Biology Chapter: Cells and Organelles

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Questions and Answers

Which process involves the conversion of a signal into a cellular response through the use of a second messenger?

Transduction (correct)

Competitive inhibition

Gibbs free energy

Energy coupling

Which statement accurately describes the role of GTP in the context of G-protein coupled receptors (GPCR)?

GTP binds directly to the enzyme triggering cAMP production.

GTP inhibits the activation of the intracellular receptor.

GTP activates the G-protein to initiate a signaling cascade. (correct)

GTP is converted to ATP to provide energy for the receptor.

What defines a catabolic reaction in terms of Gibbs free energy?

It neither absorbs nor releases energy and reaches equilibrium.

It is dependent solely on temperature changes in the system.

It absorbs energy and has a positive Gibbs free energy change.

It releases energy and results in a negative Gibbs free energy change. (correct)

In metabolic pathways, which type of inhibition affects the active site of an enzyme by mimicking the substrate?

Competitive inhibition Signup and view all the answers

Which of the following statements about entropy is correct?

Creation of order locally increases the total entropy of the universe. Signup and view all the answers

What is a key characteristic that distinguishes prokaryotic cells from eukaryotic cells?

Loose DNA structure Signup and view all the answers

Which component of the nucleus is responsible for synthesizing ribosomal RNA?

Nucleolus Signup and view all the answers

Which organelle is primarily involved in the process of cellular respiration?

Mitochondria Signup and view all the answers

What type of transport mechanism requires energy to move substances against their concentration gradient?

Active transport Signup and view all the answers

Which part of the cytoskeleton is specifically responsible for muscle contraction?

Microfilaments Signup and view all the answers

What defines the function of the Golgi apparatus in a cell?

Modification and shipping of molecules Signup and view all the answers

Which junction is characterized by its ability to prevent leakage between cells?

Tight junctions Signup and view all the answers

What unique feature distinguishes membrane proteins from one another?

Presence of integral and peripheral types Signup and view all the answers

During which stage of cellular signaling does the recognition of a signaling molecule occur?

Reception Signup and view all the answers

What process allows large molecules to enter a cell via vesicles?

Endocytosis Signup and view all the answers

Study Notes

Eukaryotic vs. Prokaryotic Cells

Eukaryotic cells have less surface area per unit volume, making exchange processes less efficient.
Prokaryotic cells have more surface area per volume, making nutrient and energy uptake easier.
Eukaryotic cells have DNA enclosed in a nucleus.
Prokaryotic cells have loose DNA.
Eukaryotic cells contain membrane-bound organelles.
Prokaryotic cells lack membrane-bound organelles.

Vacuoles

Vacuoles are large vesicles used for storage of water, and other substances.

Chloroplasts

Chloroplasts are specialized organelles responsible for harnessing energy through photosynthesis.
Thylakoids are stacked to form grana.
Stroma is the fluid surrounding the grana.

Mitochondria

Mitochondria are responsible for cellular respiration, converting fuel into usable energy (ATP).
Cristae are the folds of the inner membrane.
Matrix is the fluid in the mitochondrion.

Nucleus

The nucleus contains DNA which is organized into chromatin.
The nucleus is encased by an envelope (double membrane).
The nucleolus is found inside the nucleus and is responsible for ribosome production. Made of rRNA and proteins.
Ribosomes are made in the nucleolus.

Endoplasmic Reticulum (ER)

Smooth ER is involved in lipid synthesis, detoxification, and calcium storage.
Rough ER is the site of protein synthesis and modification.
Rough ER has ribosomes attached to its surface.

Golgi Apparatus

The Golgi apparatus modifies, sorts, and packages proteins for shipping.
Proteins are modified before being shipped in vesicles.

Lysosomes

Lysosomes are sacs of digestive enzymes.
Phagocytosis is "cell eating."
Autophagy is the recycling of cellular components.

Cytoskeleton

Microtubules: Involved in cell division, movement of cilia and flagella.
Intermediate filaments: Provide structural support and anchor.
Microfilaments (actin): Crucial in muscle contraction.

Membrane Proteins

Membrane proteins have various functions allowing communication with the external environment like transport.
Integral membrane proteins are embedded in the membrane, and peripheral proteins are loosely attached.

Plasma Membrane

The plasma membrane regulates what enters and leaves the cell.
The plasma membrane is fluid due to unsaturated fatty acid tails, and cholesterol.
Cholesterol helps maintain membrane fluidity.

Active Transport

Active transport moves molecules against their concentration gradient, requiring energy (ATP).

Passive Transport

Passive transport moves molecules down their concentration gradient, requiring no energy(ATP). -Simple diffusion means movement until equilibrium is reached at random. -Osmosis is a type of diffusion where water moves across a selectively permeable membrane, from an area of high water concentration to an area of low water concentration.

Cell Signaling

Reception: A signaling molecule binds to a receptor protein.
Transduction: The signal is converted into a form that can trigger a specific cellular response.
Response: The cell responds to the signal by altering its activities.

-Different signaling pathways can exist from local or long distances such as endocrine system, nervous system signaling and paracrine signaling, etc.

Metabolism

Anabolic pathways synthesize larger molecules from smaller ones (absorbing energy).
Catabolic pathways break down larger molecules into smaller ones (releasing energy).
Energy coupling uses an exergonic reaction to drive an endergonic reaction.
Enzymes are biological catalysts that speed up metabolic reactions.

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Description

Explore the fundamental differences between eukaryotic and prokaryotic cells in this quiz. Learn about various organelles such as vacuoles, chloroplasts, mitochondria, and the nucleus. Test your knowledge on how these components function and their roles in cellular processes.