Week 1 - Chapter 1 Flashcards
Eukaryotic vs prokaryotic
Eukaryotic - nucleus, animals, plant, fungi
Prokaryotic - unicellular, bacteria and archaea
Phospholipids in plasma membrane
phosphoglycerides + phosphingolipids
The plasma membrane (3 functions)
1) Isolates the cell’s internal and external environments
2) Regulates flow of materials into and out of the cell
3) Allows for interaction with other cells
The plasma membrane is _______ - the inside and outside faces are _____
asymmetrical, different
More cholesterol in plasma membrane =
less fluid
Glycocalyx definition
layers of carbohydrate on the cell’s outer surface
Glycocalyx is thought to act as
specificity markers for the cell and as an antennae to pick up signals
Cytoplasmic matrix definition
a structure within the cytosol that makes up the cytoskeleton
= cytoskeleton + fluid
Cytoplasmic matrix provides (4 functions)
1) Structural support
2) Framework for positioning organelles
3) Network to direct movement inside cell
4) Means of independent locomotion for specialized cells
3 components of the cytoskeleton
Microtubules, microfilaments, intermediate filaments
Fluid of cytoplasmic matrix contains
small molecules such as glucose, AA, oxygen, and CO2
Microtubules
rigid structures that provide mechanical support for the cell to determine its shape
Microfilaments are
assembled/disassembled for locomotion, changes in cell shape, phagocytosis etc
Intermediate filaments
provide mechanical strength to cells
Cytoplasmic matrix also functions in
intercellular communication, transfer of DNA/RNA
The structural arrangement of the cytoplasmic matrix may influence
all metabolic pathways including glycolysis, FA synthesis etc.
Mitochondria - site of
energy production, oxygen use, cellular respiration
Outer mito membrane is
porous
Inner mito membrane is (2)
folded to increase SA, selectively permeable
Inner mito membrane is the site of
ETC
ETC is central to the process of
ox phos
The function of the ETC is to
couple the energy released by nutrient oxidation to the formation of ATP
Nuclear envelope is composed of
2 bilayer membranes (inner and outer)
Nucleoli is
condensed chromatin - contains DNA, histones, and RNA
Nucleus activity
initiates and regulates most cellular activities
Chromatin is the
spread out form of DNA, condenses into chromosomes when ready to divide
DNA BP
ATGC
RNA BP
AUGC
Nucleotide pairing (complementary base pairing) occurs by
hydrogen bonds
Cell transcription uses what enzyme
RNA polymerase
After transcription,
splicing of introns by spliceosome - mature mRNA leaves nucleus
mRNA is synthesized in the ______ then moves to ______
nucleus, rough ER
What brings AA to mRNA on ribosomes?
tRNA
If the abundance of a protein increases, it’s most likely due to
increased translation
The primary mechanism by which gene expression is modified by bioactive factors in food appears to be
interaction with transcription factors
Western blot -
proteins separate by weight, electrical separation
Can be used to see if treatment with a drug increased protein expression
Western blot
Sequencing protein can be done by
first separating on western blot
Southern blot separates
DNA
Northern blot separates
RNA
Smooth ER is associated with what function
lipid synthesis
Rough ER associated with what function
protein synthesis
Sarcoplasmic reticulum is
smooth ER in muscle
Sarcoplasmic reticulum contains the
calcium ion pump - a necessity for the contractile process
The ER is a quality control organelle in that…
it prevents proteins that have not achieved normal tertiary or quaternary structure from reaching the cell surface
Golgi is further from nucleus than
ER
Golgi function
protein trafficking and sorting - packages materials into vesicles for transport and folds proteins into usable shapes or adds lipids/carbs
Cis-golgi
entrance
Trans-golgi
exit
Golgi connected to ER by
transport vesicles
What dictates what protein goes where?
