Chapter 3 Flashcards
What is the cell theory?
1 The cell is the smallest structural and functional living unit
2. Organismal functions depend on individual cell functions and collective
What is the plasma membrane?
Membrane composed of phospholipids, cholesterol, and proteins, that encloses cell contents; outer limiting cell membrane
Plasma membrane play a dynamic role in?
Cellular activity
What do the plasma membrane separate?
ICF from ECF
Cholesterol
A plasma membrane lipid that stiffens the membrane while increasing the membranes stability and fluidity
Phospholipids
Are a membrane lipid (75% of plasma membrane)
- phosphate head: polar and hydrophilic
- fatty acid tails: nonpolar and hydrophobic
Where are peripheral proteins located?
On either monolayer
Selective permeability
Allows passage of sure substances ; limits other
Glycolipids
A membrane lipid with polar sugar groups an outer membrane surface
There are plenty of ___ embedded in ___?
Proteins; membrane
Where are integral proteins located?
Within the membrane
What are the 7 examples of integral proteins?
- Channels
- Transporters
- Receptors
- Intracellular junctions
- Enzymes
- Cytoskeleton anchors
- Cell identity markers
What is selective permeability dependent on?
Molecular size
Lipid solubility
Charge
If substance cannot get through membrane, what does it go through?
Channels and transporters
3 membrane Junctions
- Tight Junctions
- Desmosomes
- Gap Junctions
What are tight junctions?
Impermeable junctions that encircle adjacent cells
What are desmosomes?
Anchoring junctions between cells
- more flexible
What are gap junctions?
Communicating junctions that allow substance to pass from one cell to another
Passive process
- No cellular ATP
- From high → law concentration gradient
Simple diffusion
Unassisted transport across a plasma membrane of a lipid soluble or very small particle.
Facilitated diffusion is a
Passive process
Osmosis is a
Passive process
Active process
Energy ATP required
- low to high concentration gradient
Where do active processes occur?
In living cell membranes
What factors affect diffusion?
-Increased temperature
- greater concentration
- larger surface area
- smaller particle sizes
-Time
How does passive transport flow?
Substances diffuse down the concentration gradient; no energy is required
Osmosis
Transport of water without energy
What is an aquaporin?
Water moves from low → high solute concentration
Tonicity
Example of osmosis
What is tonicity?
Changes the shape of cells by altering their internal volume
What is a isotonic solution?
Solute concentration is the same inside and outside the cells.
How much saline solution is isotonic to human plasma
0.9%
Hypertonic solution
Solution with higher [ solute] than inside the cells
Hypotonic solution
Solution with lower[ solute] than inside cells
Exocytosis
Transports out of cell
Endocytosis
Transports into cell
Transcytosis
Transports into, across, and out of cell
Substance (vesicular) trafficking
Transport from one organelle in a cell to another
Membranous bound cytoplasmic organelles
- Mitochondria
- Peroxisomes
- lysosomes
- ER
- Golgi apparatus
Nonmembranous band cytoplasmic organelles
- Cytosteleten
- centrioles
-Ribosomes
Mitochondria
Provides most of cells ATP
Ribosomes
Site of protein synthesis
Smooth ER
Synthesis of steroid based hormones
-No ribosomes
Rough ER
Manufactures all secreted proteins
Golgi apparatus
Modifies, concentrate, and packages proteins and lipids
Lysosomes
Sorts, recycles, gets rid of, and break down wastes,
Nucleus
Cell’s control center; houses DNA; all human cells have nucleus
Nuclear envelope
Double membrane outside the cell
Nucleolus
Site of ribosome assembly in the cell
What phases are in the cell cycle
Interphase and cell division(mitosis)
What are the 3 subphases of interphase?
G1,S, G2
What is interphase?
Cell formation → to cell division
What happens in the G1 (gap)phase?
Vigorous growth and metabolism
What happens in the S (synthetic) phase?
DNA replication
What happens in the g2 (gap2) phase?
Preparation for mitosis
What are the four stages of mitosis?
- Prophase
- Metaphase
- Anaphase
4 telophase
What are the mitotic phase events?
Mitosis and cytokinesis
Cytokinesis
Division a cytoplasm by cleavage furrow
Prophase
Chromosome is visible → mitotic spindle form between centrosomes as a result of them growing away from each other → nuclear envelope breaks down → as a result, microtubules attach to chromosomes
Metaphase
Chromosome line up at the equator
Anaphase
Chromosomes split simultaneously → then are pulled to opposite poles of the cell
Telophase
2 sets of chromosomes uncoil to form chromatin → nuclear membrane forms around chromatin → nucleus reappears
Cytokinesis
Division of the cytoplasm; actin microfilaments form a cleavage→ two daughter cells are pinched apart that each have a nucleus
DNA → RNA → Protein
Central Dogma of Biology
What is a gene?
Segment of DNA with blueprint for one polypeptide
Transcription
DNA → mRNA; occlus in nucleus
Translation
Nuclei acids → proteins ; occurs in ribosomes
