Chapter 2 Flashcards
(28 cards)
Nucleus
-Double membrane (nuclear envelope) with pores that control what enters and leaves the nucleus
-stores DNA
-Synthesis of RNA
Rough ER
-ribosomes on surface
-package proteins for secretion
-send transport vesicles to Golgi
Smooth ER
-no ribosomes on surface
-synthesis lipids
-metabolize carbs
-store Ca2+
-detox
Golgi Apparatus
-Synthesis and packaging of materials for transport
-produce lysosomes
Characteristics of prokaryotes
-no nucleus
-DNA in a nucleiod
-no organelles other than ribosomes
-small size
ex: bacteria
Characteristics of Eukaryotes
-Has nucleus and nuclear envelope
-membrane bound organelles
-larger in size
-more complex
ex: plant and animal cells
Why is it important for cells to be small?
To have a large surface area to volume ratio.
Large surface area to volume ratio causes an INCREASE in rates of chemical exchange between cell and environment
Ribosomes
-protein synthesis
Passive transport
NO Energy needed
Diffusion DOWN the concentration gradient (high to low)
Lysosomes
-intracellular digestion
-recycle cell’s materials
-apoptosis (programmed cell death)
Vacuoles
storage of materials
Mitochondria
-site of cellular respiration
-double membrane: outer and inner membrane
Chloroplasts
site of photosynthesis
Plasma membrane is selectively permeable
Small, nonpolar molecules can cross easily
The hydrophobic core prevents the passage of ions and large, polar molecules
Phospholipids: Amphipathic
-Hydrophilic head outside, hydrophobic taill towards inside
-this creates a hydrophobic barrier: keeps hydrophilic molecules out
Membrane fluidity
-Temperature
-cholesterol
-saturation
-Low temp: Phosphlipids closer together, less fluid. High temp: phospholipds farther apart, more fluid
-cholesterol inserts itself between phsopholipids. At low temps, this prevents them from packing close together, increasing fluidity and hinders solidification
-Unsaturated tails are bent, preventing packing and incresing fluidity
Integral proteins
Embedded in membrane, fully passes through
Peripheral proteins
Extracellular or cytoplasmic sides of membrane
NOT embedded
Water moves to
Where there is a higher concentration of solute
Facilitated Diffusion
Transport proteins help hydrophilic substances cross the plasma membrane
Active transport
Requires ATP to move substances AGAINST the concentration gradient
Cotransport
Membrane protein enables “downhill” transport of one solute to drive “uphill” transport of another
isotonic solution
Solute concentration is equal
hypertonic
Higher solute concentration outside