MD 103: Histology Quiz 1 - Introduction to the Cell

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Questions and Answers

What is the effect of colchicine on microtubules at low concentrations?

Destabilizes microtubule structures

Inhibits tubulin polymerization

Stabilizes microtubule structures (correct)

Enhances tubulin polymerization

Which function is NOT associated with the plasma membrane?

Embedding proteins

Synthesis of steroid hormones

Surrounding the cell

Stabilizing microtubules (correct)

At high concentrations, what does colchicine do to microtubules?

Enhances their polymerization

Destabilizes them (correct)

Inhibits their formation

Stabilizes them

What primary component is identified in the structure of the plasma membrane?

Phospholipids Signup and view all the answers

Which of the following accurately describes the role of colchicine in gout treatment?

Inhibits tubulin polymerization Signup and view all the answers

How is the plasma membrane visualized in histological studies?

With transmission electron microscopy Signup and view all the answers

What is the primary role of ribosomes in the cell?

Translation of mRNA into amino acid sequences Signup and view all the answers

Which component is primarily responsible for maintaining membrane fluidity?

Cholesterol Signup and view all the answers

What type of proteins are primarily found on the cytoplasmic surface of the membrane?

Peripheral proteins Signup and view all the answers

In which type of tissue is cholesterol primarily a precursor for steroid biosynthesis?

Steroidogenic tissue Signup and view all the answers

Which organelle is often referred to as the powerhouse of the cell?

Mitochondria Signup and view all the answers

Which three enzymes are known to be present in peroxisomes?

Catalase Signup and view all the answers

What is the main function of integral proteins in the cell membrane?

Facilitate cell signaling and substance transport Signup and view all the answers

What characterizes euchromatin compared to heterochromatin?

Euchromatin is transcriptionally active. Signup and view all the answers

How do ribosomes translate genetic information?

By assembling amino acids into proteins Signup and view all the answers

How does heterochromatin differ from euchromatin in terms of transcriptional activity?

Heterochromatin shows little or no transcriptional activity. Signup and view all the answers

What structural feature of phospholipids contributes to their amphipathic nature?

A long hydrocarbon tail and a hydrophilic head Signup and view all the answers

Which of the following statements about chromatin is true?

Euchromatin stains lightly due to its dispersed nature. Signup and view all the answers

What is a major function of the enzymes found in peroxisomes?

To defend against reactive oxygen species (ROS). Signup and view all the answers

Which type of chromatin is known to be more prominent in metabolically active cells?

Euchromatin Signup and view all the answers

Which characteristic is NOT associated with heterochromatin?

It displays regions of active transcription. Signup and view all the answers

What distinguishes the appearance of euchromatin under a microscope from heterochromatin?

Euchromatin is less compact and stains lightly. Signup and view all the answers

What role do mitochondria serve in cellular function?

They regulate cellular biochemistry and produce energy. Signup and view all the answers

What is required for active transport mechanisms such as the Sodium Potassium pump?

Energy for solute movement against the concentration gradient. Signup and view all the answers

Which of the following best describes the Sodium Potassium pump?

It actively transports sodium ions out of and potassium ions into the cell. Signup and view all the answers

What is the primary result of active transport processes like glucose transport and the Sodium Potassium pump?

Creation of a concentration gradient necessary for various cellular functions. Signup and view all the answers

In the context of cellular transport, what is a consequence of decreasing the efficiency of the Sodium Potassium pump?

Increased intercellular ion concentration leading to potential cell malfunction. Signup and view all the answers

Why is the Sodium Potassium pump critical for cell survival?

It maintains electrical and concentration gradients essential for nerve impulse transmission and muscle contraction. Signup and view all the answers

Study Notes

Reactive Enzymes in Peroxisomes

Peroxisomes contain three key reactive enzymes: catalase, superoxide dismutase (SOD), and glutathione peroxidase.
These enzymes serve as cellular defenses against reactive oxygen species (ROS).

Chromatin Types

Euchromatin:
- Characterized by active transcription, stains lightly, and is less dense.
- Contains DNA undergoing active transcription, prevalent in metabolically active cells.
Heterochromatin:
- More compact than euchromatin, showing little to no transcriptional activity.

Colchicine and Microtubules

Colchicine is a drug that affects microtubule dynamics by stabilizing microtubules at low concentrations and destabilizing them at high concentrations.
It is commonly used for the treatment of gout.

Plasma Membrane Composition

The plasma membrane (plasmalemma) consists of a lipid bilayer formed from amphipathic phospholipids, with cholesterol serving as a stabilizing agent.
Integral and peripheral proteins are embedded within the membrane, playing key roles in cellular functions.
Cholesterol is a primary precursor for steroid hormone synthesis in steroidogenic tissues.

Ribosomes and Protein Synthesis

Ribosomes are responsible for synthesizing proteins by translating mRNA into amino acid sequences.
They act as the site where the genetic code is interpreted during protein synthesis.

Mitochondria: The Powerhouse of the Cell

Mitochondria are known as the powerhouse of the cell due to their crucial role in ATP production and cellular energy regulation.

Active Transport Examples

Active transport mechanisms, such as the sodium-potassium pump and glucose transport, require energy to move solutes across membranes against concentration gradients.

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Description

Test your knowledge on histology and cellular structures with this introductory quiz. Focus on identifying key reactive enzymes and their functions. Ideal for students in CMED 1A under Dr. Erwin Jandoc.