Exam 3/Practicum 1 Flashcards
Cell
Structural and functional unit of life
Plasma membrane consists of
Membrane lipids that form a flexible lipid bilayer
Lipid bilayer is made up of
75% phospholipids 5% glycolipids 20% cholesterol
Phospholipids consists of two parts
Phosphate heads: are polar (charged), so are hydrophilic (water-loving) Fatty acid tails: are nonpolar (no charge), so are hydrophobic (water-hating)
Glycolipids
Lipids with sugar groups on outer membrane surface
Cholesterol
Increases membrane stability
Membrane proteins
Allow cell communication with environment
Integral proteins
Function as transport proteins (channels and carriers), enzymes, or receptors
Peripheral proteins
Enzymes and cell-to-cell connections
Membrane protein tasks
Transport, receptors for signal transduction, attachment to the cytoskeleton and extracellular matrix, enzymatic activity, intercellular joining, cell to cell recognition
Transport
receptors for signal transduction
Attachment to the cytoskeleton and extracellular matrix
Enzymatic activity
Intercellular joining
Cell to cell recognition
Tight junction
Protective layer - Keeps out bacteria and other things that are unwanted in the cell
Desmosomes
Allows flexibility (give) and hold it together
Gap junctions
Allow for rapid communication
Diffusion
Area of high concentration to an area of lower concentration
Energy not required
Speed of diffusion
Size (small) and temperature (high)
Diffusion
The nonpolar, hydrophobic lipid core of plasma membrane blocks diffusion of most molecules
Simple diffusion
Nonpolar lipid-soluble (hydrophobic) substances diffuse directly through phospholipid bilayer
Examples: oxygen, carbon dioxide, fat-soluble vitamins
Facilitated diffusion
transported passively down their concentration gradient by:
Carrier-mediated facilitated diffusion
Channel-mediated facilitated diffusion
Substances move through water-filled channels
Osmosis
Diffusion of a solvent, such as water, across a selectively permeable membrane
Water moves by osmosis from areas of low solute (high water) concentration to high areas of solute (low water) concentration
Hydrostatic pressure
Osmotic pressure
Tonicity
Ability of a solution to change the shape or tone of cells by altering the cells’ internal water volume
Isotonic solution
Same osmolarity as inside the cell, so volume remains unchanged
Hypertonic solution
Higher osmolarity than inside cell, so water flows out of cell, resulting in cell shrinking
Shrinking is referred to as crenation
Hypotonic solution
Lower osmolarity than inside cell, so water flows into cell, resulting in cell swelling
Can lead to cell bursting, referred to as lysing
Active Transport
Requires carrier proteins (solute pumps)
Moves solutes against their concentration gradient (from low to high)
This requires energy (ATP)
Two types of active transport
Primary active transport
Required energy comes directly from ATP hydrolysis
Secondary active transport
Required energy is obtained indirectly from ionic gradients created by primary active transport
Sodium-potassium pump
Potassium in (high) - negative charge inside
Sodium out (high)
Pumps where it’s already highly concentrated
Phagocytosis
Cell eating
Pinocytosis
Cell drinking
Voltage
Difference in electrical charge between two points
Resting membrane potential (RMP)
Electrical potential energy produced by separation of oppositely charged particles across plasma membrane in all cells
Compartmentalization
Separation
Mitochondria
“Power plant” of cells because they produce most of cell’s energy molecules (ATP)
Ribosomes
Site of protein synthesis
Made up of protein and ribosomal RNA (rRNA)
Free ribosomes
Free floating
Membrane-bound ribosomes
Attached to membrane of endoplasmic reticulum (ER)
Rough ER
Site of synthesis of proteins that will be secreted from cell
Smooth ER
Lipid metabolism
Absorption, synthesis, and transport of fats
Detoxification of certain chemicals
Converting of glycogen to free glucose
Storage and release of calcium
Golgi Apparatus
Modifies, concentrates, and packages proteins and lipids received from rough ER
Peroxisomes
Detoxifying
Two main detoxifiers: oxidase and catalase
Play a role in breakdown and synthesis of fatty acids
Lysosomes
Digestive enzymes (acid hydrolases)
Centrosome
Cell center
Generates microtubules; organizes mitotic spindle (for cell division or mitosis)
Consisting of centrioles — microtubular (churros)
Cilia
Whiplike, motile extensions on surfaces of certain cells
Thousands of cilia work together in sweeping motion to move substances (example: mucus) across cell surfaces in one direction
Flagella
Longer extensions that propel the whole cell
Microvilli
fingerlike extensions of plasma membrane used to increase surface area for absorption
Chromatin
Consists of 30% threadlike strands of DNA, 60% histone proteins, and 10% RNA
Chromosomes
Condensed chromatin
Interphase
Cell grows and carries on its usual activities
Cell division
Cell splits into two
S Phase - Synthesis
Replicate DNA
DNA replication
RNA starts replication by laying down short strand that acts as a primer
DNA polymerase attaches to primer and begins adding nucleotides to form new strand
End result: two identical “daughter” DNA molecules are formed from the original