Midterm Metabolism & Hormones Flashcards
Breakdown process for different macromolecule polymers
Carb, Protein, Nucleic Acid-> Hydrolysis
Lipids-> Lipolysis
Basic Carbohydrate structure
- 2:1 ; Hydrogen: Oxygen
- Carbon backbone
Monosaccharides
GLUCOSE-> ATP FRUCTOSE-> Aids glycolysis & replenishment of liver glycogen GALACTOSE All are C6H12O6 RIBOSE-> pentose sugar of RNA (C5H10O5) DEOXYRIBOSE-> Sugar of DNA C5H10O4
Disaccharides
Maltose (glucose-glucose)-> in beer cereal germinating seeds not as prevalent in diet
Sucrose (glucose-fructose) -> 25% dietary calories in USA
Lactose (galactose- glucose)-> least sweet
POLYSACCHARIDES-> Starch structure
storage of carb in plants
Amylose: long straight chain in helical coils (slow breaking)
Amylopectin: highly branched glucose chains (fast breaking)
POLYSACCHARIDES-> Glycogen structure
- storage form within animals’ muscle and liver
- highly branched like AMYLOPECTIN
- fast to breakdown
- converted to glucose via GLYCOGENOLYSIS
POLYSACCHARIDES-> Cellulose structure
- most common
- natural in plant walls
- long straight rigid chains
- slow and hard breaking
POLYSACCHARIDES-> Chitin structure
- arthropod exoskeleton & fungal cell wall
- long rigid chain
PROTEIN- functions in body
basically everything:
- catalyzing chem. rxn.
- synthesize and repair DNA
- Transport b/w cells
- receive & send chem. signals
- Respond to stimuli
- provide structural support
Protein formation 4 steps
- Primary Protein Structure- sequence of a chain of amino acids
- Secondary Protein Structure- Local folding of the polypeptide chain into helices (alpha helix) or sheets (beta pleated sheet)
- Tertiary Protein Structure- 3 dimensional folding pattern of a protein-due to side chain interactions
- Quaternary Protein Structure- protein consisting of more than one amino acid chain
what are enzymes and their two main categories?
- Proteins that Catalyze, -^ rxn rate enables life
- ANABOLIC-build more complex molecules from their substrates’
- CATABOLIC- Break down their substrate
4 enzymes in digestion
Amylase: Carb to glucose in mouth and S.I.
Pepsin: Protein to A.A. in Stomach
Lipase: Emulsify fat in S.I.
Trypsin: More protein breaking to A.A. in S.I.
HORMONES: roles, structure,
-often are proteins, sometimes lipids secreted by endocrine cells
Regulate and Control: growth, development, metabolism, Reproduction
EX: Insulin & blood glucose
Other proteins are receptors that detect [hormone] and send response
LIPIDS- structure, role
- C,H,O in varying ratios
- Non-polar.
- Transported via LIPOPROTEINS
- 3 types: Fats, Phospholipids, Steroids
- Saturated- solid @ room temp
- Unsaturated- one or more double bond/ kink - liquid @ room temp - cis and trans
Phospholipids, structure
- 2 fatty acids + phosphate group = diacylglycerol.
- Phosphate group is negatively charged, polar, & hydrophilic
- Tails are nonpolar, uncharged, hydrophobic
Steroids
- reproduction, absorption, metabolism regulation, brain activity
- Fused ring structure, 4 linked carbon rings
Energy Balance equation
Energy Intake = internal heat produced + External Work + Internal Work +Energy Storage
food energy-> metabolic pool and energy storage ->internal and external work-> thermal energy
Energy Input
- Energy in ingested food
- cells capture some of energy from high-energy bonds of ATP
- Becomes Energy output
Energy Output
External Work-> is when Skeletal muscle contract
Energy not used to perform work is transformed into thermal energy. only ~25% chem. energy in food is to do biological work. ~75% converted to heat
Energy Storage
INTERNAL WORK. All other forms of bio energy spending that aren’t mechanical work. EX skeletal muscle expenditure for balance and shivering and everything else that goes into maintaining life.
3 states of energy balance
Neutral - output = input. Maintain body weight
Positive- input > output. Adipose stores increase
Negative- Output > Input. Body uses stored energy
Metabolic Rate
Metabolic Rate = energy expenditure/ unit of time
to find BMR do a CALORIMETRY
factors influencing metabolic rate: Thyroid hormone levels (!! determinant of BMR), Sympathetic Stimulation (epin/norepin), Exercise, Daily Activities, Sex, Age
Cellular Metabolism
all the chem rxns that take place inside cells are part of cell metabolism. Enzyme catalysts speed up these chem rxns by lowering activation energy.
