Cell biology Flashcards
(20 cards)
Outline cell theory + atypical examples
3 elements:
- living things are composed of cells
- cells are the smallest unit of life
- all cells come from existing cells
exceptions:
- muscle fibers are very long (multiple nuclei)
- most fungi have hyphae (thread structure with many nuclei)
- giant algae are much larger
List the 7 functions of life (Mr H. Nerg)
- metabolism: chemical reactions
- reproduction: making offspring
- homeostasis: keeping inside conditions controlled
- nutrition: getting food
- excretion: removal of waste products
- response: responding to stimuli
- growth: increase in size
what are the 7 functions of life in paramecium
- meta: yeast turns blue in cytoplasm
- rep: cell division thru mitosis
- homeo: contractile vacuole fills with water
- nutr: food vacuoles (yeast enters thru oral grove)
- excre: plasma membrane excreting yeast/waste
- resp: responds to cotton fiber + increase in food
- growth: will get larger
compare light microscopes vs electron microscopes
Light
- uses light to bounce thru specimen + lens
- cheaper
Electron:
- uses electrons to bounce off specimen (creates more detail)
- more expensive + larger
how to do calculate magnification
mag = size of drawing/size of specimen (actual)
mm x 1000 to get nM (and round to sig figs)
Label and describe functions of the parts of a prokaryote
- pili: used for cell adhesion (look like tentacles)
- nucleoid region: naked loop of DNA
- plasma membrane: control what goes in and out
- ribosomes: location of protein synthesis
- plasmid: to store genes + DNA
- flagela: used for motion
- cell wall: structure and protection
- cytoplasm: fluid, place for enzyme reactions
compare prokaryote vs eukaryote
Similarities
- cytoplasm for reactions
- smallest unit of life
- enzymes
- ribosomes
- plasma membrane
- DNA
Differences
- pro: nucleous region, euk: true nucleous
- pro: no mitochondria, euk: yes mitochondria
- pro: much smaller, euk: larger
- pro: have pili, euk: no pili
- pro: 70s ribosomes, euk: 80s ribosomes
- pro: naked DNA, euk: histone protein DNA
compare plant and animal cells
Animal
- no chloroplasts
- no cell wall
- small to no vacuole
- lysosomes
Plant:
- chloroplasts
- cell wall
- water vacuole
- no lysosomes
Both:
- plasma membrane
- eukaryotic
- nucleolus
- vacuoles
- mitochondria
Compare the Davson-Danielli vs Singer-Nicolson membrane models and the evidence they used
Davson-Danielli
- protein sandwich with phospholipid bilayer in middle
- examined membranes with electron microscopes showing railroad with dark edges (protein) and lighter centers (phospholipid)
Singer-Nicolson
- fluid mosaic model: several kinds of proteins
- proven by the fluidity of the membrane and ability of proteins to mix and flow with others (tagged red and green)
- not a smooth membrane
How do amphipathic (hydrophobic + philic) properties of membranes maintain their structure?
- phospholipids have two ends, hydrophilic (non-polar) tails and hydrophobic (polar) heads
- the heads want to be near water, like outside or cytoplasm, and tails want to be away from water
- creates amphipathic bilayer so they don’t move
what is the role of cholesterol in animal membranes?
- is hydrophobic, so stays near tails
- decreases membrane fluidity in hot temps
- increases fluidity in cold temps
- reduces permeability for hydrophilic ions
define diffusion and osmosis + their lab application
Osmosis
- movement of water across membrane from low solute concentrate to high
- showed by dialysis tubing lab - water passed thru tube to reach corn syrup concentration
Diffusion:
- simple: movement of particles from high to low concentration
- facilitated: simple diffusion through the help of hydrophilic channel or pore in membrane
explain active transport across membranes by simple diffusion and facilitated diffusion
- Active transport cannot use diffusion, particles are going against the concentration gradient
- ATP is used to carry out, particles move thru globular proteins
what is the role of protein pumps + ATP in active transport?
- protein pumps are like channels in the protein, open to ions the cannot pass thru simple diffusion
- ATP allows the pumps to change openings for ions to pass
Outline the 5 steps of the sodium-potassium pump
- three sodium ions enter pump and attach to sides when protein opens to inside of axon
- ATP transfers a phosphate group, changing shape of protein
- pump opens to exterior of axon and ions release
- 2 potassium enter and bind to inside
- binding causes phosphates to release, pump changes shape and potassium ions released to exterior of axon
How do vesicles transport materials within the cell between rough endoplasmic reticulum, golgi apparatus, and plasma membrane?
- a vesicle containing proteins from ribosomes binds to the rough ER and is transported by the walking proteins pulling the vesicle along the fibers
- the vesicle then connects to the membrane of the golgi body, where the particles are packaged and another vesicle buds of the golgi
- this vesicle is transported to the membrane, where it connects and releases the packaged protein.
How does the fluidity of membranes allow it to change shape, break, and re-form during endocytosis and exocytosis?
- during endocytosis, a substance (usually water), will come into contact with the membrane, causing it to change shape to form a sac around it that can be moved within the cell
- proteins in the membranes carry out the process with ATP
- during exocytosis: the membrane creating the structure of the vesicle has fluidity to fuse with existing membrane for excretion.
How do you estimate osmolarity by viewing samples in hypotonic, isotonic, and hypertonic solutions?
- determining osmolarity is determining the solute concentration of the substance to tissue
- estimate by finding the isotonic concentration, when substance and tissue are of equal concentration
list the elements of a plasma membrane
- hydrophilic heads and hydrophobic tails
- cholesterol (around tails)
- transmembrane protein (all the way across)
- glycoprotein (on one side with parts sticking out)
- glycolipid (sticks out of heads)
- integral protein and peripheral protein (on one side, peripheral covering exterior of integral and sticks out)
List the parts and functions of plant and animal cells
Animal
- vesicles (small circles): transport proteins + substances
- centriole (look like churros): used for cell division
- smooth ER (lines without dots): system of tubes w/o ribosomes, responsible for lipid production
- plasma membrane: controls what goes in and out
- ribosomes (small dots): location of protein synthesis
- nucleolus (large circles): produces ribosomes
- nucleus (smaller circle within): storage and synthesis of DNA
- cytoplasm: liquid inside, location of reactions
- golgi apparatus (grate shaped): packaging + exportation or proteins
- lysosomes (double circle): digestion using enzymes
- vacuole: storage of food and water
- rough ER: system of tubes and protein synthesis
- mitochondria: powerhouse, produce ATP
Plant Only
- cell wall: structure + protection
- cholorplasts: location of photosynthesis
