Cell Signaling, Transport, and Mitochondrial Processes: A Comprehensive Biology Review

What type of transport is the sodium-glucose transport mechanism?

Secondary transport.

In sodium-glucose transport, does glucose move with or against its concentration gradient?

Against the concentration gradient.

What physical change occurs to a receptor protein when a ligand binds to it?

It changes shape.

How does an enzyme typically alter the structure of its substrate?

It changes the substrate's shape.

In signal transduction, what is the term for a molecular relay where one molecule activates another in a sequence?

Cascade.

Under what condition does a signal transduction event lead to a long-term phenotypic change in a cell?

When transcription or translation in $DNA$ is impacted.

Name three examples of physical stimuli that cells can process as signals from the environment.

Light, sound, and temperature.

What event is required to activate a receptor and trigger its kinase activity?

Ligand binding and subsequent shape change.

What process occurs when a mitogen binds to its receptor, causing the receptor to add phosphate groups to itself?

Autophosphorylation.

What inactive molecule is attached to the RAS protein before it is activated?

GDP.

How does an activated receptor allow RAS to become active?

It initiates events that allow RAS to bind GTP.

In the MAP kinase cascade, what protein does activated RAS bind to and activate?

MAP3K.

Which specific protein kinase is phosphorylated and activated by MAP3K?

MAP2K.

The protein kinase MAP2K phosphorylates and activates which molecule?

MAP kinase (MAPK).

Where does activated $MAP$ kinase ($MAPK$) travel to initiate gene expression changes?

The nucleus.

What is the primary cellular response stimulated by the mitogen-activated $MAP$ kinase pathway?

Cell division.

Transmembrane proteins convert an extracellular signal into what type of signal?

An intracellular signal.

List three rapid cellular responses that can be triggered by signal transduction.

Growth, division, and movement.

What term is used to describe a cell signal indicating it is time for the cell to change its functional state?

Differentiate.

Name three examples of second messengers mentioned in the signal transduction notes.

$cAMP$, calcium, and G proteins.

How many subunits compose a G protein?

Three subunits.

Activation of a G protein by a receptor involves the exchange of $GDP$ for which molecule?

$GTP$.

In an insulin receptor, what are the names of the two distinct binding sites?

Alpha and beta sites.

To which specific site of its receptor does insulin bind?

The alpha site.

Which proteins connect the intracellular environment to the extracellular matrix and protrude from both sides of the membrane?

Anchor proteins.

What is the organized network of material produced and secreted by cells called?

Extracellular matrix (ECM).

What is the function of the ECM that allows cells to remain attached to surfaces or each other?

Cell adherence.

List two structural functions provided by the extracellular matrix (ECM) to cells.

Mechanical support and structural integrity.

The formula $CH_{2}O + O_{2} \rightarrow CO_{2} + H_{2}O + ATP$ represents which cellular process?

Aerobic respiration.

The formula CO2 + H2O → CH2O + O2 represents which cellular process?

Photosynthesis.

What are the two distinct membranes found in a mitochondrion?

The outer and inner membranes.

What is the name of the internal space inside the mitochondrial inner membrane?

Matrix.

Name two types of genetic/translational machinery found within the mitochondrial matrix.

DNA and ribosomes.

What percentage of $ATP$ production in animal cells is attributed to oxidative phosphorylation?

Around $88\%$.

What percentage of $ATP$ is produced via substrate-level phosphorylation?

Around $12\%$.

In the process of aerobic respiration, what molecule serves as the final electron acceptor?

Oxygen ($O_{2}$).

In which specific location within the cell does glycolysis take place?

The cytosol.

What is the primary output of pyruvate oxidation that enters the Krebs cycle?

Acetyl $CoA$.

What are the two high-energy electron carriers produced during the citric acid/Krebs cycle?

$NADH$ and $FADH_{2}$.

What is the primary carbon-based waste product of the Krebs cycle?

Carbon dioxide ($CO_{2}$).

What chemical term describes $NAD^{+}$ when it gains electrons to become $NADH$?

Reduced.

During oxidative phosphorylation, into what space are electrons/protons pumped?

The intermembrane space.

Why do electrons require specific transporters to move through mitochondrial membranes?

They cannot pass through themselves because of their charge.

Which enzyme uses a proton gradient to synthesize ATP from ADP and phosphate?

ATP synthase.

According to the notes, how many protons are needed by ATP synthase to produce ATP?

Three protons.

What occurs when the signal in a transduction pathway is amplified?

More than one responder molecule is activated in the cell.

Which molecule binds to its receptor to ensure cells keep dividing?

Mitogen.

What describes the state of a G protein when no signal is present?

Inactive with GDP bound.

What is the role of a responder protein in signal transduction after it is activated by a receptor?

It activates or deactivates other cellular effectors.

What function of the ECM helps protect the cell by filtering out some particles?

Barrier function.

In the context of cellular respiration, which stage immediately follows glycolysis?

Pyruvate oxidation.

The exchange of GDP for GTP in G protein activation is explicitly described as different from what chemical process?

Hydrolysis.

Where does the citric acid cycle occur within the cell?

Mitochondrial matrix.

What happens to the potential energy stored in NADH and FADH2?

It is used during oxidative phosphorylation to produce ATP.

What is the structural characteristic of the mitochondrial inner membrane mentioned in the notes?

It is folded.