Each enzyme is able to control a single type of chem rxn, therefore if an enzyme is not active the entire pathway will stop working.
Metabolic regulation- Inhibition
sometimes necessary to inhibit enzyme to reduce rxn rate. Competitive Inhibition- it binds to substrate Active Site to block enzyme.
Non- Competitive Inhibition- binds to enzyme at Allosteric Site, active site still available for binding but the inhibitor changes the shape so it’s no longer an effective catalyzer.
Metabolic regulation- activators
Increase reaction rate
Allosteric Activators- bind to allosteric sites and change substrate shape so enzyme can bind and catalyze.
Cofactors and Coenzymes- non-protein helper molecs (on/off button). Most commonly dietary vitamins. They promote optimal conformation and function for the enzyme.
Feedback Inhibition
when a rxn. is used to regulate its own further production. Cells in metabolism use feedback inhibition by using products of enzymatic rxns to inhibit further enzyme activity.
This allows reactions to proceed according to cellular demands and maintain equilibrium.
Metabolic process where triglycerides are made into energy
B-oxidation
~1/2 of excess fat is in adipocytes in subcutaneous tissue, rest in adipocytes in other tissues and organs
Oxidation-Reduction reactions
- category of rxns important in energy transfer
- phosphate group added to ADP (phosphorylation) along with the energy to form ATP
Energy Transfer equation
C6H12O6+6O2—–>6CO2+6H2O
Energy Transfer/ cell resp. equation
Energy Released
^^^
C6H12O6+6O2——>6CO2+6H2O
3 phases to cell resp.
Glycolysis
Kreb’s/ TCA
Electron Transport
Glycolysis and Glycogenolysis
monosaccharides (Glucose, Fructose)-> cross cell wall of SI-> into circulatory system to liver.
GLYCOLYSIS = breaking of glucose to pyruvate
Liver HEPATOCYTES either pass glucose through circulatory system or store as glycogen
GLYCOGENOLYSIS = breakdown of glycogen into glucose
Krebs/ TCA cycle location and basic steps
In mitochondria
O2 available-> pyruvate (from glycolysis) transported to mitochondria -> made into acetyl CoA.-> CLOSED LOOP of REDOX and DECARBOXYLATION rxns. (these rxns remove high energy electrons and carbon dioxide.)-> (electrons stored in NADH & FADH2 are used to make ATP in the ETC)–>CO2 is produced as Kreb by product, so is 1 ATP, 3 NADH, 1 FADH2
Bulk of ATP in cell resp. from this step:
electron transport chain
ETC basic steps
4 redox rxns.
CHEMIOSMOSIS- Protons into intermembrane space though ATP synthase channels->Proton flow catalyze pairing of phosphate with ADP-> makes ATP
FERMENTATION- how is it different from cell resp.
- in RBC and muscle when NO O2 present
- NADH made in glycolysis has to be re-oxidized to NAD+ for reuse as an electron carrier
- Fermentation used by humans is lactic acid fermentation
Dispelling Lactate
when it accumulates it must be removed via circulatory system, meaning it goes to liver. When in liver it can be further metabolized and used as a brain fuel too.
Fat to energy process
- fat broken into FATTY ACID and GLYCEROL via lipolysis in cytoplasm
- Resulting fatty acids are oxidized by B-oxidation into acetyl CoA (then used by Kreb’s)
Protein as fuel
AA’s enter cell resp at pyruvate, Acetyl CoA, or Kreb’s stages
Exocrine vs Endocrine
exocrine NOT hormones- secret products into ducts are expelled on outside of body
Sudoriferous (sweat) glands, Sebaceous (oil) glands, Mucous glands, Digestive glands
endocrine YES hormones
Endocrine Path
hormones: from gland-> into circulatory ->to organ-> onto specific protein receptors cells-> activated cells now active for special task
Hormone 3 main paths for action
Endocrine- via blood. act on distant cells
Paracrine- act on neighboring cells
Autocrine- Acts on the same cell that secreted them
Lipid soluble hormones
:steroid hormones, thyroid hormones, nitric oxide.
