HNII Final Exam Flashcard Set

all macronutrients can be converted into

Acetyl CoA

Acetyl CoA can enter what processes?

Citric Acid Cycle, Oxidative Phosphorylation, Fatty Acid Synthesis

Citric Acid Cycle and Oxidative Phosphorylation generate what molecule?

ATP

What is metabolic fuel?

circulating compound taken up by tissues for energy production

Examples of metabolic fuel

glucose, free fatty acids, ketone bodies, amino acids, lactate, glycerol, alcohol

How are metabolic fuels metabolized?

Enter citric acid cycle

Body fuel store of adipose triglycerides

85%

Body fuel stores of Glycogen

0.6% (0.4% in skeletal muscle and 0.2% in liver)

Body fuel stores of protein

14.4% (in skeletal muscle)

How many calories of energy are stored in the human body?

80,000

Equation for Total Energy Expenditure (simplified)

TEE= BMR + TEF + TEA

RMR vs BMR

Resting Metabolic rate vs Basal metabolic rate

T/F: Red blood cells can only utilize glucose

True

What are the only tissues capable of gluconeogenesis?

Liver and Kidney

What glucose levels can the brain not function at?

Less than 3 mmol/L (54 mg/dL)

Fuels used by skeletal muscle

Fatty acids, ketone bodies, BCAAs (leucine, isoleucine, valine)

Fuel Metabolism of the Liver

• glucose —> glycogen —> glucose

• Lactate, AA, glycerol —> G6P —> glycogen or glucose

• FA —> re-esterification, oxidation, KB production

• Alcohol metabolism

When were the first RDAs set

1941 by the National Research Council; now serve as basis for federal and state food and nutrition programs and policies

When were DRIs developed

1994; based on known relationships between intake and adequacy and chronic disease prevention

Reference intakes for carbohydrates

• RDA= 130g/d

• EAR= 100g/d

• AMDR= 45-65% total kcal

Reference intakes for Fiber

• AI= 14g/1000 kcal

Reference intakes for fat

• AMDR= 20-35% total kcal

Reference intakes for Protein

• AMDR= 10-35% total kcal

• RDA= 0.8-1.2 g/kg body weight (depending on life stage)

• EAR= .66-1.0 g/kg body weight depending on life stage

What are the essential amino acids?

Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, selenocysteine, tryptophan, valine

What are the branched chain amino acids (BCAAs)?

isoleucine, leucine, and valine

What are the nonessential amino acids?

alanine, aspartic acid, asparagine, glutamic acid, serine

What amino acids are considered conditionally essential?

arginine, cysteine, glutamine, glycine, proline, tyrosine

Important features of the plasma membrane

• selective permeability

• fluidity/unique composition

• contains embedded proteins, CHO, and lipids

  • proteins act as receptors sensitive to external stimuli and channels that regulate movement of substances into/out of cell

what molecule enhances the stability of the plasma membrane while maintaining it’s fluidity?

cholesterol

Intracellular/Extracellular fluid concentrations of major electrolytes

• Na+ = 12 mmol/L intracellular, 145 mmol/L extracellular

• K+ = 155 mmol/L intracellular, 4 mmol/L extracellular

What molecules are dissolved in the cytoplasm?

electrolytes, proteins, glucose, glycogen, amino acids and lipids

What processes are influenced by the cytoplasmic matrix?

• glycolysis

• hexose monophosphate shunt

• glycogenesis and glycogenolysis

• fatty acid synthesis

What is the site of ATP production?

Mitochondria

Different parts of the ER

• Rough: studded with ribosomes involved with protein synthesis

• Smooth: involved in lipid synthesis

• Sarcoplasmic reticulum: calcium ion pump

Function of Golgi Apparatus

• builds some carbohydrates

• packaging site of exocytosis

Lysosomes vs Peroxisomes

• both are enzyme filled organelles

• Lysosomes: cells “digestive system”

• Peroxisomes: site of oxidative catabolic reacitons

Functions of Nucleus

• storage/processing of DNA

• site of DNA localization

• Site of DNA transcription

• Site of rRNA production

Complementary base pairing of amino acids

• A-T (DNA

• A-U (RNA)

• G-C

central dogma of DNA

DNA —> RNA —> aa organization —> protein

Transcription

DNA —> mRNA

Translation

mRNA —> protein

What is required to link amino acids

hydrolysis of 4 high energy peptide bonds from ATP/GTP

Types of cellular proteins

• receptors: bind a signal molecule with a high degree of specificity that triggers intracellular events

• transport proteins: regulate flow of materials into and out of cell

• enzymes: catalysts for biochemical reactions

types of receptors

• intracellular transcription factor receptors

• steroid hormone superfamily of receptors

• plasma membrane receptors (ex. insulin receptor, ion channels, G-protein linked receptors)

