Cell Structure (T1M1) Flashcards
What is a eukaryotic cell
True nucleus with genetic material
Plant, animal, fungi
What is a prokaryotic cell
No true nucleus
Bacteria
What is a microbiome
Populations of microbes in an environment
Give some examples of bacteria found in a healthy body
Streptococcus salivarus
Upper respiratory tract, creates tooth plaque
Staphylococcus haemolyticus
On skin but dangerous in body (staph infections)
Bacteroides thetaiotaomicron
Digestive enzymes in colon
The four classes of macromolecules are:
Nucleus acids
Proteins
Carbohydrates / Polysaccharides
Fats / Phospholipids
What are some purposes for a cell membrane?
Separate environments with different chemical compositions
Protect from toxins
Facilitate entry and exit of wastes
Describe the composition of a phospholipid
The head contains a polar group at the top, followed by a phosphate group attached to a glycerol (C3H8O3)
Fatty acid tails are attached to the glycerol
Phospholipid heads are _______ while the tails are _______
hydrophilic, hydrophobic
Define ampipathic
Both hydrophobic and hydrophilic
Fatty acid tails have:
How many carbons?
What types of bonds?
What type of shape?
16-18
Single aka saturated, double aka unsaturated
Double bonds cause kinks
Describe the structure of steroids
4 hydrocarbon ring structure
Eg cholesterol
What are lipid micelles?
Aggregation of free lipids that forms a ball with hydrophobic tails on the core and hydrophilic heads on the surface.
They can absorb fat soluble vitamins and other lipids.
What are some factors that affect cell membrane fluidity? How do the affect fluidity?
More unsaturated fatty acids lead to more kinks in the membrane, which increases fluidity.
Longer carbon chains reduces fluidity
Higher temperature means more fluidity
More cholesterol at NORMAL temperatures means less fluidity
More cholesterol at LOWER temperatures means more fluidity
About how much of the bilious membrane is cholesterol?
50%
True or false: more fluid membranes are more permeable
True
How do each of the following molecules cross the cell membrane?
Small nonpolar molecules
Gases
Hydrophobic molecules
Small ions
Water soluble materials
Large charged and polar molecules
1-3 pass through the easiest
4 may need some assistance
5 must pass through transport proteins
6 basically don’t cross at all
Differentiate between:
1) passive / simple diffusion
2) passive transport or facilitated diffusion
3) active transport
1) high to low ccn, directly across the bilaye, includes (gases, water, lipid-soluble molecules, polar molecules)
2) high to low ccn,through embedded proteins, no ATP required, transports ions and hydrophilic molecules
3) low to high ccn, through transport proteins and ATP
What is osmosis
Passive transport across a membrane
How does osmosis change volumes and concentrations between two solutions?
Water diffuses from a less concentrated area (hypotonic) to a more concentrated (hypertonic) area
Diluted do not move across a membrane
The process creates equal osmolarity
What are aquaporins
Transport water through osmosis in to and out of the cell
Define
1) isotonic
2) hypotonic
3) hypotonic
1) osmolarity interior = osmolarity exterior
2) osmolarity interior > osmolarity exterior
water flows in to cell
3) osmolarity interior < osmolarity exterior
water flows out of cell
Define:
1) primary active transport
2) secondary active transport
1) proteins use ATP directly to pump against the gradient
2) neighbouring proteins benefit off of the electrochemical gradients created by primary transport, indirect use of ATP
Describe the Na-K pump
For every 3 Na+ pumped out, 2K+ are pumped in
3Na+ bind to the protein
ATP gives up phosphate group
P binds to protein, creating the necessary confirmation to release Na+ outside of the cell
2K+ bind to protein, P group breaks off, protein confirmation changes
K+ enters the cell
Creates a more positively charged cell exterior
