Bio Exam #2 Flashcards
what’s the cell theory?
-All living organisms are made of cells
-cell = basic unit of life
-All cells arise from preexisting cells that have divided
Ribosomes
-site of protein synthesis
There's two kinds -Free ribosomes (in cytosol) -bound ribosomes (bound to ER)
-Structure: rRNA and protein in nucleus not organelles
Endoplasmic Recticulum (ER)
-Network of membranous tubules and sacs
-function: biosynthetic factory
-structure: membrane continuous with outer nuclear envelope
-lumen: inside
Golgi apparatus
- A receiving, sorting, shipping “machine”
Function:
-modify ER proteins
-polysaccharide synthesis
-sorting and packaging into vesicles
–cis face = receiving side
–trans face = shipping side
Lysosome
-Digestive compartment with hydrolytic enzymes
Function:
Phagocytosis
Autophagy
-helps in digestion, eats broken parts of cells to obtain nutrients for something else, “food vacuum”
why is the plasma membrane described by the fluid mosaic model?
the individual phospholipid molecules making up the bilayer can move around making the membrane structure flexible and constantly changing in shape. Mosaic because the embedded proteins in the bilayer resemble tiles of a mosaic due to their varying shapes, sizes and pattern.
what’s the difference between an integral and peripheral protein?
Both are passive transport
Integral protein:
-lets specific molecules pass through membrane
-moves down gradient
ex: ion channels, H2O
what’s the difference between active and passive transport?
Active transport:
-moves solute in and out the cell
-potassium = inside cell
-sodium= outside cell
passive transport:
-facilitated diffusion
-moves molecules down gradient
-can also change shape to bind with molecules to move down gradient
how does an animal cell behave in a hypotonic, isotonic, and hypertonic environment?
hypotonic:
-water enters the cell = lysed
isotonic:
-water moves in and out at same rate = normal
hypertonic:
- water leaves cell = shriveled
Explain how phagocytosis, pinocytosis, and receptor-mediated endocytosis work.
Phagocytosis:
- “cell eating”
- cell membrane pinches food participles outside the membrane
- that later becomes a food vacuole
Pinocytosis:
- “cell drinking”
-cell membrane pinches solutes outside the membrane into a coated pit (coated protein)
-that later becomes a coated vesicle
Receptor-Mediated Endocytosis:
-“magnets” for specific things
- coated vesicles with specific solutes bound to a receptor
- Recycles receptors after the solute is inside the cell
how does a plat cell behave in a hypotonic, isotonic, and hypertonic environment?
Hypotonic:
-water enters cell
-stops further water uptake
-turgid= frigid = healthy plant
isotonic:
-water enters and leaves as it enters
-flaccid= limp= plant sagging
hypertonic:
-water loss at a great amount
-membrane pulls away from cell wall
-Plasmolyzed = PLANT DEATH
what’s the difference between endocytosis and exocytosis?
endocytosis:
-cell takes in molecules and particle matter by forming new vesicles from plasma membrane
exocytosis:
-cell ships molecules by fusion of vesicles with plasma membrane
what is metabolism?
sum of organism’s chemical reactions
Does metabolism reach equilibrium in a living cell?
No and if it does all cell dies and you die too
what’s the difference between catabolism and anabolism?
Catabolism:
-breakdown pathway
-polymers to monomers
-“downhill” - energy released
Anabolism:
- Biosynthetic (building) pathways
- monomers to polymers
- “uphill” - energy required
what’s the difference between an exergonic and endergonic reaction?
Exergonic:
-energy released
-high reactants to low products
- spontaneous
- think “exit”
Endergonic:
-energy required
-low reactants to high products
-nonspontaneous
- think “enter”
what are the structures of ATP and ADP?
ATP:
Adenosine Triphosphate
-3 phosphate groups
-Ribose
-Adenine
(same structure as nucleotide)
ADP:
Adenosine diphosphate
-inorganic phosphate
-2 phosphate groups
-ribose
-adenine
- plus energy
what type of reaction is ATP hydrolysis and what is it?
Exergonic reaction because it uses its breaking down the ATP to ADP
ATP hydrolysis:
When ATP
why is ATP a renewable resources?
When ATP is used it turns into ADP, ADP can be recharged by adding a phosphate. So ATP can be recycled
how does ATP drive cellular work?
by transferring a phosphate group to another molecule (a process called phosphorylation)
how is energy stored in cellular fuels (organic molecules)?
As ATP
what type of organic molecules serve as fuel?
glucose
Define catabolism
The breakdown of complex organic molecules into simpler ones.
what four basic features do all cells share ?
1.chromosomes (DNA)
2.ribosomes
3.plasma membrane
4.cytosol