- > circulate bound to transport proteins
- > diffuse across the plasma membrane
- > bind to receptors w/in target cell
- > activate genes to allow ribosomes to synthesize specific proteins
Water-soluble hormones
:amine hormones, peptide and protein hormones, eicosanoid hormones
- > water-soluble hormones circulate freely in the plasma
- > Bind to receptors on the exterior surface of the target cell
- > activate a secondary messenger to phosphorylate cellular proteins
Phosphorylation
will either activate (excitatory) or inactivates (inhibitory)
Phosphorylation
will either activate (excitatory) or inactivates (inhibitory)
Phosphorylation- water soluble hormones
will either activate (excitatory)
->when activated proteins
produced through chain
reaction
or inactivates (inhibitory)Hormone regulation-receptor regulated
hormones can be regulated by their receptors
up regulated: in presence of low concentrations
Down regulated: in presence of high concentrations
Target cell response to hormone based on:
concentration of hormone in blood
# of hormone receptors on target cell
Influences by other hormones
->synergistic effect of
hormones together
->Antagonistic effect of
hormones that oppose
one anotherHormone secretion Regulated by:
-Chemical changes in blood
-Signals from the nervous system
-other hormones
usually a feedback system needed for regulation (+ve or -ve)
Major Endocrine Glands
Hypothalamus Pituitary Gland (posterior and anterior)
Hypothalamus
- link b/w nervous and endocrine
- 7 hormones release which drive endocrine by acting on pituitary
- 5 are releasing hormones
- 2 are inhibiting hormones
Pituitary Gland Hypothalamus
hypothalamus-> INFUNDIBULUM (stalk)->pituitary.
Hormones travel b/w them via HYPOPHYSEAL PORTAL SYSTEM
Pituitary Anatomy
anterior lobe=75% weight, w/in anterior there are 5 types of cells that secrete 7 hormones.
most plentiful
posterior lobe neurohypophysis = made of neural tissue. Does not synthesize hormones, but stores and releases 2.
5 releasing hormones of hypothalamus
- Thyrotropin releasing hormone
- Corticotropin releasing hormone
- Gonadotropin releasing hormone
- Prolactin releasing hormone
- Growth hormone releasing hormone
2 inhibiting hormones of hypothalamus
- Growth hormone inhibiting hormone (somatostatin)
- Prolactin inhibiting hormone (dopamine)
Anterior Pituitary Gland 7 hormones, and the 5 cells that secrete them
^^Human growth hormone- somatotrophs
Prolactin-lactotrophs
thyroid stimulating hormone- thyrotrophs
Follicle stimulating hormone- gonadotrophs
luteinizing hormone- gonadotrophs
Adrenocorticotrophic hormone- corticotrophs
melanocyte stimulating hormone- corticotrophs
Posterior Pituitary Gland 2 hormones and regulation
Oxytocin, released in stretch response and suckling from infant
Antidiuretic hormone- secretion varies depending on blood pressure. decreases urine if signaled to by osmoreceptors in hypothalamus that monitor blood osmotic pressure. (decrease blood volume, increase ADH)
HGH
human growth hormone
most plentiful in anterior pituitary and builds muscles and bones.
Controlled by the hypothalamic hormones: GH-releasing hormone and GH-inhibiting hormone
TSH
thyroid stimulating hormone
stimulate production of thyroid hormones from thyroid glad and controlled by thyrotropin releasing hormone
PRL
Prolactin initiates and maintains secretion of milk from mammary glands when pair with other relevant hormones
FSH
Follicle stimulating hormone
In female, initiates dev and secretion of estrogen in ovaries
In Males, stimulates sperm production in the testes
LH
luteinizing hormone
in females, stimulates estrogen secretion by ovarian cells to cause ovulation and stimulates formation of corpus luteum and secretion of progesterone
In males, stimulates interstitial cells of testes to secrete testosterone
ACTH
Adrenocorticotrophic hormone
controls the production and secretion of hormones called glucocorticoids by the cortex of the adrenal gland
Thyroid Gland Anatomy
Butterfly shaped gland inferior to the larynx and anterior to trachea
-> composed of follicular cells and parafollicular cells
Follicular cells of thyroid
Stimulated by TSH to produce thyroxine (T4) & Triiodothyronine (T3) (aka the thyroid hormones)
Increase BMR, Help maintain normal body temperature, stimulate protein synthesis, Increase use of glucose and fatty acid for ATP making, upregulate B receptors that attach to catecholamines, Work with hGH and insulin to accelerate body growth
Parafollicular cells of thyroid gland, Role
produce hormone calcitonin, Calcitonin helps regulate calcium homeostasis by stimulating osteoblasts and inhibiting osteoclast activity, which lowers the level of calcium in the blood
parathyroid glands Anatomy
Located on the posterior aspect of each lobe of the thyroid gland are two parathyroid glands
•one inferior, one superior
Total of 4 pea-sized lobes
Parathyroid Gland Role
- Increase # and rate of Osteoclasts
- increase rate of calcium & magnesium reabsorption (in kidney)
- promotes calcitriol formation in kidneys-> increases absorption of calcium and magnesium from GI tract
Calcium control
Adrenal gland anatomy
top of each kidney
outer cortex and inner medulla
Adrenal cortex hormones and roles:
Mineralocorticoids- regulate mineral homeostasis
Glucocorticoids- affects glucose homeostasis
Androgens- masculinizing effects
Aldosterone
major mineralocorticoid, for regulation of sodium and potassium.
