KNH 505 Exam 1

experimental

group in a research study that receives the treatment or intervention being tested

control

group in a research study that does not receive the treatment or receives the standard treatment, placebo, or no intervention

placebo

a substance with no active effect given to mimic experimental trial

double-blind

study that is designed to ensure neither participants or researchers know which individuals are in the experimental or control group, reducing bias

correlational research

examines relationship between two or more variables without manipulating them; can show whether variables are related but cannot prove cause and effect

correlation

2 variables change together, but one does not necessarily cause the other to change

causation

one variable directly influences the other, which is shown through controlled, experimental research

experimental

research that manipulates a variable to test its effect on an outcome; randomized control trials (RCTs); can establish cause-and-effect, but are expensive

observational

research that collects data without intervening; cross-sectional studies, cohort studies, and case-control studies; can identify associations but cannot prove cause and effect

laboratory

research that is performed in controlled settings to explore biological mechanisms; cell cultures, tissue, animals; mechanistic studies; high control over variables but may not always translate to humans

systematic review and meta-analyses

types of research that summarize and statistically analyze results from many studies, providing a high level of evidence; reproducible search protocol; identifies patterns by synthesizing evidence; quality determined by strength of included studies

literature review

type of research that offers a critical summary of existing research to identify major themes and gaps; carry a risk of selection bias; non-reproducible methods; cannot claim comprehensive coverage or provide pooled effect sizes

metabolic fluctuations

the body’s metabolism fluctuates due to eating, physical activity, and exercise

tissue regulation

energy metabolism in different tissues is influenced by substrate availability and hormones

substrate requirements

for ATP to be available, cells require a constant supply of energy substrates, including glucose, fatty acids, and amino acids

metabolic pathways

a linked series of chemical reactions within a cell that catalytically convert a starting molecule into a final product; these are broken down in metabolic pathways, transferring energy to the high-energy bonds of ATP

plasma membrane

a fluid, sheet-like structure that encapsulates the cell; contains both hydrophobic and hydrophilic moieties in a lipid bilayer

eukaryotic cells

feature a defined nucleus and evolve from prokaryotic cells

fatty acid

the ___________ portion of the plasma membrane forms the hydrophobic core, while glycerol and phosphate portions are hydrophilic

cholesterol

influences the plasma membrane’s overall permeability

cytoskeleton

provides essential framework for a cell and organelles

cytoskeleton/cytoplasmic matrix

provides structural support, acts as a framework for positioning organelles, and creates a pathway for intercellular communication and transport; primary components include microtubules, intermediate filaments, and microfilaments

metabolic pathways

some of the key ______________ that occur in the cytoplasm include glycolysis, hexose monophosphate shunt, glycogenesis, glycogenolysis, and fatty acid synthesis

glycolysis

metabolic pathway: anaerobic breakdown of glucose ending with pyruvate; occurs in cytoplasm

hexose monophosphate shunt

metabolic pathway: provides substrates for making fatty acids; occurs in cytoplasm

glycogenesis

important metabolic pathway for storing carbs in liver and muscle; occurs in cytoplasm

glycogenolysis

important metabolic pathway in controlling blood sugar; occurs in cytoplasm

fatty acid synthesis

metabolic pathway: can create fat using carbs and essential fatty acids; occurs in cytoplasm

nucleus

largest organelle, surrounded by nuclear envelope; contains cell genome (DNA)

nucleolus

within nucleus; site of RNA transcription and ribosome assembly

nucleic acids

__________ include DNA and RNA, these both have the bases adenine, guanine, and cytosine in common

uracil

________ is the base that is unique to RNA

thymine

__________ is the base that is unique to DNA

adenine

base-pairing: _______ pairs with thymine or uracil

cytosine

base-pairing: ________ pairs with guanine

mitochondrion

the primary site of cellular energy production and features a highly specialized double-membrane structure

outer

the _______ membrane of the mitochondrion is relatively porous to allow molecule passges

inner

the _______ membrane of the mitochondrion is selectively permeable barrier and site of electron transport chain; crucial for oxidative phosphorylation and ATP generation

mitochondrial matrix

site of TCA cycle and fatty acid oxidation

endoplasmic reticulum

a network of membranous channels; rough and smooth

rough ER

a network of membranous channels that is studded with ribosomes for protein synthesis

smooth ER

a network of membranous channels that handles lipid synthesis

golgi apparatus

manages protein trafficking and sorting through tubular networks

lysosomes

serves as the cell’s digestive system, degrading proteins and nucleic acids

peroxisome

site of oxidative catabolic reactions, such as oxidation of ethanol

cellular assembly line

-rough and smooth ER

-golgi apparatus

-lysosomes

-peroxisomes

adenosine triphosphate (ATP)

major storage form of energy in cells

Gibbs free energy

-energy is derived from macronutrients, releasing potential energy from chemical bonds