Result of fast signal transduction

increased glycogen breakdown

General features of cell signaling

• secretion of messenger

• messenger sent to target cell

• messenger binds to receptor on target cell

• response

• signal ceases

How can cells augment their ability to respond to a message

• receptor phosphorylation/dephosphorylation

• receptor down-regulation/up-regulation

• allosteric modification

Energy requiring processes

• mechanical work

• biosynthesis

• active transport systems

• transfer of genetic info

• heat to maintain body temp

Cells derive their energy through an overall ___ series of reactions

exothermic

composition of ATP

Adenosine-Ribose-Phosphate-Phosphate-Phosphate

major pathway of ATP production

oxidative phosphorylation

T/F: ATP can be stored

False; can be consumed and regenerated

Most energy transformations resulting in ATP require ___

O2

Only pathway of fuel metabolism that generates ATP without O2

anaerobic glycolysis

1 calorie =

4.18 joule

1 joule =

0.2389 calories

Cellular oxidation of fuels yields

CO2, H2O, energy

Exothermic

• G reactants > G procducts

• energy releasing

Endothermic

• G reactants < G products

• Energy requiring

Which type of reactions are favored

exothermic

Molecules involved in hydrolysis

• PEP

• phosphocreatine

• ATP

• AMP

• G6P

What catalyzes the conversion of creatine into phosphocreatine

creatine kinase

AMPK

cellular sensor of intracellular AMP/ATP ratios

Adipocyte

role in whole body metabolic homeostasis

ER stress

imbalance between the cellular demand for ER function and ER capacity

• cause: changes in protein folding and/or Ca 2+ homeostasis

• response: activation of UPR pathway

Structures of Digestive Tract and Digestive Process

• main structures: oral cavity, esophagus, stomach, small and large intestine

• Accessory organs: pancreas, liver, gallbladder

What makes up the upper digestive tract

oral cavity, esophagus, stomach

4 main layers surrounding GI tract

• mucosa

• submucosa

• muscularis externa

• serosa/adventitia

Enzymes in saliva

alpha amylase and lingual lipase

4 main regions of the stomach

• cardia region

• fundus

• body (reservoir for food and main production site of gastric juices)

• Antrum/distal pyloric region (grinds food and gastric juices to form chyme)

Gastric glands of the stomach

• cardiac glands (esophagus to stomach)

• oxyntic glands (body of stomach)

• pyloric glands (antrum)

Role of different components of gastric juice

• HCl (converts pepsinogen to pepsin, denatures proteins, release nutrients, act as bacteriocide)

• enzymes: pepsin, amylase, lipase

• mucus: lubrication and protection

• intrinsic factor: B12 absorption

Regulation of gut motility and gastric emptying

pacemaker located between fundus and body of stomach determines frequency of contractions

Small intestine

main site for nutrient digestion and absorption

regions of small intestine

duodenum, jejunum, ileum

Structures of small intestine

• folds of kerckring: large circular folds of mucosa

• villi: finger like projections

• microvilli: hair like extensions of cells’ plasma membrane

• brush border: consists of microvilli and coat of oligosaccharides and contains most digestive enzymes

• crypts of liberkuhn: small pits that lie between villi

Enteric nervous system control functions

• motor control

• secretions/blood flow regulation

• neurons release neurotransmitters

Immune system protection of the GI tract

• mucosa associated lymphoid tissue

• gut associated lymphoid tissue

Secretions of SI

• CCK

• secretin

• GIP

What does pancreatic juice contain

bicarbonate, electrolytes, and pancreatic digestive enzymes

What do the pancreatic digestive enzymes digest

50% of all ingested carbs, 50% of protein and almost all fat

Largest internal organ

Liver

function of portal vein

transports blood rich in nutrients from digestive tract to liver

functions of gallbladder

bile storage

Function of large intestine

mix and dehydrate materials, absorb Na, Cl, and water

Probiotics vs prebiotics

• Probiotics: foods containing live bacterial cultures

• prebiotics: food ingredients that promote bacterial growth

Functions of probiotics

• enhance immunity

• lower pH of colon

• transform/promote excretion of toxic substances

• enhance fecal bulk

Where does most digestion and absorption occur?

Small intestine

Different types of absorption

• diffusion

• facilitated diffusion

• active transport

• pinocytosis/endocytosis

Long vs Short term energy balance regulation

• Long term: leptin/fat stores

• Short term: gut signals CCK from SI, ghrelin from stomach, and insulin form pancreas

Mediators of Energy balance

ghrelin

cholecystokinin

neuropeptide Y

peptide YY

Monosaccharides

Glucose, Fructose, Galactose

Disaccharides

• maltose (glucose + glucose)

• sucrose (glucose + fructose)

• Lactose (glucose + galactose)

Complex carbs

• oligosaccharides: short chains of monosaccharides joined by covalent bonds

• polysaccharides: long chains of monosaccharide units that number from several to 100s to 1000s

Structure of carbohydrates

• all but one C are bonded to OH

• Other C part of a Carbonyl group, either an aldehyde or ketone

What carbohydrates form ring structures

pentoses and hexoses

• generates an additional chiral C, called the anomeric carbon

What carbohydrates are readily synthesized in the cell and incorporated into metabolically important compounds such as DNA, ATP, and NAD+

pentoses (think pentose phosphate pathway)

What is the plant energy storage carb?

starch

2 types of starch

amylose: unbranched with alpha 1—>4 links

Amylopectin: branches every 24-30 sugars with alpha 1—>6 links

15-20% of starch in plants is ___

amylose