Aldosterone controlled by renin-angiotensin pathway
Glucocorticoids (cortisol)
regulated by corticotropin
functions: protein breakdown, glucose formation, lipolysis, resistance to stress, inflammation, immune responses
Major Androgen from Adrenal cortex is Dehydroepiandrosterone (DHEA)
- females, DHEA play a major role in promoting libido and are converted to estrogens
- In males the hormone testosterone is secreted in much larger quantities, so DHEA has virtually no effect
Adrenal Medulla role
stimulated by sympathetic nervous system to release catecholamines-> adrenaline and noradrenaline
Pancreas role
Exocrine and Endocrine gland
- Exocrine cells produce digestive enzymes for GI
- Among exocrine cells are endocrine tissues called pancreatic islets
Pancreatic Islets (islets of langerhans)
4 types of cells, (only concerned with 2)
Alpha cells -> glucagon
Beta cells -> insulin
Pineal gland anatomy and role
- Attached to roof of 3rd ventricle of brain
- secretes melatonin- linked to dark/ light circadian cycle
- seasonal affective disorder from overproduction
Thymus Anatomy and Role
located between sternum and lungs
produces hormones to promote T cell maturation
Insulin roles
is high in fed state when blood glucose levels are high- insulin gets glucose INTO cells
-increase glucose oxidation, increase glycogen synthese, increase fat synthesis, increase protein synthesis
Absence of insulin
glucose cannot enter muscle or fat cell
so blood glucose accumulates
Creatine Phosphate Mechanism
replenishes ATP for immediate muscle contractions.
At onset of exercise CP system supplies muscle cells with first few seconds of APT, enabling glycolysis to be initiated before stores are depleted
glucose and insulin interaction at cell wall
insulin receptor on cell of fat or muscle, when insulin detected GLUT4 one way transporters let glucose into cell. IN LIVER (hepatocytes) one way transporter is GLUT2
ATPase
able to split terminal phosphate from the compound
Roughly 70% of energy released from bond degraded to heat, and ~30% to do work
how does glycolysis take place
glycolytic enzymes present in cytosol.
Not as good as oxidative phosphorylation but does allow access to ATP in absence of oxygen
how does Oxidative respiration work
breaks down fuel aided by oxygen in mitochondria. AKA cell. resp.
Makes lots of ATP for long time
MET (metabolic equilivant)
1 met is resting state, or
3.5 mL/min/kg
metabolic requirements of muscles heart brain liver and kidneys
Increase in muscle work leads to:
As o2 is taken from capillaries the difference b/w arterial and venous o2 concentrations grows (difference gets bigger)
Fick Equation
VO2 = Q x (AV-O2)
cardiac output and oxygen utilization (AV-O2 diff) enables rate of oxygen uptake (VO2) to be determined by this equation
A LINEAR relationship between cardiac output and oxygen uptake in submaximal exercise.
Exercise ^ ->o2 extraction from muscle ^ -> growing diff in arteriovenous o2 content
Cholesterol roles
- Cholesterol is most common steroid
- synthesized in liver
- precursor to: Vitamin D, estrogen, testosterone, progesterone, synthesizing aldosterone (for osmoregulation), -Contributes to formation of cortisol
Law of thermodynamics
Energy cannot be created or destroyed