-free energy (G, change is ΔG) is transferred from one form to another

spontaneous

when ΔG is negative, an exergonic reaction (releases energy) is ____________

energy

when ΔG is positive, an endergonic reaction requires ___________ input

4.18

1 kcal or cal is equivalent to ______ J or kJ

coupled metabolic reactions

cells link energy-releasing and energy-demanding chemical reactions; makes the overall reaction favorable, allowing cells to perform work to build molecules and transfer substances against concentration agents

high-energy phosphate compounds

Phosphorylation involves adding a phosphate; contain more energy than ATP and can phosphorylate ADP to ATP, as seen with phosphoenolpyruvate, creatine phosphate, and 1,3-biphosphoglycerate

transcription, translation, elongation

what are the 3 steps of protein synthesis?

transcription

1st step of protein synthesis; DNA molecule synthesizes corresponding mRNA; introns are intervening sequences, while exons require no post-translational processing

translation

2nd step of protein synthesis; mRNA move through rough ER, where 3-base sequence codons code for amino acids

elongation

3rd step of protein synthesis: tRNA brings specific amino acids to the ribosome, forming peptide bonds until a nonsense codon signals the end

proteins

cellular _________ act as critical mediators of cellular function

environment

cellular protein receptors modify the cell’s response to its ____________

ligands

molecular stimuli that attach to cellular protein receptors, which can function as ion channels or internalize stimuli

enzymes

serve as catalysts for biochemical reactions to break down macronutrients

holoproteins

some enzymes require non-protein cofactors (minerals) or coenzymes (B vitamins) to become active __________

reaction velocity

the velocity of an enzyme-catalyzed reaction increases if all active sites are filled

Michaelis Constant (Km)

indicates how strongly an enzyme binds to its substrate; it is defined as the substrate concentration at which the enzyme is working at half of its maximum speed

substrate affinity

Michaelis Constant (Km) and its relation to how strongly an enzyme binds to a substrate

low

______ Km indicates high affinity, meaning the enzyme binds tightly and works efficiently with little substrate

high

______ Km indicates low affinity, meaning the enzyme does not bind tightly to substrate

oxidized

when one compound is ________, it is coupled to another compound that is reduced, and vice versa

metabolism

recycling of substituents is very important in ____________

catabolic pathway

compounds are broken down for a purpose, such as energy production; oxidative (redox)

anabolic pathway

construction of new compounds; reduction (redox)

reversible

dynamic equilibrium is a ___________ metabolic pathway

irreversible

energy and carbon steps and strategic control reactions are __________ metabolic pathways

allosteric regulation

PTM; fast shape changing kinetics; involves a molecule binding to a site other than the active site

key metabolic pathways occurring in the cytoplasm

-glycolysis

-hexose monophosphate shunt

-glycogenesis

-glycogenolysis

-fatty acid synthesis

covalent modification

chemical tags; adds or removes a chemical tag, such as a phosphate or methyl group, to change enzyme activity; enzyme is inactive until modification is made

induction

PTM; slow genetic translation shifts; creates changes in the concentration

proteins

post translational modifications (PTM) are called this because they are how the __________ are already built, and are not changes in how they are put together

apoptosis

the programmed process of cell death; triggered by distinct mechanisms; can be triggered by intracellular or extracelluar stimuli

intracellular/intrinsic

apoptosis can be triggered by _______________ stimuli, which is irreparable DNA damage and hypoxia, which signals the release of cytochrome c

extracellular/extrinsic

apoptosis can be triggered by _______________ stimuli, which is when the tumor necrosis factor family of cytokines binds to specific cell surface death receptors

30

the digestive tract is ~___ ft in length

alimentary canal

what is another name for the digestive tract?

main structures of the digestive tract

-oral cavity

-esophagus

-stomach

-small/large intestines

accessory structures of digestive tract

-pancreas

-liver

-gallbladder

oral cavity

consists of the mouth and pharynx; the entryway of the digestive glands; includes the salivary glands; digestion here includes both physical (mastication) and chemical processes

salivary glands

-parotid

-submandibular

-sublingual

salivary alpha-amylase

enzyme in saliva that begins carb digestion

lingual lipase

enzyme in saliva that begins lipid digestion; particularly important in infants for digesting breastmilk fat

swallowing mechanics

the esophagus moves the bolus from the oral cavity to the stomach; has 3 parts - swallowing, peristalsis, and sphincters

swallowing

involves voluntary, pharyngeal, and esophageal phases; part of swallowing mechanics

peristalsis

voluntary and involuntary muscle movement propels the bolus; part of swallowing mechanics

sphincters

the lower-esophageal (gastroesophageal) sphincter controls entry into the stomach; part of swallowing mechanics

gastroesophageal reflux disease (GERD)

a disorder where stomach contents move back into esophagus due to a relaxed sphincter or pressure changes; causing burning or ulceration; lower esophageal sphincter is relaxed; some factors of this include smoking, chocolate, high fat, alcohol, and peppermint

main regions of the stomach

-cardia

-fundus

-body

-antrum or distal pyloric region

chyme

the stomach mixes food with gastric juices to form ________ using 3 layers of muscle

neck cells

gastric cells that secrete mucus

G cells

gastric cells that secrete the hormone gastrin, stimulating parietal and chief cells

parietal (oxyntic) cells

gastric cells that secrete HCl and intrinsic factor

chief (peptic or zymogenic) cells

gastic cells that secrete pepsinogen and gastric lipase