BIO TEST 1 MODULES 1 & 2 Flashcards
What is a zygote?
a fertilized egg
What are the characterstics of eukaryotic cells?
Compartmentalized organelles;
nucleus;
Plants cells, animals cells fungi
What are the characteristics of prokaryotic cells?
No compartmentalized organelles;
No nucleus but has a nuclear space and a long ribosome
What is a microbiome?
all the population of microorganisms or microbes in an organism
How many microorganisms does a healthy human have?
10,000
STREPTOCOCCUS SALIVARIUS
an inhabitant of the upper respiratory tract and oral cavity and it contributes to dental plaque;
One of the 1st microbes to colonize a germ-free newborn’s dental cavity and gastrointestinal tract
STAPHYLOCOCCUS HAEMOLYTICUS
Resides on the skin;
Its harmless for the most part but can be pathogenic in the body;
Can cause the immune system to become active
BACTEROIDES THETAIOTAOMICRON
A very common intestinal bacteria
Forms enzymes which can break down plant material we ingest (oat fiber)
What are the 4 macromolecules that make up living cells?
Nucleic acids, proteins, phospholipids, carbohydrates
What is a nucleic acid?
has hereditary information and is found in DNA; chromosome/nucleoid
What are proteins?
the structural components of the cell, and can perform metabolic activities (ribosomes, enzymes)
Carbohydrates (polysaccharides)
Important structural components of many cells and sources of stored energy
Phospholipids
primary component of the cell membrane
Why is cell permeability important?
Important to separate internal and external environments of the cell;
Allows controlled entry of important compounds and disposal of metabolic wastes
What are cell membranes made up of?
Made up of lipid macromolecules which have hydrophobic and hydrophilic properties. This is known as the phospholipid bilayer
are the hydrocarbon fatty acid tails polar or non-polar?
non-polar (hydrophobic)
is the phosphate head group polar or non-polar?
polar (hydrophilic)
What are lipid micelles?
formed by phosphates; important for absorbing fat-soluble vitamins and complex lipids in the body; generate spontaneously without energy; water will interact with head regions and lipid aggregates form spontaneously, without energy
What are phospholipids made up of?
Has a glycerol molecule linked to 2 fatty acid tails;
Hydrophobic region is where fatty acids are located;
Hydrophilic head groups (glycerol plus phosphate)
what is a distinct characteristic of phospholipids?
amphipathic
hydrocarbon chains in phospholipids
made of hydrocarbon chains which are usually made up of 16-18 carbons in a single chain;
bonds can be single (saturated) or in double bonds (unsaturated);
Single chains are straight, left tail
Chains with double bind will have kink at the end (right tail)
how does the saturation of fatty acids affect the fluidity of cell membranes?
longer chains are packed together more tightly than the shorter ones, reduces permeability; areas that are more fluid will have unsaturated tails (non-lipid raft region); saturated areas less fluid because there will be stronger hydrophobic regions (lipid raft)
What are the factors that affect fluidity of a cell membrane?
unsaturated and saturated fatty acids, number of carbons in the fatty acid tails, temperature, presence/absence of steroids in the form of cholesterol
how does number of carbons in the fatty acid tails affect fluidity of cell membranes?
double bonds create kinks in the phospholipid, pushes neighbouring phospholipids far apart making it more fluid
how does temperature affect the fluidity of cell membranes?
high temps = more fluidity (cold adapted organisms have unsaturated phospholipids in their membranes to promote fluidity_
how does the presence/absence of cholestrol affect membrane fluidity?
cholesterol works like lipids and keeps phospholipids fluid in nature;
Makes sure that it isn’t solid at low temps