ATP or light energy
- Against conc./ electrochem. gradient requires energy + carrier protein
- No proton = no sugar
Carrier Protein
- Passive transport (intermediate)
- Bind to specific solute, transform in order carry solute across membrane
- Needs solute to fit to binding site, shuts down, changes/ transforms and opens up to let out
Channel Proteins
- Passive Transport (Rapid)
- Generally for water, bigger stuff, solutes w/ water, opens up like a river
- Allows many basic things thru that help build molecules in body & enzymatic formation
Endocytosis
Transportation of large molecules into cell
3 Types of Endocytosis
- Phagocytosis (eating)
- Pinocytosis (drinking)
- Receptor mediated endocytosis (coated pits)
Phagocytosis
Eating
Ingestion of large particles
Engulfing something INTO body
Pinocytosis
Drinking
Ingestion of liquids from surrounding environment
Pulling in cytosol around you
Receptor-Mediated Endocytosis
Receptor on the outside pinch off to form coated versicles
Clathrin coated pits
Fuses w/ golgi bodies or vacuoles to release contents
Vesicle Mediated Transport
Transportation of large molecules or particles
Releases contents into cell wall, plasma membrane remains
Pushing it back out, Exocytosis
Signal Transduction Pathway
Process where cell converts an extracellular message into a response
3 Basic Steps of Signal Transduction Pathway
Reception
Transduction
Induction
The ___ ___ plays a key role in signal recognition
Plasma Membrane
In plants, signals are typically ___
Hormones (chemical messengers)
Reception
Binding hormone to its specific receptor in the plasma membrane
Transduction
Cell is stimulated for initial stimulus then sets off secondary messenger, signal is activated
Induction
Second messenger activates inter cellular processes
Response is generated
Plasmodesmata
Small threads connecting protoplasts of adjacent cells
* The interconnection is known as the symplast
(Movement of substances cell to cell via plasmodesmata called symplastic transport)
Movement of substances in the cell wall continuum or apoplast is known as __ __
Apoplastic Transport
Movement of substances, like water, from cell to cell via the plasmodesmata is called ___ Transport
Symplast