Leader sequence at the amino end of the protein
Lysosomes and peroxisomes similarity
look similar, bundles of enzymes surrounded by a single membrane
Lysosomes function nickname
cell’s digestive system, recycling center
Peroxisomes function overall
site of oxidative catabolic reactions, detox
Lysosomes 4 functions
phagocytosis, autolysis, bone resorption, hormone secretion and regulation
Phagocytosis
foreign substances taken up by the cell are digested
Autolysis
intracellular components, including organelles, are digested
Peroxisomes 3 functions
oxidize FA to acetyl CoA, AA catabolism, detox reactions
Intracellular stimuli of apoptosis (3)
1) DNA damage
2) Release of cytochrome C from the mitochondria into the cytoplasm
3) hypoxia
Extracellular stimuli of apoptosis
Tumor necrosis factor hormones
3 mechanisms of apoptosis
intracellular, extracellular, oncosis (cellular swelling)
Dead cells are removed by
phagocytosis
With apoptosis cell contents are
never released into the extracellular fluid
Apoptosis (programmed cell death) vs pathological cell death
pathological - causes inflammation and possible autoimmune reactions
The mitochondrial membrane protein ____ can prevent apoptosis by blocking the release of cyt c
bcl-2
Both these vitamins are involved in cell death/survival pathways
retinoic acid form of vitamin A and vitamin D
3 types of cellular proteins
receptors, transport proteins, enzymes
CAM is
cell adhesion molecule - protein that binds one cell to another
Cell identity marker protein
Glycoprotein that distinguishes identity, can distinguish self from foreign
3 types of receptors
1) Internal chemical signal
2) Ion channel
3) Internalization stimulus
Internal chemical signal receptor example
cAMP - activates proteins that phosphorylate (activate/deactivate) enzymes
Ion channel receptor type
binding of ligand signals channel to open allowing ions (ex: sodium) through
Internalization stimulus receptor
ligand binds with receptor, ligand and receptor move into a clathrin-coated pit, pit closes off and forms a vesicle, ligand is used by cell or undergoes lysosomal degradation, receptor is recycled to membrane
Interalization stimulus receptor examples
insulin, triiodothyronine
Transport proteins can be…
channels (always open) of gated ion channels
Proteins can act as a transporter but also have
a secondary role (ex: enzyme)
Vmax
enzyme velocity at substrate saturation - no matter how much more substrate you give the reaction rate has topped out
Km
Michaelis-Menton constant; concentration of a substrate when reaction is at 1/2 of Vmax
High Km = ___ affinity of enzyme for substrate
low affinity; they’re inversely related
If a reaction is reversible it means
the same enzyme can catalyze a reaction in both directions
3 modes of enzyme regulation
1) Covalent modification
2) Modulation of allosteric enzymes
3) Enzyme induction
Covalent modification of enzymes means
an enzyme is inactive until a modification is made (ex: phosphorylation)
Allosteric site
any site on an enzyme other than the active site
Allosteric modulators work by
changing the conformation of parts of the enzyme; may be positive or negative
Enzyme induction
changes in concentration of inducible enzymes; increasing enzyme synthesis or blocking mRNA production for enzyme
Diagnostic enzymology
focuses on measuring serum levels of enzymes which indicates the cell is damaged and thus has leaked enzymes
Conditions for (enzyme) diagnostic suitability (4)
1) Organ/tissue specific
2) Steep concentration gradient between cell and surroundings
3) Must function in cytoplasm
4) Must be stable
1 cal = _ J
4.18
ATP synthesis is what type of reaction
endothermic, requiring energy, “uphill”
Exothermic reactions still require
a catalyst
The quantity of energy release in an exothermic reaction is ____ the quantity required for the reverse endothermic reaction
the same as
Activation energy
the energy needed to raise the energy of a reactant sufficiently to cause an exothermic reaction to occur
Nutrigenomics (4 principles)
1) Environmental factors have an effect on the expression of genes
2) Identifying which genes respond to which environmental factors
3) Defining the mechanisms involved
4) Determining useful health-related application of these interactions
