BI358 midterm 1

metabolism

the sum of all chemical reactions in the cell

which one is NOT a chemical reaction

melting, freezing, evaporating, dissolving

The chemical formula for hydrolysis

A-B + H2O ←> A-OH + H-B

rates of chemical reactions depend on….

activation energy

transition state

enzymes

protein catalysts that increase the rate of biochemical reactions

how does enzymes increase the rate of biochemical reactions?

reducing activation energy

substrate

the reactant bound by an enzyme

What is the specific region of an enzyme molecule where a substrate binds?

the active site

What temporary structure is formed when a substrate binds to an enzyme molecule?

the enzyme substrate complex

what is NOT one of the two possible fates of a substrate once it forms an enzyme-substrate complex?

it may degenerate

True or False: When a product leaves an enzyme, the enzyme is altered and cannot bind to another substrate.

False, the enzyme is freed to bind with another substrate

rates of enzyme catalyzed reactions depend upon the following except

changes to a reaction’s overall thermodynamics and chemical equilibrium

Competitive inhibition

modulator molecule that is not a substrate binds the active site and prevents the entry of substrate

allosteric modulation

modulator binds a regulatory site far from the active site

covalent modification

covalent bond adds/removes a chemical group that alters activity

substrate level phosphorylation

occurs in absence of O2, such as anaerobic glycolysis

oxidative phosphorylation

depends on supply of O2 for oxidation reactions in mitochondria. The primary mode of ATP production in most cells.

energy metabolism

encompasses the pathways needed to convert the enrgy in food to ATP to power cellular functions

ATP production in energy metabolism

carbohydrates, lipids, proteins

ATP consumption in energy metabolism

movement, membrane transport, molecular synthesis

Glucose oxidation

glycolysis → linking step → krebs cycle → oxidative phosphorylation

glycolysis and linking step

breaks down glucose and produces two molecules of pyruvate

glycolysis occurs in the…

cytosol

gluconeogenesis

a reverse series of reactions to regenerate glucose from pyruvate, which only occurs in some tissues

krebs cycle

Acetyl-coA enters the Krebs cycle in the mitochondrial matrix

oxidative phosphorylation

NADH and FADH2 donate their electrions to electron acceptors in the electron transport system and are oxidized to NAD+ and FAD

when you’re hungry, what comes first?

sensory cues

cell to cell communication is largely performed by

intercellular chemical messengers

If there is no receptor for ligands

there will be no response/signal

autocrine/paracrine signalling

messengers act locally reach target cells - diffusion

endocrine signalling

hormones secreted by endocrine cells reach targets via circulation - slow acting

neural signalling

neurotransmitters secreted by neurons at synapse with targets - fast acting

which one is NOT apart of hormonal cell signaling?

purines and fatty acids

which of the following is NOT apart of neurotransmitter cell signaling?

steroids and purines

which of the following is not apart of auto/paracrine cell signaling?

steroids and purines

peptides, purines, and most biogenic amines are __________

hydrophilic

steroids, fatty acid derivatives, and a small number of biogenic amines are _________

hydrophobic

what does not classify as a catecholamine?

serotonin

what are catecholamines?

neurotransmitters and hormones made from tyrosine

growth hormone

hormone released by anterior pituitary

Growth hormones are considered as a _________

peptide/protein messenger

atrial natriuretic peptide

hormone released by the heart to regulate sodium reabsorption by the kidneys

active peptides are released by Ca2+. This initiates…?

exocytosis

why does active peptides released by Ca2+ initiate exocytosis?

Ca2+ acts as positive feedback signal for specific ion channels.

steroid messengers

produced from cholesterol by the gonads and placenta and the adrenal cortex

eicosanoids

made from phospholipids

eicosanoids act like…

neurotransmitters or paracrine/autocrine agents

what is NOT one of the two main functions of membrane proteins

passive transport

does not require energy

active transport

mechanisms that require energy, move substances against diffusion gradients

Simple diffusion

concentration gradients provide a chemical driving force for diffusion, driving the overall movement of solute from regions of higher to lower concentration

diffusive equilibrium

net flux is zero