Intro/Carbs - Exam 1 Flashcards
definition of homeostasis
expenditure of energy to reassume the ordered state
cytoplasm allows cells to be
isolated
the exchange of heat, oxygen, waste, nutrients, etc. describes an
open system
6 components of a biological membrane
lipids, proteins, carbs, water, divalent cations (2+ charge), cholesterin
inner mitochondrial membrane has a high concentration of ______ because …….
proteins; transport between mitochondria & membrane via ETC
gram positive bacteria has a high concentration of ______ because ………
protein; microtubules manipulate membrane for movement and division
eukaryotic cell consists of which membranes
plasma membrane, nuclear membrane (in/out), ER and Golgi Apparatus membranes, mitochondrial membrane (in/out), peroxisomes, lysosomes
purpose of the nucleus
genetic information, transcription, hormone receptors
purpose of the ER
synthesis of proteins, lipids, calcium store, post translational modifications
purpose of the Golgi apparatus
protein processing, post translational modifications, polysaccharide synthesis, phosphorylation, packing of proteins for transport
purpose of the mitochondria
oxidation of carbs and lipids
purpose of lysosomes
digestion of macromolecules
purpose of peroxisomes
oxidation of organic molecules, catalase
which 3 cycles play a role in cellular metabolism
glycolysis, CAC, ETC
ATP stands for ______ ; function
adenosine triphosphate; energy in the cell
when ATP releases it’s energy it becomes
ADP
what 2 metabolic intermediates are converted into ATP
NADH, FADH2
what are the functions of carbs; general formula
energy source, energy storage, communication, cell wall of bacteria; (CH2O)3-8
synonyms for carbs
___saccharides, glycogen
2 main carbs are
ribose, glucose
ribose shape
5 carbon (pentose)
glucose shape
6 carbon (hexose)
in aqueous solution, what happens to glucose
switches between alpha ring, beta ring, and open chain forms
what is an isomer ; examples
same chemical formula, different arrangement ; i.e.: fructose, glucose, mannose
what is an enantiomer ; examples
mirror image of same molecule ; i.e.: D&L sugars
what is a sugar derivative
replacement of a single OH group by another group
what bonds link monosaccharides ; what is lost in the process
glycosidic bonds ; H2O
oligosaccharides contain how many monosaccharides
3-10
polysaccharides contain how many monosaccharides
> 10
galactose + glucose =
lactose
where does carb digestion start ; via what enzyme
mouth & intestinal lumen ; amylase (ptyalin)
what are 4 main carbs we ingest
starch, glycogen, saccharose, & lactose
where is the 2nd step of carb digestion
pancreas
where is the 3rd step of carb digestion
intestinal mucosa (surface)
where are carbs absorbed ; via which transport mechanisms
cytosol (duodenum, upper jejunum) ; SGLT1, GLUT 5, & GLUT 2
what is SGLT1
facilitated carrier for sodium glucose transport
what is GLUT 5 & GLUT 2
facilitated carrier for glucose but doesn’t use sodium, insulin induced, tissue specific
what exactly is lactose intolerance
abnormal degradation of disaccharides (actually goes into the large intestine, pulls water, which causes the symptoms)
why is lactose intolerance age related
as you get older the enzymes are either reduced or deficient so unable to break down lactose as well
what is oxidation
loses electron
what is reduction
gains electron
what are catabolic pathways
breakdown of large energy molecules to make small, energy poor byproducts
what are anabolic pathways
build up of small molecules to make complex ones; requires energy
what is GK and how does it work
glucokinase ; helps convert glucose into pyruvate in the cytosol, active when glucose present, when not present will go back to the nucleus and bind to GKRP (glucokinase regulatory protein) and become inactive
what is anaerobic glycolysis
cytosol; glucose -> 2 pyruvate + 2 NADH -> 2 ATP; lactic acid fermentation
which cells use anaerobic glycolysis
RBC and muscle cells
what is aerobic glycolysis ; what tissues use it
mitochondria; 1 glucose -> 2 pyruvate -> 8 NADH + 2 FADH + 2 GTP (net ATP is 36!!) ; neurons, liver & muscle cells
activation of glycolysis via _______ ; example
phosphorylation ; insulin (quick)
inhibition of glycolysis via _______ ; example
dephosphorylation ; glucagon (quick)
hormonal regulation of glycolysis
long-lasting
what are other names for the TCA cycle and what does it do
Citric Acid Cycle/Tricarboxylic Acid Cycle/Kreb’s Cycle ; carbs, fatty acids, and amino acids converge “traffic circle” near ETC (inner membrane -> matrix of mitochondria), aerobic, delivers reduced NADH and FADH2
5 energy events that occur in the mitochondria
TCA, ETC, ATP synthesis, Beta oxidation, pyruvate -> Acetyl CoA
what does the respiratory chain consist of and where does it occur
3 transmembrane enzymatic complexes + 2 mobile electron carriers ; inner mitochondrial membrane
proton pump process
proton from intermembrane space -> proton channel (F0) -> ATP synthase (F1) -> matrix
proton pump reversal process
proton from matrix -> ATP hydrolysis -> intermembrane space
what is gluconeogenesis
the production of glucose from non-sugar molecules (amino acids, lactate, glycerol)
when do we use gluconeogenesis
prolonged fast (because hepatic glycogen stores are used up)
tissues that use gluconeogenesis
liver and kidney
what is the Cori cycle
lactate from exercising muscles or RBC converted to glucose (pyruvate) in the liver
characteristics of glucogenic amino acids
used as substrate 1st in TCA cycle then used in gluconeogenesis 2nd as oxaloacetate
examples of ketoacids
anything that ends in “ine” or “ate”
what happens to glycerol during gluconeogenesis
released during the hydrolysis of TAGs in adipose tissue and enters the cycle as glycerol phosphate
which 4 reactions are unique in gluconeogenesis
pyruvate carboxylase, PEP carboxykinase, Fructose 1 6 bisphosphatase, Glucose 6 phosphatase
what is glucagon and how does it stimulate gluconeogenesis
hormone from pancreas; modifies enzyme activity & induces enzyme synthesis
what is glycogenesis, where does it occur, what does it need
store glucose as glycogen in order to mobilize it when needed (no food) “back-up”; cytosol; ATP & UTP
what tissues in the body store glycogen through glycogenesis
skeletal muscle & liver
what is glycogen
polysaccharide made of D glucose
insulin effect on carb metabolism
increase glycogenesis ; decrease glycogenolysis
glucagon/epinephrine effect on carb metabolism
increase glycogenolysis; decrease glycogenesis
what is the hexose pathway also known as, where does it occur, and what does it do
pentose phosphate cycle; cytosol; produces ribose for DNA/RNA synthesis, used in liver/fat/RBC, produces a lot of NADPH for fatty acid/steroid synthesis, drug metabolism, etc.
what is the respiratory burst
in phagocytic cells (steps: chemotaxis, adherence, ingestion, destruction) to break apart bacteria
what is an aldose
contain an aldehyde group
which steps of glycolysis require an investment of energy
1-3
what is the irreversible, rate limiting step of glycolysis
phosphorylation of fructose 6 phosphate to fructose 1, 6 bisphosphate
what is the first step of the TCA cycle
oxaloacetate -> citric acid
