BIO Midterm 2

Nuclear pore complexes

Control what enters and exits the nucleus.

Nuclear lamina

Provides structure to the nucleus.

Chromatin

Combination of DNA and protein, contains genetic material.

Nucleolus

Makes ribosomes from RNA and protein from cytoplasm.

ER lumen

Where substances are made and enclosed by the endoplasmic reticulum.

Rough ER

Processes proteins by adding carbohydrates through glycosylation.

Glycosylation

The process of adding sugar to a protein to form a glycoprotein.

Smooth ER

Involved in synthesizing lipids, detoxifying harmful substances, and storing calcium ions.

Lysosomes

Contain acid hydrolases and enzymes that are active at low pH.

Autocrine signaling

Cell targets itself.

Paracrine signaling

Cell targets nearby cells, with effectiveness decreasing as distance increases.

Endocrine signaling

Cell targets distant cells via the bloodstream.

G-protein coupled receptors

Receptors that, when activated by a ligand, trigger a response by exchanging GDP for GTP.

Signal transduction pathway

A group of proteins that carry messages away from the cell surface.

Sensitivity to external signals

Determined by the number of receptors present, receptor-ligand binding percentage, and ligand affinity for receptors.

HER2+

A condition causing cells to grow too quickly.

Ion Channel Receptors

Gated channels that open and close in response to a signal.

Steroid receptors

Found mostly inside the cell and influence gene transcription directly.

Second messengers

Molecules that transmit signals inside cells, often involved in signaling pathways.

Apoptosis

Programmed cell death characterized by cell shrinkage and membrane blebbing.

Entropy (S)

A measure of disorder that happens spontaneously.

Chemical energy

Potential energy stored in chemical bonds.

ATP

A high-energy molecule that powers various cellular processes.

Competitive inhibitors

Molecules that compete with substrate for the active site of an enzyme.

Noncompetitive inhibitors

Molecules that bind to sites other than the active site of an enzyme.

Allosteric enzymes

Enzymes that can exist in either an active or inactive state and are regulated by noncompetitive inhibitors.

Feedback inhibition

A process where the end product of a pathway inhibits an enzyme involved in its production.

Oxidative phosphorylation

The process of generating ATP using the energy from a proton gradient across the mitochondrial membrane.

Glycolysis

The process of converting glucose into 2 pyruvate, occurring in the cytoplasm without requiring oxygen.

Citric Acid Cycle (Krebs Cycle)

A cycle that oxidizes Acetyl-CoA to produce CO2 and transfer electrons to carriers.

ETC (Electron Transport Chain)

A series of proteins that transfer electrons and pump protons to create a gradient.

Chemiosmosis

The process of generating ATP using energy from a proton gradient.

Ethanol fermentation

A type of fermentation that produces ethanol, CO2, and NAD+.

Lactic Acid Fermentation

A process occurring in animal cells where pyruvate is converted to lactic acid, regenerating NAD+.

G-protein coupled receptors

ligand binds to G-protein coupled receptor, which causes the alpha part of the heterotrimeric G protein to exchange GTP to GDP

GTP

active

GDP 

inactive

Enzyme-linked receptors

ligand binding site combines with another receptor when both receptors have a signaling molecule, making a dimer, then the activated tyrosine kinase regions form unphosphorylated ATP and transforms it into ADP, the relay proteins pick up the message then carry it to another relay protein

Different cellular responses

Pathway leads to a single response

Pathway branches → two responses

Cross-talk occurs between 2 pathways

Different receptor leads to different response

Affect of ACH on heart muscle

decreased rate and force of contraction

Affect of ACH on skeletal muscle

contraction

Affect of ACH on salivary gland

secretion

Enthalpy (H)

energy contained in a molecule’s chemical bonds

Equation

ΔG=ΔH-TΔS

Endergonic 

uses energy

Exergonic

releases energy

When products contain more free energy than reactants

ΔG is positive - endergonic

When reactants contain more free energy than products

ΔG is negative - exergonic

Allosteric inhibitors 

non-competitive inhibitors that bind to the allosteric site to inactivate the enzyme

Oscillation

going between active form and inactive form

Pyruvate oxidation

produces CO2 and NADH, occurs in mitochondrial matrix, coenzyme A completes the reaction in 3 steps

Glycolysis, pyruvate oxidation, citric acid cycle, 1 glucose has been oxidized to produce

6 CO2, 4 ATP, 10 NADH, 2 FADH2

ETC

enzymes remove electrons from NADH and FADH2 and pass them along the chain, energy released pumps protons into inter membrane space, creates a concentration gradient: protons are more abundant in the inter membrane space than the mitochondrial matrix

Chemiosmosis

uses energy from the proton gradient to generate ATP, protons pass through ATP synthase, releasing energy that is used to make ATP, ATP synthase uses mitochondrial proton gradient to make ATP, produces 34 ATP